Post-match recovery of eccentric knee flexor strength in male professional football players

Abstract

Objectives: This study aimed at verifying the effect of a football match on the eccentric knee flexor strength of male professional players along a 72-h period.

Study design: Quasi-experimental study.

Setting: Football club facilities.

Participants: Fifteen players were assessed in four timepoints: 24 h before, immediately after, 48 h and 72 h after the match.

Main outcome measures: The eccentric knee flexor strength was assessed during the Nordic hamstring exercise execution.

Results: Players presented a significant strength reduction immediately after match (Δ = 12%; p = 0.001; large effect size, d = 1.10), and did not recover their strength capacity within a 48 h-period (Δ = 6%; p = 0.011; moderate effect size, d = 0.57). At 72 h after the match, strength was similar to baseline levels (Δ = 3.5%; p = 0.122; small effect size, d = 0.34). Secondarily, individual response analysis considered a player 'fully recovered' when his strength deficit compared to the baseline measure was lower than the measurement coefficient of variation (i.e., <5%). Only 6 (40%) and 9 (60%) players were 'fully recovered' at 48 h and 72 h after the match, respectively.

Conclusion: Professional football players experienced an immediately post-match drop on the eccentric knee flexor strength, and significant strength deficits persisted for a 48-h period. Some players were not recovered at 72 h after the match.

Keywords: Injury; Nordic hamstring exercise; Prevention; Soccer.