Mj. Price et Ig. Campbell, Thermoregulatory and physiological responses of wheelchair athletes to prolonged arm crank and wheelchair exercise, INT J SP M, 20(7), 1999, pp. 457-463
Seven wheelchair athletes participated in this study. On separate occasions
all athletes performed 60 min of arm crank ergometry and wheelchair ergome
try at 60% of the ergometer specific (V)over dotO(2)peak in cool conditions
(21.5 +/- 1.3 degrees C; 54.2 +/- 6.3% relative humidity, 21.2 +/- 1.9 deg
rees C; 55.5 +/- 11.9% relative humidity, respectively). The order of testi
ng was randomised. Aural and skin temperatures were continually measured th
roughout the 60 min test. Expired air was collected at 5, 15, 30, 45, and 6
0 min during the exercise period. Oxygen consumption was similar for both t
rials (1.09 +/- 0.21 and 1.16 +/- 0.33 I x min(-1), for the ACE and WCE tri
als, respectively). Heat storage was calculated at these time-points. Aural
temperature was elevated from rest between 25 to 45 min of wheelchair ergo
metry (0.5 +/- 0.3 degrees C; P < 0.05) when compared to between 20 min of
exercise and 5 min of recovery (0.6 +/- 0.3 degrees C; P < 0.05) during the
arm crank ergometry trial. On the cessation of arm crank ergometry, heat s
torage was elevated above values observed at 5 min of exercise (P < 0.05).
On the cessation of wheelchair ergometry, heat storage was not elevated abo
ve values at 5 minutes of exercise. Upper arm skin temperature was cooler d
uring wheelchair ergometry when compared to arm crank ergometry (P < 0.05).
All other skin temperature responses were similar during both exercise mod
es. The efficiency of arm crank ergometry was greater than wheelchair ergom
etry throughout the exercise period (18.5 +/- 3.5% and 8.9 +/- 3.7% at 60 m
inutes of exercise, respectively; P < 0.05). The results of this study sugg
est that although ACE demonstrates greater efficiency than WCE prolonged ar
m crank ergometry elicited greater thermal and physiological strain when co
mpared with prolonged wheelchair ergometry. The lower thermal strain during
WCE was suggested to be related to the propulsion biomechanics which may r
esult in some degree of local cooling, and consequently heat dissipation, w
hen compared to ACE. Due to the greater thermal strain during arm crank erg
ometry, it is recommended that for studies examining the exercise responses
of wheelchair users wheelchair ergometry should be employed.