OVERLOAD TRAINING IN SPRINT SWIMMING: KINEMATIC AND DYNAMIC PARAMETERS

Abstract

Overload training is used frequently to increase specific strength endurance in competitive sprint swimming. The training stimulus is provoked by exerting the competitive swimming technique, moving added external loads. These loads create an additional water resistance force to be overcome by the swimmer, thus influencing the kinematic parameters of the swimming cacle. Since quantitative data about the loads applied and the resulting changes in the swimmer's motions are not available, it is the objective of this study to present absolute data about the additional water resisitance of load equipment types commonly used, and to give an insight into the changes within the swimming cycle kinematics under defined load conditions. Two elite swimmers (male and female) being well familiar with overload training procedures served as test persons, carrying out experiments as 1) swimming with maximal effort with and without added loads, 2)towing tests at constant mean velocities as measured in free swimming with and without loads, in a passive situation as well as performing imitated crawl movenments of arms and legs but without generating any propulsive forces. The different loads applied were: clothes (as used in rescue competitions), resistance belt, and a bucket attached to the swimmer. Kinematic parameters were obtained by using a "Control Aqua Training System" (C.A.T.S.), delivering the swimmer's moving speed by registeration of the movement of a cable attached to the swimmer's waist. The towing forces were measured during gtethered swimming by use of a strain gauge system fixed to a carriage moving above a 50m indoor pool. The discussion of the numerical results is based on the mean values of swimming speed and the average towing forces, respectively, in order to avoid inertial effects or problems of nonstationary processes. In the force domain, the additive forces come to 30 to 50 percent of the water resistance during swimming without load, while a speed decrease up to 50 percent of the mean free swimming speed due to the loads added was measured. The combination of added loads and pertinent speed values shows an individual trend for each test person, allowing to perform a controlled overload training, within reasonable force and velocity ranges.