Differential motor unit firing rate and hypertrophic adaptations of the vastus lateralis despite similar strength increases following high-load versus combined high- and low-load resistance training i
3 hours ago
- #motor unit
- #resistance training
- #muscle hypertrophy
- Both high-load (H) and combined high- and low-load (H + L) resistance training resulted in similar increases in strength (1-RM and MVC) over six weeks.
- The H + L group showed significantly greater muscle hypertrophy (21% increase in mCSA) compared to the H group (4% increase).
- Motor unit adaptations differed: H + L training led to hypertrophy in higher-threshold MUs (RTs ≥ 20% MVC), decreased firing rates in those MUs, and lower normalized EMG amplitude, while H training increased firing rates in lower-threshold MUs without changes in MU size or EMG.
- Early strength gains are not necessarily driven by muscle hypertrophy, but motor unit behavior changes are sensitive to training specificity or morphological adaptations.