The Structural Model of Indicators of Educational Leadership for Primary School Principals

This research aimed at creating a structural model of the indicators of Educational Leadership for Primary School Principals in Thailand, which is considered to be a theoretical model that has been used to test for coherence with the empirical data collected from a sample group of 580 participants, who were selected from 30,719 Primary School Principals from across the country. To create this theoretical structural model, a study of the suitability of the indicators was carried out so that it could be further used in the selection within the model, as well as in the model’s coherence test with the empirical data and in the investigation of the factor loading. The results of the research were as follows: Firstly, all indicators, which had been applied in the research were selected and were then placed into the theoretical structural model because the average and distribution coefficient values were as set in the criteria. Secondly, the theoretical model is coherent with the empirical data as the values of relative Chi-square, Root Mean Square Error of Approximation, Goodness-of-Fit Index, Adjusted Goodness-of-Fit Index, Comparative Fit Index, and Normed Fit Index were as set in the criteria. Finally, the factor loadings of the key elements, sub-elements, and the indicators were as set in the criteria. This showed that the theoretical model from this research can be beneficial for the research population with construct validity.

There are discussions about Educational Leadership Models from many figures, such as University of Western Sydney (2007(;Elias (2011(;Morrison (2013(;Brooke (2013(;Keenan (2013(;Richardson (2014(;Meador (2015(;Kitendo (2016(;Driscoll (2016(;Wagner (2016(;Money-Zine Website (2016(;Concordia University (2017(;New Zealand Ministry of Education (2017(;and Sutcliffe (2017(, etc. These are also the important references, which have been used in this research as the theories to establish the key elements and sub-elements of each key element, as well as the indicators of each sub-element. From these sources, they have then been proposed as "The Structural Relationship Model of Indicators of Educational Leadership for Primary School Principals," which has been employed in this research.
This model is considered as a theoretical model or hypothetical model, which was tested with the empirical data in order to determine its fit in accordance with the criterion or with the lack thereof. If the result was positive, the model could be used in the educational administration of the research population with construct validity. According to Wiratchai (2 0 0 2 (, a model after the test will have the quality in data reduction in a form that is easily used resulting in a reduction of the complicity of the data, which is the inference of data management. This will also be used to follow, review, and make decisions at the departmental, organizational, or national level.

Objectives
This research aimed at creating a theoretical model, which shows the structural relationship between the key elements of Educational Leadership with the sub-elements of each key element and the indicators of each subelement. There was also an investigation of the indicators, which were developed with respect to their suitability to be selected and to be put in the model before testing the model with the empirical data. In addition, there was an investigation of the factor loading of the key elements, sub-elements, and the indicators in accordance to the criteria.

Research Hypothesis
To create this theoretical model, the researcher studied theories from various sources to determine the key elements, sub-elements, and the indicators to be used in the research. Therefore, the following would be the predicted answers: 1 ( the indicators used in the research are suitable with the theoretical model as set in the criterion, 2( the theoretical model fits with the empirical data as set in the criterion, and 3 ( the factor loading of the key elements, sub-elements, and indicators are as set in the criteria. Wiratchai (2002 )has discussed the three ways in which to develop educational indicators: 1 ) Pragmatic definition is the way in which the researcher applies his/her own experiences when selecting the variables to present in a model. 2 ) Theoretical definition is a way in which a researcher applies theories and other model creation research to present a model for ready-to-use purposes, or the experts investigates the model before using it. 3 ) Empirical definition is the way in which a researcher applies theories about model creation and then tests the model with empirical data. If there is a coherence from the Confirmative Factor Analysis, the model can be used in managing and developing human resources and the organization. This research applied the empirical definition in the development of the indicators, which Sanrattana (2018) sees as a more logical way than other ways because of the use of the empirical data, which is collected from the sample group and which consists of choosing randomly selected participants to determine the construct validity without involving the personal feelings and experiences of the researcher or the experts. The details of the research methodology are as follows:

Population and Sample Group
The population of the research was 30,719 Primary School Principals under the Office of the Basic Education Commission in Thailand. The determination of the sample size was based upon the ratio rule between the sample unit and the parameter of 20:1 in accordance with Gold (1980(. Free parameter was used to determine the value of the parameters because the model of this research is a confirmatory factor analysis model among variables with an influence line. The parameters were comprised of five latent variables, 13 observed variables, and 17 influence lines, which made 35 parameters in total and which then resulted in having 700 participants in the sample group.

Research Tools
The research tool was a questionnaire, which was divided into two parts. The aim of the first part was to investigate the status of the informants consisting of information about gender, age, school size, educational background, and work experiences. The second part had 60 questions consisting of the indicators of Educational Leadership, which had been categorized in accordance with the key elements and sub-elements in the form of a 5-rating scale: The Most, Much, Medium, A Little, and The Least.

The Creation and Quality Investigation of the Tools
Because the researcher chose to apply the Empirical definition, which represents a way in which a researcher can apply model creation theories, the creation of the research tool originated from the study of theories, which were utilized to synthesize and determine the key elements, the sub-elements of each key element, and the operational definitions, which were connected to the indicators, which determined each of the sub-elements, and which further led to creation of the questions from the indicators.
The 60 questions in the questionnaire were tested for Index Of Congruence: IOC with the indicators and operational definitions by three experts in Educational Administration and two experts in Evaluation & Assessment. The result was that the value of IOC was more than 0. 50 for every question, which indicated that the questions were coherent with the indicators and the operational definitions.
The completed version of the questionnaire was used as a 'try-out' with 30 primary school principals, who were not a part of the sample group. The collected data was analyzed for alpha coefficient of reliability using Cronbach's approach. It was found that the questionnaire had 0.976 as alpha coefficient of reliability. In the following key elements, the values were as follows: "Having Vision" (0.933); "Communication Skills" (0.936); "Inspiration" (0 . 9 4 6 ), and "Commitment" (0 .9 3 8 ). This showed that the questionnaire had a higher alpha coefficient of reliability than the set criterion which was 0.70 (See the questionnaire in the Appendix.).

Data Collection
Multi-stage random sampling was used to select 700 participants from 30,719 Primary School Principals. The questionnaire was sent to the participants by mail; 580 copies were returned (82.85%). This was enough to be used in Confirmatory Factor Analysis because Kaiser-Mayer-Olkin Measurers of Sampling Adequacy of each model's key element assessment were between 0 . 933 -0.976, which was higher than the criterion (0 . 80) ( Cerny & Kaiser, 1977(.

Data Analysis and Coding Criterion
Computers were used to manage the data by analyzing for statistical values as follows: 1 ( averages, standard deviations, and distribution coefficients were used to test the first research hypothesis, and 2) Confirmatory Factor Analysis was used to test the second research hypothesis with the following statistical values:

The Criterion for Coherence between the Theoretical Model and the Empirical Data Test
The coherence test between the theoretical model and the empirical data applied the criterion, which was suggested by Holmes-Smith (2006 )and Hair, Black, Babin & Anderson (2010): Relative Chi-Square: CMIN/DF between 1 -3 or less, 2) Root Mean Square Error of Approximation: RMSEA lower than 0.05, 3) Goodness-of-Fit Index: GFI between 0.90 -1.00, 4) Adjusted Goodness-of-Fit Index: AGFI between 0.90 -1.00, 5) Comparative Fit Index: CFI between 0.90 -1.00, and 6) Normed Fit Index: NFI between 0.90 -1.00.

