***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: OBJECTIVE To investigate the efficacy of high-frequency whole-body vibration ( WBV ) on balancing ability in elderly women . DESIGN R and omized controlled trial . Subjects were r and omized to either the WBV intervention or the no-treatment control group . SETTING Community-living elderly women . PARTICIPANTS Sixty-nine elderly women aged 60 or above without habitual exercise . INTERVENTION Side alternating WBV at 20Hz with 3 minutes a day and 3 days a week for 3 months in the WBV intervention group . Those in control group remained sedentary with normal daily life for the whole study period . MAIN OUTCOME MEASURES Limits of stability in terms of reaction time , movement velocity , directional control , endpoint excursion , maximum excursion , and the functional reach test were performed at baseline and endpoint . RESULTS Significant enhancement of stability was detected in movement velocity ( P<.01 ) , maximum point excursion ( P<.01 ) , in directional control ( P<.05 ) . CONCLUSIONS WBV was effective in improving the balancing ability in elderly women . This also provides evidence to support our user-friendly WBV treatment protocol of 3 minutes a day for the elderly to maintain their balancing ability and reduce risks of fall OBJECTIVES To investigate the effects of 24 weeks of whole-body-vibration ( WBV ) training on knee-extension strength and speed of movement and on counter-movement jump performance in older women . DESIGN A r and omized , controlled trial . SETTING Exercise Physiology and Biomechanics Laboratory , Leuven , Belgium . PARTICIPANTS Eighty-nine postmenopausal women , off hormone replacement therapy , aged 58 to 74 , were r and omly assigned to a WBV group ( n=30 ) , a resistance-training group ( RES , n=30 ) , or a control group ( n=29 ) . INTERVENTION The WBV group and the RES group trained three times a week for 24 weeks . The WBV group performed unloaded static and dynamic knee-extensor exercises on a vibration platform , which provokes reflexive muscle activity . The RES group trained knee-extensors by performing dynamic leg-press and leg-extension exercises increasing from low ( 20 repetitions maximum ( RM ) ) to high ( 8RM ) resistance . The control group did not participate in any training . MEASUREMENTS Pre- , mid- ( 12 weeks ) , and post- ( 24 weeks ) isometric strength and dynamic strength of knee extensors were measured using a motor-driven dynamometer . Speed of movement of knee extension was assessed using an external resistance equivalent to 1 % , 20 % , 40 % , and 60 % of isometric maximum . Counter-movement jump performance was determined using a contact mat . RESULTS Isometric and dynamic knee extensor strength increased significantly ( P<.001 ) in the WBV group ( mean+/-st and ard error 15.0+/-2.1 % and 16.1+/-3.1 % , respectively ) and the RES group ( 18.4+/-2.8 % and 13.9+/-2.7 % , respectively ) after 24 weeks of training , with the training effects not significantly different between the groups ( P=.558 ) . Speed of movement of knee extension significantly increased at low resistance ( 1 % or 20 % of isometric maximum ) in the WBV group only ( 7.4+/-1.8 % and 6.3+/-2.0 % , respectively ) after 24 weeks of training , with no significant differences in training effect between the WBV and the RES groups ( P=.391 ; P=.142 ) . Counter-movement jump height enhanced significantly ( P<.001 ) in the WBV group ( 19.4+/-2.8 % ) and the RES group ( 12.9+/-2.9 % ) after 24 weeks of training . Most of the gain in knee-extension strength and speed of movement and in counter-movement jump performance had been realized after 12 weeks of training . CONCLUSION WBV is a suitable training method and is as efficient as conventional RES training to improve knee-extension strength and speed of movement and counter-movement jump performance in older women . As previously shown in young women , it is suggested that the strength gain in older women is mainly due to the vibration stimulus and not only to the unloaded exercises performed on the WBV platform OBJECTIVE To test whether training on a high-frequency ( 28Hz ) vibrating platform improves muscle power and bone characteristics in postmenopausal women . DESIGN R and omized controlled trial with 6-month follow-up . SETTING Outpatient clinic in a general hospital in Italy . PARTICIPANTS Twenty-nine postmenopausal women ( intervention group , n=14 ; matched controls , n=15 ) . INTERVENTION Participants