The effect of acute low-load resistance exercise with the addition of blood flow occlusion on muscle function in boys and men

• Published in: European journal of applied physiology Vol. 121; no. 8; pp. 2177 - 2185
• Main Authors: Bax, Alyssa M., Amiaka, Chimerem O., Falk, Bareket, Gabriel, David A., Tokuno, Craig D.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.08.2021; Springer Nature B.V
• Subjects: Biomedical and Life Sciences; Biomedicine; Blood flow; Children; Children & youth; Contraction; Electromyography; Exercise; Force; Health sciences; Human Physiology; Load; Motor units; Muscle function; Occlusion; Occupational Medicine/Industrial Medicine; Original Article; Physical fitness; Physical training; Physiology; Sports Medicine; Strength training; Wrist; Electromyography; Children; Blood flow occlusion; Strength; Resistance exercise
• ISSN: 1439-6319; 1439-6327
• DOI: 10.1007/s00421-021-04687-4

Purpose In adults, low-load resistance training with blood flow occlusion (BFO) mimics strength increases that occur from high-load training, without the need to experience high mechanical stress. In view of child–adult differences in exercise responses, this study examined whether BFO during exercise elicits differential changes in maximal voluntary contraction (MVC) and electromyographical (EMG) activity in children and adults. Methods Sixteen men (24.4 ± 2.5 years) and 14 boys (10.7 ± 2.0 years) performed low-load resistance exercise (25 repetitions at 35% MVC) of the wrist flexors with and without BFO. MVC wrist flexor force and EMG activity of the flexor carpi radialis (FCR) were obtained at the beginning and end of the exercise. Results Both groups demonstrated a larger decrease in MVC force following BFO (− 18.6 ± 12.5%) than the control (without BFO) condition (− 6.2 ± 15.0%; p  < 0.001). Whereas the men’s EMG amplitude increased 16.3 ± 20.5% ( p  = 0.005) during BFO, the boys’ EMG amplitude did not change over time or between conditions. In both groups, the mean power frequency (MPF) of the EMG signal decreased more during BFO (− 20.1 ± 9.6%; p  < 0.001) than the control condition (− 5.6 ± 9.7%; p  = 0.002). Conclusions Low-load exercise with BFO resulted in similar neuromuscular responses between boys and men, except for an observed increase in the EMG amplitude in men but not boys. While this result might suggest that men relied on a greater activation of higher-threshold motor units during BFO, it does not explain why there were similar decreases in MPF between groups. Therefore, it remains unclear whether the effectiveness of BFO training is similar for children and adults.