Smartphone-Assessed Single-Leg Deadlift Stability is Associated with Sprint Velocity in Youth Soccer Players: A Cross-Sectional Study

Abstract

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Objectives: To investigate the relationship between core stability and neuromuscular performance (i.e., sprint velocity and change-of-direction speed) among adolescent male football players. Methods: In this cross-sectional study, sixteen high-level male football players were divided into higher and lower core stability groups based on their performance in a partial range single-leg deadlift (SLD) test, assessed using a smartphone application (OCTOcore© app). Neuromuscular performance was assessed with a 30-m maximal sprint test (with 5-m split intervals) and a V-cut test, and these outcomes were correlated with SLD test results. Results: Statistically significant differences were observed between higher and lower core performance groups in the SLD test (p = 0.001) and between SLD non-dominant and 30-m maximal sprint test (p = 0.001–0.005), while no differences were founded between SLD performance and V-cut test (p>0.05). A large correlation was found between non-dominant SLD and 10-m sprint performance (r = 0.765, p = 0.001), while moderate correlations were observed for the 15-, 20-, 25-, and 30-m sprints (r = 0.508–0.562, p = 0.023–0.044). No significant correlations between SLD performance and the V-cut test (p>0.05). Conclusion: Core stability appears to be positively associated with sprint performance (0–30 m) but not with change-of-direction speed, suggesting that it plays a greater role in linear acceleration than in multidirectional tasks.