Mechanical Principles of the Standing Broad Jump

Mechanical principles of movement

The standing broad jump, also known as the standing long jump, is a standard way of testing how fit one is (Huston, 2009). The major aspect being tested is usually the explosive strength of the legs. The critical bit of it is that the jumper does not run to build momentum. Instead, it is a requirement for the jumper to stand at a given spot and employ his muscles to jump horizontally as far as possible. The jump thus takes place without any form of a lead-in. The very evident benefit is being able to impart strength and have better control over the muscles that make it possible for one to jump great distances. A longer jump is interpreted as having greater lower body power. For athletes, the standing broad jump can help run faster. The fact that the upper body has to be used as well in the standing broad jump indicates the strength of the upper body. This standard fitness test makes use of major muscles like the glutes, calve, and quadricep muscles. Having a great control of all these muscles leads to a long horizontal jump. The standing broad jump can be done with arm swing or without arm swing. Arm swing ideally helps the jumper to jump higher vertically by increasing the hip joint work. In a study to investigate the effect of arm swing on effective energy during vertical jumping, Blache and Monteil (2013) found out that the vertical jump height was approximately 20% higher when arm swing was employed than when arm swing was not used. In another study to investigate the influence of arm swing on the standing long jump performance, (Grospretre et al. (2018) concluded that arm swing is only advantageous to beginners in the sport. Experts in the sport tend to perform well with or without the arm swing. This study seeks to compare the use of arm swings with standing broad jumps. The findings of the study are predicted to be of great help for coaches who train athletes, since knowledge of the mechanical principles of movement will help improve their jumping performance.

Objectives of the study

The main objective of this research is to investigate the influence of arm swing on the standing broad jump. This goal will be achieved through the following specific objectives:

Analyzing the horizontal and vertical distances jumped achievable with and without arm swing

Analyzing the effect of the hip and knee angle on the vertical and horizontal jump distances

Study hypotheses

If the jump is performed without arm swing, the vertical and horizontal jump distance will decrease.

Null hypothesis

The angle of arm swing has no effect on the vertical and horizontal jump distances.

Analysis

For analysis, two major aspects are considered - i) the jumper and ii) the recorder

The jumper

The jumper is required to follow the following steps

The jumper places the feet shoulder-width or slightly less apart than shoulder-width. The toes should be pointed straight forward towards the jumping direction. The feet should be flush with each other, not one of them behind or in front of the other one.

For the “with arm swing” version, the jumper stretches up the arms and rises onto the balls of the feet, having the hips extended.

The jumper then throws the arms behind the back and bends the knees and hips.

The jumper explosively throws the body up and forward, aim at the highest jump possible and greatest horizontal distance possible.

The jumper, being airborne, extends the hips up and throws the feet forward.

The jumper lands flatfooted and strives to stay on his feet, not falling backward or forward and not touching the ground after landing.

The steps outlined above can be categorized into four jump phases namely:

Take-off downward - where the jumper moves to the hip to the lowest point before taking off into the air

Take-off upward - where the jumper moves from the lowest hip point to the point the feet just break contact with the ground

Flight - from the point the feet break contact to the ground up to when the feet land

Landing - from the point the feet make contact with the ground up to the point the jumper stands back stably on his feet

The recorder

The recorder needs the following equipment and tools to make the analysis possible - video camera, camera tripod, Quintic Software, V29, Microsoft Office Excel, 30-meter measuring tape, plumbline, joint marker tape, metre rule, and spirit level

The recorder follows the following steps for the 2D analysis

The recorder looks for a place with adequate lighting, without much clutter, and large enough for the jumper to perform the standing broad jump and the cameraman to record.

The camera is placed at 90 degrees to the plane of motion. This is made possible by drawing a 3-4-5 triangle with the two shorter sides being the plane of motion and the line of view of the camera

The camera is placed on the line of view at sufficient distance from the plane of motion so as to have a wide-enough field of view.

A moveable screen, preferably white is placed on the other side of the plane of motion so as to make the background clear, non-reflective and contrasting with the jumper.

The field of view is made uncluttered by removing unwanted items and covering any reflective items.

