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Standing Long Jump


Introduction    The Study    Results

 

Introduction

A standing long jump is often used as a functional test to assess leg power, but the test may underestimate the athlete’s true potential if the athlete does not use the best possible technique. The selection of takeoff angle is one of the most important technique variables. Masaki Wakai studied the effects of changes in takeoff angle on performance in the standing long jump. The aim was to identify the optimum takeoff angle and to explain the underlying biomechanics of the standing long jump.

 

The Standing Long Jump Study

Performance in the standing long jump is evaluated by the total jump distance, which is the horizontal distance from takeoff line to the mark made by the heels at landing. The total jump distance is the sum of three component distances; takeoff distance, flight distance, and landing distance (Figure 1).

Figure 1. The three component distances that make up the total jump distance.

 

Five physically active male subjects performed maximal-effort standing long jumps over a wide range of takeoff angles. All jumps were recorded at 50 Hz using two video cameras placed about 10 m away from the takeoff line and landing pit. An Arial Performance Analysis System was used to determine the takeoff speed, takeoff angle, height difference between takeoff and landing, takeoff distance, and landing distance.

 

Results

The takeoff angle that maximises the jump distance is not 45°, as predicted from a naive application of the equation for the range of a projectile in free flight,

In the standing long jump, both the takeoff speed, v, and the height difference between takeoff and landing, h, vary with changes in takeoff angle, q. To calculate the optimum takeoff angle, the measured relations between takeoff speed, height difference, and takeoff angle must be inserted into the equation.

 

For all five subjects, the takeoff speed decreased with increasing takeoff angle (Figure 2). This decrease arises because as the takeoff angle is raised, a greater fraction of the jumper’s muscular force is required to overcome the weight the body, and so less force is spent accelerating the body. The takeoff speed at high takeoff angles is therefore not as great as at low takeoff angless. The decrease in takeoff velocity reduces the optimum takeoff angle to well below 45° (This phenomenon occurs in other projectile sports, such as the shot put.)

 

Figure 2. Decrease in takeoff speed with increasing takeoff angle

 

In the standing long jump, the flight distance is the largest component of the total jump distance. However, the takeoff and landing distances also make significant contributions. Both the takeoff and landing distances decrease with increasing takeoff angle, and so further reduce the optimum takeoff angle (Figure 3). In the standing long jump the optimum takeoff angle is not 45°, but under 30°.

 

Figure 3. Dependence of jump distance and the component distances on takeoff angle.

 

To find out more about the standing long jump study, see:

Wakai, M. and Linthorne, N.P. (2005). Optimum take-off angle in the standing long jump. Human Movement Science, 24 (1), 81–96. (Publisher)