***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Background Diminished control of st and ing balance , traditionally indicated by greater postural sway magnitude and speed , is associated with falls in older adults .  Tai Chi ( TC ) is a multisystem intervention that reduces fall risk , yet its impact on sway measures vary considerably . We hypothesized that TC improves the integrated function of multiple control systems influencing balance , quantifiable by the multi-scale “ complexity ” of postural sway fluctuations . Objectives To evaluate both traditional and complexity-based measures of sway to characterize the short- and potential long-term effects of TC training on postural control and the relationships between sway measures and physical function in healthy older adults . Methods A cross-sectional comparison of st and ing postural sway in healthy TC-naïve and TC-expert ( 24.5±12 yrs experience ) adults . TC-naïve participants then completed a 6-month , two-arm , wait-list r and omized clinical trial of TC training . Postural sway was assessed before and after the training during st and ing on a force-plate with eyes-open ( EO ) and eyes-closed ( EC ) . Anterior-posterior ( AP ) and medio-lateral ( ML ) sway speed , magnitude , and complexity ( quantified by multiscale entropy ) were calculated . Single-legged st and ing time and Timed-Up– and -Go tests characterized physical function . Results At baseline , compared to TC-naïve adults ( n = 60 , age 64.5±7.5 yrs ) , TC-experts ( n = 27 , age 62.8±7.5 yrs ) exhibited greater complexity of sway in the AP EC ( P = 0.023 ) , ML EO ( P<0.001 ) , and ML EC ( P<0.001 ) conditions . Traditional measures of sway speed and magnitude were not significantly lower among TC-experts . Intention-to-treat analyses indicated no significant effects of short-term TC training ; however , increases in AP EC and ML EC complexity amongst those r and omized to TC were positively correlated with practice hours ( P = 0.044 , P = 0.018 ) . Long- and short-term TC training were positively associated with physical function . Conclusion Multiscale entropy offers a complementary approach to traditional COP measures for characterizing sway during quiet st and ing , and may be more sensitive to the effects of TC in healthy adults . Trial Registration Clinical Trials.gov Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more This work analyses the short-term physiological and neurophysiological effects of a brisk walking programme in ageing , healthy , active men . Twenty-one men 63 to 72 years of age were recruited and separated into 2 groups . One group performed a walking programme ( WP ) ( n = 11 ) and another served as control ( C ) group ( n = 10 ) . The walking programme lasted for twelve weeks and included five sessions per week . Several parameters were assessed before and after the programme for the WP group . The same tests were performed ( separated by twelve weeks ) in group C. During each assessment , the subjects were put through static and dynamic balance tests , spatio-temporal gait analysis , body composition measurements and determination of aerobic capacity and bone mineral density . The statistic analysis showed a significant improvement in dynamic balance performance , especially in lateral sway when the subjects kept their eyes open , an increase of VO(2 ) max and loss of fat mass in the WP group . However , no alterations appeared in spatiotemporal gait characteristics , static balance performance , lean mass or bone mineral density ( total body and hip ) . According to these results , this walking programme may have positive effects on preventing ageing subjects from falling BACKGROUND Taiji ( T'ai Chi ) has been shown to have generally positive effects on functional balance . However , few studies have investigated the mechanisms by which Taiji may improve balance . The goal of this study was to evaluate changes in sensory and biomechanical balance mechanisms as a consequence of a traditional Taiji exercise program for healthy older adults that intentionally emphasized both Taiji forms and Qigong meditation . MATERIAL / METHODS This was a r and omized controlled trial with blind testers . Forty-nine healthy older adults ( mean age 80.4 , SD . 8.6 ) were r and omized to participate in Taiji-Qigong ( TQ ) training ( N=33 ) or a wait-list control group ( WC , N=16 ) . TQ instruction was provided 1 hour/session , 3 sessions a week for six months . Somatosensory , visual , and vestibular ratios of the Sensory Organization Test , and quiet stance Base of Support ( BoS ) and feet opening angle measures were collected prior to instruction ( T0 ) , at two months ( T2 ) , and six months ( T6 ) . RESULTS TQ  group vestibular ratio scores ( normalized to T0 ) were + 22 % and + 47 % greater than WC at T2 and T6 , respectively . The TQ group exhibited an increase in quiet stance BoS over time but not feet opening angle , indicating that the increase in BoS was due to the adoption of wider stances . CONCLUSIONS Improved use of vestibular input and wider stances are two mechanisms by which Taiji-Qigong training may improve healthy older adults ' balance . Further study is needed to evaluate