Abstract
Background: Greater knee flexion angles have been reported to facilitate a more effective attenuation strategy for the impact forces experienced during landing. This study sought to analyze the correlation between knee flexion angles and electromyography of the lower extremity muscles during landing from broad jump.
Methods: Eight male and 9 female healthy recreational athletes (age: 26.00 +/- 3.55 years; height: 1.67 +/- 0.05 m; weight: 67.05 +/- 10.66 kg) participated in this study. Participants performed 4 trials of broad jump. Peak knee flexion angles and electromyography of gluteus maximus, quadriceps, hamstring were evaluated during the landing phase. Pearson (r) correlation was performed to determine the relationship between the knee flexion angles and lower extremity muscle activation. Also, regression analysis was conducted to determine the predictors of the knee flexion angle.
Results: A significant strong negative correlation was found between gluteus maximus and peak knee flexion angles (r = -0.64, p = 0.003); whereas quadriceps exhibited a significant moderate negative correlation with peak knee flexion angles during landing from broad jump (r = -0.45, p = 0.03). Regression analysis revealed that gluteus maximus was the only significant predictor for knee flexion angle (R-2 = 0.410, p = 0.006) (Knee flexion = 146.09 + (-0.92 * Glut max)).
Conclusion: The gluteus maximus accounted for approximately 41% of the variation in knee flexion angles. Greater knee flexion angles (soft landing technique) were correlated with decreased activation of gluteus maximus and quadriceps muscles. Soft landing technique may assist athletes in dissipating the impact forces experienced during landing.