The Result of the Theoretical Model Creation
As a result of the study of University of Western Sydney (2007(;Elias (2011(;Morrison (2013(;Brooke (2013(;Keenan (2013(;Richardson (2014(;Meador (2015(;Kitendo (2016(;Driscoll (2016(;Wagner (2016(;Money-Zine Website (2016(;Concordia University (2017(;New Zealand Ministry of Education (2017(;and Sutcliffe (2 0 1 7 ( , the four key elements of Educational Leadership: LED were: ( 1 )"Having Vision": VIS, (2 ) "Communication Skills": CMC, ( 3 )"Inspiration": MVT, and ( 4 )"Commitment": COM. Each element consisted of sub-elements, which were relative as a measurement model as shown in Table 1: The key elements of Educational Leadership and the sub-elements of each key element mentioned previously are shown as The Structural Relationship Model of Indicators of Educational Leadership for Primary School Principals. These are considered to be the theoretical model used in the research as shown in Figure 1 :

Having Vision
Being Optimistic 1) having positive ways of thinking when encountering problems 2) believing in one's own abilities 3) possessing a positive attitude 4) being hopeful Communicating Effectively 1) participating in the process of transmitting or communicating between individuals 2) using one's own abilities to communicate with others 3) expressing one's needs, desires, and feelings 4) aiming to invite the message receiver to respond 5) understanding the meaning as intended Taking Risks 1) being brave when having to make decisions 2) being creative 3) being brave when encountering problems 4) having self-confidence 5) being brave and trying new things Leading towards Excellence 1) aiming for the best quality when carrying out tasks 2) constantly having higher goals 3) building a sustainable future 4) always improving the organization's potential 5) continuing to perform in an outstanding manner Communication Skills Being a Good Listener 1) listening with a purpose 2) listening with manners 3) knowing how to examine the content of a message 4) understanding the main ideas and the sub-ideas Communicating Clearly 1) delivering messages that are easy to understand 2) delivering clear messages 3) creating co-perceptions 4) establishing a suitable communicative context Motivating Others 1) being an internal driving force 2) demonstrating behaviors without persuasion 3) achieving goals Inspiration Being a Visionary 1) having a vision for the future 2) having future goals 3) having plans for the future 4) understanding the direction of the missions 5) having a thoughtful approach and reflecting 6) being determined until success is reached Being Reliable 1) being reliable at work 2) being responsible for work 3) completing the hard work 4) behaving appropriately in all situations 5) exhibiting good personal behaviors Empowering others 1) engaging in the process of increasing the potential of individuals 2) supporting/encouraging 3) allowing others to freely make decisions 4) managing an appropriate work environment 5) encouraging the improvement of the work potential of an individual 6) solving both one's own problems, as well as the organization's problems Commitment Focusing on the Goal 1) having future desires 2) having plans to achieve goals at work 3) being able to achieve through management processes Being Loyal 1) respecting the organization 2) being willing to work 3) dedicating one's self to the organization 4) supporting and protecting the organization 5) having the intention to work Having a Positive Attitude 1) finding different positive perspectives from the normal ones 2) being useful in life 3) being useful in the lives of others 4) eliminating negative attitudes 5) having good feelings that lead to success

Research Objective 2:
To test the theoretical model's fit with the empirical data in accordance with the criterion. The results of the analyses were as follows: 2.1) Pearson's Correlation Coefficient was utilized to consider the levels and directions of the correlation. It was found that the indicators in all measurement models had a positive relation with a statistical significance of 0.01 (p< 0.01). In addition, the measurement model in the aspects were as follows: 1) "Having Vision" showed correlation coefficient figures between 0.228 -0.802; 2) "Communication Skills" showed 0.389 -0.729; 3) "Inspiration" showed 0.316 -0.758; and 4) "Commitment" showed 0. 3) The Kaiser-M ayer-Olkin Measurers of Sampling Adequacy (KM O) were used to measure the sufficiency of the sample group. It was found that the KMO of the measurement model in the aspects of "Having Vision," "Communication Skills," and "Commitment" had ranged between 0.922 -0.963, which meant that the size of the sample group used in the research had been sufficient for the Confirmatory Factor Analysis.

2.4) First Order Confirmatory Factor
Analysis of the four measurement models, which were "Having Vision," "communication Skills." "Inspiration," and "Commitment", was utilized to find the statistical numbers to investigate the fitness of the models with the empirical data from the set criteria as follows: 1) the Relative Chi-Square: CMIN/DF was between 1 -3 or less, 2) the Root Mean Square Error of Approximation: RMSEA was lower than 0.05, 3) the Goodness -of-Fit Index: GFI was between 0.90 -1.00, 4) the Adjusted Goodness-of-Fit Index: AGFI was between 0.90 -1.00, 5) the Comparative Fit Index: CFI was between 0.90 -1.00, and 6) the Normed Fit Index: NFI was between 0.90 -1.00 as shown in Table 2 :  Table 2 shows all four models. These were developed from the theories, which were coherent to the empirical data and were important elements ("Having Vision," "Communication Skills," "Inspiration," and " 2.5 Second Order Confirmatory Factor Analysis was utilized to find statistical numbers as a model investigation criterion from the created sub-element scale. The four measurement models were the "H aving Vision" measurement model with four sub -elements, the "C ommunication Skills" measurement model with three sub-elements, the "Inspiration" measurement model with three subelements, and the "Commitment" measurement model with three sub-elements. The results of the data analysis were as follows: The results of the fitness investigation of the sub-elements of each model were that every sub-element had shown suitable statistical numbers for the second order confirmatory factor analysis: ( 1 )Pearson's Correlation Coefficientthe 13 sub-elements had shown a positive correlation that was statistically significant at 0 . 01 (p< 0.01) with the correlation coefficient between 0 . 918 -0 . 963; ( 2 )the Correlation matrix between variables was different from the identity matrix with a statistical significance of 0 . 01 with 6 6 9 0 . 2 1 3 of Bartlett Test of Sphericity, which had a 0 .01 (p< 0.01) possibility; and ( 3 ) Kaiser-Mayer-Olkin Measurers of Sampling Adequacy: KMO was 0.932.
The results of the data analysis to test the fitness of the models were that the models fit with the Empirical data given that the relative Chi-square: CMIN/DF) = 2 .408, the Root Mean Square Error of Approximation: RMSEA = 0 .0 4 9 , the Goodness-of-Fit Index: GFI) = 0 .9 8 6 , the Adjusted Goodness-of-fit index: AGFI = 0 .944, the Comparative Fit Index: CFI = 0 .995, and the Normed Fit Index: NFI = 0 .992. These were all as set in the criteria. Additionally, from the investigation, it was found that the factor loading of the four key elements had been positive (between 0.60-1.29) and had shown a statistical significance of 0 .01. When used to create element scale, the equation was LED = 1.46 (MVT) + 1.44 (VIS) + 1.00 (COM) + 0.89 (CMC).

Research Objective 3:
To investigate the factor loading of the key elements, sub-elements, and the indicators in accordance with the following criteria: 1) the factor loading of the key elements = 0.7 or higher and 2) the factor loading of the sub-elements and the indicators = 0.30 or higher. The results of the data analysis were as follows: 3.1 All four key elements of Educational Leadership had shown positive factor loadings of between 0.60 -1.29 and had also had a statistical significance of 0.01. The factor loading from highest to lowest had been "Inspiration," "Commitment," "Having Vision," and "Communication Skills" at 1.46, 1.00, 0.89, and 0.89, respectively. 3.2 All sub-elements of the Key Element of 'Having Vision' had shown positive factor loadings of between 0.60 -1.00 with a statistical significance of 0 . 01. The factor loadings from highest to lowest had been "Leading towards Excellence." "Communicating Effectively," "Taking Risks," and "Being Optimistic" at 1.00, 0.79, 0.78, and 0 .60, respectively.

