Physiological strain unique to field hockey.

Unique requirements of field hockey include dribbling the ball and moving quickly in a semi-crouched posture. First, the net physiological strain due to dribbling was examined. Seven male hockey players completed a 5 min run on the treadmill at 8 km h-1 and 10 km h-1: subjects also ran at these speeds whilst dribbling a hockey ball. Dribbling increased energy expenditure by 15-16 kJ min-1 above that observed in normal running. Heart rates and perceived exertion were also increased. The posture in dribbling is likely to cause back ache among players: 53% of respondents (n = 81) reported experience of lower back pain. Finally, the shrinkage of spinal length during dribbling was examined. Subjects (n = 7) ran for 7 min on the treadmill whilst dribbling a ball. Shrinkage occurred at a rate of 0.4 mm min-1, which is greater than previously reported for other activities. The peculiar postural requirements of field hockey seem to cause physiological strain and spinal loading in excess of orthodox motion.