stood on a ground-based oscillating platform for three 2-minute sessions for a total of 6 minutes per training session , twice weekly for 6 months . The controls did not receive any training . Both groups were evaluated at baseline and after 6 months . MAIN OUTCOME MEASURES Muscle power , calculated from ground reaction forces produced by l and ing after jumping as high as possible on a forceplate , cortical bone density , and biomarkers of bone turnover . RESULTS Over 6 months , muscle power improved by about 5 % in women who received the intervention , and it remained unchanged in controls ( P=.004 ) . Muscle force remained stable in both the intervention and control groups . No significant changes were observed in bone characteristics . CONCLUSION Reflex muscular contractions induced by vibration training improve muscle power in postmenopausal women According to experimental studies , low-amplitude high-frequency vibration is anabolic to bone tissue , whereas in clinical trials , the bone effects have varied . Given the potential of whole body vibration in bone training , this study aim ed at exploring the transmission of vertical sinusoidal vibration to the human body over a wide range of applicable amplitudes ( from 0.05 to 3 mm ) and frequencies ( from 10 to 90 Hz ) . Vibration-induced accelerations were assessed with  skin-mounted triaxial accelerometers  at the ankle , knee , hip , and lumbar spine in four males st and ing on a high-performance vibration platform .  Peak vertical accelerations of the platform covered a range from 0.04 to 19 in units of G ( Earth 's gravitational constant ) . Substantial amplification of peak acceleration could occur between 10 and 40 Hz for the ankle , 10 and 25 Hz for the knee , 10 and 20 Hz for the hip , and at 10 Hz for the spine . Beyond these frequencies , the transmitted vibration power declined to 1/10th-1/1000 th of the power delivered by the platform . Transmission of vibration to the body is a complicated phenomenon because of nonlinearities in the human musculoskeletal system . These results may assist in estimating how the transmission of vibration-induced accelerations to body segments is modified by amplitude and frequency and how well the sinusoidal waveform is maintained . Although the attenuation of vertical vibration at higher frequencies is fortunate from the aspect of safety , amplitudes > 0.5 mm may result in greater peak accelerations than imposed at the platform and thus pose a potential hazard for the fragile musculoskeletal system Background Whole-body vibration ( WBV ) is a new type of exercise that has been increasingly tested for the ability to prevent  bone fractures and osteoporosis in frail people . There are two currently marketed vibrating plates : a ) the whole plate oscillates up and down ; b ) reciprocating vertical displacements on the left and right side of a fulcrum , increasing the lateral accelerations . A few studies have shown recently the effectiveness of the up- and -down plate for increasing Bone Mineral Density ( BMD ) and balance ; but the effectiveness of the reciprocating plate technique remains mainly unknown . The aim was to compare the effects of WBV using a reciprocating platform at frequencies lower than 20 Hz and a walking-based exercise programme on BMD and balance in post-menopausal women .  Methods Twenty-eight physically untrained post-menopausal women were assigned at r and om to a WBV group or a Walking group . Both experimental programmes consisted of 3 sessions per week for 8 months . Each vibratory session included 6 bouts of 1 min ( 12.6 Hz in frequency and 3 cm in amplitude with 60 ° of knee flexion ) with 1 min rest between bouts . Each walking session was 55 minutes of walking and 5 minutes of stretching . Hip and lumbar BMD ( g·cm-2 ) were measured using dual-energy X-ray absorptiometry and balance was assessed by the blind flamingo test . ANOVA for repeated measurements was adjusted by baseline data , weight and age . Results After 8 months , BMD at the femoral neck in the WBV group was increased by 4.3 % ( P = 0.011 ) compared to the Walking group . In contrast , the BMD at the lumbar spine was unaltered in both groups . Balance was improved in the WBV group ( 29 % ) but not in the Walking group . Conclusion The 8-month course of vibratory exercise using a reciprocating plate is feasible and is more effective than walking to improve two major determinants of bone fractures : hip BMD and balance This study