The three sub-elements of the Key Element of 'Communication Skills' had had positive factor
loadings of between 1.00 -1.29 with a statistical significance of 0.01. The factor loadings from highest to lowest had been "Being a Good Listener," "Communicating Clearly," and "Motivating Others" at 1.29, 1.26, and 1.00, respectively.

The three sub-elements of the Key Element of 'Inspiration' had positive factor loadings of between
0.98 -1.08 with a statistical significance of 0.01. The factor loadings from highest to lowest had been "Being a Visionary," "Empowering Others," and "Being Reliable" at 1 .08, 1.00, and 0.98, respectively. 3.5 The three sub-elements of the Key Element of 'Commitment' had positive factor loadings of between 0.61-1.00 with a statistical significance of 0.01. The factor loadings from highest to lowest had been "Having a Positive Attitude," "Being Loyal," and "Focusing on Goals" at 1.00, 1.00, and 0.61, respectively.
Furthermore, the factor loading of 60 indicators was positive between 0.68 -1.34 with a statistical significance at 0 . 01. The indicator with highest factor loading had been "Building a Sustainable Future" (1.34), whereas the indicator with the lowest factor loading had been "Listening with a Purpose" (0.68).
To summarize, the factor loading of the key elements, sub-elements, and the indicators had been positive and had been in accordance with the criteria of a statistical significance at 0 . 01. This indicated that the theoretical correlative models of the Educational Leadership indicators for Primary School Principals, which were used in this research, had been comprised of four key elements, 13 sub-elements, and 60 indicators and could be used as measurement for Educational Leadership for Primary School Principals with construct validity. From the previously mentioned data analysis, the adjusted model is shown in Figure 2 :

Discussion and Suggestions
From the results of the data analysis, it was shown that the structural models had created the indicators of Educational Leadership for Primary School Principals, which were comprised of 4 key elements, 13 subelements, and 60 indicators. These had been developed from theories, which were determined to be coherent with the empirical data as stated in the research hypothesis. However, given that there is the dissemination of the theories arising from globalization, the original sources of the theories could have originated from the theoretical definitions, which were used to create the models and which were coherent with the expressive behaviors of the sample research group. Giddens (1990) stated that globalization is a social correlative process with no obstacle of distance or borders. Moreover, it could be due to the concept of dissemination of innovations by Rogers (1995), who stated that the changes in a society are caused by the application of an innovation from another society. Another reason could stem from the fact that the rapid changes of digital technology in 21 st century may have resulted in a global knowledge and information society, which has caused the dissemination of knowledge or information from one corner of the world to another very quickly and widely (Ceulemans, 2012;Rawat, 2020;Adhiarso, Prahastiwi & Hastjarjo, 2019). The reasons, which have been discussed, are in alignment with the reasons used in the discussion of the research results, which tested the models of the indicators of leadership in Thailand, as well as the results of other research studies, such as Indicators of Resourceful Leadership for Secondary School Principals: Developing and Testing The Structural Relationship Model ( Marwiang, Sanrattana & Suwannoi, 2018), Indicators of Innovative Leadership for Secondary School Principals: Developing and Testing the Structural Relationship Model (Somsueb , Sutheejariyawatana & Suwannoi, 2019), The Structural Relationship Model of Indicators of Mindful Leadership for Primary School Principals in Thailand (Wongkom, Sanrattana & Chusorn, 2019), and The Indicators of Authentic Leadership for Teachers in the General Education Session of Buddhist Scripture Schools (Moonsarn, Sanrattana & Suwannoi, 2019).
From the research results of both the test of fitness of the theoretical models and the empirical data & the factor loading of the elements, it was found that the structural model of the indicators of Educational Leadership for Primary School Principals, which was comprised of 4 key elements, 13 sub-elements, and 60 indicators, can be used with reliability in construct validity and is, therefore, suitable for Thai society. The suggestions are as follows: 1 ( The application of the models from this research should be encouraged and used as guidelines in the development of Educational Leadership for the population of this research, which were Primary School Principals under the Office of the Basic Educational Commission in Thailand. In addition, what should be kept in mind is the importance of the key elements, sub-elements, and the indicators from the highest factor loading to the lowest: -Ranked from the highest to the lowest, the four key elements of the Educational Leadership had been: 'Inspiration,' 'Commitment,' 'Having Vision,' and 'Communication Skills.' - The sub-elements of the key element of 'Having Vision' ranked from the highest to the lowest had been "Leading towards Excellence," "Communicating Effectively," "Taking Risks," and "Being Optimistic." - The sub-elements of the key element of 'Communication Skills' ranked from the highest to the lowest had been "Being a Good Listener," "Communicating Clearly," and "Motivating Others." -Ranked from the highest to the lowest, the three sub-elements of the key element of 'Inspiration' had been "Being a Visionary," "Empowering Others," and Being Reliable." - The three sub-elements of the key element of 'Commitment' ranked from the highest to the lowest had been "Having a Positive Attitude," "Being Loyal," and "Focusing on the Goal." -From an examination of the 60 indicators, the one with the highest factor loading was found to be "Building a Sustainable Future," while the lowest one was "Listening with a Purpose." 2) Regarding the cases that are worth studying for future academic benefits, the suggestions are as follows: a . Using qualitative research methodology, a study of the key elements, sub-elements, and the indicators should be conducted in the context of Thai society. Grounded theory should be utilized in order to create a model from the qualitative research results, and these should be compared with the ones from the results of this quantitative research. b . This research has studied the definitions of the academics or departments and has found that there are more key elements of Educational Leadership. However, because there was a limitation to the determination of the elements, high frequency was used as a criterion of the selection, which resulted in those theoretical elements not being used in this research. Therefore, in the future, other logic should be applied when making selections instead of using the high frequency approach. In this way, the elements with lower frequency could be used in the research, which may be important and may lead to new discoveries. You work with future goals. 33 You plan for the future. 34 You have directions for your tasks. 35 You reflect in pro-active ideas. 36 You are determined to succeed. Sub-Element 2: Being Reliable 37 You are expected to be able to complete your tasks. 38 You have a working process that is reliable, and success is guaranteed.

39
You work hard and succeed; people trust you. 40 You behave appropriately in situations. 41 You have good personal behaviors and are fair and unbiased.

Sub-Element 3 : Empowering others
42 You have ways to increase an individual's potential. 43 You support your team. 44 You give freedom to your team when making decisions. 45 You manage an environment that is appropriate for work. 46 You encourage the work abilities of individuals. 47 You support individuals to solve problems on their own, which leads to the organization's success.

Key Element 4: Commitment Sub-Element 1: Focusing on the Goal
48 You determine what you want in the future. 49 You plan for work achievements. 50 You have a management process for work achievements.

51
You have good feelings toward your organization. 52 You are willing to work. 53 You dedicate yourself to your organization. 54 You have bonds, love, and support; you protect your organization. 55 You intend to achieve the organization's goals. Sub-Element 3: Having a Positive Attitude 56 You look for different positive aspects from the usual aspects. 57 You have positive ways of looking at things in order to do useful things in your life. 58 You have positive ways of looking at things in order to do useful things in the lives of others. 59 You have ways to eliminate negative attitudes. 60 You eliminate negative attitudes for better feelings, which can lead to making achievements.


