A review of propulsive mechanisms in rowing

This paper reviews the fluid dynamic mechanisms that are fundamental to the rowing stroke. Complex interactions occur between the oar blade and water, and over the last 30 years our understanding of the mechanisms that govern rowing propulsion has developed significantly. The oar blade was once believed to rip through the water, generating a drag force acting normal to the blade. Current research indicates that the oar blade acts as an aerofoil making use of lift forces to propel the boat through the water early and late in the stroke, with drag being the dominant propulsive force when the oar is perpendicular to the boat. Early on-water research showed variations in the fluid dynamic behaviour of different oar blades. Recently, more controlled laboratory tests have isolated the oar blade from the rower–boat–water system to obtain blade characteristics. The isolated nature of recent oar blade studies and the complex nature of the oar blade–water interaction have led to suggestions that computational fluid dynamics (CFD) may be used to advance understanding of oar blade behaviour as a precursor to a more informed design process. By integrating a dynamic CFD model with a mathematical model of rowing mechanics, a full optimization of rower technique, boat rigging, and equipment design could be performed

Coordination pattern variability provides functional adaptations to constraints in swimming performance

In a biophysical approach to the study of swimming performance (blending biomechanics and bioenergetics), inter-limb coordination is typically considered and analysed to improve propulsion and propelling efficiency. In this approach, ‘opposition’ or ‘continuous’ patterns of inter-limb coordination, where continuity between propulsive actions occurs, are promoted in the acquisition of expertise. Indeed a ‘continuous’ pattern theoretically minimizes intra-cyclic speed variations of the centre of mass. Consequently, it may also minimize the energy cost of locomotion. However, in skilled swimming performance there is a need to strike a delicate balance between inter-limb coordination pattern stability and variability, suggesting the absence of an ‘ideal’ pattern of coordination toward which all swimmers must converge or seek to imitate. Instead, an ecological dynamics framework advocates that there is an intertwined relationship between the specific intentions, perceptions and actions of individual swimmers, which constrains this relationship between coordination pattern stability and variability. This perspective explains how behaviours emerge from a set of interacting constraints, which each swimmer has to satisfy in order to achieve specific task performance goals and produce particular task outcomes. This overview updates understanding on inter-limb coordination in swimming to analyse the relationship between coordination variability and stability in relation to interacting constraints (related to task, environment and organism) that swimmers may encounter during training and performance