Effects of an eight-week high-speed resistance training program on rate of torque development in older adults

Abstract

Background: The aging process frequently entails a reduction in muscle strength, attributed to factors such as neural changes resulting in decreased voluntary muscle activation (1). Despite these challenges, it is crucial to implement strategies aimed at enhancing or, at the very least, mitigating these declines associated with aging. Purpose: This study assessed the impact of an eight-week high-speed resistance training (HSRT) program on rate of torque development (RTD) in independent older adults. Methods: This study included 36 physically independent older adults (age, 68.08 ± 2.93 years). The HSRT program lasted eight weeks, with three sessions per week with 50–60min, each session being comprised of five-six exercises, two-three sets, and six–ten reps/exercise. The intensity gradually increased after each session in accordance with the movement velocity (concentric phase) (>1.3 to 0.75 m/s) representing approximately 20% to 65% of one repetition maximum. Participants executed the exercises rapidly and explosively making all repetitions for each shortening phase (concentric phase) performed as quickly as possible with the lengthening phase of the muscle (eccentric phase) being controlled for 2–3 sec. The velocity of the concentric phase in each exercise was monitored through a BEAST™ sensor (Beast Technologies, Brescia, Italy). Peak RTD and RTD time intervals were measured for knee extension and flexion before and after the eight-week program using an isokinetic dynamometer (Biodex System 3) with three trials at 60º/s. Results: After the intervention, the peak RTD demonstrated significant improvements on extension of the dominant (p<0.001, ES=0.57 [0.31, 0.84]) and non-dominant side (p<0.001, ES=0.59 [0.37, 0.83]), as well as on flexion of the dominant (p=0.001, ES=0.59 [0.26, 0.95]) and non-dominant side (p=0.001, ES=0.55 [0.23, 0.88]). All time intervals between 0 to 30 ms showed significant improvements, namely on extension of the dominant (p<0.001, ES=0.56 [0.27, 0.86]) and non-dominant side (p<0.001, ES=0.53 [0.28, 0.78]), as well as on flexion of the dominant (p<0.001, ES=0.67 [0.31, 1.06]) and non dominant side (p=0.001, ES=0.54 [0.21, 0.89]). Discussion and conclusions: As RTD is recognized as a critical neuromuscular parameter, particularly sensitive to chronic changes in neuromuscular function (2), these findings are clinically significant, suggesting that HSRT can effectively enhance or prevent the decline in the ability to generate muscle strength, both in terms of magnitude and speed, among older adults. Furthermore, these improvements may represent significant benefits for older people’s autonomy, as RTD has been associated with better postural control and balance (3). In conclusion, the findings highlight the potential of the HSRT program to substantially enhance RTD in older adults.