Relationships between measures of boat acceleration and performance in rowing, with and without controlling for stroke rate and power output.

Ana C Holt,Kevin Ball,William G Hopkins,Rodney Siegel,Robert J Aughey,Nuno Miguel Correia Leite

doi:10.1371/journal.pone.0249122

Abstract

PurposeBoat acceleration profiles provide a valuable feedback tool by reflecting both rower technique and force application. Relationships between measures of boat acceleration and velocity to inform interpretation of boat acceleration profiles in rowing were investigated here.MethodsThirteen male singles, nine female singles, eight male pairs, and seven female pairs participated (national and international level, age 18–27 y). Data from each stroke for 74 2000-m races were collected using Peach PowerLine and OptimEye S5 GPS units. General linear mixed modelling established modifying effects on velocity of two within-crew SD of boat acceleration variables for each boat class, without and with adjustment for stroke rate and power, to identify potential performance-enhancement strategies for a given stroke rate and power. Measures of acceleration magnitude at six peaks or dips, and six measures of the rate of change (jerk) between these peaks and dips were analyzed. Results were interpreted using rejection of non-substantial and substantial hypotheses with a smallest substantial change in velocity of 0.3%.ResultsSeveral boat acceleration measures had decisively substantial effects (-2.4–2.5%) before adjustment for stroke rate and power. Most effect magnitudes reduced after adjustment for stroke rate and power, although maximum negative drive acceleration, peak drive acceleration, jerk during the mid-drive phase, and jerk in the late recovery remained decisively substantial (-1.8–1.9%) in some boat classes.ConclusionGreater absolute values of maximum negative drive acceleration and jerk in the late recovery are related to improved performance, likely reflecting delayed rower centre-of-mass negative acceleration in preparation for the catch. Greater absolute values of peak drive acceleration, first peak acceleration, and jerk in the early and mid-drive are also associated with improved performance, likely reflecting propulsive force during the drive. These proposed mechanisms provide potential strategies for performance enhancement additional to increases in stroke rate and power output.

Highlights

Boat acceleration profiles provide insight into rower force application and centre-of-mass (COM) movement, and are frequently used by coaches and sport scientists to provide feedback on rowing technique
Most effect magnitudes reduced after adjustment for stroke rate and power, maximum negative drive acceleration, peak drive acceleration, jerk during the mid-drive phase, and jerk in the late recovery remained decisively substantial (-1.8–1.9%) in some boat classes
Greater absolute values of maximum negative drive acceleration and jerk in the late recovery are related to improved performance, likely reflecting delayed rower centre-of-mass negative acceleration in preparation for the catch

Summary

Introduction

Boat acceleration profiles provide insight into rower force application and centre-of-mass (COM) movement, and are frequently used by coaches and sport scientists to provide feedback on rowing technique. Research investigating relationships between boat acceleration and rowing performance is mostly limited to the assessment of men’s pairs, often with small sample sizes, and involves the comparison of crews with varying success levels [1, 4,5,6], adding to the difficulty faced by coaches and sport scientists in identifying favourable measures of boat acceleration. Conflicting positive [4] and negative [1, 5] relationships with rowing success level have been observed for the magnitude of maximum negative acceleration occurring early in the drive (marker 1 in Fig 1) in elite men’s pairs. Acceleration magnitude at the first positive peak of acceleration occurring during the drive (marker 2 in Fig 1) is positively associated with rowing success level [1], with larger magnitudes in sweep compared to sculling boat classes [6]. Only a small section of the acceleration profile (up to marker 4 in Fig 1) has been examined, whereby the association between boat acceleration in the recovery phase and rowing performance is not known

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