Recovery

What It Is

The time you leave before training the same muscles again.

Why It Matters

The 48-hour advice in exercise guidelines traces to short-term studies of muscle made to contract by electrical stimulation, in rats and in people, rather than to trials that compared training schedules over months.¹ Small randomized trials have since made that comparison. In one, young men lifting on three consecutive days a week gained strength and lean mass that could not be told apart from the gains of men running the same program on alternate days;¹ in another, trained young men who repeated each routine after 24 hours rather than 72 gained strength and lost fat much as the 72-hour group did.²

Taken together, the evidence suggests that waiting 48 hours may make little to no difference to the strength and muscle you build, but the trials were small and studied only young men, so neither can rule out a real advantage for either schedule.^1,2 Some studies of single workouts point to 48 hours or more for strength to come back fully,¹ yet how fast you recover from one session is a different question from how much you gain over months. Jump height, the one measure of power, was tested only in the shortest trial and gave no clear answer,² and no trial isolating the interval has studied women or adults over 60.

So plan your sessions around your week and your weekly sets, not around a 48-hour rule: if a session lands the day after one that trained the same muscles, there is no clear reason to move it, as long as your loads and repetitions hold.^1,2 That is not a case for training the same muscles every day, and it is no reason to push through soreness or fatigue that is dragging your sessions down. How many sessions to divide your weekly sets over is a separate question, with its own guidance.

• 1 Yang, Y. et al. (2018). Effects of Consecutive Versus Non-consecutive Days of Resistance Training on Strength, Body Composition, and Red Blood Cells. Frontiers in Physiology. doi.org/10.3389/fphys.2018.00725
• 2 Lopes, C.R. et al. (2023). Effects of resistance training on consecutive and non-consecutive days on hormonal, neuromuscular and morphological responses in recreationally trained men. Revista Brasileira de Cineantropometria & Desempenho Humano. doi.org/10.1590/1980-0037.2023v25e85848