A study of sculling swimming propulsive phases and their relationship with hip velocity

The purpose of this study was to identify the effect of sculling propulsive arm actions in displacement on the intra-cycle velocity of the hip. Four phases were defined (based on hand movements) prior to the development of the study: inward, pronation, outward and supination. A group of 9 international synchronized swimmers participated in the study. A displacement of 15 m was recorded using a velocimeter and underwater video cameras (bottom and sagittal views). Mean cycle velocity 0.548m/s, duration 0.828s, sculling frequency 1.220 sculling length 0,455 m and percentage of phase duration: inward (38.6%), pronation (10.3%), outward (33.5%) and supination (17.6%) were obtained. The mean body velocities were similar in the phases, while the durations where significantly different. The sculling propulsive action helps body displacement in the inward, outward and supination phases; while the pronation had a reduced contribution. Reversal stroke actions help to support the hand fixed it the water while the arm muscles are contracted helping the next propulsive phases (inward or outward) to move the hand an body forward. KEY WORDS: unsteady propulsion, kinematics, velocimetry, vortex recapture INTRODUCTION: Swimming stroke propulsion is composed of different hand and forearm propulsive actions that were classified as: outsweep, downsweep, insweep and upsweep (Costill, Maglischo, & Richardson, 1992). These propulsive actions can be studied from an steady or quasi-steady approach (Schleihauf, 1979) or considering unsteady propulsiv