TAKE-OFF KINEMATICS OF BEAM DISMOUNTS

Abstract

Beam dismounts require great courage, the highest level of precision of movement, and a special take-off technique. They have only marginally increased in difficulty in recent years, however, their technical execution has reached close to technical perfection. The technical criteria for the execution of successful beam dismounts are essentially similar to those of floor take-offs. Nevertheless, the configurations of the beam, its small width (10cm) and surface stiffness relative to the floor, put considerable limitations on the performer and subsequently change the take-off technique somewhat greatly. The purpose of the study was to investigate the biomechanical characteristics of dynamic beam dismounts performed by eight female gymnasts at the World Gymnastics Championships in Brisbane, 1994. Data was captured at 50 Hz by two video cameras positioned on the catwalks above the floor of the competition venue, which permitted the calculation of 3D kinematic data. Mean and standard deviations of selected kinematic and temporal parameters were calculated in order to: identify special biomechanical characteristics of takeoff technique for the balance beam, identify the differences in take-offs between the different types of dismounts performed, and to compare the data to those reported previously. Analysis of the data revealed, that the most important performance factor determining somersault height, the vertical velocity at take-off of the CM, ranged from 1.84 to 3.04 m/s, with a mean value of 2.49 ±0.40 m/s, which is considerably lower then for floor take-offs. The mean values for the horizontal velocity at take-off were 1.57