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

International Journal of Sports Physiology and Performance, 1–7. Doi.org/10.1123/ijspp.2020-0713


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.

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).

Senior players showed 18% to 26% lower H:Q ratio compared with all younger age groups (P≤0.026). 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=0.048), whereas quadriceps strength increased gradually from U-13 to senior level.

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.

Lasse Ishøi
Lasse Ishøi
Head of Sport and Data Science at Football Club Nordsjælland (a Danish first tier club), and postdoc at Sports Orthopedic Research Center - Copenhagen (SORC-C)

My research interests include sport science, sport physiotherapy, and sport injuries.