Effect of genu varum deformity on free moment and loading rate variables during stance phase of running
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Department of sports biomechanics, faculty of physical education and sport sciences, university of mazandaran, babolsar, iran
Free moment (FM) about the vertical axis located at the center of pressure and increased loading rate (LR) in stance phase of running are known as risk factors in lower extremity injuries (stress fractures and osteoarthritis, respectively). Genu varum deformity (GVD) due to structural changes in the medial-lateral direction of the lower extremity could increase the possibility of exerting greater force (in this direction) and FM. In addition, due to functional changes around the knee, the possibility of inefficient muscles loading response in these individuals is increased. Therefore, purpose of this study was to compare FM and LR variables during the stance phase of running in individuals with GVD and normal knee.
It is a semi-experimental study on 24 recreational male athletes with GVD and normal knee in two groups (12 in each group, average age=21.57 years). Medial femoral epicondyle distances in individuals with GVD considered more than 4 cm. Kinetic data related to the FM and vertical ground reaction force variables during stance phase of running were recorded by a force-plate (with a sampling frequency of 1000 Hz). Independent sample t-test at the significant level of p <0.05 was used to compare the variables between two groups.
There were no significant differences between two groups in the mean of the FM, maximum adductor FM, maximum abductor FM and range of FM (p=0.054, p=0.864, p=0.137, p=0.625 respectively). Also There was no significant difference between two groups in the mean of the LR (p=0.092).
It seems that individuals with GVD have normal kinetic factors, such as FM and LR, when they’re acting daily activities without maximal stress, such as jogging and running. probably compensatory mechanisms (such as increased activity of lower limb muscles) in individuals with GVD adjusts the deficiencies caused by imbalance of lower extremity.