Biomechanical analysis of sub-elite performers in the women’s long jump

A Biomechanical analysis of subelite competitions enriches the pool of knowledge about technique in athletics events. The purpose of this study was to describe the kinematics of the approach and take-off of competitors in the women’s long jump competition at the 2006 European Cup 1st League-Group B. It was found that all the participants utilise the “longer penultimate-shorter last stride” ratio previously described for top-level performers. All but one increased their horizontal velocity during the last stride. Mean horizontal and vertical take-off velocities were 8.71m/sec (standard deviation: 0.26) and 2.45m/sec (0.12) respectively, resulting in a mean take-off angle of projection of 18.1 degrees (0.7). The values of the selected biomechanical parameters were either in range (i.e. loss of horizontal velocity during contact with the board, energy loss in take-off) or lower (i.e. take-off velocity, angle of projection) than results obtained at higher-level events such as the World Championships or Olympic Games. ships. However, there is a lack of data concerning the technique employed by subelite long jumpers competing in international events. This missing information is important as sub-elite athletes can be assisted in their preparations by knowledge that allows comparisons with the world’s best. The aims of this study are: a) to describe the kinematics of the participant’s run-up and the take-off by presenting biomechanical parameters exhibited in the women’s long jump competition at the 1st league of the 2006 European Cup, and b) to comment on the results when they are compared with findings from the literature 6, . The technical factors affecting performance in the long jump include the accuracy of the approach, the technique used during the final strides of the approach, the role of elastic energy in the take-off, the initiation and control of the jumper's angular momentum, and the technique used in the landing. The horizontal velocity of the approach is strongly correlated with the jump distance and thus the jumper’s aim is to develop and maintain horizontal velocity for as long as possible when reaching the take-off board. To fulfil this requirement, elite long jumpers adjust their body position in order to prepare for take-off during the penultimate stride simply by increasing their stride length and by decreasing the height of their body’s centre of mass (CM). The last stride is thus quite a bit shorter, leading to the so-called “longer penultimate-shorter last stride” ratio. The lowering of the height of the CM leads to a larger vertical displacement of the CM during contact at the board, resulting in a greater vertical take-off velocity and a smaller loss of horizontal velocity. Transformation of the initial kinetic energy is needed in order to perform the takeoff. Some loss of the jumper’s total energy is expected during this process but there is an optimum limit to this loss in an effective jump. The efficient re-utilisation of elastic energy, stored in the leg extensor muscles in the early stages of the contact, assists in generating an additional amount of vertical velocity at take-off. Placement of the foot on the board leads to a high braking force, which causes a forward rotation about a transverse axis through the CM. This forward angular momentum must be controlled in order to avoid a loss in the distance of the jump. Therefore, long jumpers must counteract the effects of the forward rotation and maintain their body orientation during the flight by executing appropriate arm and leg movements. The most common flight techniques are the 2/2 hitch-kick, 3/2 hitch-kick and the hang.