Abstract

Kayakers have traditionally used a fixed seat but in 2005 a “swivel seat”, able to rotate in the horizontal plane, was approved for use in races. While anecdotal evidence has suggested that the swivel seat may improve performance, the available data are limited and mainly physiological. The aim of this study was to investigate the effect of the swivel seat on kinematics and trunk muscle activation during paddling on ergometer.
Nine experienced kayakers volunteered for this study and each completed two maximal trials of 30 s on the ergometer, one with the swivel seat and the other with a fixed seat. Three-dimensional motion analysis and performance data were collected at 200Hz during the central 10 s of each trial. Surface electromyographic (EMG) signals were recorded at 2000Hz bilaterally from the rectus abdominis, external oblique, internal oblique, latissimus dorsi and the erector spinae muscles.
The use of the swivel seat was observed to improve performance through a significant increase in peak flywheel RPM (p = 0.033), right paddle recovery time (p = 0.043) and paddle antero-posterior displacement (p = 0.015). Shoulder rotation increased when using the swivel seat but trunk rotation decreased significantly (p = 0.019). In addition, EMG analysis suggested greater activation of the trunk muscles during the swivel seat condition, where body position was closer to the recommended upright orientation and the knee range of motion was increased (p < 0.01).