Effects of Plyometric, Strength and Change of Direction Training on High-School Basketball Player’s Physical Fitness

Abstract The study aim was to compare the effects of a 7-week plyometric, strength and change of direction (COD) training program on basketball-specific performance measures in high-school players. Forty male players were randomly assigned to one of the four groups: plyometric (PG, n = 10), strength (SG, n = 10), COD (CODG, n = 10), and control group training (CG, n = 10). Two training sessions were performed at weekly intervals before basketball training. Performance of the counter movement jump (CMJ), Abalakov jump (ABKJ), 10 m zig-zag sprint, 20 m in line sprint (measurements at 10 and 20 m), and sit and reach flexibility test (SRFT) was assessed before and after the intervention. A 4 (group) × 2 (time) repeated measures analysis of variances (ANOVA) was conducted for each variable. Bonferroni post-hoc tests were used when the interaction was significant. Significant (all p < 0.05) time x group interaction was noted for SRFT, CMJ, ABK, sprint, and zig-zag 10 m, in favor of the experimental groups compared to the control group. However, improvements in physical fitness were similar between the three experimental groups. In conclusion, 7 weeks of specific plyometric, strength and COD training produced similar medium to large improvements in physical fitness of high-school basketball players.

Introduction
Basketball is a globally popular sport in which improved performance depends on training a combination of skills. Although basketball requires good aerobic recovery from high-intensity activity, there is agreement that good basketball performance depends on anaerobic capacity (Canovas-Lopez et al., 2014;Delextrat and Cohen, 2009), hence it is very important for players to follow a good conditioning program. For example, jumping, sprinting and dribbling are of great importance for basketball players and depend on strength, speed, and coordination (Komi and Bosco, 1978).
Three different kinds of training were used in this investigation: plyometric training, strength training, and change of direction (COD) training. The plyometric exercises combined eccentric and concentric muscle actions in what is termed the stretch-shortening cycle (SSC) (Saez de Villarreal et al., 2009). The SSC improves the ability of the muscle-tendon unit to produce maximal force in minimum time (Komi, 2000). The strength training program comprised traditional resistance training techniques, including selfloading exercises and exercises with additional weight (Harrison, 2010). Finally, the COD training program consisted of circuits performed with a basketball that involved rapid, whole-body movements involving changes of velocity and direction .
Plyometric training has been shown as an effective method to improve performance of explosive actions (e.g., jump, sprint, and COD) (Sáez de Villarreal et al., 2015;Slimani et al., 2016). Several authors concluded how the magnitude of adaptive responses to plyometric training could be different depending on participants' characteristics (e.g., training level, sex, and especially maturity status) (Moran et al., 2017a(Moran et al., , 2017b. In this regard, recent studies have reported that maturation may play a crucial role in training adaptations Moran et al., 2017b). Thus, previous studies have revealed the importance of trainability associated with natural accelerated maturity of specific athletic skills (e.g., COD, sprint, or jump) Moran et al., 2017a).
A recent meta-analysis regarding the age-related variation and adaptive responses to plyometric training in youth athletes (Moran et al., 2017a) has found that, categorized into three maturity groups, a greater adaptive response was observed in individuals in the PRE-peak height velocity (PHV) (10-12.9 years) group and in individuals in the POST-PHV (16-18 years) group compared to those in the MID-PHV (13-15.9 years) group. However, another previous review has shown that sprint performance gains due to training are associated with the age of participants (Moran et al., 2017c). Therefore, responses to training are age and maturation dependent in the youth (Moran et al., 2017a(Moran et al., , 2017b. Plyometric and strength training programs are the most commonly used method to improve basketball-specific performance indicators such as jump height. It has been shown that plyometric (Andrejic, 2012;Asadi et al., 2017;Khlifa et al., 2010;Maćkała and Fostiak, 2015;Santos and Janeira, 2011;Zribi et al., 2014) and strength (Santos and Janeira, 2012) training programs, performed separately or in combination (Chappell and Limpisvasti, 2008;Santos and Janeira, 2008), enhance vertical and horizontal jump performance in basketball players. A few studies have described the transfer of the training effects from different plyometric or strength training methods to other skills that are nevertheless critical to young basketball players' performance, such as COD (Kilinç, 2008;Maćkała and Fostiak, 2015). It appears that plyometric training can improve ability to COD when not dribbling a basketball (Asadi et al., 2016), but it is not known whether it also improves COD with a basketball. Plyometric training may be an effective method to improve sprint and agility (Asadi et al., 2017;Banda et al., 2019) performance in youth basketball players and recent research has shown that strength training can also have a positive effect on youth basketball players' sprint performance (Gonzalo-Skok et al., 2016;Alemdaroğlu, 2012).
To the authors' knowledge, no study has examined the effects of a short (7 weeks) period of plyometric training, strength training, and COD training with a ball on vertical jump, flexibility, a zig-zag sprint with a ball and a maximal sprint with a ball in high-school basketball players. The purpose of this study was to compare the effects of plyometric, strength, and COD training on basketball-specific performance measures (jump, sprint, COD, and flexibility). We hypothesized that plyometric training would enhance players' vertical jump, sprinting, COD, and flexibility more than strength or COD training. We believed that a good combined training program and commitment from the players would have positive effects.
Participants included in this study were analyzed by the maturation equation described by Mirwald et al. (2002). Briefly, to estimate participants maturity status, anthropometric measurements were taken and entered into an equation to predict maturity offset, where maturity offset = -29.769 + 0.0003007· Leg Length and Sitting Height interaction -0.01177·age and Leg Length interaction + 0.01639·age and Sitting Height interaction + 0.445·Leg by Height ratio, where R = 0.96, R2 = 0.915 and SEE = 0.490. Based on the peak height velocity (PHV) offset, participants ranged from -0.4 to +0.4 years.
All players competed in a national league, playing one match a week and training twice a week. Players were excluded from the investigation if they met any of the following criteria: a) injured less three than months prior to the study; b) failure to recover or complete rehabilitation of a previous injury; c) suffering from a condition that would prevent them from © Editorial Committee of Journal of Human Kinetics participating in the technical and tactical basketball training, and/or the experimental training programs; d) missed two or more experimental training sessions, or two or more technical and tactical basketball training sessions. No participant was excluded from the study after recruitment. All participants were in good health and able to participate in the training interventions. Before participating in this project, which was approved by the Institutional Ethics Review Committee of the University, all participants were fully informed about the protocol and their parents or guardians provided written consent to their participation in accordance with current national and international laws and regulations governing the use of human participants in research (Declaration of Helsinki II).

Design and Procedures
We examined how four different 7 week training interventions affected a number of basketball performance variables: vertical jumping ability, hamstring and lumbar extensibility, and sprinting with a ball. The study was conducted during 7 weeks (14-session) of the basketball season with high-school players. Participating players were randomly assigned to one of the four training groups in a counterbalanced manner. All participants were tested before and after the 7 week training period to determine the effects of the 3 training interventions. The tests performed were a counter movement jump (CMJ), Abalakov jump (ABKJ), sit and reach flexibility test (SRFT), 10 m zig-zag sprint with the ball, and 20 m sprint with the ball. After the baseline assessment all participants were assigned to one of the four following groups: plyometric training (PG, n = 10); strength training (SG, n = 10); COD training with the ball (CODG, n = 10); and a control group (CG, n = 10). All training sessions were supervised by a physical and athletic performance specialist, and participants were instructed in the proper execution of all exercises. All players had experience with these training approaches and were familiarized with the exercise technique. Participants were also instructed to avoid any strenuous physical activity not related to the training intervention and to maintain their usual diet (they were not allowed to drink caffeinebased beverages) for the duration of the study.
All participants were familiarised with the test procedures one week before the baseline assessment. In addition, several warm-up sets were recorded before the actual maximal and explosive tests during each testing session to ensure stability of each measure. Both the baseline and post-training assessments were completed in a single session that took place between 17:00 and 21:00. The baseline assessment was carried out one week before the experimental training programs started and the post-training assessment was performed one week after they had finished. The tests were completed in the following order: CMJ, ABKJ, 10 m zig-zag sprint with the ball, 20 m sprint with the ball, and SRFT. Before testing all participants completed a warmup consisting of 10 min of sub-maximal running and a basketball-specific warm-up that involved vertical jumps, sprints, and joint mobility. Ten minute rest intervals between tests were given to limit the effects of fatigue on subsequent tests. All tests were conducted indoors.

