***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: Background —Tai Chi Chuan ( TTC ) exercise has beneficial effects on the components of physical condition and can produce a substantial reduction in the risk of multiple falls . Previous studies have shown that short term TCC exercise did not improve the scores in the single leg stance test with eyes closed and the sit and reach test . There has apparently been no research into the effects of TCC on total body rotation flexibility and heart rate responses at rest and after a three minute step test . Methods —In this cross sectional study , 28 male TCC practitioners with an average age of 67.5 years old and 13.2 years of TCC exercise experience were recruited to form the TCC group . Another 30 sedentary men aged 66.2 were selected to serve as the control group . Measurements included resting heart rate , left and right single leg stance with eyes closed , modified sit and reach test , total body rotation test ( left and right ) , and a three minute step test . Results —Compared with the sedentary group , the TCC group had significantly better scores in resting heart rate , three minute step test heart rate , modified sit and reach , total body rotation test on both right and left side ( p<0.01 ) , and both right and left leg st and ing with eyes closed ( p<0.05 ) . According to the American Fitness St and ards , the TCC group attained the 90th percentile rank for sit and reach and total body rotation test , right and left . Conclusion —Long term regular TCC exercise has favourable effects on the promotion of balance control , flexibility , and cardiovascular fitness in older adults BACKGROUND Regular physical exercise may improve a variety of physiological and psychological factors in depressive persons . However , there is little experimental evidence to support this assumption for adolescent population s. We conducted a r and omized controlled trial to investigate the effect of physical exercise on depressive state , the excretions of stress hormones and physiological fitness variables in adolescent females with depressive symptoms . METHODS Forty-nine female volunteers ( aged 18 - 20 years ; mean 18.8 + /- 0.7 years ) with mild-to-moderate depressive symptoms , as measured by the Centre for Epidemiologic Studies Depression ( CES-D ) scale , were r and omly assigned to either an exercise regimen or usual daily activities for 8 weeks . The subjects were then crossed over to the alternate regimen for an additional 8-week period . The exercise program consisted of five 50-min sessions per week of a group jogging training at a mild intensity . The variables measured were CES-D rating scale , urinary cortisol and epinephrine levels , and cardiorespiratory factors at rest and during exercise endurance test . RESULTS After the sessions of exercise the CES-D total depressive score showed a significant decrease , whereas no effect was observed after the period of usual daily activities ( ANOVA ) . Twenty-four hour excretions of cortisol and epinephrine in urine were reduced due to the exercise regimen . The training group had a significantly reduced resting heart rate and increased peak oxygen uptake and lung capacity . CONCLUSIONS The findings of this study suggest that a group jogging exercise may be effective in improving depressive state , hormonal response to stress and physiological fitness of adolescent females with depressive symptoms Objective Evaluating the effects of Tai Chi exercise on physical fitness , blood pressure , and perceived health in community-dwelling elderly . Design A r and omized controlled trial . Setting Community-dwelling elderly in Vinh city , Vietnam . Participants Ninety-six community-dwelling participants aged 60 to 79 years ( 68.9 ± 5.1 years ) were recruited . Intervention Subjects were divided r and omly into two groups : Tai Chi and Control groups . Participants in the Tai Chi group ( aged 69.02 ± 5.16 years ) attended a 60-minute Tai Chi practice session twice a week for 6 months . The session consisted of a 15-minute warm-up and a 15-minute cool-down period . The Control group ( aged 68.72 ± 4.94 years ) maintained routine daily activities . Outcome measures The Senior Fitness Test and Short-Form 36 ® ( SF-36 ® ) are primary outcome measures . Results After 24 weeks of the Tai Chi training program , the intervention group showed significant decrease in systole of 12 mmHg and heart rate 6.46 bpm . Body mass index and waist – hip ratio were also reduced by 1.23 and 0.04 , respectively . The Senior Fitness Test and SF-36 showed significant improvement . Conclusion In this r and