Background and Objective: Ankle instability is one of the most prevalent injuries among athletes. Biomechanical changes, sensory-motor impairments, and neuromuscular disorders have been reported in individuals with chronic ankle instability. The present study was conducted to compare the electrical activity of selected leg and thigh muscles during performing functional movements in female athletes with and without chronic ankle instability.
Methods: This case-control research was conducted on 40 female athletes in the age range of 18-30 years in two groups, including the case (with ankle instability, n=20) and healthy control (without ankle instability, n=20) groups. The electrical activity of selected leg and thigh muscles was recorded during three functional patterns, i.e., the overhead squat, overhead squat with heel lift, and single-legged squat, by electromyography apparatus. The investigated muscles consisted of the gastrocnemius medialis (GM) muscle, the gastrocnemius lateralis (GL) muscle, the tibialis anterior (TA) muscle, the fibularis longus (FL) muscle, the soleus (SO) muscle, the vastus lateralis (VL) muscle, the vastus mediali (VM) muscle, and the biceps femoris (BF) muscle.
Results: The activity of the VM, VL, BF, and TA muscles in the single-legged squat and the activity of the VM, VL, BF, SO, and TA muscles in the overhead squat showed a statistically significant increase in the case group compared to the control group (P<0.05). The highest difference in the muscle activity of the two groups was observed in the overhead squat with heel lift movement, which in this movement, except for the GL muscle, there was a statistically significant increase among all other muscles (P<0.05).
Conclusion: Functional movements culminate in increasing the electrical activity level of leg and thigh muscles in female athletes with ankle instability.

Background and Objective: Pronated foot is one of the lower extremity deformities, and obesity is considered a major dilemma in modern society. The present study aimed to determine the interactive effect of overweight and pronated foot on the frequency spectrum of lower extremity muscle activity in men during running.
Methods: This quasi-experimental study was conducted on 40 male students aged 21–35 years, who were assigned non-randomly into four groups of 10: Normal weight with normal foot, obese with pronated foot, obese with normal foot, and normal weight with pronated foot. The activity of selected muscles, including the tibialis anterior, medial gastrocnemius, vastus lateralis, vastus medialis, rectus femoris, biceps femoris, semitendinosus, and gluteus medius, was recorded during running using electromyography (EMG).
Results: The frequency spectrum of the electrical activity of the biceps femoris muscle was significantly lower in the “obese with normal foot” group compared to the “normal weight with pronated foot” group (P<0.05). The interactive effect of fatigue and group was not statistically significant.
Conclusion: In the “obese with pronated foot” group, the observed increase in muscle activity may reflect the neuromuscular system's attempt to manage biomechanical loads. Furthermore, individual differences in movement patterns, fitness levels, and compensatory strategies may contribute significantly to variations in muscle activity.

Background and Objective: Obesity is a major public health concern worldwide. Evidence suggests that fatigue can lead to significant alterations in mechanical components among obese individuals compared to their healthy counterparts. The present study aimed to determine the effect of fatigue on the mechanical values of impulse and center of pressure (COP) in obese individuals with pronated feet during a landing maneuver.
Methods: This quasi-experimental study was conducted in Ardabil Province, Iran, on 16 male students with healthy feet and normal body mass indices (BMIs<25) and 15 obese male students (BMI>30) with pronated feet. During the test, mechanical variables were recorded for both groups before and after implementing the fatigue protocol, utilizing a force plate (sampling rate: 1000 Hz) during a landing maneuver.
Results: In the between-group comparison, the mechanical impulse values along the anteroposterior axis were significantly higher in the “healthy feet with normal BMIs” group (34.69±17.9) compared to the “obese with pronated feet” group (9.41±2.07) (P<0.05). In the within-group comparison of “obese students with pronated feet”, no statistically significant differences were found before and after the fatigue protocol during a landing maneuver for the mechanical variables of vertical impulse, anteroposterior impulse, mediolateral impulse, mediolateral COP, and anteroposterior COP.
Conclusion: In the mechanical components of impulse, the “obese with pronated feet” group exhibited a statistically significant decrease compared to the “healthy feet with normal BMIs” group during a landing maneuver; however, the fatigue protocol did not alter the impulse values.