in the last decades , the process of population aging has presented exponential growth in 
 many countries , including brazil1 , 2 .
demographic studies conducted by the 
 brazilian institute of geography and statistics3 estimate that in 2020 , elderly individuals will constitute 
 approximately 15% of the brazilian population . moreover ,
present data indicate that the life 
 expectancy for women better than that for men3 .
the increase in population aging has been attributed mainly to 
 advances in medicine , which have had the largest effect in decreasing mortality .
however , 
 advances in medicine haven not been able to control the decrease in functional fitness 
 observed in the elderly , that is , the decrease in strength , muscular resistance , 
 flexibility , agility , and balance that reduce independence in daily tasks , therefore 
 reducing quality of life2 .
the scientific literature reports that the practice of strength training ( st ) reverses this 
 situation , assuring the improvement and maintenance of functional fitness ( aptitude)4 .
however , this positive fact is partly 
 countered by the fact that the elderly do not have this habit5 , 6 .
one of the possible 
 explanations for the low level of practice is the high intensity initially prescribed in 
 programs of physical exercises , which promote beneficial changes to health ; however , this 
 subjectively perceived effort produces feelings of displeasure proceeding from the 
 metabolism7 .
this displeasure felt in 
 the training session negatively affects adherence to physical exercise programs .
however , 
 this evidences was observed to a large extent in walking and running , and little is known 
 about the behavior of feelings of pleasure / displeasure in st .
recently , elsangedy et al.8 obtained , 
 with only one session of st at 70% of the one - repetition maximum ( 1rm ) in sedentary men , 
 similar unpleasant feelings as those found in vigorous aerobic exercise .
although the 
 results have been corroborated , it can not yet be affirmed that the intensity was the cause 
 of the displeasure .
therefore , st possesses greater complexity and variations of movements 
 compared with walking and running that , in turn , can influence feeling in different ways . 
 moreover , the studies on st aimed to verify only the acute behavior of feelings of 
 pleasure / displeasure , neglecting the chronic behavior . although acute unpleasant feelings 
 affect adherence to physical exercise , it can not be ruled out that individuals may achieve a 
 vigorous intensity with the same routine of training for a longer period and modify these 
 feelings . for these reasons , the objective of the present study was verify the behavior of 
 the rate of perceived exertion ( rpe ) and feelings of pleasure / displeasure in sedentary 
 elderly women during eight weeks of st with a fixed routine .
eleven sedentary women aged between 65 and 75 ( average age of 69.1  4.7 ) took part in this 
 study ( table 1table 1.anthropometric characteristicsvariablemsdage ( years)69.1  4.7height ( cm)152.6  10.2body mass ( kg)62.4  12.6bmi ( kg / m)26.3  2.9 ) .
recruitment was accomplished by means of printed announcements on public 
 notice boards and , flyers distributed in the streets in locations close to the study center . 

all the participants were classified as apparently healthy on the basis of the physical 
 activity readiness questionnaire ( par - q ) .
the exclusion criteria were a ) one or more 
 positive responses in the par - q b ) body mass index ( bmi )  27  kg / m and c ) 
 presence of limitations in joint movements and/or respiration that could affect the 
 mechanics of walking and/or strength training .
the inclusion criteria were a ) negative 
 responses to all the items of the par - q , b ) non - smoking , and c ) normal bmi value 
 ( 22  kg / m  27.0  kg / m ) . all the subjects provided informed consent 
 to participate in the study , in accordance with the guidelines in resolution 196/96 of the 
 national council of health , and the study was approved by the committee of ethics of the 
 federal university of paran ( ufpr registry number cep / sd , 1087.012.11.03 , and caae : 
 0014.0.091.000 - 11 ) .
body composition of participants was evaluated ( height , body weight , and bmi ) , and the 
 participants then participated in three sessions to familiarize them with the training 
 routine used for the study . in these sessions ,
the exercises , the bench press , leg 
 extension , pulldown , and leg curl , were first demonstrated by the study staff with 
 simultaneous verbal instructions .
after this the participants performed the action three 
 times , i.e. , 3 sets of 1012 repetitions with a light load in order to allow better 
 accomplishment and agreement of the movements .
also in the period of familiarization , 
 explanations on interpretation of the feeling scale ( 5/+5 ) and omni resistance exercise 
 scale ( omni - res ; 010 ) were repassed of individual form . the maximum load ( 100% )
was 
 determined by performing a test to determined the 1rm for all the exercises in this study 
 according to the protocol of fatouros et al9 .
once this first stage was completed , the experiment began , in which 
 the participants were subjected to 8 weeks of strength training composed of 3 sets of 10 
 repetitions per 1 minute for rest to 70% of 1rm .