Counter Movement Vertical Jump and Abalakov Jump
The CMJ consists of a jump starting from an upright position, with hands on hips and with counter-movement. The hands are placed on the hips at the start of the test and remain there throughout. The athlete squats until the knees are bent at 90 degrees, then jumps vertically as high as possible, landing on both feet at the same time. In the ABKJ the athlete squats until the knees are bent at 90 degrees while swinging the arms back behind the body. Then the arms are immediately swung forwards and the athlete jumps as high as possible, landing on both feet at the same time. Both jumps were used to assess explosive strength of the lower limbs. The tests were performed using an optical measurement system (Optojump; Microgate, Milan, Italy) that quantified flight and contact times. Each participant completed 3 trials with 5 s of rest between trials for each kind of the jump. Three trials were completed, and the best performance was used for the subsequent statistical analysis (Sáez de Villarreal et al., 2008). Participants were instructed to land in an uptight position and to bend the knees after landing.

m Zig-zag Sprint Test
Participants sprinted 10 m with a change of direction. They started from behind the baseline with their left foot forward when they Journal of Human Kinetics -volume 78/2021 http://www.johk.pl were ready and dribbled with their left hand when moving to the left and their right hand when moving to the right. The course was defined by five cones set in the center of the testing area 1.5 m apart to each other and 1.5 m from the centerline (Figure 1). Photocells (Microgate, Milan, Italy) were positioned at the beginning and at the end to measure the time taken to complete the course. Two trials were completed and the best was used for further statistical analyses. Two minutes of rest were permitted between trials.

m Sprint Test
A 20 m sprint test was selected because it is a common test used in the evaluation of basketball players' sprinting ability. After the completion of a specific warm-up (i.e. 3-5 submaximal running in the 20 m line) all participants performed two maximal 20 m sprints, each separated by two min of rest.
Participants initiated the sprint from a standardized starting position that was 0.5 m behind the start line. Photocells (Microgate, Milan, Italy) were positioned at the beginning, at the 10 th and the 20 th m, to measure the time taken for the first and second halves of the course and the total time. Two trials were completed and the best result was used for further analyses.

Sit and Reach Flexibility Test
This test was used to assess lumbar and hamstring flexibility. The participant sat on the floor with legs together, knees extended and the soles of the feet placed against the edge of a box. The thumbs were clasped so that hands were together, palms facing downwards. The participant then extended his arms as far forwards as possible. A sit and reach box was used to measure the distance reached (ACCUFLEX I Flexibility Tester, height: 32 cm; PSYMTEC, Madrid, Spain). Two trials were completed, with a pause of 30 s between trials and the best result was used for analyses.

Training program
The three experimental groups followed the appropriate experimental training protocol twice a week (Monday and Wednesday) during 7 weeks of the intervention (14 sessions), before basketball-specific training. The CG only performed standard basketball training. All 40 players completed all training sessions using appropriate boots and clothes for basketball. All sessions lasted 90 min and consisted of the following components: 10 min of a standard warm-up, 20 min of experimental training (plyometric training, strength training or COD training with the ball; experimental groups only), 55 min of standard basketball training, and 5 min of cool-down, including stretching exercises. In the experimental training protocols the rest interval between each set was 1 min. The three experimental training programs are outlined in Tables 2, 3, and 4. The plyometric training program was based on the guidelines drawn up by Radcliffe and Farentinos (1999). All training sessions for all groups were fully supervised to ensure that players used the correct technique for each exercise. All participants were carefully instructed on how to perform the experimental exercises.
They observed a practical demonstration and performed familiarisation trials. No acute injuries occurred during the training sessions.

Statistical analysis
The values are expressed as mean ± standard deviation (SD). Test-retest absolute reliability was assessed using the coefficient of variation (CV), whereas relative reliability was calculated using the intraclass correlation coefficient (ICC) with a 95% confidence interval (CI), using the one-way random effects model. Homogeneity of variance across groups was verified using the Levene's test, whereas the normality of distribution of the data was examined with the Kolmogorov-Smirnov test. A 4 (group) × 2 (time) repeated measures analysis of variances (ANOVA) was calculated for each variable. Bonferroni post-hoc tests were used when the interaction was significant. Effect sizes (ESs) were calculated with Hedges and Olkin's g (Hedges and Olkin, 1985), using the following formula: g = (Mpost -Mpre)/SDpooled, where Mpost is the post-test mean, Mpre is the pre-test mean, and SDpooled is the pooled SD of the measurements. The magnitude of the effect size statistics was considered trivial <0.20; small, 0.20-0.50; moderate, 0.5-0.80; large, 0.8-1.30; very large >1.30 (Ramírez-Campillo et al., 2014). The ES aws reported in conjunction with the 95% confidence interval (CI) for all analyzed measures. The level of significance was set at p ≤ .05. All statistical analyses were performed with the statistical software package (SPSS 20.0 version, Chicago, Illinois, USA).

Results
Analyses of variance (ANOVAs) revealed that at baseline, there were no differences between-groups in any of the strength, flexibility, agility, anthropometric and performance variables tested. The results are outlined in Table 5.

Weeks 3 and 4 3x12
Weeks 5 and 6 3x15 Week 7   Week 7 Zig-zag dribbling with cones in a straight line**

