THE ROWING CYCLE - SOURCES OF VARIANCE AND INVARIANCE IN ERGOMETER AND ON-THE-WATER PERFORMANCE

In a recent study of the kinematics of the drive phase of the rowing s troke, Lamb (1989) provided detailed evidence that ergometer performan ce simulates on-the-water performance closely. In the present experime nt, Lamb's analysis was extended in an investigation of the timing of the complete cycle of the rowing action of 5 rowers under each of thos e performance conditions. The authors followed Beek's (1992) suggestio n that the first task in the analysis of timing in skilled movement is to specify the sources of variance and invariance in each particular task by identifying the major temporal constraints and the key relativ e timing variables. In addition, the possibility that some simple math ematical relationship (e.g., Schmidt, 1985) might describe the relativ e timing between the stroke and recovery phases of the rowing action w hen performed at different speeds was investigated. Both an absolute a nd a relative variability criterion were used in assessing and compari ng timing variability over 4 speeds of rowing and between on-water and ergometer rowing in 5 elite male subjects. Criteria outlined by Gentn er (1987) were used in assessing relative timing between stroke and re covery. The results indicated that variability decreases dramatically as a function of increased rowing rate; however, when variability is e xpressed as a function of movement duration, those decreases appear mu ch less dramatic. Overall variability of the rowing cycle was caused p rincipally by variability in the recovery phase, whereas the stroke ph ase was relatively invariant under both rowing conditions. The changes in the relative timing of the rowing stroke across the 4 speeds studi ed followed a simple mathematical rule, best described as linear incre ments in the stroke proportion of the total rowing cycle with increase s in rowing rate. Moreover, those changes were similar across the 2 ro wing conditions. The present results are discussed in light of finding s from other forms of propulsion, such as walking, running, and stair climbing, in which the movement constraints are quite different.