The total mechanical tension accumulated over time is the primary stimulus for skeletal muscle hypertrophy, regardless of the temporal distribution of training sessions.

Study: Equalization of Training Protocols by Time Under Tension Determines the Magnitude of Changes in Strength and Muscular Hypertrophy

When you lift weights, your muscles grow based on how long they’re under strain during a workout—not whether you do many quick reps or fewer slow ones. This study found that as long as the total time your muscles are working is the same, you get the same muscle growth.

Study: Effect of different training frequencies on maximal strength performance and muscle hypertrophy in trained individuals—a within-subject design

Even if you lift weights once a week or three times a week, as long as you do the same total amount of work, your muscles grow the same. This supports the idea that it’s the total effort over time, not how you spread it out, that matters most.

Study: Load-induced human skeletal muscle hypertrophy: Mechanisms, myths, and misconceptions

This study says lifting weights makes muscles grow mainly because of the physical tension they create, not because of sweat, pump, or hormones — and it doesn’t matter if you lift a little every day or a lot once a week, as long as the total tension adds up.

Study: When duration matters: rethinking resistance training load through time under tension

Muscles grow when they're under tension for a long time during exercise, no matter if you do your workouts all at once or spread them out. This study shows that how long your muscles are working matters more than just how heavy the weights are.