THE EFFECT OF WRIST RESTRAINTS ON WHEELING BIOMECHANICS

Abstract

High intracarpal pressures created by hyperextension of the wrist during wheelchair propulsion is a suggested cause of median nerve dysfunction at the wrist/hand (Burnham & Steadward, 1994). An injury survey conducted by Burnham, Higgins & Steadward (1994) found that the wrist and hand were the most common sites of injury reported by wheelchair basketball players. The purpose of this study was to assess whether various forms of hand/wrist protection (visco-elastic padded glove, wrist splint, glove and splint) could effectively reduce the hyperextension seen at the wrist during wheelchair propulsion, thus potentially reducing the conditions predisposing to carpal tunnel syndrome. In addition, an evaluation of the various forms of hand/wrist protection and their effects on wheeling mechanics was also undertaken. The wheeling performances of thirteen subjects with prior wheeling experience were recorded using two SVHS videorecorders positioned to obtain a front and side view. Each subject propelled a standard wheelchair basketball chair mounted to a set of wheelchair rollers under four different conditions (no splint, visco-elastic padded glove on the palms, wrist splint, and glove and splint together). Under each of the conditions the subjects wheeled for thirty seconds both at their average speed and at their maximum speed. Reflective markers were placed on the joint centers of the shoulder and elbow, on the styloid processes of the radius and ulna, and on the distal ends of the 2nd and 5th metacarpals of the right limb to facilitate subsequent digitizing. Twelve points surrounding the activity space were filmed prior to testing and later utilized for calibration using the DLT method for three-dimensional coordinate data reconstruction, followed by smoothing of the data using a cubic spline. Three-dimensional joint angular displacement-time histories for the elbow and wrist were determined using the 3D coordinate data and the dot product identity. Data were analyzed using an one way AN OVA followed by Scheffe post hoc comparisons where appropriate. No differences were found to be significant between the conditions for the elbow angle, however significant differences were revealed for the wrist extension and wrist range of motion angles. Both splint conditions (splint, glove &splint) were significantly different from the non-restraint conditions (no splint, glove). The data suggest that the splints significantly reduced the amount of wrist extension as compared to the no restraint conditions. No significant differences were found between the conditions for maximum wheeling speed. Within the limitations of this study, it can be concluded that the wrist restraints significantly reduced wrist extension during wheeling and that the restraints did not significantly affect wheeling mechanics as suggested by the consistent elbow-angle time histories and wheeling speeds. REFERENCES Burnham, R & Steadward, R (1994). Upper extremity peripheral nerve entrapments among wheelchair athletes: prevalence, location, and risk factors. Archives of Physical Medicine and Rehabilitation, 75, 519 524. Burnham, R, Higgins, J. & Steadward, R. (1994). Wheelchair basketball injuries. Palaestra, 10(2), 43-49.