Over the last 30+ years, it has become axiomatic that performing aerobic exercise within the same training program as resistance exercise (termed concurrent exercise training) interferes with the hypertrophic adaptations associated with resistance exercise training.

It has been proposed that skeletal muscle shows signs of resistance training (RT)-induced muscle hypertrophy much earlier (i.e., ~3–4 weeks of RT) than previously thought. We determined if early increases in whole muscle cross-sectional area (CSA) during a period of RT were concomitant with edematous muscle swelling and thus not completely attributable to hypertrophy.

Muscle hypertrophy and atrophy occur frequently as a result of mechanical loading or unloading, with implications for clinical, general, and athletic populations.