Muscle Power In Older Adults Research Articles

High-Speed Power Training: A Novel Approach to Resistance Training in Older Men and Women. A Brief Review and Pilot Study

Over the past century, increases in both longevity and the number of older adults in the U.S.A. have given rise to greater numbers of functionally limited and disabled older adults. This has resulted in a decline in the quality of life of our elderly population, as well as an increased burden on our health care system. Resistance training (RT) with a strengthening component has traditionally been recommended to improve health and physical functioning in older adults. Muscle power (force x velocity), or the ability to produce force rapidly, has recently emerged as an important predictor of functioning in older men and women and has been the current focus of many RT studies. In this review, the physiological changes that contribute to the declines in muscle strength and power with aging will first be examined, followed by a discussion of the prevailing theories behind the use of traditional RT in older men and women. The rationale for high-velocity RT will then be explored, and the recent literature on novel training interventions designed to improve muscle power in older adults will be discussed. Finally, some preliminary evidence demonstrating the benefits of high-velocity power training in older men and women will be presented.

Lower Extremity Peak Power Training in Elderly Subjects with Moderate Mobility Limitations

PURPOSE: To examine the effects of a lower extremity high-velocity high-power exercise training intervention in older adults with moderate mobility impairments, and to investigate whether peak power training results in greater increases of peak muscle power output compared to traditional progressive resistance training. METHODS: Fifty-eight community-dwelling older males and females (aged 65 to 94 years) with moderate mobility limitations, as evidenced by a score of 10 or less on the Established Populations for the Epidemiologic Studies of the short physical performance battery (mean score 7.7± 1.4) were randomized to either a control group of lower extremity stretching (CON, n = 12), a traditional slow-velocity strength training group (STR, n = 22) or a high-velocity high-power training group (POW, n = 24). Training was performed three times per week for 12 weeks and subjects completed three sets (8–10 repetitions) of bilateral leg press (LP) and knee extension exercises at 70% of the one repetition maximum (1 RM). Assessment of 1RM strength and peak muscle power output was performed at baseline and post-intervention. Regional lean body mass was measured by dual-energy X-ray absorptiometry. RESULTS: Among the entire study group, baseline measurements of total leg lean mass were strongly associated with both LP strength (r = 0.79, p <0.001) and peak muscle power (r = 0.48. p <0.001). In addition, no significant differences existed between the three groups for 1RM strength or peak power output at baseline. With training, peak muscle power increased significantly in both exercise intervention groups. However, peak power in POW, but not in STR, was significantly greater compared to CON (CONΔ: – 6.4 W; STR Δ: 48.7 W; POWA: 74.8 W*, *p <0.05). CONCLUSIONS: Lower extremity high-velocity high-power exercise training increases peak muscle power in the mobility limited elderly. This increase in peak power is of a greater magnitude compared with traditional progressive resistance training. The results of this study suggest that high-velocity high-power training may be an effective exercise intervention to offset the age-related decline in peak muscle power in older adults with mobility limitations.

Older Adult Exhibit Lower Peak Muscle Power during Single Step Balance Recovery

Aging is associated with a loss of peak muscle power, and losses in muscle power can have a debilitating effect on functional capacity. This loss may also contribute to the high fall rates in older adults. PURPOSE: To investigate differences between young and older adults in peak muscle power during an experimental model of trip recovery. METHODS: Ten healthy young men (19–23 years old) and ten healthy older men (65–83 years old) were released from static forward leans to induce forward falls. After release, participants attempted to recover their balance with a single step. Upon successful recovery, this was repeated at progressively larger lean angles until participants failed to recover. Muscle power at the hip, knee, and ankle of the stepping limb were determined from the product of joint angular velocity and joint torque. An age-related difference in maximum achieved lean angle was investigated using an independent t-test. Age-related differences in peak muscle power of the stepping limb were investigated using a repeated measures ANOVA. RESULTS: Older men achieved significantly smaller maximum lean angles compared to young (p<0.01). In addition, older men generated smaller peak muscle power during recovery from their maximum achieved lean at the ankle (p<0.05), knee (p<0.01), and hip (p<0.01) of the stepping limb. Interestingly, age-related differences at equivalent lean angles did not always involve smaller peak power values in the older men. CONCLUSION: Smaller peak muscle power in older adults may be causally-related to their smaller achieved maximum lean angles. Exercise interventions aimed at increasing muscle power may help improve balance recovery capability in older adults, and in turn reduce fall rates.

