A kinematic comparison of ergometer and on-water rowing

The purpose of this investigation was to compare on- water rowing with ergometer rowing by identifying the important kinematic variables, using vector loop analy sis. Two hypotheses were investigated that provided evidence that rowing ergometers are valid simulators of actual rowing and that the trunk segment is the major contributor to the total linear oar velocity. Thirty subjects were filmed rowing on-water and on an ergom eter. The film was digitized for X and Y coordinates of the body joint locations for a cycle of rowing from catch to finish. A model of rowing was designed such that the rowing movement could be defined as comprising two closed vector loops. The digitized data were fitted to the vector loop model to derive kinematic variables from the drive phase of rowing. Five kinematic variables that described the contributions of five body segments to the total linear oar velocity were analyzed statistically to find differences in the patterns of on-water and ergometer rowing. The results indicated that the kine matics of the upper arm and forearm segments were significantly different in the two types of rowing. These differences were of minor importance because of the small contributions made by the arms at the catch. The differences at the finish were a result of the lifting of the oar from the water not exhibited in ergometer rowing. The vector loop analysis provided the major finding that the trunk segment contributed significantly more to the drive phase portion of the rowing cycle for both on-water and ergometer rowing although the legs initiated the drive phase. Despite the differences that occurred in the arm motion at the beginning and end of the drive phase, most of the kinematic variables were similar throughout the drive phase, particularly for the legs and trunk. The objective of developing a biome chanical test that uses kinematic measures obtained on an ergometer is supported by the findings of this study, and such a study would supplement physiologic measures used in the selection of rowers.