Background: The optimisation of this return to athletic activity pass by a better understanding of the behaviour of the muscle involved in knee function.In this study, we focused on the muscular activity of the muscle involved in the flexion of the knee. Preciseley on the relation between the muscular activity of the gastrocnemius and the hamstring among the patient that underwent an anterior cruciate ligament reconstruction with hamstring graft.Objective : The objective of the study is to compare, the muscular activity of the flexor knee muscle in patient that underwent an anterior cruciate ligament reconstruction with hamstring autograft and the individuals that have not undergone surgery.Methods : The participants have been divided into two groups : an healthy group and an experimental group that underwent an anterior cruciate ligament recontruction with hamstring graft. The participants had to performe a strenght test on a isocinetik dynamometer. The activity of the medial gastrocnemius, lateral gastrocnemius, femoral biceps and the semitendinosus were mesured during this test.The muscular activity of the muscle mentioned of the individuals in the first group were compared to the ones in the second group via a statistical analysis. Then, a ratio of the activity of the gastrocnemius muscle on the activity of the hamstring was calculated The results of the experimental group were then compared to the results of the control groupResults : The results showed a significative difference activity of the medial gastrocnemius, the femoral biceps and the semitendinosus muscles : the experimental group results were superior to the control group results However the evaluation of the activity reporting has shown significant differences in the two groupsConclusion : This study has allowed us to show a difference in muscular activity of the gastrocnemius and hamstring muscle between patient that underwent an anterior cruciate ligament reconstruction surgery and the heathy participants. However our approch has not allowed us to identify the relation between a heihtened gastrocnemius activity and a diminished hamstring activity following an anterior cruciate ligament reconstruction with hamstring graft. Quite on the contrary, we observed a higher activity of the two muscle groups. Nevertheless, it seem to be necessary to have a variation in situations during the analysis of the gastrocnemius muscle to fully understans its purpose in the functional activity of the knee of patient that have undergone an anterior cruciate ligament reconstruction.

Today, rupture of the anterior cruciate ligament is the most common heavy injury in athletes, but it can also occur in sedentary subjects. Its treatment, always adapted to the lifestyle, age and will of the patient, often remains surgical. However, despite its frequency and universality, there are still walking disorders following the operation. These disorders sometimes persist for several months, or even several years after surgery. The present study is therefore interested in determining the risk factors linked to walking disorders following reconstruction of the anterior cruciate ligament. The objective of this study is to determine what risk factors associated with walking disorders are after reconstruction of the anterior cruciate ligament by hamstring graft. This study focused on factors that may exist at 3 and 6 months postoperatively. Two populations participated in this study, a healthy population and a population having benefited from reconstruction of the anterior cruciate ligament. The operated test group is divided into two subgroups, one with a postoperative period of 3 months and the second at 6 months. All subjects were subjected to the same protocol, their gait on the treadmill was analyzed and evaluated with an Optogait® analysis system. A univariate analysis was carried out first. Then, a multivariate analysis by adjustment method was carried out in order to eliminate the potential confounding factors. The comparison of the results between the populations in the univariate analysis shows an absence of significant results however there are trends. The statistical results of the multivariate analysis showed interactions in the two subgroups of the operated population.In fact, it turns out that at 3 months there is a tendency to worse gait disorders in subjects with a high BMI reflecting overweight, when an associated surgical procedure has taken place on the meniscus, in subjects over 35 years of age and males. On the other hand, at 6 months, the tendency to worsening is visible only in the strata represented by subjects with a BMI corresponding to overweight, as well as in subjects having benefited from a meniscal suture associated with ACL reconstruction. .The results of the present study show that there are certain factors which tend to increase the risk of these walking disorders after reconstruction of the anterior cruciate ligament by hamstring graft, these factors are different depending on the time postoperative.

Rehabilitation following anterior cruciate ligament reconstruction with hamstring graft allows the patient to regain his functional capacities and to support him in the resumption of sports activities. Rehabilitation also aims to minimize the risk of recurrence, which is why it ensures that the patient's muscular capacities develop properly until they return to sport. Isokinetics helps strengthen and assess the strength of muscle groups in the thigh, but controversy exists as to its use by resistance to the open kinetic chain knee extension that would cause the transplant to distend. The objective of this study is to determine the influence of isokinetic muscle strengthening on the possible laxity of the anterior cruciate ligament and to be able to determine risk factors. The study relates to a population having benefited from anterior cruciate ligament reconstruction with hamstring graft from 3 to 6 months after surgery. Two groups are differentiated, one group exposed to isokinetism during rehabilitation, the other group, named unexposed, undergoes rehabilitation without the use of isokinetism. An anterior knee laxity test is performed 6 months postoperatively using the GNRB® machine for all subjects according to the same protocol. The test results were statistically analyzed to determine a relative risk of transplant distension for each group in the study. Comparison of the results of each group by univariate analysis did not reveal any significant result. Multivariate analysis showed interactions in the two strata of the study. It was argued that the use of isokinetics seems to have no effect on the risk of developing distension for the majority of subjects in the exposed group. A tendency towards transplant protection was perceived for each variable except the age under 25 years (RRa = 1.07). The use of isokinetics does not appear to be a cause of transplant distension in patients undergoing an anterior cruciate ligament reconstruction when this method is introduced 3 months postoperatively.

Anterior Cruciate Ligament (ACL) tear is currently a main issue in all of sports communities. Although the number of ACL injuries in football remains low, it’s consequences on both professional and personal lives remain a major concern of rehabilitation. If practitioners often require more time to bring athletes in the best condition, the fact remains that this concept of time before return to sport is nowadays considered as obsolete. Indeed, the better understanding of the mechanisms of lesion and the strains placed on the graft after reconstruction, allow us to establish a personalized program based on clinical criteria and the patient's objectives. The current scientific literature allows us today to optimize the return to play and performance by the use of neuromotor and neurocognitive approaches, muscle strengthening methods and a preventive program necessary to cover the previous level of the players while taking into account physiological and psychological changes due to ACL reconstruction. Indeed, it is important to have a systemic approach centered on the patient, the sports movement, as close as possible to the field in order to find an optimal function of the knee in interaction with its environment.If there is a risk of reinjury of the ACL, it appears important to be able to identify the risk factors so that the player can return to play in optimal conditions.