omized controlled trial study , Tai Chi is beneficial to improve systole blood pressure , heart rate , body mass index , waist – hip ratio , perceived health , and physical fitness . Assessment of the effects of Tai Chi may be focused more on chronic disease with a long-term training program in the future BACKGROUND Although the benefits of exercise on the health of patients with chronic obstructive pulmonary disease ( COPD ) have been widely reported , the effect of Tai Chi as an alternative exercise has not been thoroughly evaluated in patients with COPD . This study reported a r and omised controlled trial , which investigated the effects of Tai Chi on lung function , exercise capacity , and diaphragm strength in patients with COPD . TRIAL DESIGN Single blind r and omised controlled study . SETTING Department of Respiratory Medicine , Xiangya Hospital , Central South University . METHODS Forty patients with COPD were r and omised into either a control group or Tai Chi intervention group . Participants in the control group received only routine care , while participants in the Tai Chi group received routine care and completed a six-month Tai Chi exercise program .  OUTCOMES Lung function parameters , blood gas parameters , 6-min walking distance ( 6MWD ) , and diaphragm strength parameters . RESULTS Lung function parameters ( FEV1 : 1.43 ± 0.08 and FEV1 ( % ) predicted : 47.6 ± 4.76 ) , 6MWD ( 476 ± 15 ) and diaphragm strength parameters ( TwPes : 1.17 ± 0.07 , TwPga : -1.12 ± 0.06 , and TwPdi : 1.81 ± 0.09 ) were found to be significantly increased in participants who successfully completed the six-month Tai Chi program compared to participants in the control group who only received routine care ( p<0.05 ) . These parameters were also found to be significantly increased in participants who completed the Tai Chi exercise program compared to the baseline ( p<0.05 ) . In contrast , no significant differences in PaO2 and PaCO2 were observed in participants before or after completing a Tai Chi program or between Tai Chi group and control group ( p>0.05 ) . CONCLUSIONS Tai Chi  enhances lung function , exercise capacity , and diaphragm strength . However , this is only preliminary research data and a larger trial is needed for more detailed results Objective . Patients with schizophrenia residing at institutions often suffer from negative symptoms , motor , and functional impairments more severe than their noninstitutionalized counterparts . Tai-chi emphasizes body relaxation , alertness , and movement coordination with benefits to balance , focus , and stress relief . This pilot study explored the efficacy of Tai-chi on movement coordination , negative symptoms , and functioning disabilities towards schizophrenia . Methods . A r and omized waitlist control design was adopted , where participants were r and omized to receive either the 6-week Tai-chi program and st and ard residential care or only the latter . 30 Chinese patients with schizophrenia were recruited from a rehabilitation residency . All were assessed on movement coordination , negative symptoms , and functional disabilities at baseline , following intervention and 6 weeks after intervention . Results . Tai-chi buffered from deteriorations in movement coordination and interpersonal functioning , the latter with sustained effectiveness 6 weeks after the class was ended . Controls showed marked deteriorations in those areas . The Tai-chi group also experienced fewer disruptions to life activities at the 6-week maintenance . There was no significant improvement in negative symptoms after Tai-chi . Conclusions . This study demonstrated encouraging benefits of Tai-chi in preventing deteriorations in movement coordination and interpersonal functioning for residential patients with schizophrenia . The ease of implementation facilitates promotion at institutional psychiatric services PURPOSE This study evaluated the effect of Tai Chi Chuan ( TCC ) on the autonomic nervous modulation in older persons . METHODS Twenty TCC practitioners and 20 normal controls were included in this study . The stationary state spectral heart rate variability ( HRV ) measures between TCC practitioners and normal controls , and the sequential changes in HRV measures after classical Yang 's TCC were compared . RESULTS The total power , very low-frequency power , low-frequency power , normalized low-frequency power , and low-/high-frequency power ratios in TCC practitioners were all significantly higher than those of normal controls , whereas the heart rate and systolic and diastolic blood pressures were not different between these two