Acute effects of movement-specific warm-up on force production and neuromuscular activation during maximal isometric squat in resistance-trained men: a pilot study

Warm-up is a fundamental preparatory phase for optimizing performance, yet its acute effects may depend on the specificity of the protocol to the target task. This pilot study compared a General, mobility-based Warm-Up (GWU) with a low-intensity, bodyweight Movement-Specific Warm-Up (MSWU) replicating squat biomechanics on maximal isometric force and neuromuscular activation during isometric squat. Eight resistance-trained men (age 23.5 ± 1.2 years; height 182.9 ± 5.9 cm; body mass 84.3 ± 9.1 kg; 1RM back squat 146 ± 19 kg) completed two randomized, counterbalanced sessions. Each session included a standardized preliminary warm-up, baseline maximal isometric high-bar back squat at 90° knee flexion, and either the GWU or the MSWU, followed by a 2-min rest and reassessment. Peak force and surface EMG of vastus medialis (VM), vastus lateralis (VL), rectus femoris (RF), gluteus maximus (GMax), and biceps femoris (BF) were measured. Completion time did not differ between protocols (~6-7 min; p = 0.806). Peak force significantly decreased after the GWU (-3.8%; p = 0.004; d = 1.47) but was maintained following the MSWU (-1.9%; p = 0.138; d = 0.59). Between-protocol differences in peak force were not significant (p = 0.186; d = 0.52). No significant changes were observed in normalized GMax activity or total integrated EMG. These results indicate that, for isometric, task-specific performance, a brief movement-specific warm-up better preserves force-generating capacity than a general mobility routine of similar duration, emphasizing the importance of biomechanical specificity in warm-up design.