Cardiorespiratory and perceptual responses using handrims of various size in male paraplegics.

Introduction

There have been numerous research efforts quantifying exercise responses and cardiorespiratory fitness levels of persons with lower-limb disabilities. However, no one testing modality has surfaced as an accepted standard. Instrumentation such as arm crank ergometer, wheelchair ergometer, wheelchair roller systems, and wheelchair treadmill have provided some empirical data, but have also complicated the process of comparing physiological responses among investigations.

During the 1970s interest and participation in wheelchair track and roadracing events grew in popularity. By 1980, previous restrictions imposed by the National Wheelchair Athletic Association (NWAA) upon racing wheelchair designs were relaxed, permitting extensive modifications of racing equipment. The question surfaces as to what contribution wheelchair design variables make to improved performance times.

The Study

The purpose of the present investigation was to determine effects of 10 in. (0.25m) and 16 in. (0.41m) wheelchair handrims upon cardiorespiratory and perceived exertion during wheelchair propulsion at selected velocities.

Subjects were 15 asymptomatic male paraplegics with a mean age of 27 years who performed three discontinuous exercise tests (ACE=arm crank ergometer; WERG=wheelchair roller ergometer) and two 1600m performance-based track trials (TRACK) under simulated race conditions.

Results

There were no significant differences in heart rate between the 10 in. and 16 in. handrims during loadless 4 km*[h.sup.-1], weight bearing 4 km*[h.sup.-1], 8 km*[h.sup.-1], or during maximal effort.

Although not statistically significant, submaximal oxygen consumption using the 10 in. handrim was 9% lower than the 16 in. handrim at 4 km*[h.sup.-1]. However, there were significant differences at 8 km*[h.sup.-1]. During wheelchair propulsion, [VO.sub.2] for the 16 in. handrim was 13% higher than the 10 in. handrim.

Likewise, there were no significant differences in expired ventilation at loadless 4 km*[h.sup.-1], weight bearing 4 km*[h.sup.-1], or maximal effort. However, at 8 km*[h.sup.-1], expired ventilation was significantly higher using the 16 in. handrim by 23%.

Similar to previous metabolic variables, there were no significant differences during loadless pushing and weight bearing propulsion at 4 km*[h.sup.-1]. However, like oxygen uptake and expired ventilation, lactate was 56% higher at 8 km*[h.sup.-1] for the 16 in. handrim. Although there were no significant differences during loadless pushing, weight bearing propulsion at 4 km*[h.sup.-1], and maximal effort for central, peripheral, or integrated cues of perceived exertion, there were statistically significant lower differences at 8 km*[h.sup.-1] for the 10 in. handrim.

Like 4 km*[h.sup.-1] and maximal effort there were no significant differences in metabolic variables or performance time during the track performance test using 10 and 16 in. handrims. However, post-exercise fingertip lactates were found to be significantly greater when using larger handrims.

Similar to cardiorespiratory data, RPE ratings did not indicate any statistically significant differences.

Teaching/Coaching Implications

* It appears at normal ambulatory pace, handrim size is of little importance.

* Authors conclude that the 10 in. handrim is more appropriate during continuous recreational or sport activity.

* Proper biomechanical techniques utilized during maximal exercise need to be emphasized.

* Relative to the 1600m performance event, more elite wheelchair subjects are necessary.

* Handrim size may be anatomical and event specific.

Complete Details

Gayle, G.W., Davis, G.M., Pohlman, R.M. & Glaser, R.M. (1990). Cardiorespiratory and perceptual responses to arm crank and wheelchair exercise using various handrims in male paraplegics. Research Quarterly for Exercise and Sport, 61 (3) 224-232.