Figure 9.

Summary figure: a proposed model for a cellular muscle memory of previous hypertrophy. With 2 months of PoWeR training in the plantaris (see Dungan et al. 2019) and gastrocnemius (type 2a fibres in the current investigation), myonuclear number increases simultaneous with hypertrophy, and miR‐1 levels are lower (measured in the gastrocnemius). Myonuclei are also shorter after PoWeR training in the gastrocnemius. Following 6 months of detraining after PoWeR, muscle fibre size and myonuclear number return to untrained levels in the plantaris and gastrocnemius, miR‐1 levels remain lower (measured in gastrocnemius), and myonuclei are longer (gastrocnemius and plantaris). We hypothesize that lower miR‐1 levels during PoWeR facilitate hypertrophy by promoting pro‐growth gene expression, while persistently lower levels with detraining could allow for more efficient regrowth with retraining.