Discussion
The results of this experiment add knowledge to previous studies on different performance adaptations through the use of traditional strength, plyometric, and COD training with ball approaches in high-school basketball players on a set of basketball-related physical skills, namely jumping, sprinting with a ball and lumbar and hamstring flexibility. Our findings illustrate that a 7 week plyometric training approach results in a greater improvement in vertical jump and COD performance than strength and COD training. The results also show that a COD training program produces a more powerful stimulus in improving COD and sprint performance than the strength training program, and that all the training programs produce a significant improvement in the flexibility conditions.
The PG showed improvements in CMJ and ABKJ height (ES = 0.49 and ES = 0.37, respectively). These results are consistent with earlier research (Chappell and Limpisvasti, 2008;Khlifa et al., 2010;Santos and Janeira, 2011;Zribi et al., 2014) in which plyometric training of the lower limbs improved vertical jump performance. Also consistent with previous research (Tansel et al., 2008), we observed improvements in CMJ height (ES = 0.56) and ABKJ height (ES = 0.31) in the SG. Earlier research found that combined strength and plyometric training had greater effects on vertical jumping than strength training alone (Andrejic, 2012;Santos and Janeira, 2008). The CG also achieved improvements in CMJ © Editorial Committee of Journal of Human Kinetics height (ES = 0.19) and in ABKJ height (ES = 0.27) due to technical and tactical basketball training. Although the improvements in vertical jumping in the CG were trivial, they nevertheless suggest that technical and tactical basketball training can help to maintain or improve youth basketball players' jumping (Gonzalez et al., 2012). The only group whose jumping performance did not improve was the CODG, which suggests that the COD program used in this study does not improve vertical jumping. This result contrasts with earlier research in which CMJ height improved after 10 weeks of strength training, sprint training, endurance training, and technical and tactical basketball training (Kilinç, 2008). This suggests that combining COD training with strength training, sprint training, endurance training, and technical and tactical basketball training might improve vertical jumping.
Both the SG and CODG showed improvements in time for the first half of the 20 m sprint (ES = 0.42 and ES = 0.71, respectively), but these decreases were not accompanied by improvements in total time for the 20 m sprint. There were no improvements in the second half of the 20 m sprint performance; this result is in conflict with other research (Maćkała and Fostiak, 2015;Ramírez-Campillo et al., 2015a, 2015bSöhnlein et al., 2014) which found that running speed for a 20 m sprint was improved after a plyometric training program. Ramírez-Campillo et al. (2015b) reported that 6 weeks of plyometric training induced meaningful changes in the 20 m sprint (ES = -0.5) in 14-y players. The reason of discrepancy in the rate of training effect might be due to different individual adaptive responses to plyometric training . It is well known that sprint-running performance is the product of the stride rate and stride length with numerous components influencing this apparently simple task. Since both elements are clearly influenced by anthropometric characteristics, one of the main possible explanation for no improvement in sprint performance could be the anthropometric variable. This is especially important for youth athletes in the early stages of development where the technical abilities still have a great window for improvement. During maturation the natural development of sprint performance occurs due to greater muscle size, increased limb length, changes in musculotendinous tissue, enhanced neural and motor development, and better movement quality and coordination (Oliver and Rumpf, 2014).
Our results are consistent with studies (Monteiro et al., 2008;Ferrete et al., 2014) showing that a stretching program can increase flexibility in young people and adults who have followed a strength training program. All the groups in our study performed passive stretching exercises after their technical and tactical basketball training. It should be noted that all our participants were going through puberty, which may have influenced the results. In descriptive terms the PG, SG, CODG, and CG showed increased flexibility after the 7 week study period. Both the PG and SG showed differences compared with the CODG. These results suggest that it may be worth incorporating stretching exercises into strength training, and technical and tactical basketball training.
Basketball requires athletes to execute complex skills, not only on their preferred side using their dominant hands, but also on their nonpreferred side. Flexible use of the dominant and non-dominant hand is crucial, especially in competitive play, when athletes face pressure from opponents and have to select an appropriate action rapidly (Stöckel et al., 2011). It is relevant to this that only the CODG showed an improvement in performance on the 10 m zig-zag sprint test (ES = 0.91). The structure of COD training with the ball is much more complex than without the ball. In addition, the basic skills without the ball have much stronger relation among speed, agility, and quickness than the skills with the ball (Sporiš et al., 2011). This may be why the other groups did not show improvement in this test.
Finally, throughout the 7 weeks of training none of the players suffered a lower limb injury during training or match play. Neuromuscular training, resistance training, and plyometric training seem to improve the hamstring-quadriceps neuromuscular properties (Pettitt and Bryson, 2002), thus reducing the risk of injury.
In conclusion, the current study demonstrates that 7 weeks of different training programs (plyometric, strength, and COD) significantly improve vertical jump, sprint, COD, and flexibility performance in high-school Journal of Human Kinetics -volume 78/2021 http://www.johk.pl basketball players. The estimated improvements in the vertical jump, sprint, and COD as a result of plyometric and strength training could be considered as practically relevant and of high importance for athletes in basketball. Finally, the current study was focused on young male participants. As young males and females clearly experience different effects from plyometric training according to sex specific maturational development, future studies should take a similar approach for female participants. Considering that biological maturity may affect adaptations to strength and conditioning practices in general, and resistance training and plyometric training in particular, future plyometric training studies should strive to include youth athletes' biological maturity as a moderator in the analyses. Despite these limitations, the current study makes an original and significant contribution to the literature and clearly shows the merits on including plyometric training as part of a wellrounded athletic development program to enhance jumping, sprinting and COD performance in young basketball players.


The Family Thought of Marx and Engels and Its Enlightenment in the New Era

In the Marxist theoretical system, "family" is a very important theoretical category, which is not only the "mystery" Marx and Engels has been trying to solve, but also an important reflection of Marxist philosophy. Marx and Engels held the conviction that the development of the family went through the consanguinity family, the Punaluian family, the paring family and the monogamous family. Marital relationship is the basis of forming a family; blood relationship is the bond of forming a family; family is the organizational form of human social life. Those are the essential characteristics of family. In the new era, while promoting the harmonious development of family, we must know the harmonious marriage relationship is the foundation of family harmony, and that the harmonious parent-child relationship is the key to family harmony. Meanwhile, we should pay attention to the harmonious unity of family and society.

The development form of family
Marx and Engels conducted an in-depth analysis of the development process of prehistoric human society on the basis of Morgan's family history research, combining a large number of reliable empirical materials. They affirmed Morgan's view that "the concept of the family has gone through several successive stages of development before reaching maturity" [1] , holding that the family is concrete and historical, and family depends on the development of productive forces in the final analysis, and concluded the different forms of family development.

Consanguine family
The consanguinity family is the first family form from the primitive promiscuous sexual relations, which belongs to the initial stage of the group marriage system. During this period, people's hunting skills had been improved to a certain extent. In order to obtain more food sources, the division of age came into being. Men and women of similar age form groups, hunt together and live together, which naturally causes the original group to split up and the transition was made from promiscuous sexual state to blood family. That is, as Marx said, "In order to make a living, a primitive group must break up into small groups and to form blood families" [2] . Consanguinity families are characterized by intermarriage between siblings. Marx and Engels further pointed out that the existence of blood family is the premise of all subsequent family evolution, it first made provisions for the original promiscuous sexual relations, and restricted the sexual relations between different generations, which was the first progress in the development of the family.

The Punalua family
The second form of family development was the Punalua family, which was an advanced stage of communal marriage. During this period, people began to forbid the intermarriage between brothers and sisters because they found that the intermarriage was harmful to their offspring in practical life, and the intermarriage system was implemented. In this family structure, a group of sisters of the same age and a group of brothers of the same age got married together, that is, "mutual co-husband and co-wife within a certain range of families" [3] , but the man's own brothers and the woman's own sisters were excluded. The husbands no longer call each other brothers, and the wives no longer call each other sisters. Instead, they call each other punaluya (Hawaiian), which means "intimate partner". The bonding of the sexes in the Punaluian family was no longer based on blood relations. This limitation of consanguinity was not only a great ethical and moral progress, but also improved the intelligence and physical ability of the offspring, promoted the development and strength of the tribe, and thus established the clan.

Pairing family
The third form of family that followed the Punalua family was the pairing family. It is no longer a form of group marriage, but an unstable family form in which a man and a woman were united. This kind of family form had already begun under the system of group marriage, that is, men have one master wife among many spouses, and women have one master husband among many spouses. However, with the development of the clan and the frequent communication between the clan, the men's visits made women to feel with pressure and shame, and the group marriage gradually transferred to the pairing family. Under the communist family economy, the family was isolated from the society, and the production of the family was only to meet the needs of each member of the family, rather than to be used for exchange. Women had the same power as other family members to coordinate and manage the production and distribution of the family. As Engels mentioned, "Everyone is equal and free, including women" [4] . But in the later period of the paired family, with the improvement of productivity, the appearance of metal tools, and the development of agriculture and animal husbandry, men began to dominate the production. At the same time, as men mastered private property and their economic status was greatly improved, they had the desire to let their own children inherit the property, which accelerated the decline of the pair family and the collapse of the matriarchy.

Monogamous families
The pairing family was followed by the monogamous family, which consist of a man and a woman. The biggest difference between the monogamous family and the pairing family is that the marriage relationship cannot be dissolved at will. The monogamous family is the result of the development of productive forces and the establishment of ownership of means of production. The monogamous family is finally established when the level of productivity is high enough to allow the individual family to become an independent productive unit and social cell. The monogamous family was finally established when private ownership was established, requiring children to inherit their father's property. In monogamous families, men are dominant and have the right to dissolve the marriage, while women gradually lose their voice and can only rely on their husbands. Thus so-called monogamy is in fact exclusive mating of the wife, which failed to pose limitations on the "overt or secret polygamy" of the husband [4] . This suggests that monogamous families are the product of economic relationships based on private property, rather than "the result of personal sexual love" [3] .

