Hamstring and Quadriceps Muscle Strength in Youth to Senior Elite Soccer: A Cross-Sectional Study Including 125 Players

Abstract

Purpose: Increasing age, high quadriceps strength, and low hamstring muscle strength are associated with hamstring strain injury in soccer. The authors investigated the age-related variation in maximal hamstring and quadriceps strength in male elite soccer players from under-13 (U-13) to the senior level. Methods: A total of 125 elite soccer players were included from a Danish professional soccer club and associated youth academy (first tier; U-13, n = 19; U-14, n = 16; U-15, n = 19; U-17, n = 24; U-19, n = 17; and senior, n = 30). Maximal voluntary isometric force was assessed for the hamstrings at 15° knee joint angle and for the quadriceps at 60° knee joint angle (0° = full extension) using an external-fixated handheld dynamometer. Hamstring-to-quadriceps strength (H:Q) ratio and hamstring and quadriceps maximal voluntary isometric force levels were compared across age groups (U-13 to senior). Results: Senior players showed 18% to 26% lower H:Q ratio compared with all younger age groups (P ≤ .026). Specific H:Q ratios (mean [95% confidence interval]) were as follows: senior, 0.45 (0.42–0.48); U-19, 0.61 (0.55–0.66); U-17, 0.56 (0.51–0.60); U-15, 0.59 (0.54–0.64); U-14, 0.54 (0.50–0.59); and U-13, 0.57 (0.51–0.62). Hamstring strength increased from U-13 to U-19 with a significant drop from U-19 to the senior level (P = .048), whereas quadriceps strength increased gradually from U-13 to senior level. Conclusion: Elite senior soccer players demonstrate lower H:Q ratio compared with youth players, which is driven by lower hamstring strength at the senior level compared with the U-19 level combined with a higher quadriceps strength. This discrepancy in hamstring and quadriceps strength capacity may place senior-level players at increased risk of hamstring muscle strain injuries.

Eccentric Hamstring Strength Imbalance among Football and Soccer Athletes

“…Previous literature indicates that hamstring strength imbalances may contribute to HSI incidence 19,20 . As these athletes age, strength increases and muscle flexibility decreases 33,34 . We demonstrated that imbalances are more prevalent among younger athletes; however, data in young soccer athletes indicate a greater degree of hamstring flexibility, which may be injury protective 33 .…”

“…19,20 As these athletes age, strength increases and muscle flexibility decreases. 33,34 We demonstrated that imbalances are more prevalent among younger athletes; however, data in young soccer athletes indicate a greater degree of hamstring flexibility, which may be injury protective. 33 These findings are consistent with prior reports that increasing age, despite decrease hamstring strength asymmetry with age, and hamstring stiffness are associated with hamstring injury.…”

Biomechanical Comparison Between Double-Row Repair and Soft Tissue Tenodesis for Treatment of Proximal Rectus Femoris Avulsions

“…Although our results showed that suture-bridge repair (SBR) was superior to TR at time zero in terms of the failure load and stiffness, their results suggest the importance of further investigation into how each repair procedure is coordinated with the other quadriceps during the subsequent healing process. Ishoi et al 14 reported that the mean quadriceps force among senior soccer players was 737.3 N. Since this value is much higher than the failure load after these 2 repair techniques, further clinical studies to investigate postoperative quadriceps muscle strength after these 2 repair methods are required.…”

Maximal and Explosive Muscle Strength During Hip Adduction Squeeze and Hip Abduction Press Test Using A Handheld Dynamometer: An Intra- and Inter-tester Reliability Study

“…In elite sport settings there is often a need to efficiently measure athletes' lower body strength in a short time frame, such as during periodic testing. 11,41 This can be achieved by using handheld dynamometers which easily accommodate various testing setups, such as unilateral hip adduction (ICC: 0.93) and abduction (ICC: 0.97). 13 In strong athletes, external fixation may be needed dependent on the tester's upper body strength to obtain valid measures, 15, 18 but this is not always feasible due to time constraints when large cohorts need testing.…”