Effect Of Elastic Band Resistance Training During Simulated Microgravity On Neuromuscular Function

Abstract

Prolonged duration in a weightless environment results in decreased neuromuscular function. In Earth's 1-g environment, resistance exercise helps prevent muscle atrophy and its subsequent attenuations in strength and power. Previous studies have attempted to apply findings of gravity-based research to a microgravity environment. Although it has been shown that the decrease in neuromuscular function from a weightless environment can be attenuated through resistance training in 1-g, studies have not been completely successful utilizing resistance training in a microgravity environment to completely counter these negative neuromuscular changes. To examine the effect of elastic band resistance training in a microgravity-simulated environment on muscle size, strength, power, and muscle activity pre- and post- training. Twenty college-age males were randomly assigned to a training (T) group (n = 13; age = 20.15 ± 1.34years; height = 178.85 ± 8.23 cm; mass = 77.47 ± 8.63 kg) or a control (C) group (n = 7; age = 21.71 ± 1.70 years; height = 174.8 ± 4.56 cm; mass = 73.90 ± 8.70 kg) that refrained from any training during the nine-week period. Kinetic and kinematic variables, as well as electromyography (EMG) of the vastus lateralis (VL), were collected and analyzed before and after the training period in which the T group completed a progressive resistance protocol consisting of six sets often dead lifts utilizing elastic bands while in the custom-made microgravity apparatus. Muscle size was obtained through a DEXA scan, strength was measured by one-repetition maximum (1RM) squat, power was assessed through a countermovement jump (CMJ) at body mass, and muscle activity was determined through EMG of the VL. Squat 1RM strength increased significantly in the T group (103.65 ± 26.94 kg to 115.38 ± 25.43 kg, p < 0.001) as compared to no change in the C group (121.43 ± 30.78 kg to 125.71 ± 21.62 kg). No statistically significant changes were observed in power during the CMJ (4738.61 ± 700.70 W to 4562.59 ± 971.31 W) after training. Changes in muscle size and activity were insignificant. This was the first study to examine the effectiveness of elastic resistance bands in a microgravity training environment. This model was effective in inducing strength gains. Utilizing resistance bands may be a viable exercise countermeasure to combat the negative neuromuscular effects experienced from prolonged exposure to microgravity. With the inefficacy of free weights in microgravity, it is necessary to find an alternative means of resistance training. Elastic resistance band training provides a practical and cost-effective method to increase strength in microgravity. Because this is the first study to utilize elastic resistance bands in a simulated microgravity environment, more research is warranted to determine the optimal training variables such as sets, reps, and rest periods needed to produce the greatest hypertrophy and strength gains. Additionally, future investigations should include this microgravity-simulated exercise protocol during a concurrent period of bed rest. Acknowledgment: This investigation was funded by a North Carolina Space Grant - New Investigations Program Grant.