Comparison the Timming of Lower Limb Muscle Activity during Cutting Manuvre between Athletes and Individuals with Anterior Cruciate Ligament Reconstruction History

Anterior cruciate ligament rupture is very common in athletes (1). Dysfunction of the musculoskeletal system leads to joint instability in various motor maneuvers, resulting in the introduction of abnormal forces into the anterior cruciate ligament (1). The cutting maneuver is one of the most common movements in various sports (3). During the descent from a height, the contraction of the hamstring muscle causes the tibia to pull back and reduce the amount of shear force applied to the anterior cruciate ligament. In contrast, the quadriceps muscle causes the anterior tibia to move over the femur and apply shear to the with anterior cruciate ligament (ACL) (4, 5). In some simulated models, the posterior leg muscles have been introduced as knee stabilizers (5).Usually, the average activity of quadriceps muscles in women is higher than in men (6) and the ratio of hamstring to quadriceps muscle activity in the stop stage of lateral shear maneuver is lower than the lateral movement stage (7). On the other hand, when walking, the timing of hamstring activity before the foot hits the ground is different between men and women (8). Due to the fact that hamstring muscle activity reduces the shear force in the knee joint, the relative decrease in hamstring muscle activity in women is one of the reasons for the higher risk of ACL injury in women than men (8). It is clinically important to evaluate the activity and timing of muscles in various sports movements, including lateral incision (9,10). Because in the cutting manuvre movement, the knee of the support foot is placed in the position of the valgus and this movement is one of the mechanisms of anterior cruciate ligament injury, there is very little information about the function of the knee muscles during this maneuver in athletes (9, 10). One of the limitations of previous research is that researchers often examine the intensity of muscle activity in this movement and no information is available on the coordination and timing of knee muscle activity. The interaction between knee ligament injury and poor muscle function has not yet been well understood. The aim of this study was to evaluate the activity of lower limb muscle activity in people with a history of anterior cruciate ligament reconstruction compared to healthy individuals during cutting maneuvers. 

10 healthy male soccer players participated as a control group and 10 soccer players with a history of anterior cruciate ligament reconstruction participated as an experimental group in this study. The experimental group underwent anterior cruciate ligament reconstruction using the technique of two Gracilis-semi- tendinous bundles. Electromyographic activity of tibialis anterior, medial gastrocnemius, lateral gastrocnemius, vastus medialis, vastus lateralis, semitendinosus, and biceps femoris with BTS Free EMG 300 device was recorded during cutting maneuvers. Before performing the main tests and recording the data, the subjects were first instructed to run at a speed of 2.5 m / s and perform a cutting maneuver. To perform a cutting maneuver, subjects ran a 5-meter path and then cut the path at a 45-degree angle to the side (left or right). Electromyographic signals with a frequency of 2500 Hz and a bandwidth of 1250 Hz were recorded in computer memory. Later, with a bandwidth filter, signals above 500 Hz and below 10 Hz were removed. A 50 Hz notch filter was also used to remove electrical device signals. The device GAIN was considered equal to 1250. The linear envelope technique was used in the EMG Graphing software environment to obtain the time to start muscle activity. This means that in the Linear envelop diagram, a point of 10% relative to the signal peak of each activity was considered as the beginning of muscle activity. Simultaneously with the recording of electromyographic signals, the kinematic variables of the lower extremities were recorded using the Vicon motion analysis system with 4 T-series cameras and a sampling frequency of 200 Hz. Plug-in-gait marking model was used to track the lower limb and determine the moment of heel contact with the ground (HC) and the moment of toe separation from the ground (TO). Before using this device, the cameras were calibrated using a space of 3 meters long /0 0.9 meters wide × 2 meters high. Camera system data recording and electromyography were simultaneous. For data analysis, first, the Shapiro-Wilk test was used to evaluate the normality of data distribution. All data had a normal distribution. Then, multivariate analysis of variance was used to compare the research variables between groups. Statistical analysis was performed using SPSS-23 software and p <0.05 was considered as the significance level.

The activity onset of tibialis anterior, medial and lateral gastrocnemius muscles was earlier in the experimental group than the control group; (p<0.05). Also, the time to reach the peak of tibialis anterior and medial gastrocnemius major muscle activity in the experimental group was earlier than the healthy group (p≥0.05).

The results of the present study showed that in cutting maneuver motion, the moment of onset of tibialis anterior muscle activity in patients with ACL injury was earlier than in healthy individuals. This muscle plays an important role in dorsiflexion and supination of the foot (13, 14). The tibialis anterior plays an important role in dorsiflexion and supination of the foot. Researchers believe that the tibialis anterior muscle is one of the stabilizers of the ankle joint at the moment of the heel's initial contact with the ground when walking and running. Researchers have also shown that the tibialis anterior plays a role in stabilizing the ankle joint in the stance phase of cutting maneuvers (13, 14). This muscle helps maintain the stability of the knee by maintaining tibial stability. (13). Some researchers believe that this muscle stabilizes the ankle joint in the phase of the initial contact of the foot with the ground (19, 20). Changes in the timing and magnitude of muscle activity are considered as a compensatory mechanism in people with ACL rupture (20,21). Early-onset of gastrocnemius muscle activity in people with ACL rupture compared to healthy individuals can be a protective mechanism to maintain knee stability (22). The earlier activity of the gastrocnemius muscles in people with anterior cruciate ligament injury compared to healthy people can be explained by the fact that it is a protective mechanism to maintain the stability and strength of the knee. Muscular responses and the mechanism of joint mechanical behavior are closely related to the time to reach maximum muscle activity (22). These muscular responses may be related to muscle function in maintaining knee joint stability before, during, and after movement. In fact, due to the rupture of the ACL, the joint position and the sense of movement are disturbed and the movement pattern may change. Anterior cruciate ligament reconstruction is associated with changes in lower limb muscle function in terms of onset time. It seems that after the surgery, a new kind of muscular adaptation develops. Further investigation is needed to determine the association between this compatibility and the risk of osteoarthritis or re-rupture. Injury to a joint in the body causes a change in the activity of the muscles around the joint; ACL injury also affects the function of the quadriceps, hamstrings, and twin muscles of the knee joint (18). Evidence suggests that ACL injury affects twin muscle function and strategies (12. This research also has certain limitations. These limitations are that the research results are based on male subjects and due to individual differences between men and women in anatomical and biomechanical characteristics, the generalization of these results to the whole male and female community will be difficult. It seems that differences in size and body size and Q angle of women may show different results.