Enhancing Jump Performance Through Blood Flow Restriction Squat Exercise: A Muscle Synergy Analysis Using Wavelet Packet Transformation

To explore neuromuscular control during blood flow restriction (BFR) squat exercise using wavelet packet transform (WPT) combined with non-negative matrix factorization (NMF). Fifteen resistance-trained males completed four sets of squats at 40% arterial occlusion pressure. Countermovement jump (CMJ) height and reactive strength index modified (RSImod) alongside surface electromyographic activity from eight lower-limb muscles were assessed before after the exercise. CMJ height and RSImod significantly increased post-exercise (P < 0.001, Cohen's d = 0.45 and 0.34, respectively). Four muscle synergy modules were consistently identified, though primary muscle contributions shifted across movement phases. The tibialis anterior (TA) was the primary contributor in Synergy1, while the gastrocnemius lateralis (GL) dominated Synergy 2, accompanied by a significant increase in gluteus maximus (GM) weight (P = 0.032). In Synergy 3, the rectus femoris (RF), vastus lateralis (VL), and vastus medialis (VM) were predominant, with significant changes in GM and VM muscle weights (P = 0.013, 0.039). Synergy 4 was characterized by contributions from the semitendinosus (ST), biceps femoris (BF), and GM, with a significant increase in VL muscle weight (P = 0.024). WPT-NMF analysis revealed distinct time-frequency synergy modules in CMJ movements before and after BFR squat exercise. Significant changes in activation weights were observed within the 0-250 Hz range (P < 0.05). BFR squat exercise acutely enhances countermovement jump performance by refining muscle synergy and neuromuscular activation patterns, providing novel insights into neuromuscular control strategies.