At return to play following hamstring injury the majority of professional football players have residual isokinetic deficits

Abstract

BackgroundThere is an ongoing debate regarding the optimal criteria for return to sport after an acute hamstring injury. Less than 10% isokinetic strength deficit is generally recommended but this has never been documented in professional football players after rehabilitation. Our aim was to evaluate isokinetic measurements in MRI-positive hamstring injuries.MethodsIsokinetic measurements of professional football players were obtained after completing a standardised rehabilitation programme. An isokinetic strength deficit of more than 10% compared with the contralateral site was considered abnormal. Reinjuries within 2 months were recorded.Results52 players had a complete set of isokinetic testing before clinical discharge. There were 27 (52%) grade 1 and 25 (48%) grade 2 injuries. 35 of 52 players (67%) had at least one of the three hamstring-related isokinetic parameters that display a deficit of more than 10%. The percentage of players with 10% deficit for hamstring concentric 60°/s, 300°/s and hamstring eccentric was respectively 39%, 29% and 28%. There was no significant difference of mean isokinetic peak torques and 10% isokinetic deficits in players without reinjury (N=46) compared with players with reinjury (N=6).ConclusionsWhen compared with the uninjured leg, 67% of the clinically recovered hamstring injuries showed at least one hamstring isokinetic testing deficit of more than 10%. Normalisation of isokinetic strength seems not to be a necessary result of the successful completion of a football-specific rehabilitation programme. The possible association between isokinetic strength deficit and increased reinjury risk remains unknown.

Hamstring strength and flexibility after hamstring strain injury: a systematic review and meta-analysis

“…A total of 12 studies used clinical criteria,26 28 33 34 36 37 42 48 66–69 10 used MRI,26 28 29 33 34 62 65 67–69 5 had medical or health practitioner diagnosis,39 41 43 48 7 used a questionnaire or self-report,40 46 47 49 58 63 71 2 used ultrasound36 37 and 2 had unclear methods of diagnosis 45 70. Description of severity of injury varied significantly between studies, with the most common being time to return to play26 28 29 40–43 48 49 63 67 and grade (I–III) of injury 29 31 33 39 62 66 68 69 70. Description of time from injury to testing varied significantly between studies (range, 2–690 days).…”

“…Concentric strength was measured isokinetically at 60°,29 40 48 61–63 66 67 71 180°29 40 61 71 and 300°/s 39 40 62 71. A statistically significant small effect for lower concentric strength at 60°/s was found in previously injured legs (effect size −0.33; 95% CI −0.53 to −0.13; I 2 0%), but no significant effects were found at 180° or 300°/s (figure 2).…”

A comprehensive strength testing protocol offers no clinical value in predicting risk of hamstring injury: a prospective cohort study of 413 professional football players

“…Both these studies incorporated a structured criteria-based rehabilitation programme, including a large number of QSL players. The first randomised controlled trial reported a low re-injury rate of 6%23 compared with other football leagues 42. A reduced risk in previously injured players has been reported before43 due to the effect of successful intervention programmes.…”

Intramuscular tendon involvement on MRI has limited value for predicting time to return to play following acute hamstring injury

“…Time to RTP was defined as the number of days from injury to completion of a six-stage criteria-based rehabilitation programme, including three sport-specific training phases 15. Participants progressed from one phase to the next based on predefined clinical progression criteria, while the treating physiotherapist remained blinded to MRI results.…”