the rest between the sessions of 
 experimental tests followed the recommendations suggested by the american college of sports 
 medicine10 . in the experimental session ,
the exercises were always performed in the same sequence 
 ( bench press , leg extension , pulldown , and leg curl ) , and in the rest between each series , 
 the rpe and feelings of pleasure / displeasure were measured . for measurement of the rpe
, the participants were instructed in memory anchoring with the 
 omni -res according to the procedures proposed by robertson et al12 .
the procedure was as follow : in the breaks between each 
 series , the scale was presented , and the following question was asked : at this moment during 
 the exercise , how much effort do you feel have exerted throughout the body ?
affective 
 valence during the training sessions was assessed with the feeling scale , which uses a 
 bipolar sorting from 11 points , varying by + 5 to 5 , with an anchor of zero ( neutral ) and 
 all the odd whole numbers corresponding to description of  very good  ( + 5 ) to  very bad  

the anchoring procedure used was memory , following the protocol of hardy and 
 rejeski12 .
for testing of the 1rm , we adopted the following criteria with the intention of minimizing 
 the margin of error : a ) standardized instructions throughout data collection ; b ) instruction 
 regarding the technique in execution of the exercise ; c ) the appraiser will stay intent 
 during all the execution of the movement to avoid erroneous interpretations of props up them 
 obtained , d ) verbal encouragement of the participants during execution of the movement , and 
 e ) survey of the weights used in the study with a precision scale .
the volunteers initially performed a warm - up as specified for the equipment with a load 
 chosen for proper execution , which was comfortable for accomplishing 15 repetitions11 . at the end of the warm - up
, they were instructed to perform the movement with one weight at 
 time , as direct by the appraiser . in the case
that they had enough strength for an 
 additional movement , the load was increased and another attempt was executed after 3 to 5 
 minutes of rest , following the procedures of fatouros et al10 .
it is worth emphasizing that repetitions were considered valid 
 when they were made with the complete cycle of movement and the appropriate technique .
after 
 48 hours , the reproducibility of loads obtained in the first test was evaluated .
all 
 the data were analyzed using the pasw statistics ( version windows ) , with level of 
 significance stipulated as p < 0.05 for all the analyses .
descriptive statistics with 
 measures of central trend and variability ( mean and standard deviation ) were used for 
 characterization of the participants in the study .
for verification of the normality of the 
 data set , the shapiro - wilk test was used . finally ,
analysis of variance ( anova ) was used to 
 analyze rpe and feelings of pleasure / displeasure and post hoc tests were used to identify 
 the significant differences .
the anthropometric characteristics of the participants are presented as the mean ( m ) and 
 standard deviation ( sd ) in table 1 .
after one month ( fifth week ) of training , strength increased in all exercises , and after 
 this period , only the pulldown exercise showed higher strength when comparing the first and 
 fifth weeks ( p < 0.05 ) ( table 2table 2.loads of training at 70% of 1rmexercisesweek 1 week
5week 8bench press16.36.120.87.022.26.3leg curl15.15.920.04.820.74.5pulldown24.34.527.05.228.65.4leg extension 39.49.545.510.546.24.5 * statistically different from the first week ( p < 0.05 ) .  
* statistically different from the first week ( p < 0.05 ) .   statistically different from the fifth week ( p < 0.05 ) rpe decrease at the end of the first month , and it was significantly different only for leg 
 curl at the end of the second month ( p < 0.05 ) ( table 3table 3.perceptual responses during eight weeks of strength trainingexercisesweek 1week 5week 8bench press3.91.73.51.33.81.4leg curl4.71.43.41.63.71.8pulldown3.21.13.01.23.01.3leg extension 3.91.43.41.23.71.8*statistically different from the first week ( p < 0.05 ) ) .
* statistically different from the first week ( p < 0.05 ) the subjects reported feelings of pleasure for all the exercises , and in the leg extension , 
 pulldown , and leg curl , the feelings of pleasure increased ( table 4table 4.responses regarding feelings of pleasure / displeasure feelings during eight weeks 
 of strength trainingexercisesweek 1week 5week 8bench press3.81.04.40.94.20.9leg curl3.40.94.00.84.00.9pulldown3.81.14.41.04.40.8leg extension 3.70.94.21.03.81.0*statistically different from the first week ( p < 0.05 ) ) .
the aim of the present study was to verify the effect of eight weeks of st with a fixed 
 routine on the behavior of rpe and feelings of pleasure / displeasure in elderly women 
 performing physical exercises .
strength , as expected , increased within five weeks of 
 training due to neural adjustments .
rpe only showed a reduction in value in the fifth week 
 in the leg curl exercise ( table 2 ) .
it is know 
 that the elderly use the upper limbs more ; however , locomotion levels tend to diminish , and 
 thus the lower limbs are little stimulated
. moreover , the hamstring naturally possesses 40% 
 less strength relative to compared with the quadriceps13 , 14 .