other balance mechanisms and the individual and combined effects of different aspects of traditional Taiji practice The prevention of injury associated with falls in older people  is a public health target in many countries around the world . Although there is good evidence that interventions such as multifactorial fall prevention and individually prescribed exercise are effective in reducing falls , the effect on serious injury rates is unclear . Historically , trials have not been adequately powered to detect injury endpoints , and variations in case definition across trials have hindered meta- analysis . It is possible that fall-prevention strategies have limited effect on falls that result in injuries or are ineffective in population s who are at a higher risk of injury . Further research is required to determine whether fall-prevention interventions can reduce serious injuries . Prevention of Falls Network Europe ( ProFaNE ) is a collaborative project to reduce the burden of fall injury in older people through excellence in research and promotion of best practice ( www.profane.eu.org ) . The European Commission funds the network , which links clinicians , members of the public , and research ers worldwide . The aims are to identify major gaps in knowledge in fall injury prevention and to facilitate the collaboration necessary for large-scale clinical research activity , including clinical trials , comparative research , and prospect i ve meta- analysis . Work is being undertaken in a 4-year program . As a first step , the development of a common set of outcome definitions and measures for future trials or meta- analysis was considered BACKGROUND Balance disorders increase considerably with age due to a decrease in posture regulation quality , and are accompanied by a higher risk of falling . Conversely , physical activities have been shown to improve the quality of postural control in elderly individuals and decrease the number of falls . The aim of this study was to evaluate the impact of two types of exercise on the visual afferent and on the different parameters of static balance regulation . METHODS  Static postural control  was evaluated in 44 healthy women aged over 60 years . Among them , 15 regularly practice d proprioceptive physical activities ( Group I ) ,  12 regularly practice d bioenergetic physical activities ( Group II ) , and 18 controls walked on a regular basis ( Group III ) . RESULTS Group I participants displayed lower sway path and area values , whereas Group III participants displayed the highest , both in eyes-open and eyes-closed conditions . Group II participants displayed intermediate values , close to those of Group I in the eyes-open condition and those of Group III in the eyes-closed condition . Visual afferent contribution was more pronounced for Group II and III participants than for Group I participants . CONCLUSIONS Proprioceptive exercise appears to have the best impact on balance regulation and precision . Besides , even if bioenergetic activity improves postural control in simple postural tasks , more difficult postural tasks show that this type of activity does not develop a neurosensorial proprioceptive input threshold as well , probably on account of the higher contribution of visual afferent In a well-executed golf swing , golfers must maintain good balance and precise control of posture . Golfing also requires prolonged walking over uneven ground such as a hilly course . Therefore , repeated golf practice may enhance balance control and confidence in the golfers . The objective is to investigate whether older golfers had better balance control and confidence than non-golfing older , healthy adults . This is a cross-sectional study , conducted at a University-based rehabilitation center . Eleven golfers and 12 control subjects ( all male ; mean age : 66.2 ± 6.8 and 71.3 ± 6.6 years , respectively ) were recruited . Two balance control tests were administered : ( 1 ) functional reach test which measured subjects ’ maximum forward distance in st and ing ; ( 2 ) sensory organization test ( SOT ) which examined subjects ’ abilities to use somatosensory , visual , and vestibular inputs to control body sway during stance . The modified Activities-specific Balance Confidence ( ABC ) determined subject ’s balance confidence in daily activities . The golfers were found to achieve significantly longer distance in the functional reach test than controls . They manifested significantly better balance than controls in the visual ratio and vestibular ratio , but not the somatosensory ratio of the SOT . The golfers also reported significantly higher balance confidence score ratios . Furthermore , older adults ’ modified ABC score ratios showed positive correlations with functional reach , visual and vestibular ratios , but not with somatosensory ratio . Golfing is an activity which may enhance both the physical and psychological aspects of balance control . Significant correlations between these measures reveal the importance of the balance control under reduced or conflicting sensory conditions in older adults ’ balance confidence in their daily activities . Since cause- and -effect could not be established in the present cross-sectional study , further prospect i ve intervention design is warranted OBJECTIVES To compare the effects of short-term and long-term Tai Chi training on the sensorimotor and balance performance of able-bodied subjects . DESIGN A nonr and omized cross-sectional controlled trial . SETTING Sport laboratory . PARTICIPANTS Forty-eight healthy subjects , 16 with 3 months of experience in Tai Chi training , 16 with 1 to 3 years of experience in Tai Chi training , and 16 with no experience in Tai Chi training .  