Validation of Bertec Force Plate Treadmill for Asymmetry Measures

BACKGROUND: The current literature establishes the existence and detrimental impact of high levels of asymmetry in a range of physical capacities in the general population as well as performance athletes. Given the influence of symmetry, there is a need to identify validated ways to measure it. Despite this, no uniform method of quantifying inter-limb differences exists to date. Furthermore, few studies compare bilateral data when limbs act concurrently as a functional system. One possible application of this measure is to measure the impact of an asymmetric training protocol on bilateral force production. Its theoretical applications remain untested in many circumstances, one of which is in support of the concept of whole-body symmetry for the crucial role of injury prevention. PURPOSE: Validation of Bertec split belt Treadmill and Vicon combination for asymmetric force measures during pushups. METHODS: Subjects were instructed to perform as many pushups as possible on the split belt Bertec treadmill. The Vicon camera system was used to track marker position which was placed on the cervical vertebrae 5. Using the vertical trajectory of the marker, we identified and segmented individual pushups using custom MATLAB script. The Bilateral Asymmetry Index was calculated using the mean force produced by the left and right sides independently during each pushup repetition. RESULTS: The number of pushups performed by subjects ranged from 8-52 across 10 subjects. The average BAI across subjects 3.53± 2.52. CONCLUSION: We have validated this methodology to measure interlimb asymmetry. This validated measure is part of an ongoing study analyzing the effect of an asymmetric weightlifting program in bilateral asymmetry force production.