these facts are 
 associated with the accentuated reduction in muscular strength in the process of aging in 
 the elderly , and not performing physical exercise is possibly the cause of this15 .
after five weeks of training , the 
 participants had probably obtained greater recruitment of motor units of strength , improving 
 the intra- and intermuscular coordination and in this way diminishing the rpe in the leg 
 curl exercise .
the mean rpe values for all the exercises at 70% of 1rm in present study were different 
 from those reported in literature . according to the american college of sports medicine 
 ( acsm ) , an intensity reaching of 60 to 70% of 1rm which would correspond to vigorous effort , 
 is necessary for strength increases and hypertrophy to occur , and on the omni - res scale ( 0 
 to 10 points ) , this would be equivalent to between 7 and 8 points and classified as 
  difficult10 . in the present study , 

day et al.16 , gearhart et al.17 , and lagally et al.18 also found similar values for the intensity of 70% of 1rm not 
 corresponding to the recommendations of the acsm .
independent of this previous studies have 
 demonstrated a well established concept , that is , performing a small number of repetition 
 with higher percentages of 1rm as being more difficult that performing repetitions with 
 lower percentages of 1rm19 .
however , they 
 have not demonstrated a relation between the rpe and intensity ( percentage of 1rm ) of st due 
 to lack of control for different muscular contractions , that is , submaximal repetitions ( 12 
 repetitions to 30% of 1rm ) versus maximal repetitions ( 45 repetitions to 90% of 1rm ) .
maximum and submaximal muscular contraction induces different metabolic and neural 
 responses , directly influencing the perception of effort19 . in this regard ,
we believe that the results of the rpe may have 
 been underestimated owing to the fact that the participants not having to perform the 
 exercises until concentric failure .
this contributed positively to their feelings , which 
 were of pleasure for all the exercises .
ekkekakis et al.7 reported that low levels of effort perception provide pleasant 
 feelings , contributing to adherence to physical exercise programs .
the evidence found in 
 this investigation corroborates the findings in the literature and demonstrates this inverse 
 relation accurately ; that is the lower the perceived effort , the greater the feeling of 
 pleasure observed in the leg curl exercise6 .
however , curiously , even without changes in the rpe , the feelings 
 of pleasure also increased in the pulldown and leg extension exercises over the eight weeks . 

thus , it is perceived that the feelings of pleasure / displeasure feelings in st are not 
 solely modulated by the intensity of the exercise and rpe .
from this perspective , we 
 concluded that the physical and functional benefits obtained by increasing muscular strength 
 in a chronic work seem to positively influence feelings independent of whether or not is 
 reduced .
besides , the prescription of strength training with repetitions of 70% of 1rm 
 without concentric failure increased muscle strength and , contrary to what we thought , did 
 not cause feelings of displeasure . in addition , we observed that the feelings of 
 pleasure / displeasure varied over the period of training , suggesting that they are capable of 
 increasing the enjoyment levels of even for a prescribed intensity .
the rpe underwent 
 changes during the exercises due to differences in the movements , despite the percentage 1rm 
 being fixed .
therefore , we suggest that further studies aim to verify other variations of 
 strength training exercises and rpe responses along with the feelings of 
 pleasure / displeasure .
 [ purpose ] the aim of the present study was to verify the rate of perceived exertion and 
 feelings of pleasure / displeasure in elderly women , who did normally perform physical 
 exercises , following eight weeks of strength training in a constant routine . [ subjects and 
 methods ] eleven sedentary women were subjected to anthropometric assessment . 
 the maximum 
 load ( 100% ) for each used in this study was determined by performing a test to determined 
 the 1rm for each of them according to the protocol of fatouros et al . and 
 the feeling 
 scale and rpe scale were explained to the women . 
 after these initial procedures , the 
 subjects followed a routine for strength training , performing three sets of repetitions at 
 70% of the one - repetition maximum for each exercise ( bench press , leg extension , pulldown , 
 leg curl ) without modifying the exercises and their execution order . 
 the frequency of 
 training was three days per week . 
 anova was used to analyze the behavior of the dependent 
 variable , and the post hoc tests were used to identify significant differences . 
 [ results ] 
 strength increased only in the fifth week . 
 the rate of perceived exertion showed a 
 reduction only in the fifth week in the leg extension , pulldown , leg curl . 
 [ conclusion ] 
 the percentage of 70% the one - repetition maximum recommended to increase the strength 
 gains and hypertrophy of skeletal muscle does not provide feelings of displeasure when 
 performing proposed exercise . 
 however , it may be possible to modulate this percentage to 
 obtain more pleasant feelings over two months . 
INTRODUCTION
SUBJECTS AND METHODS
RESULTS
DISCUSSION