The Rowing Cycle: Sources of Variance and Invariance in Ergometer and On-the-Water Performance.

Area of Science:

• Biomechanics
• Human Movement Science
• Sports Science

Background:

• Previous research by Lamb (1989) established close simulation between ergometer and on-water rowing kinematics.
• Analysis of skilled movement timing requires identifying temporal constraints and key relative timing variables (Beek, 1992).

Purpose of the Study:

• To extend Lamb's (1989) analysis by investigating the complete rowing cycle timing.
• To identify sources of variance and invariance in rowing action timing.
• To explore mathematical relationships describing relative timing between stroke and recovery phases across different rowing speeds.

Main Methods:

• Investigated timing of the complete rowing cycle in 5 elite male rowers under ergometer and on-water conditions.
• Assessed timing variability using absolute and relative criteria over 4 rowing speeds.
• Applied Gentner's (1987) criteria for assessing relative timing between stroke and recovery phases.

Main Results:

• Rowing cycle variability significantly decreases with increased rowing rate, though less dramatically when normalized for movement duration.
• The recovery phase accounted for most of the rowing cycle's variability, while the stroke phase remained relatively invariant.
• Relative timing changes across speeds followed a linear rule, with stroke proportion increasing with rowing rate, consistent across both rowing conditions.

Conclusions:

• The rowing stroke phase is a stable temporal pattern, while the recovery phase exhibits adaptability across different rowing rates and conditions.
• A simple mathematical relationship governs the relative timing adjustments in the rowing stroke as a function of speed.
• Findings offer insights into human propulsion mechanics, comparing rowing to other activities like walking, running, and stair climbing.