Ergonomic Considerations of Fin Size for Working Divers

Abstract

Four divers conducted two identical work protocols, consisting of swimming against a graded resistance on an underwater ergometer at a depth of ten feet. In one protocol the divers used fins each having a surface area of 540 cm2 and in the second protocol they used fins whose surface area was 940 cm2. Oxygen consumption, heart rate, ventilation, breathing frequency and kick rate were monitored throughout the twenty minute work period. The 540 cm2 fins demanded a siqnificantly higher metabolic rate than the 940 cm2 fins (50.85 ± 1.54 compared to 46.99 ± 1.52 ml.min.-1.kg-1). The smaller fins also elicited higher heart rates (171.8 ± 4.3 min.-1) than the larger fins (142.5 ± 8.7 min.-1) and induced a higher kicking frequency than was required with the larger fins (43 ± 4 min.-1 and 32 ± 1 min.-1 respectively). Ventilatory volume at the end of the final workload was 128.6 ± 7 1/min. with small fins and 111.1 ± 6.5 1/min. with large fins. These data suggest that the larger fins are more economical in terms of minute ventilation and metabolic cost and are less demanding on the cardiovascular system. Subjectively, the larger fins were perceived as less fatiguing than the smaller fins.