|dc.description.abstract||The rower and coach are challenged with identifying the appropriate skiff setup, technique, and the movement pattern that best fits the rower’s anthropometry and performance level. Limited research has investigated different skiff setups and the impact they have on a rower’s performance. The series of studies in this doctoral thesis aimed to: (1) provide an overview of knowledge regarding the ideal rowing technique from a biomechanical perspective; (2) provide indicators of on-water and ergometer performance reliability; and (3) evaluate experimentally the effects of altering the footstretcher angle on rowing performance and technique.
Prior to investigating the effects of changing the foot-stretcher angle on on-water sculling or ergometer rowing, the ability of rowers to replicate their performance was determined. Reliability of repeated 90 s on-water sculling trials was between 4-5% and 1-2° for performance and oar angle parameters respectively. Performance reliability of 500 m and 2000 m simulated races on the RowPerfect and Concept II ergometers were then calculated. The results clearly showed that performance by national level rowers was more reliable over 2000 m than 500 m and on the Concept II ergometer compared with the RowPerfect ergometer. The typical variation expected in a national level rower’s performance for 2000 m trials on the Concept II ergometer (race time = 0.7%, 95% CL = 0.4 – 1.5; mean power = 1.3%, 95% CL = 0.8 – 2.9) is small enough for worthwhile changes in performance to be detected.
Rowing performance and technique were assessed during 2000 m trials on the Concept II ergometer with the foot-stretcher angle set at the standard foot-stretcher angle (41°) plus five degrees either side (36° and 46°). Overall, mean power output and total 2000 m time significantly improved at the steeper foot-stretcher angle of 46°. The clarity of the performance improvements was not mirrored by kinetic and kinematic changes. For the male rowers, an increase in time to reach peak normal foot-stretcher force during the drive phase was pre-empted at the catch by a reduction in the ankle angle, placing greater stretch on the plantarflexors. It is suggested that the delay in time to peak normal foot-stretcher force may be due to a combination of the greater stretch on the soleus muscle and increased seat displacement required for the same lower limb angular positions to be achieved with application of peak force. Relative to the male rowers, the small changes exhibited by the female rowers at steeper foot-stretcher angles may be associated with reduced functional strength. Because changes in rowing technique cannot always be visually observed with improvements in performance, it is suggested that sensors on a skiff are necessary to assist the coach in judging when performance (skiff velocity) improves with some form of intervention.
This research has contributed knowledge regarding the reliability of on-water and ergometer rowing protocols. For the first time, significant performance improvements have been demonstrated with a foot-stretcher angle of 46°, compared with 36° or 41°. Applying these performance improvements to competitors’ race times at international regattas would equate to improved placing’s. Rowers and coaches need to consider the mechanical advantages the foot-stretcher angle may contribute to rowing performance. Further investigation using skiffs rather than ergometers is required once the technical difficulties of conducting such studies are overcome.||en_NZ