HYPOTHESIS: The addition of WR worn on the lower legs during an on-field warm-up would lead to decreases in relatively high-intensity external TL metrics, such as distance covered >6.11 m∙s-1 and acceleration and deceleration >/<3 m∙s-2 and increases in internal TL during the warm-up, yet would have little effect on the subsequent training session when WR was removed.

STUDY DESIGN: Matched-pair randomized design.

LEVEL OF EVIDENCE: Level 3.

METHODS: A total of 28 soccer players were allocated to either a WR training (WRT = 14) or unloaded (control [CON] = 14) group. Both groups performed the same warm-up and on-field training for 8 weeks, with the WRT group wearing 200 g to 600 g loads on their lower leg during the warm-up. External TL was measured via global positioning system data and internal TL was assessed using session rating of perceived exertion (sRPE × time per session).

RESULTS: No statistically significant between-group differences (P ≥ 0.05) were identified for any TL measurement during either warm-ups or training sessions. Lower leg WR resulted in trivial to moderate effects for all external TL metrics (-16.9% to 2.40%; d = -0.61 to 0.14) and sRPE (-0.33%; d = -0.03) during the warm-up and trivial to small effects on all external TL metrics (-8.95% to -0.36%; d = -0.45 to -0.30) and sRPE (3.39%; d = 0.33) during training sessions.

CONCLUSION: Warming up with lower leg WR negatively affects neither the quality and quantity of the warm-up nor the subsequent training session once WR is removed.