***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 Studies of the cardioprotective effects of exercise training in patients with coronary artery disease have yielded contradictory results . Exercise training has been associated with improvement in myocardial perfusion even in patients who have progression of coronary atherosclerosis . We therefore conducted a prospect i ve study of the effect of exercise training on endothelial function in patients with coronary artery disease . METHODS We r and omly assigned 19 patients with coronary endothelial dysfunction , indicated by abnormal acetylcholine-induced vasoconstriction , to an exercise-training group ( 10 patients ) or a control group ( 9 patients ) . To reduce confounding , patients with coronary risk factors that could be influenced by exercise training ( such as diabetes , hypertension , hypercholesterolemia , and smoking ) were excluded . In an initial study and after four weeks , the changes in vascular diameter in response to the intracoronary infusion of increasing doses of acetylcholine ( 0.072 , 0.72 , and 7.2 microg per minute ) were assessed . The mean peak flow velocity was measured by Doppler velocimetry , and the diameter of epicardial coronary vessels was measured by quantitative coronary angiography . RESULTS In the initial study , the two groups had similar vasoconstrictive responses to acetylcholine . After four weeks of exercise training , coronary-artery constriction in response to acetylcholine at a dose of 7.2 microg per minute was reduced by 54 percent ( from a mean [ + /-SE ] decrease in the luminal diameter of 0.41+/-0.05 mm in the initial study to a decrease of 0.19+/-0.07 mm at four weeks ; P<0.05 for the comparison with the change in the control group ) . In the exercise-training group , the increases in mean peak flow velocity in response to 0.072 , 0.72 , and 7.2 microg of acetylcholine per minute were 12+/-7 , 36+/-11 , and 78+/-16 percent , respectively , in the initial study . After four weeks of exercise , the increases in response to acetylcholine were 27+/-7 , 73+/-19 , and 142+/-28 percent ( P<0.01 for the comparison with the control group ) . Coronary blood-flow reserve ( the ratio of the mean peak flow velocity after adenosine infusion to the resting velocity ) increased by 29 percent after four weeks of exercise ( from 2.8+/-0.2 in the initial study to 3.6+/-0.2 after four weeks ; P<0.01 for the comparison with the control group ) . CONCLUSIONS Exercise training improves endothelium-dependent vasodilatation both in epicardial coronary vessels and in resistance vessels in patients with coronary artery disease INTRODUCTION In patients with cardiac diseases , lifestyle changes such as an increase in physical activity are recommended to prevent further cardiac events . In Germany this is possible by attending outpatient heart groups . A problem inherent in these programs is the lack of adherence since more than two thirds of patients stop attending cardiac rehabilitation programs after six months . An alternative to the conventional implementation of heart groups is Tai Chi , which was found to improve adherence to cardiac rehabilitation programs in international studies . METHODS Patients were r and omly assigned to a conventional heart group or a heart group with Tai Chi exercises . At the beginning of the study , a medical history was taken and physical and instrumental tests were carried out , including an assessment of anxiety/depression ( HADS question naire ) and physical well-being ( SD-12 ) . Follow-up tests were performed every three months . RESULTS Patients were 62.6 ± 8.5 years old , the mean BMI was 28.6 ± 62 kg/m(2 ) , and the proportion of women was 29.8 % . The groups were different in terms of age ( conventional heart group : 65.0 ± 7.5 ; Tai Chi group : 59.9 ± 8.9 years ) . Therefore , age-adjusted analyses were performed in addition to the planned analyses . Regarding the primary endpoint of the study , there was no difference between the groups . After twelve months , 50 % of subjects were active in the Tai Chi group and 48 % in the conventional heart group ( odds ratio 0.92 , p = 0.891 ) . After adjustment for age by logistic regression , the odds ratio was 0.47 ( p = 0.285 ) . Furthermore , both the participation period in weeks ( Tai Chi group : 43.3 ± 26.0 ; conventional group : 45.5 ± 24.2 , p = 0.766 ) and the participation rate ( Tai Chi group : 66.8 ± 19.2 % Tai Chi , conventional group : 76.3 ± 16.5 % , p = 0.074 ) did not differ between the two groups . A further analysis showed a non-significant trend for improvement of anxiety , depression and physical well-being in the Tai Chi group compared with the conventional group . CONCLUSION The insight gained in international studies regarding a better adherence to Tai Chi-guided prevention programs was not transferable to heart group participants from Germany . However , there was a trend regarding a better mental condition in the Tai Chi group 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 Patients with a recent myocardial infa rct ion ( MI ) present a reduction in functional capacity expressed as a decrease in peak oxygen consumption ( Vo2 peak ) . The impact of a Tai Chi Chuan ( TCC ) cardiac rehabilitation program for patients recovering from recent MI has yet to be assessed . Our goal is to evaluate functional capacity after a TCC-based cardiac rehabilitation program in patients with recent MI . METHODS A single-blind r and omized clinical trial was conducted . The research ers who performed the tests were blinded to group allocation . Between the 14th and 21st days after hospital discharge , all patients performed a cardiopulmonary exercise testing and a laboratory blood workup .  Mean age was similar ( 56±9 years in the TCC group and 60±9 years in the control group ) . Patients allocated to the intervention group performed 3 weekly sessions of TCC Beijin style for 12 weeks ( n=31 ) . The control group participated in 3 weekly sessions of full-body stretching exercises ( n=30 ) . RESULTS After the 12-week study period , participants in the TCC group experienced a significant 14 % increase in Vo2 peak from baseline ( 21.6 ± 5.2 to 24.6 ± 5.2 mL/kg per minute ) , whereas control participants had a nonsignificant 5 % decline in Vo2 peak ( 20.4 ± 5.1 to 19.4 ± 4.4 mL/kg per minute ) . There was a significant difference between the 2 groups ( P<.0001 ) . CONCLUSIONS Tai Chi Chuan practice was associated with an increase in Vo2 peak in patients with a recent MI and may constitute an effective form of cardiac rehabilitation in this patient population Tai chi -- moving for better balance , a falls-prevention program developed from a r and omized controlled trial for community-based use , was evaluated with the re- aim framework in 6 community centers . The program had a 100 % adoption rate and 87 % reach into the target older adult population . All centers implemented the intervention with good fidelity , and participants showed significant improvements in health-related outcome measures . This evidence -based tai chi program is practical to disseminate and can be effectively implemented and maintained in community setting 
    Output:
    
Conclusion : Compared to no exercise or other types of exercise with low-to-moderate intensity , Tai Chi seems a good choice for coronary disease rehabilitation in improving cardiorespiratory fitness .