INTERVENTION Experimental . MAIN OUTCOME MEASURES The reflex contraction latencies ( reaction time ) of medial hamstrings and gastrocnemius after perturbation , the active knee joint angle-repositioning error , and the balance time on a tilt board were measured and analyzed with 1-way analysis of covariance . Significant results were further analyzed with post hoc linear contrasts . RESULTS Long-term Tai Chi practitioners had a significantly faster reflex reaction time in hamstrings ( P<.000 ) and gastrocnemius ( P=.043 ) muscles and a longer balance time on a tilt board ( P<.000 ) than short-term Tai Chi practitioners and nonpractitioners . Both long- and short-term Tai Chi practitioners had significantly less knee joint angle-repositioning error than nonpractitioners ( P=.001 and P=.027 , respectively ) . CONCLUSIONS Tai Chi training of more than 1 year might have the benefits of faster hamstrings and gastrocnemius reflex reaction and improved knee joint position sense ( JPS ) . These changes might be associated with an improved dynamic st and ing balance . Better knee JPS was shown in subjects with 3 months of Tai Chi practice , but this had not led to a significant improvement in balance Background Evidence , mainly from cross-sectional studies , suggests that physical activity is a potentially important modifiable factor associated with physical performance and strength in older age . It is unclear whether the benefits of physical activity accumulate across life or whether there are sensitive periods when physical activity is more influential . Purpose To examine the associations of leisure-time physical activity across adulthood with physical performance and strength in midlife , and to test whether there are cumulative benefits of physical activity . Methods Using data on approximately 2400 men and women from the UK Medical Research Council National Survey of Health and Development , followed up since birth in March 1946 , the associations of physical activity levels during leisure time self-reported prospect ively at ages 36 , 43 , and 53 years with grip strength , st and ing balance , and chair rise times , assessed by nurses at age 53 years ( in 1999 ) , were examined in 2010 . Results There were independent positive effects of  physical activity at all three ages on chair rise performance , and at ages 43 and 53 years on st and ing balance performance , even after adjusting for covariates . These results were supported by evidence of cumulative effects found when using structured life course models . Physical activity and grip strength were not associated in women and , in men , only physical activity at age 53 years was associated with grip strength . Conclusions There are cumulative benefits of physical activity across adulthood on physical performance in midlife . Increased activity should be promoted early in adulthood to ensure the maintenance of physical performance in later life OBJECTIVES To assess inter-rater reliability and validity of the Newcastle Ottawa Scale ( NOS ) used for method ological quality assessment of cohort studies included in systematic review s. STUDY DESIGN AND SETTING Two review ers independently applied the NOS to 131 cohort studies included in eight meta-analyses .  Inter-rater reliability was calculated using kappa ( κ ) statistics . To assess validity , within each meta- analysis , we generated a ratio of pooled estimates for each quality domain . Using a r and om-effects model , the ratios of odds ratios for each meta- analysis were combined to give an overall estimate of differences in effect estimates . RESULTS Inter-rater reliability varied from substantial for length of follow-up ( κ = 0.68 , 95 % confidence interval [ CI ] = 0.47 , 0.89 ) to poor for selection of the nonexposed cohort and demonstration that the outcome was not present at the outset of the 
    Output:
    
Results Limited evidence provided by a small number of RCTs , and evidence from observational studies of moderate method ological quality , suggest that free-living PA of between one and 21 years ’ duration improves measures of balance in older healthy community-dwelling adults .
Statistical analysis of observational studies found significant effects in favour of more active groups for neuromuscular measures such as gait speed ; functionality using Timed Up and Go , Single Leg Stance , and Activities of Balance Confidence Scale ; flexibility using the forward reach test ; and strength using the isometric knee extension test and ultrasound .
A significant effect was also observed for less active groups on a single sensory measure of balance , the knee joint repositioning test .