ASSOCIATION BETWEEN CORE MUSCLES ACTIVATION AND THE 400-METER OVERGROUND SPRINTING VELOCITY IN WHEELCHAIR RACERS

Abstract

Objective: To measure the activity of the core muscles and the middle trapezius in T54 class wheelchair racers during full-effort over ground sprinting and to determine its association with propulsion velocity. Material and Method: Eightmale international wheelchair racershaving normal upper limband partial to normaltrunk function(T54 class athletes) propelled their racing wheelchairs on 400-m competition trackwith maximal effort. Electromyography(EMG)of the rectus abdominis (RA), iliocostalis lumborum (IL), longissimus thoracis (LT) and middle trapezius (MT) were recorded at each 100-m reach using a wireless surface EMG recorder. Percentage of maximal voluntary contraction (%MVC)was measuredand correlated with propulsion velocity. Results:Median %MVC of RA, IL, LT and MT were 54.2, 43.9, 30.6 and 35.6% respectively. Positive associationto propulsion velocity was found in RA (p = 0.04, r = 0.73). Negative association to propulsion velocity was also found in MT (p = 0.03, r = -0.77). Conclusion: Abdominal function wasactivated most andassociated with propulsion velocity in male T54 class wheelchair racers. In addition, optimizing scapularretraction may benefit propulsionvelocity.