Optimal Load for Increasing Muscle Power During Explosive Resistance Training in Older Adults

Muscle power (force x velocity) recedes at a faster rate than strength with age and may also be a stronger predictor of fall risk and functional decline. The optimal training paradigm for improving muscle power in older adults is not known, although some literature suggests high velocity, low load training is optimal in young adults. One hundred twelve healthy older adults (69 +/- 6 years) were randomly assigned to either explosive resistance training at 20% (G20), 50% (G50), or 80% (G80) one repetition maximum (1RM) for 8-12 weeks or to a nontraining control group (CON). Participants trained twice per week (five exercises; three sets of eight rapidly concentric and slow eccentric repetitions) using pneumatic resistance machines. Repeated-measures analysis of variance and covariance (ANOVA and ANCOVA) were used to determine the effects of training. Average peak power increased significantly and similarly in G80 (14 +/- 8%), G50 (15 +/- 9%), and G20 (14 +/- 6%) compared to CON (3 +/- 6%) (p < .0001). By contrast, a positive dose-response relationship with training intensity was observed for relative changes in average strength (r = .40, p = .0009) and endurance (r = .43, p = .0005). Average strength increased in G80 (20 +/- 7%), G50 (16 +/- 7%), and G20 (13 +/- 7%) compared to CON (4 +/- 4%) (p < .0001). Average muscle endurance increased in G80 (185 +/- 126%, p < .0001), G50 (103 +/- 75%, p = .0004), and G20 (82 +/- 57%, p = .0078) compared to CON (28 +/- 29%). Peak muscle power may be improved similarly using light, moderate, or heavy resistances, whereas there is a dose-response relationship between training intensity and muscle strength and endurance changes. Therefore, using heavy loads during explosive resistance training may be the most effective strategy to achieve simultaneous improvements in muscle strength, power, and endurance in older adults.

Improved Physical Performance in Older Adults Undertaking a Short-Term Programme of High-Velocity Resistance Training

Background: The age-related loss of muscle power in older adults is greater than that of muscle strength and is associated with a decline in physical performance. Objective: To investigate the effects of a short-term high-velocity varied resistance training programme on physical performance in healthy community-dwelling adults aged 60–80 years. Methods: Subjects undertook exercise (EX; n = 15) or maintained customary activity (controls, CON; n = 10) for 8 weeks. The EX group trained 2 days/week using machine weights for three sets of eight repetitions at 35, 55, and 75% of their one-repetition maximum (the maximal weight that an individual can lift once with acceptable form) for seven upper- and lower-body exercises using explosive concentric movements. Results: Fourteen EX and 10 CON subjects completed the study. Dynamic muscle strength significantly increased (p = 0.001) in the EX group for all exercises (from 21.4 ± 9.6 to 82.0 ± 59.2%, mean ± SD) following training, as did knee extension power (p < 0.01). Significant improvement occurred for the EX group in the floor rise to standing (10.4 ± 11.5%, p = 0.004), usual 6-metre walk (6.6 ± 8.2%, p = 0.010), repeated chair rise (10.4 ± 15.6%, p = 0.013), and lift and reach (25.6 ± 12.1%, p = 0.002) performance tasks but not in the CON group. Conclusions: Progressive resistance training that incorporates rapid rate-of-force development movements may be safely undertaken in healthy older adults and results in significant gains in muscle strength, muscle power, and physical performance. Such improvements could prolong functional independence and improve the quality of life.

Optimal Load for Increasing Muscle Power during Explosive Resistance Training in Older Adults

0200 Muscle power (force × velocity) recedes at a faster rate than strength with age and may also be a stronger predictor of fall risk and functional decline. The optimal training paradigm for improving muscle power in older adults is not known, although some literature suggests high velocity/low load training is optimal in young adults. PURPOSE: To determine the optimal training intensity during explosive resistance training for improving peak muscle power in adults ≥ 60 years of age. METHODS: 112 healthy older adults (69 ±6 yrs) were randomized to explosive resistance training at either 20% (G20), 50% (G50), or 80% (G80) maximal strength (1RM) for 8–12 weeks or a non-training control group (CON). Subjects trained twice per week (five exercises; 3 sets of 8 rapidly concentric/slow eccentric repetitions) using pneumatic resistance machines. Repeated measures ANOVA and ANCOVA were used to analyse effects of outcome variables. RESULTS: Average peak power increased significantly and similarly in G80 (14±8%), G50 (15±9%), and G20 (14±6%) compared to CON (3±6%) (p<.0001). A positive dose-response relationship with training intensity was observed for relative changes in average strength (r = .40, p = .0009) and endurance (r = .43, p = .0005). Average strength increased in G80 (20±7%), G50 (16±7%), and G20 (13±7%) compared to CON (4±4%) (p<.0001). Average muscle endurance increased in G80 (185±126%, p<.0001), G50 (103±75%, p = .0004), and G20 (82±57%, p = .0078) compared to CON (28±29%). CONCLUSION: Peak muscle power may be improved similarly using light, moderate, or heavy resistances, whereas there is a dose-response relationship between training intensity and muscle strength and endurance changes. Therefore, using heavy loads during explosive resistance training is the most effective strategy to achieve combined improvements in muscle strength, power, and endurance.