was design ed to investigate the effects of vibration on muscle performance and mobility in a healthy , untrained , older population . Forty-three participants ( 23 men , 20 women , 66 - 85 y old ) performed tests of sit-to-st and ( STS ) , 5- and 10-m fast walk , timed up- and -go test , stair mobility , and strength . Participants were r and omly assigned to a vibration group , an exercise-withoutvibration group , or a control group . Training consisted of 3 sessions/wk for 2 mo . After training , the vibration and exercise groups showed improved STS ( 12.4 % , 10.2 % ) , 5-m fast walk ( 3.0 % , 3.7 % ) , and knee-extension strength ( 8.1 % , 7.2 % ) compared with the control ( p < 0.05 ) . Even though vibration training improved lower limb strength , it did not appear to have a facilitatory effect on functional-performance tasks compared with the exercise-without-vibration group . Comparable mobility and performance changes between the experimental groups suggest that improvements are linked with greater knee-extension strength and largely attributed to the unloaded squats performed by both exercise groups To determine whether 10 weeks of whole-body vibration ( WBV ) training has a significant effect on strength , muscle mass , muscle power , and mobility in older women , 26 subjects were r and omly assigned to a  WBV training group ( n=13 ; mean age 79 years ) and a control ( CON ) group ( n=13 ; mean age 76 years ) . Maximal voluntary isometric contraction ( MVIC ) increased 38.8 % in the WBV group , without changes in the CON group . Electromyographic activity of the vastus medialis ( VM ) , the vastus lateralis , and the biceps femoris ( BF ) did not change in either group . Thigh muscle cross-sectional area increased significantly after training in VM ( 8.7 % ) and BF ( 15.5 % ) . Muscle power at 20 % , 40 % , and 60 % MVIC decreased from pre-test to post-test in the CON group ; however , WBV training prevented the decrease in the WBV group . Consequently , mobility , measured by the Timed Up and Go test , increased significantly after training ( 9.0 % ) only in the WBV group . Ten weeks of lower limb WBV training in older women produces a significant increase in muscle strength induced by thigh muscle hypertrophy , with no change in muscle power . The adaptations to WBV found in the present study may be of use in counteracting the loss of muscle strength and mobility associated with age-induced sarcopenia Background and aims : Exercise may enhance the effect of alendronate on bone mineral density ( BMD ) and reduce chronic back pain in elderly women with osteoporosis . The aim of this study was to determine whether whole-body vibration exercise would enhance the effect of alendronate on lumbar BMD and bone turnover , and reduce chronic back pain in post-menopausal women with osteoporosis . Methods : Fifty post-menopausal women with osteoporosis , 55–88 years of age , were r and omly divided into two groups of 25 patients each : one taking alendronate ( 5 mg daily , ALN ) and one taking alendronate plus exercise ( ALN+EX ) . Exercise consisted of whole-body vibration using a Galileo machine ( Novotec , Pforzheim , Germany ) , at an intensity of 20 Hz , frequency once a week , and duration of exercise 4 minutes . The study lasted 12 months . Lumbar BMD was measured by dual energy X-ray absorptiometry ( Hologic QDR 1500W ) . Urinary cross-linked N-terminal telopeptides of type I collagen ( NTX ) and serum alkaline phos-phatase ( ALP ) levels were measured by enzyme-linked immunosorbent assay and st and ard laboratory techniques , respectively . Chronic back pain was evaluated by face scale score at baseline and every 6 months . Results : There were no significant differences in baseline characteristics , including age , body mass index , years since menopause , lumbar BMD , urinary NTX and serum ALP levels , or face scale score between the two groups . The increase in lumbar BMD and the reduction in urinary NTX and serum ALP levels were similar in the ALN and ALN+EX groups . However , the reduction in chronic back pain was greater in the ALN+EX group than in the ALN 
    Output:
    
Conclusion : Whole body vibration is beneficial for enhancing leg muscle strength among older adults .
However , the review suggests that whole body vibration has no overall treatment effect on bone mineral density in older women .
No r and omized trial has examined the effects of whole body vibration on bone mineral density in older men