Associations and predictive value of isometric strength, isokinetic strength, and anaerobic power for 100-m freestyle performance in young swimmers

Zied Abbes (Physical Education Department, College of Education, Qatar University)
Rabeh Labbadi (Higher Institute of Sports and Physical Education of Kef, University of Jendouba)
Faten Salhi (Higher Institute of Sports and Physical Education of Kef, University of Jendouba)

Sport, Exercise, and Injury
Vol. 2 No. 1 (2026): Sport, Exercise, and Injury

Background: Multiple physical and physiological factors influence sprint swimming performance; however, the relative contributions of isometric strength, isokinetic strength, and anaerobic power to 100-m freestyle performance in young swimmers remain unclear. Objectives: This study investigated the associations and predictive contributions of physical characteristics, isometric and isokinetic upper-body strength, and anaerobic power to 100-m freestyle swimming performance in young swimmers. Methods: A cross-sectional study was conducted with 21 male swimmers aged 10–13 years, selected purposively. Eligibility criteria included a minimum of three years of structured swimming training, regular participation in 3–5 training sessions per week, and absence of musculoskeletal injuries. Upper-body strength was assessed using isometric and isokinetic dynamometry (60°/s and 180°/s), while anaerobic power was measured using the 30-s Wingate Anaerobic Test. Swimming performance was evaluated using a 100-m freestyle time trial. Pearson correlation and linear regression analyses were performed after verification of regression assumptions. Results: Swimming speed was significantly correlated with isometric elbow flexor strength (r = .49, p < .05), isokinetic flexor strength at 60°/s (r = .41, p < .05), and Wingate peak power (r = .37, p < .05). Simple linear regression analysis identified isometric elbow flexor strength as the strongest predictor of swimming performance (B = 0.005, p = .026, R² = .235), followed by isokinetic flexor strength at 60°/s (B = 0.004, p = .038, R² = .210) and Wingate peak power (B = 0.001, p = .031, R² = .198). No significant associations were observed for isokinetic strength at 180°/s. Conclusions: Upper-body muscular strength, particularly isometric elbow flexor strength, is a significant determinant of 100-m freestyle swimming performance in young swimmers. These findings highlight the importance of maximal force-generating capacity, alongside anaerobic power development, for sprint swimming performance.