Research

Hormonal

Low-load resistance training (50% 1RM) produces greater acute muscle swelling (cellular hydration) than high-load resistance training (85% 1RM) when volume load is equated, primarily due to increased time under tension and training density.

If your goal is to maximize the 'pump' (acute muscle swelling) in a single workout, use lighter weights (around 50% of your max) and perform more reps until you can't do another one. This creates more time under tension and metabolic stress than heavy lifting, which may support muscle growth mechanisms, even though the total weight moved is the same.

ModerateQualifiesMEDIUM confidence
These results suggest that LL training promotes superior post-session increases in muscle thickness, indicating that RT protocols with longer times under tension and densities are beneficial when the goal is to promote acute cell swelling.
Gabriel Incerpi Agentilho et al. · International journal of exercise science · 2023

Why this rating

Small sample size (n=8), short-term acute design, and lack of statistical significance between conditions despite effect size favoring LL.

Source

Low-Load x High-Load Resistance Exercise: Greater Cell Swelling After a Training Session

Gabriel Incerpi Agentilho et al. · International journal of exercise science · 2023

DOI 10.70252/uiyf2129

crossover · n=8Cited 5×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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