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.

Plantar flexors (PF) spasticity is known to poorly correlate with active dorsiflexion (DF) impairment throughout the swing phase of hemiparetic gait. Spastic Cocontraction, instead, stemming from descending pathways, potentially misdirect antagonist PF activity opposing DF during swing. Electromyographic (EMG) recordings, while unable to differentiate between reflex-based and descending origins, may offer valuable insights into this distinction by exploring PF EMG activity after tibial nerve neurotomy (which eliminates PF spasticity). Eleven subjects with hemiparesis walking at comfortable velocity and 11 controls walking at comfortable and slow velocity, underwent kinematic and PF/DF EMG analysis. Five of the hemiparetic subjects underwent tibial neurotomy >1 year prior. We evaluated spasticity at rest (Tardieu scale), maximal ankle dorsiflexion, tibialis anterior agonist recruitment and gastrocnemius medialis and soleus cocontraction coefficients during swing. At slow velocity, controls (0.80±0.12 m/s) moved at a similar pace as hemiparetic subjects (0.73±0.37 m/s, NS). Hemiparetic subjects showed: (i) reduced ankle DF across swing (ii) increased PF cocontraction, including before any DF (iii) higher cocontraction despite absent spasticity in tibial neurotomy subjects (iv) higher tibialis anterior recruitment. Increased PF cocontraction occurs in the absence of spasticity or ankle DF despite higher agonist recruitment. Spastic cocontraction is a major factor limiting active DF at swing, unlike spasticity.

Background: Muscle wasting is a common phenomenon in oncology and appears to be alleviated by exercise training. This study aims to determine the degree of aggressiveness of cancer-induced muscle wasting in two different phenotypic muscles, and whether exercise training can attenuate this muscle dysfunction. Methods: Fifty Sprague-Dawley rats were randomly assigned to four experimental groups, two control groups (sedentary and exercised) and two breast cancer model groups (sedentary and exercised) induced by 1-methyl-1-nitrosoureia (MNU). After 35 weeks of endurance training the animals were sacrificed and the gastrocnemius and soleus muscles were harvested for morphometric analysis. Results: A significant reduction in cross-sectional area (P < 0.05) was found in both muscles of sedentary tumor-bearing animals. Interstitial fibrosis was significantly higher in the gastrocnemius of sedentary tumor-bearing animals (P < 0.05), but not in the soleus. A shift from large to small fibers was observed in the gastrocnemius of sedentary tumor-bearing animals. Long-term exercise training was able to prevent this cancer-related mus-cle dysfunction. Conclusions: The Gastrocnemius muscle showed a very pronounced reduction in cross-sectional area and marked interstitial fibrosis in sedentary animals with tumors. The soleus muscle showed a less pronounced but significant reduction in cross-sectional area, and collagen deposition did not differ between tumor groups. These contrasting results confirm that can-cer-induced muscle wasting can affect specific fiber types, and specific muscles, namely fast glycolytic muscles, and that exercise training can act to improve it.