We report isokinetic results of anterior cruciate ligament reconstruction with patellar tendon or hamstring graft from the literature analysis. The literature was defined from two search “textwords”: Isokinetic and Anterior cruciate ligament reconstruction, and from three databases: Medline, Pascal, and Herasmus. Two independent physicians (Physical Medicine and Rehabilitation) carried out an analysis according to the French National Accreditation and Health Evaluation Agency recommendations. Fifty-three studies were selected: 29 reported isokinetic results after anterior cruciate ligament reconstruction with patellar tendon graft, 15 reported isokinetic results after anterior cruciate ligament reconstruction with hamstring graft, and 9 studies compared the two surgical procedures. After discussing different bias and in reference to prospective randomised and comparative studies, the anterior cruciate ligament reconstruction with patellar tendon graft involves a knee extensors deficit during several months. The hamstring surgical procedure involves a less important knee extensor deficit (from 6 to 19 % against 8 to 21 %). Knee sprain and intra-articular surgery involve a long-lasting knee extensors deficit. Anterior cruciate ligament reconstruction with hamstrings graft involves a knee flexors deficit over several months. The patellar tendon surgical procedure involves a less important knee flexors deficit (from 1 to 15 % against 5 to 17 %). In reference to isokinetic parameters, no difference between the two surgical procedures (patellar tendon graft or hamstring graft) is shown after more than twenty-four post-surgical months.

In this prevalence cohort study, injuries sustained during 15 seasons in a professional soccer team were investigated according to the different soccer seasons, number of matches per season, month the injury occurred, location, severity, playing position and the team’s rank at the end of the French professional championship. Altogether, 903 injuries in 173 professional soccer players were reported. Injury incidence per 1 000 h of exposure during matches and training was 4.7±5. This incidence did not vary significantly between seasons. However, injury incidence increased after the year 2003 and constantly exceeded 4.2. In the same way, after 2002 muscle injury incidence always exceeded 2 per 1 000 h of exposure. Injury incidence peaked during the month of January. Hamstring muscle injury represented the most frequent injury. No difference in injury incidence was found according to the playing position or to the season whether the team participated or not in the European cup. No correlation was found with the team’s rank at the end of the French championship. This study highlighted no significant variation on injury incidence over a 15-season period except for the muscle injury rate in high level soccer players.

Twenty-eight elite soccer players (23 years ± 3.3; 74 kg ±7.5; 178 cm ± 6.5) were tested to find out whether isokinetic parameters could identify sportsmen who had previously suffered from hamstring muscle injury. Eleven players with 15 previous moderate or major hamstring muscle injuries in the preceding 2 years were compared with 17 controls. Strength was measured using a Cybex Norm isokinetic dynamometer on a concentric and eccentric contraction at the angular speed of 60°/s. An ipsilateral concentric Hamstring-to-Quadriceps ratio lower than 0.6 and an eccentric hamstring asymmetry of more than 10% did not enable identification of soccer players with previous hamstring muscle injury. On the other hand, concentric hamstring torque asymmetry of more than 10% identified the uninjured soccer players (probability of 90.1%). A dynamic control ratio(eccentric hamstring-to-concentric quadriceps) lower than 0.6 provided the best predictor of previous hamstring muscle injury (probability of 77.5%). In conclusion, concentric and eccentric isokinetic evaluation of hamstring muscle at the speed of 60°/s renders the search for previous hamstring muscle injury possible by revealing muscle torque asymmetry, which persists despite the resumption of competitive soccer.

Previous studies investigating the ability of isokinetic strength ratios to predict hamstring injuries in soccer players have reported conflicting results. to determine if isokinetic ratios are able to predict hamstring injury occurring during the season in professional soccer players. case-control study; 3. from 2001 to 2011, 350 isokinetic tests were performed in 136 professional soccer players at the beginning of the soccer season. Fifty-seven players suffered hamstring injury during the season that followed the isokinetic tests. These players were compared with the 79 uninjured players. The bilateral concentric ratio (hamstring-to-hamstring), ipsilateral concentric ratio (hamstring-to-quadriceps), and mixed ratio (eccentric/concentric hamstring-to-quadriceps) were studied. The predictive ability of each ratio was established based on the likelihood ratio and post-test probability. the mixed ratio (30 eccentric/240 concentric hamstring-to-quadriceps) <0.8, ipsilateral ratio (180 concentric hamstring-to-quadriceps) <0.47, and bilateral ratio (60 concentric hamstring-to-hamstring) <0.85 were the most predictive of hamstring injury. The ipsilateral ratio <0.47 allowed prediction of the severity of the hamstring injury, and was also influenced by the length of time since administration of the isokinetic tests. isokinetic ratios are useful for predicting the likelihood of hamstring injury in professional soccer players during the competitive season.