(English) Episode 107-The Science of "The Pump" - How Load, Reps and Time Under Tension Drive Muscle Cell Swelling

This research investigated the acute effects of low-load (LL) versus high-load (HL) resistance training on muscle cell swelling and related physiological responses in experienced male lifters. The study compared changes in elbow flexor muscle thickness, arm circumference, and blood lactate concentration following volume-equated workouts. While both LL and HL protocols significantly increased muscle thickness and lactate, the LL protocol demonstrated a greater magnitude of increase in muscle thickness and lactate, along with higher total repetitions, time under tension, and training density. These findings suggest that LL training, which promotes longer durations of muscle engagement and higher training density, is more effective for acutely inducing cell swelling, a factor believed to contribute to muscle growth. The researchers acknowledge limitations, including a small sample size and short-term design, which may limit the generalizability of the results to other populations or long-term adaptations.(Agentilho GI, DE Lucena EGP, Teixeira LFM, Boas VV, Ribeiro IC, Barroso R, et al. Low-load x high-load resistance exercise: Greater cell swelling after a training session. Int J Exerc Sci [Internet]. 2023;16(3):513–24. Available from: http://dx.doi.org/10.70252/UIYF2129)