Variability in Drag Forces
Variability in Measurement of Swimming Forces:
A Meta-Analysis of Passive and Active Drag
Rod Havriluk, Ph.D.
Research Quarterly for Exercise and Sport, 2007, 78(1), 32-39.
An analysis was conducted to identify sources of true and error variance in the measurement of swimming drag force so that valid conclusions could be drawn about performance factor effects. Studies were grouped according to three methods for measuring active drag and three methods for measuring passive drag. The drag coefficient was calculated for the criterion measure.
Data from 36 studies were examined. It was concluded that two active drag methods had sources of systematic error. In contrast, there was remarkable consistency in the passive drag methods that made it possible to determine the effects of performance factors. Significant differences were found for body positions, but no significant differences were found for gender or attire.
The variability of the active drag coefficient values is in stark contrast to the extremely consistent passive drag coefficient values. In part, this is due to the drastically different methodologies used in the active drag studies. More importantly, it reflects the difficulty in measuring active drag and the imaginative attempts that have been designed to analyze the complex activity of human swimming.