The essential characteristics of the family
Marx and Engels believed that the essential characteristics of the family were hidden in various forms of the family itself, which was accompanied by the whole process of family changes. The essential characteristics of the family mainly include three inseparable aspects.

Matrimonial ties are the foundation of a family
From the actual process of the evolution of family history, it is not difficult to find that the matrimonial ties between men and women is the common basis of the evolution of family history. Marx and Engels believed that the foundation of family is the sexual relationship between husband and wife, which exists in the conclusion of human marriage from the very beginning. The promiscuous sexual relations in the primitive society, the elimination of the sexual relations between different generations in the blood family, the restrictions on the sexual relations between brothers and sisters of the same father and mother in the Punaluya family, and the unstable relationship between husband and wife in the dual family can be removed at any time. The loss of women's family status in monogamous families and the fact that love becomes the basis of marriage in the future communist families all show that sexual relations have existed since the existence of human beings and are the basis for the formation of family relations.

Blood ties are the ties that bind families together
The blood relationship plays a special role in the mutual connection between family members, which connects family members into a stable community. Father, mother and child form a stable family triangle, and parents bear the responsibility of raising and educating their children. From the first skills of picking and hunting, to the techniques of making and using tools of production, to the expression and recording of language and writing, to the present guidance of thought, although with the continuous development of productive forces, the content of parents' education for their children has changed greatly, every generation of parents had been trying to do a good job in their role in upbringing and education, and the family is closely linked under this strong blood relationship.

Family is the organization form of social life of human beings
Family is not a simple "relationship" form, but a form of social organization in which people live together. Organized by marriage and consanguinity, people cohabit and eat together, forming a living community that supports each other in economy and influences each other in thought and emotion. It is based on marital ties and tied by blood ties, so it also bears the responsibility of procreation, upbringing and education. These responsibilities are fulfilled not only by biological means, but also by social means, which closely link people's own production with the production and consumption of material goods. In the agricultural society, due to the limitation of productive forces, families include various life contents such as labor, creation and consumption, forming a complete social life community. With the development of productive forces, social production is gradually separated from the family, and the family becomes a community of consumption of means of living.

Enlightenment in the new era
Whether a family is harmonious or not is not only related to the family members themselves, but also affects the stable development of the whole society. The family thought of Marx and Engels enlightens us that the harmonious development of family in the new era should be based on the organic unity of the harmonious marriage relationship, the harmonious intergenerational relationship, the harmonious family and social relationship.

A harmonious marriage relationship is the basis of maintaining a harmonious family
First, marriage is based on love.Marx and Engels first emphasized that "love" was the "only basis" for marriage. Engels pointed out that "mutual love between men and women should be above everything else" [3] , which failed to be replaced by anything. With the development of China's socialist market economy, the status of money in people's hearts is increasing, and many young men and women are more inclined to sacrifice love and surrender their marriage for material things. In such historical background, it is especially important to promote love. At the same time we should note that Marx and Engels said that love is the only basis of marriage and it is based on great material production. Although socialism with Chinese characteristics has entered a new era and people's economic conditions have been greatly improved, there is still a certain gap between love and marriage as the only basis. Therefore, while actively advocating a marriage based on love, we should not make a negative moral evaluation of men and women who consider economic conditions when choosing a mate.
Secondly, integration of freedom of marriage and self-restraint. Marx and Engels believed that marriage is free, but the freedom of marriage is limited to certain scope rather than arbitrary marriage and divorce. With the deepening of reform and opening up and economic globalization, the concept of freedom of marriage is gradually misunderstood while deeply rooted in people's hearts. Many people pursue love and sex beyond marriage under the guise of love, which leads to the decline of trust between husband and wife. They ignored the exclusivity of love and marriage and absolutized the freedom of marriage. While enjoying the freedom of marriage, the husband and wife should also take single-minded and faithful as the bottom line to maintain the marriage relationship, and they should actively fulfill moral obligations, undertake family responsibilities, and combine the freedom of marriage with self-restraint.

The harmonious parent-child relationship is the key to maintaining the harmonious family relationship
First, we should care and educate our children in a rational manner. Marx and Engels believed that parents should not only "nurture" their children, but also "love" and "nurture" them in a reasonable way. When Chinese parents overindulge their children, they also take them as a tool to realize their own personal ideals. Once their children deviate from their expectations, they will be denied and criticized. This way of caring and education is easy to aggravate children's rebellious psychology towards their parents, which is not conducive to the formation of a harmonious parent-child relationship. To realize the free and comprehensive development of human beings is Marx and Engels' outlook on family education of the times. Parents should follow the laws of children's natural development and stimulate their development potential. At the same time, parents, as children's first teachers, should set an example and integrate education and emotion to cultivate children's good moral character. President Xi Jinping also mentioned that there are many noble qualities he should learn from his father [5] .
Secondly, the elderly should be accompanied with love. The unity and harmony of a family is not only the selfless care and good education of the elders to the younger generation, but also the understanding and gratitude of the children to the elderly. At present, China is in the process of social transformation and demographic transformation with the advancement of urbanization, the continuation of low fertility rate, the change of family concept and the improvement of housing conditions and facilities, the traditional extended family is gradually replaced by the nuclear family formed by a husband and wife and their unmarried children. This small family model can quickly adapt to the socialist market economy, which give rise to the separation of the younger generation from the older generation, resulting in the absence of family warmth and emotional care. The elderly should be the center of the family. While actively meeting their material needs, children should pay more attention to the emotional needs of the elderly, accompany and take care of them from time to time, and let them rely on their old age.

Harmony and unity between family and the society
Firstly, families should actively adapt to social changes. As one of the organizational forms of human social life, families are the product of certain productive forces, production relations and social system, which are closely related to the whole social form. Marx and Engels believed that the family must change with the change of society. Since the 21st century, the external impact brought by the modernization transformation, such as marketization, globalization, acceleration of urbanization, popularization of the Internet and the progress of modern medicine, has prompted great changes to the family once again. For example, sexual behavior and reproductive behavior are gradually separated, the family based reproductive function is weakened, the family size is miniaturized, the families in the new era are experiencing a "modern revolution", the families should conduct active adjustment to adapt to the changes of new society.
Secondly, to view the society from the perspective of family and promote the harmony and unity of the two sides. In the view of Marx and Engels, the family is the natural basis and necessary condition of the existence of the state and society. The family is a micro society, and the changing characteristics of family structure, family function and family relationship also reflect the social problems that China is facing at present. For example, the miniaturization of the family scale and the empty-nesting of the family will further weaken the function of the family care for the aged with the severe problem of our society in pension. To some extent, the increase of the proportion of stepmarried families reflects the increasingly prominent social problem in stepchild education. Through the perspective of the family, we can examine the current social changes and social problems, so as to promote the harmony and unity of the two.

Conclusion
Family, as a quiet harbor, is the place of our soul. At the same time, family is also the cell of society, which is closely related to the development of society. Marx and Engels comprehensively discussed the various forms of family development, scientifically explained the essential characteristics of the family, and provided action guidelines for promoting the harmonious development of the family. At present, China is in the period of socialist transition. Although some progress have been made in the family development, there are still many difficulties and problems. Although the social situation and family problems in the new era are very different from those of Marx and Engels at that time, it does not mean that their family thoughts are out of date. The essence of their thoughts still shows fresh vitality. On the whole, family construction in the new era can be achieved with the value of times of Marx and Engels' family thought, and the study of Marx and Engels' family thought can better guide us to understand the connotation of Xi Jinping's thought on family and construction thought of family style so as to correctly grasp the development direction of family construction in the new era.


