The vertical ground reaction force (GRF) parameters in a sit-to-stand movement are useful for measuring lower-limb muscle strength and power in older adults. The purpose of this study was to examine which GRF parameters would be more strongly associated with a person's physical functioning, history of falls, fear of falling and mobility limitations, all of which are known to be related to lower-limb muscle strength and power. We performed cross-sectional analyses on 363 community-dwelling older adults, which included 160 men and 203 women, aged 65-85 years (73.4 ± 5.3 years). Five parameters were measured: peak reaction force, two rate of force development and two time-related parameters. Their rate of force development was relatively higher correlated with results from timed “up and go” tests, standing times from a long sitting position and 4-way choice reaction times (partial r = -0.37 ∼ -0.52); these tests were accompanied with a dynamic movement of lower-limb; than their peak reaction force and time-related parameters. The rate of force development were poorer in subjects reporting falls, a fear of falling or a mobility limitation compared with those reporting no falls, fear of falling or mobility limitation. These results suggest that measuring the rate of force development in a sit-to-stand movement provide a better assessment of lower-limb muscle strength and power.

The purpose of this study was to examine the effects of 9 weeks of resistance training, with and without static acceleration training (AT), on participants' lower-limb muscle strength, power, and physical function. Healthy participants (19 men and 28 women), aged 65-75 years, were assigned to a static AT group (AT, n = 31) or a non-AT control group (C, n = 16). The AT group and the C group trained three times/week for 9 weeks. The AT group performed unloaded static AT and low-intensity aerobic activity. The C group performed dynamic weight-bearing resistance training without whole-body vibration and the same aerobic activity as the AT group. We collected and analyzed data from 45 participants (AT = 30, C = 15) who completed pre- and post-tests. There was no significant Group × Time interaction on any measurements of lower-limb muscle strength, power, or physical function. Significant time effects were observed in the following tests:isokinetic knee extensor and flexor peak torque, 5-time sit-to-stand, usual gait speed, timed up and go, standing time from a long sitting position, and sit and reach. All of these 7 variables showed positive changes. These results suggest that static AT is a suitable training method having approximately the same efficiency as conventional, weight-bearing, dynamic resistance training for improving lower-limb muscle strength and power, mobility, and flexibility in community-dwelling Japanese older adults.

The purpose of this study was to investigate the relationship between cognitive function and physical performance in Japanese older adults. Ninety four older adults, aged 65 to 87 years (mean age 71.9±5.3 years), were recruited as participants. Cognitive function was evaluated by Five-cognitive Function Test (FCFT). The FCFT, which was developed specially for Japanese older adults, consists of 5 subscale elements: attention, verbal memory, visuospatial cognition, word fluency, and associate learning. Hand dexterity (3 items), muscle strength (2 items), balance (3 items), flexibility (2 items), walking ability (2 items) and reaction ability (2 items) were defined as lifestyle-related physical performances. After adjusting for age, educational level and systolic blood pressure the FCFT score was significantly correlated with observed data of hand dexterity (hand working with a peg board, r=0.485, p<0.001), lower-extremity muscle strength (5-repetition sit-to-stand, r=-0.231, p<0.05), walking ability (5-m habitual walk, r=-0.225, p<0.05; timed up and go r=-0.304, p<0.01), and reaction ability (simple reaction time, r=-0.415, p<0.001; 4-way choice reaction time, r=-0.401, p<0.001). Multiple regression analysis revealed that the FCFT score was explained by the hand working with a peg board (F=42.36, p<0.001) and 4-way choice reaction time (F=29.62, p<0.01). The contribution rate on this model was 42%. These results suggest that cognitive functions were associated with some physical performance. Especially, hand dexterity (hand working with a peg board) and reaction ability (4-way choice reaction time) may be the useful synthetic indicators of cognitive functions in Japanese older adults.

The purpose of this study was to examine whether volunteering as exercise instructors over a continuous period of time affected the physical and cognitive functions of community-dwelling, elderly women. Longitudinal analysis was conducted on data from 18 volunteer leaders (Leader group) aged 65-79 years (69.6 ± 3.9 years) and 18 age-matched survey participants (Control group). We evaluated physical function using 8 physical performance tests along with their standardized total score, and we evaluated cognitive function using the Five Cognitive Function Test. We used two-way ANOVA to examine the effectiveness of engaging in a yearlong volunteer activity and Cohen's d for effect size. There were significant interactions in timed up and go, hand working with pegboard, standardized score of performance tests and the Five Cognitive Function Test score (P < 0.05). The Leader group improved significantly in sit and reach (d = 0.55), 5-repetition sit-to-stand (d = 0.77), timed up and go (d = 0.77), 5-m habitual walk (d = 0.88), 4-way choice reaction time (d = 0.86), standardized score of performance tests (d = 0.96) and the Five Cognitive Function Test score (d = 0.93). Although the Control group also improved significantly in some tests, the effect size tended to be lower: sit and reach (d = 0.49), hand working with pegboard (d = 0.57), standardized score of performance tests (d = 0.38) and the Five Cognitive Function Test score (d = 0.54). These results suggest that volunteering as an exercise instructor improves volunteers' physical and cognitive functions.