Biomechanical Evaluation of Time as a Golden Measure in the Assessment of Change of Direction Speed Performance

Change of direction speed is globally assessed through temporal measurements. The underlying biomechanical mechanisms affecting Change of direction speed performance, however, could not be fully understood using performance duration. A more precise biomechanical analysis of change of direction speed performance in different phases of movement, including the deceleration, turning maneuver and reacceleration could cast a light on the importance of each phase during movement. This study investigated a new approach to Change of direction speed drill analyses using three factors of the radius of curvature, accuracy and speed. Twenty-four collegiate athletes (Age: ۲۱.۶۷±۲.۲۹years, Height: ۱.۷۹±۰.۰۷m, body mass: ۷۱.۳۸±۳.۱۲Kg) performed ۶ trials of ۵-۰-۵ Change of direction speed test with both dominant (n=۳) and non-dominant (n=۳) legs at the turning point. Paired sample T-test was run to determine the differences between biomechanical characteristics of the center of mass, such as radius of curvature (Rc), deviation, length and speed, as well as the performance time in both dominant and non-dominant legs. Data acquisition took place using ۶ optoelectronic cameras (Vicon motion capture system – ۲۴۰Hz). Outcomes indicated that the time difference between dominant and non-dominant leg performances was negligible; however, measurements of distances travelled and the associated speeds were significantly higher with non-dominant legs (p≤۰.۰۱). Rc and deviation were also higher in non-dominant legs (p≤۰.۰۳). It was shown that when the Change of direction speed was approached using the non-dominant leg, athletes performed the test with higher velocities and utilized more muscular engagements to compensate deficits in their performance. Measurements of time for drill duration however, failed to reveal such performance characteristics.  

کلیدواژه ها:

Radius of curvature ، Accuracy ، Deviation ، Execution time ، ۵-۰-۵ test