The camera is attached to a steady tripod on the predetermined line of view and connected to an external monitor to allow for convenience when adjusting the field of view. The height of the camera is set to coincide with the jumper’s hip height. A dummy object exactly in the midpoint of the field of view is used to adjust the position of the camera.

The shutter speed is set to 1/600th of a second to avoid blurring of still images when digitizing the motion. The aperture and lighting are also optimized to ensure the images are clear enough.

The jumper’s motions are recorded and finally the Quintic software used to digitize the jumper’s motion and export the parameters to MS Excel.

Results

Table 1 - 4 - Kinesiological analysis comparison tables

Findings

Blache and Monteil (2013) found out that the jump length was approximately 20% more when arm swing is used as compared to a standing broad jump without arm swing. In the current study, the toe displacement obtained when the jump is performed with hands on hips is about 1.40 m. The toe displacement obtained when the jump is performed with arm swing is about 1.60 m. This is an increase of about 15%. In both studies, there is a positive increase in the length of jump when the jumper swings the arm. This can be attributed to an increase in momentum when the arms are swung forward and then backwards. The difference in the percentage increase between the current study and Blache and Monteil’s (2013) study may be attributed to differences in strength between the jumpers. For the hands on hip standing broad jump, the current study records a minimum hip angle before takeoff of 76 degrees, while for the arm swing version, the value is 85 degrees. In the same study by Blache and Monteil (2013), the minimum hip angles are r roughly the same values. When arms are at akimbo, the hip has to undergo greater flexion for it to be able to propel the body further during the jump. With swinging arms, the hip flexion doesn’t need to be as much because the arms assist in giving the body the required momentum. Under the current study, the minimum knee angle before take off is 114 degrees for both hands-on-hips and arm swing methods. Hara et al. (2006) found out that the arm swing significantly reduced the work done by the knee. The current study contradicts this since having the same knee angle before take off implies the same amount of work comparing the hands-on-hips and arm-swing versions. On the contrary, the total work done by the three lower extremity joints was significantly higher with the arm swing in that study by Hara et. al. (2006). The current study agrees with this finding. The shoulder and elbow are able to increase the work done by the lower extremities by boosting the momentum of the lower body.

Under the current study, the maximum hip joint horizontal velocity obtained with arms akimbo is 2.2 m/s2. Hraski et al. (2015) found the value to be 2.6 m/s2. This difference is basically as a result of the difference in the athletic abilities of the persons performing the standing broad jump experiment. In both studies, the length of the jump is significantly influenced by the horizontal velocity at take-off.

Recommendations

For this experimental data to be of help to the NYS coaches, the following are the key recommendations.

Huston (2009) recognized the need for the highest maximum horizontal and vertical velocity at take-off in order to increase the length of the jump. The hip velocity is directly proportionate to the work done by the hip joints, which is additionally proportionate to the hip angle at take off. With arms swinging, the hip angle at take off should be about 80 degrees, but this again depends on the mass and age of the jumpers.

Blache and Monteil (2013) recommend the use of arm swinging to increase the vertical jump height, which further increases the length of the jump. The higher vertical jump height is a result of greater hip joint muscle work, which depends on the force and velocity aspects of the jump. To increase the effective energy during the jump, the jumpers should focus on the total muscle work, and not the efficacy ratio.

References

Blache, Yoann & Monteil, Karine. (2013). Effect of arm swing on effective energy during vertical jumping: Experimental and simulation study. Scandinavian journal of medicine & science in sports. 23. 10.1111/sms.12042.

Grospretre, S., Ufland, P. and Jecker, D. (2018) 'The adaptation to standing long jump distance in parkour is performed by the modulation of specific variables prior and during take-off'. Movement and Sport Sciences, pp.27-37.

Hara, M., Shibayama, A., Takeshita, D. and Fukashiro, S. (2006) 'The effect of arm swing on lower extremities in vertical jumping'. Journal of Biomechanics, 39(13) pp.2503-2511.

Hraski, M., Hraski, Ž. and Prskalo, I. (2015) 'COMPARISON OF STANDING LONG JUMP TECHNIQUE PERFORMED BY SUBJECTS FROM DIFFERENT AGE GROUPS'. Baltic Journal of Sport and Health Sciences, 3(98) pp.2-12.

Huston, R. (2009) Principles of biomechanics. Boca Raton: CRC Press.