The purpose of this study was to determine whether a walking program supplemented by tasks designed to challenge balance and mobility (WALK+) could improve physical function more than a traditional walking program (WALK) in older adults at risk for mobility disability. 31 community-dwelling older adults (M ± SD age = 76 ± 5 yr; Short Physical Performance Battery [SPPB] score = 8.4 ± 1.7) were randomized to treatment. Both interventions were 18 sessions (1 hr, 3×/wk) and progressive in intensity and duration. Physical function was assessed using the SPPB and the 400-m-walk time. A subset of participants in the WALK group who had relatively lower baseline function showed only small improvement in their SPPB scores after the intervention (0.3 ± 0.5), whereas a subset of participants in the WALK+ group with low baseline function showed substantial improvement in their SPPB scores (2.2 ± 0.7). These preliminary data underscore the potential importance of tailoring interventions for older adults based on baseline levels of physical function.
Anthony P. Marsh, Elizabeth A. Chmelo, Jeffrey A. Katula, Shannon L. Mihalko, and W. Jack Rejeski
Anthony P. Marsh, Michael E. Miller, W. Jack Rejeski, Stacy L. Hutton, and Stephen B. Kritchevsky
It is unclear whether strength training (ST) or power training (PT) is the more effective intervention at improving muscle strength and power and physical function in older adults. The authors compared the effects of lower extremity PT with those of ST on muscle strength and power in 45 older adults (74.8 ± 5.7 yr) with self-reported difficulty in common daily activities. Participants were randomized to 1 of 3 treatment groups: PT, ST, or wait-list control. PT and ST trained 3 times/wk for 12 wk using knee-extension (KE) and leg-press (LP) machines at ~70% of 1-repetition maximum (1RM). For PT, the concentric phase of the KE and LP was completed “as fast as possible,” whereas for ST the concentric phase was 2–3 s. Both PT and ST paused briefly at the midpoint of the movement and completed the eccentric phase of the movement in 2–3 s. PT and ST groups showed significant improvements in KE and LP 1RM compared with the control group. Maximum KE and LP power increased approximately twofold in PT compared with ST. At 12 wk, compared with control, maximum KE and LP power were significantly increased for the PT group but not for the ST group. In older adults with compromised function, PT leads to similar increases in strength and larger increases in power than ST.
Melissa Daly, Meghan E. Vidt, Joel D. Eggebeen,, W. Greg Simpson, Michael E. Miller, Anthony P. Marsh, and Katherine R. Saul
Aging leads to a decline in strength and an associated loss of independence. The authors examined changes in muscle volume, maximum isometric joint moment, functional strength, and 1-repetition maximum (1RM) after resistance training (RT) in the upper extremity of older adults. They evaluated isometric joint moment and muscle volume as predictors of functional strength. Sixteen healthy older adults (average age 75 ± 4.3 yr) were randomized to a 6-wk upper extremity RT program or control group. The RT group increased 1RM significantly (p < .01 for all exercises). Compared with controls, randomization to RT led to greater functional pulling strength (p = .003), isometric shoulder-adduction moment (p = .041), elbow-flexor volume (p = .017), and shoulder-adductor volume (p = .009). Shoulder-muscle volumes and isometric moments were good predictors of functional strength. The authors conclude that shoulder strength is an important factor for performing functional reaching and pulling tasks and a key target for upper extremity RT interventions.
Anthony P. Marsh, W. Jack Rejeski, Stacy L. Hutton, Cristal L. Brown, Edward Ip, and Jack M. Guralnik
Lateral mobility is integral to many activities of daily living involving transfer from one position to another. The objective of this study was to develop and evaluate the validity and test–retest reliability of a lateral-mobility (LATMOB) task for older adults. Measurements of lateral mobility, balance, and strength and self-reported and performance-based physical functioning were obtained in 63 women and 77 men ≥50 years of age. The LATMOB task was significantly correlated with age, knee-extensor strength, grip strength, functional reach, and one-leg-stance time. Test–retest reliability of the task was excellent. The LATMOB task was highly correlated with the car task. Balance was significantly correlated with time to get into and out of a car and performance on the LATMOB task. The LATMOB task was significantly correlated with the Short Physical Performance Battery score. The LATMOB task is valid and reliable, but additional work is needed to assess its sensitivity to change and predictive validity.