EFFECTIVENESS OF POWER TRAINING COMPARED TO STRENGTH TRAINING IN OLDER ADULTS: A SYSTEMATIC REVIEW AND META-ANALYSIS

M. el Hadouchi^1,2, H. Kiers^2,1, R. de Vries¹, C. Veenhof^3,4, J. van Dieën¹

¹Vrije Universiteit Amsterdam, Department of Human Movement Sciences, Amsterdam, Netherlands, ²University of Applied Sciences Utrecht, Institute for Human Movement Studies, Utrecht, Netherlands, ³University of Applied Sciences Utrecht, Research Group Innovation of Human Movement Care, Utrecht, Netherlands, ⁴University Medical Center Utrecht, Department of Rehabilitation, Physical Therapy Science and Sport, Utrecht, Netherlands

Background: Aging is associated with a decrease in both muscle strength (the ability to produce large muscle force) and muscle power (the ability to produce large muscle force at high contraction velocity). Research suggests that the annual decline in muscle power is larger than that of muscle strength, and that muscle power is a more critical determinant of physical functioning in older adults. Therefore, signifying the potential importance of emphasizing muscle power in the training and rehabilitation of older adults instead of focusing on muscle strength.

Purpose: The objective of the study was to systematically review the literature on the effects of power training compared to strength training in older adults using tests categorized within the function, activity, and participation domain of the International Classification of Functioning, Disability, and Health (ICF). Our goal was to differentiate between constructs of muscle power (function), two groups of activity-based tests under controlled conditions (activity): generic tests and tests with emphasis on movement speed), and physical activity in daily life (participation) in preparation of the development a standardized test protocol to measure the effects of power training in older adults.

Methods: A systematic search for randomized clinical trials comparing effects of power training to strength training in older adults was performed in PubMed, Embase, Ebsco/CINAHL, Ebsco/SPORTDiscus, Wiley/Cochrane Library and Scopus. Risk of bias was assessed using the Cochrane Collaboration Tool. Standardized mean difference (SMD) and 95% confidence intervals (CI) were calculated for outcomes separately using a random effects model. The quality of evidence was evaluated using the GRADEpro Guideline Development Tool.

Results: Fifteen trials and 583 participants were included in the meta-analysis. Seven of the 15 trials were considered to have low risk of bias while the remaining studies were scored as being unclear or having high risk of bias. Results indicated a statistically significant benefit of power training on all reported outcomes (muscle power SMD: 0.99, 95% CI: 0.54 to 1.44, p<0.001; generic activity-based tests SMD: 0.37, 95% CI 0.06 to 0.68; p=0.02; activity-based tests emphasizing movement speed SMD: 0.43, 95% CI 0.23 to 0.62, p<0.001). None of the included studies used physical activity level in daily life as an outcome. The quality of evidence was rated as being moderate to high.

Conclusions: Power training offers more potential for improving muscle power and performance on activity tests in older adults than strength training. Future research should assess training parameters used in power training interventions for older adults. In addition, the validity, reliability, and responsiveness of the tests used measure the effect of power training must be evaluated to establish a standardized test protocol. This protocol should also include measurements of physical activity in daily life.

Implications: These results contribute to a better understanding of the role of muscle power and highlight the capacity for power training interventions to improve and maintain physical performance and physical functioning in older adults, positively contributing to their ability to live independent lives.

Funding acknowledgements: This work was supported by the Dutch Research Council (NWO 2017/BOO/00279639).

Keywords:
Muscle power
Power training
Strength training

Topics:
Older people
Health promotion & wellbeing/healthy ageing/physical activity
Musculoskeletal

Did this work require ethics approval? No

Reason: The Medical Ethical Review Committee at the University of Applied Sciences Utrecht advised us that ethics approval was not required because the present study is a systematic review.