groups of subjects . After TCC , the normalized high-frequency power increased significantly from 22.8 + /- 14.6 normalized units ( nu ) before TCC to 28.2 + /- 16.1 nu 30 min after TCC and to 30.6 + /- 18.4 nu 60 min after TCC . In contrast , the low-/high-frequency power ratio decreased significantly from 2.5 + /- 2.4 before TCC to 1.8 + /- 1.4 30 min after TCC and to 2.2 + /- 2.9 60 min after TCC . The heart rate , systolic blood pressure , diastolic blood pressure , mean arterial blood pressure , and pulse pressure also decreased sequentially after TCC . CONCLUSION The short-term effect of TCC was to enhance the vagal modulation and tilt the sympathovagal balance toward deceased sympathetic modulation in older persons . TCC might be good health-promoting calisthenics for older persons Abstract This study assessed clinical and cardiorespiratory responses after an interval training programme in sedentary elderly adults using the ventilatory threshold ( Vth ) as the index of exercise training intensity . A selection of 22 subjects were r and omized into two groups : 11 subjects served as the training group ( TG ) and the others as controls  ( CG ) . Maximal exercise tests were performed on a treadmill before ( T0 ) , each month ( T1 , T2 ) and after the 3-month interval training programme period ( T3 ) . The TG subjects were individually trained at the heart rate corresponding to Vth measured at T0 , T1 and T2 as the breakpoint in the oxygen uptake-carbon dioxide production relationship . Their training programme consisted of walking/jogging sessions on a running track twice a week . The sessions consisted of varying duration s of exercise alternating with active recovery in such a way that the subjects slowly increased their total exercise time from an initial duration of 30 min to a final duration of 1 h. During training the heart rate was continuously monitored by a cardiofrequency meter . Compared with the daily activities of the controls , no training programme-related injuries were observed in TG . Moreover , programme adherence ( 73 % ) and attendance ( 97.3 % ) were high . The maximal oxygen uptake and Vth were increased in TG , by 20 % ( P<0.05 ) and 26 % ( P<0.01 ) , respectively . Interval training at Vth also significantly increased maximal O2 pulse ( P<0.05 ) and maximal ventilation ( P<0.01 ) . A significant decrease in submaximal ventilation ( P<0.05 ) and heart rate ( P<0.01 ) was also noted . These results would suggest that for untrained elderly adults , an interval training programme at the intensity of Vth may be well-tolerated clinical ly and may significantly improve both maximal aerobic power and submaximal exercise tolerance PURPOSE This study prospect ively evaluated the training effect of a 1-yr Tai Chi Chuan ( TCC ) program for low-risk patients with coronary artery bypass surgery ( CABS ) after a postoperative outpatient ( phase II ) cardiac rehabilitation program . METHODS Twenty patients with mean age of 56.5+/-7.4 yr completed this study . The  TCC group included nine men who practice d classical Yang TCC  with an exercise intensity of 48 - 57 % heart rate range ( HRR ) . The control group included 11 men whom were recommended to do a home-based self-adjusted exercise program with similar intensity of phase II cardiac rehabilitation . Grade d exercise tests were performed before and after 1 yr of training for all subjects . RESULTS Mean attendance of the TCC group was 3.8+/-1.5 times weekly in contrast to 1.7+/-1.1 times for the control group . During the follow-up examination , the TCC group increased 10.3 % in VO2peak ( from 26.2+/-4.4 to 28.9+/-5.0 mL x kg(-1 ) min(-1 ) , P<0.01 ) and increased 11.9 % in peak work rate ( from 135+/-26 W to 151+/-28 W , P<0.01 ) . However , the control group showed slight decrease in VO2peak from 26.0+/-3.9 to 25.6+/-4.6 mL x kg(-1 ) x min(-1 ) and in peak work rate from 131+/-23 W to 128+/-32 W. At the ventilatory threshold , the TCC group also showed significant increase in VO2 and work rate ( P<0.05 ) . The control group did not significantly change in these variables . CONCLUSIONS The study demonstrated that a 1-yr TCC program for low-risk patients with CABS could favorably enhance cardiorespiratory function BACKGROUND Aging is associated with increases of sympathetic nervous system activation implicated in the onset of hypertension and cardiovascular disease . The purpose of this study was to examine whether the practice of Tai Chi Chih ( TCC ) , a 
    Output:
    
The results are encouraging and suggest that Tai Chi may be effective in improving cardiorespiratory fitness in healthy adults .