Distant Education of Mature Age Students – Motivational Aspects

The aim of our paper is to share our experience with fostering motivation of mature students to develop new competences to use technology in learning. For some mature age students, technology may be another source of anxiety, because they do not have sufficient previous experience in this respect. This is the reason why, an important role for a teacher of mature age learners is that of preparing them to use the technology in a non-threatening context meant to build positive attitudes in adults towards both technology and learning. Our pilot study refers to the changes of attitudes adult learners might have experienced when their fears to use technology had been reduced.

Introduction
Unlike younger learners, the adults almost always have a sound reason why they are studying (Bilčík et al. 2019), and that reason will be their primary motivation (Merriam et al. 2007). Perceiving education as a way to improve their self-image and reach various personal goals (Hargaš 2019), adult learners are usually highly motivated from the very beginning of the instruction process, and this makes it much easier for the teacher to perform his/her role as a motivator. Harmer (2007) points out, "many adults are able to sustain a level of motivation by holding on to a distant goal in a way that teenagers find more difficult" (p. 84).
Adults are certainly more cooperative learners, and, what is more important, their cooperation comes as a natural consequence of their seeing the point of various instructional situations in which they are involved (Wahl et al. 2019). There are also situations when students generally have more learning experience behind them, but this aspect can prove to be both beneficial and problematic (Orvis 2018). They have certain expectations about the learning process, and, in case these expectations are not met, learners may become critical towards the new context of instruction. Thus, on the one hand, adult students have built well-developed learning strategies that had previously served them well in other settings (in other schooling), and the teacher could help them use these strategies to their advantage. On the other hand, adults are less confident in their intellectual abilities, and this might make them anxious about learning (Dobrovská and Andres 2016). In relation to the anxieties, insecurities, and fears of the adults who return to school, the adult educator Stephen Brookfield (2005) discussed the term "impostor syndrome", denoting a collection of feelings of inadequacy, of chronic selfdoubt which make people think that their accomplishments are nowhere near as good as those of the people around them.
Modern trends in education are characterized by an overall shift towards the use of digital technologies especially when regular in class teaching cannot be applied for some reason -this has recently occurred during the corona virus quarantine at many European universities. Technological innovation extends learning opportunities depending on the efficient use of the learning environment with an emphasis on elearning, m-learning, MOOC, social networking, educasting, shared e-learning support through cloud computing services.

Methodology
The aim of our study was to implement new teaching methods into a study program of mature students during corona virus quarantine in March, 2020 and to analyze their reactions and attitudes in new situation. Our questions were: what is the level of entrance ICT knowledge of our students, are they ready to use technologies to improve learning, are teachers of mature students ready to prepare webinars in a form which may encourage students to do so and is there any attitude change after student experience with Microsoft Teams.
In Fig. 1 abrupt growth of distant electronic forms of teaching during corona virus quarantine is displayed. The CTU in Prague had to react within few days to a new situation. As displayed in Fig. 2, within a short period of time academic staff was able to adapt to new conditions and set up distance learning using Microsoft Office 365/Microsoft Teams. Cloud services were deployed on a global scale and encouraged communication during pandemic, in terms of management level, as well as for educational purposes, organizing lectures, exercises and seminars. Starting from March 10, 2020, so-called non-contact teaching methodology was introduced at the CTU in Prague, full deployment started on March 16, 2020, with 2,255 Teams established during first ten days. Computing and Information Centre opened up and filled these Teams approximately with 900 students and teachers on the basis of data available (identities) in the study information system. By 18 March 2020, approximately 50 Teams had been formed from two or more subjects (by merging), roughly 50 Teams were created according to timetable sheets (by splitting).
After webinars and workshop had been delivered to students a feedback was required from them: it was based on a questionnaire with open-ended questions. We asked mature age students to indicate their feelings and opinions on electronic support they had received. A sample of 124 mature age students of the study program "technical teacher education", aged 29-45, gave the feedback. The aim was to maintain maximum variation across a wide range of variables -age, gender, ability to comprehend and deal with assessment requirements. The items of the questionnaire focused to the self-confidence, motivation increase and assessment of the e-material distributed to them. More than half of the students declared their knowledge, competence and skills increased considerably or to some extent, 20% believed their knowledge did not change and the rest could not answer the question. More than 84% of answers indicated the growth of motivation to use electronic devices for study purposes. 90% of students appreciated appropriate reaction of teaching staff to encourage their motivation and to support their ICT knowledge.

Results and Discussion
The items of our questionnaire related to: • Previous experience with e-learning, especially with Microsoft Teams. Students were asked to assess their entrance technology knowledge on the scale 1-7 (1 being no experience, 7 advanced technology knowledge) • Previous motivation and readiness to use technology for study reasons • Disruptions in learning how to use new technology (anxiety, fear, other negative emotions) • Perceived quality of webinars and workshop (specially user friendliness and intelligibility) • Attitude changes after 2 weeks' contact with online learning • Readiness to re-use technology in future learning.

Previous Experience with E-Learning and Microsoft Teams Platform
We anticipated student higher early experience with other forms of e-learning than with MS Teams. This assumption was confirmed. Students mostly declared low or moderate experience with e-learning, most of them assessed their knowledge between 2-4, less than 5 per cent believed to be fully familiar with it. But almost 90% confirmed no previous experience with Microsoft teams (Table 1).

Previous Motivation and Readiness to Use Technology for Study
Our expectations about previous mature student readiness to use technology for study purpose was to be mostly low or moderate. But almost 20% expressed no motivation at all. In additional answers, students explained they had been used to traditional ways of learning and teaching and planned no changes in this respect (Table 2).

Disruptions in Learning How to Use New Technology (Anxiety, Fear)
Possible disruptions were declared by half of mature student group. Additional student comments underlined necessity of using a small range of technologies being used for a wide range of tasks to reduce anxiety from learning too many technologies which were not universally successful in terms of usage and adoption (Table 3).

Perceived Quality of Webinars and Workshop (User Friendliness)
Mature students appreciated improved access to information in an intuitive way. In their opinions, webinars made a flexible learning experience thanks to the time convenience they yielded (Table 4).

Attitude Changes of Mature Students
More than half of the students declared their knowledge, competence and skills increased considerably or to some extent, 20% believed their knowledge did not change and the rest could not answer the question. More than 84% of answers indicated the growth of motivation to use electronic devices for study purposes. 90% of students appreciated appropriate reaction of teaching staff to encourage their motivation and to support their ICT knowledge (Table 5).

Conclusions
The online classroom for mature age students is different enough from the traditional one. Faculty members need to create contents for digital delivery that are substantially different from those they teach on campus. Teaching online requires an even keener focus on mature student engagement than the face-to-face model does.
To engage mature students who are not in the room during a lesson, the course should mix spurts of discussions, collaboration, video and audio clips, and hands-on   exercises with text and possibly brief video lectures. Long lectures probably aren't the best way to engage a face-to-face classand might be even more ineffective online. Presenting information in 10-minute "chunks" and varying the format in an easy way would be another suggestion. The question of how to explore and support the development of mature age students' motivation to use e-technologies for study purpose is far from simple. Since adults frequently feel rather insecure in their position as students, teachers should provide support and encouragement when asking them to take risks or try new skills. The teacher should be focusing on the positive emotional aspects of learning process and on the progress that mature age learners are making.