Background: The Forward Lunge is a representative squash-specific footwork movement involving rapid acceleration, braking, postural stabilization, and return propulsion. This study examined whether pre-competition neuromuscular electrical stimulation (NMES) combined with weighted squats was associated with differences in Forward Lunge performance and neuromuscular control in squash athletes. Methods: Thirty-six male squash athletes were randomly assigned to three groups: Weighted Squats, Fake Stimulation, and Real Stimulation, with 12 participants in each group. After the assigned acute intervention, all participants completed the squash-specific star test. Completion time was recorded using a Microgate Witty photocell timing system, while surface electromyographic (sEMG) signals from 14 right-side muscles were collected using a Delsys Trigno wireless electromyography system. High-speed video was used to identify the Forward Lunge movement cycle, and transistor-transistor logic (TTL) synchronization enabled temporal alignment among timing, video, and sEMG signals. Normalized root mean square (RMS), muscle co-activation index (CI), and non-negative matrix factorization (NMF)-based muscle synergy parameters were calculated. Between-group differences were analyzed using one-way analysis of variance (ANOVA) with Bonferroni post hoc comparisons, and false discovery rate (FDR) correction was applied to secondary neuromuscular outcomes. Results: Star test completion time differed significantly among the three groups (F = 28.65, p < 0.001, *2 = 0.63). The Real Stimulation group showed a shorter completion time (10.35 ± 0.45 s) than the Weighted Squats group (11.80 ± 0.55 s) and Fake Stimulation group (11.55 ± 0.50 s). During the Forward Lunge movement cycle, normalized RMS values of the rectus abdominis (ABS; F = 18.56, p < 0.001, *2 = 0.55) and latissimus dorsi (LD; F = 13.42, p < 0.001, *2 = 0.44) were significantly higher in the Real Stimulation group. The gluteus maximus-biceps femoris (GLM-BF) co-activation index also differed significantly among groups (F = 58.42, p < 0.001, *2 = 0.78), with higher values in the Real Stimulation group. Muscle synergy analysis showed group differences in selected muscle activation weights and temporal activation parameters. Conclusions: In this parallel-group acute intervention study based on post-intervention measurements, real NMES combined with weighted squats was associated with shorter star test completion time and altered neuromuscular control during the Forward Lunge movement cycle. The integrated use of photocell timing, wireless sEMG, high-speed video, and TTL synchronization provided temporally aligned sensor-based evidence for evaluating acute pre-competition activation strategies. However, due to the absence of baseline measurements, the findings should be interpreted as post-intervention between-group differences rather than definitive evidence of individual improvement.
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