Objectives Exercise training during the acute phase of burns is difficult to implement but offers. potential benefits. This multicenter trial explored the effects of an exercise program on. muscular changes and quality of life during burn center stay. Methods Fifty-seven adults with burns ranging between 10% and 70% TBSA were allocated to receive. either standard of care (n = 29), or additionally exercise (n = 28), consisting of resistance. and aerobic training, commenced as early as possible according to safety criteria. Muscle wasting (primary outcome), quantified by ultrasound-derived quadriceps. muscle layer thickness (QMLT) and rectus femoris cross-sectional area (RF-CSA), muscle strength and quality of life (Burn Specific Health Scale-Brief (BSHS-B) and EQ-5D-5 L) were assessed at baseline, four and eight weeks later, or hospital discharge. Mixed models were used to analyze between-group changes over time with covariates. of interest added in stepwise forward modelling. Results The addition of exercise training to standard of care induced significant improvements. in QMLT, RF-CSA, muscle strength and the BSHS-B subscale hand function (ßcoefficient. 0.055 cm/week of QMLT, p = 0.005). No added benefit was observed for other. quality-of-life measures. Conclusions Exercise training, administered during the acute phase of burns, reduced muscle. wasting, and improved muscle strength throughout burn center stay.