Triple Jump phases

Approach/lead up phase- The aim of the approach steps is for athletes to reach their maximum speed, which they will maintain throughout the remaining sequences until they land (Blazevich, A. 2010). The first step of the phase sees athletes apply a force in the horizontal direction in order to begin the forward motion. Horizontal velocity is the rate at which an object is travelling parallel to the earth (Blazevich, A. 2010). Horizontal velocity is acquired during the approach and is lost primarily due to ground contact during the three phases (Antonini 2015). Preservation of velocity can be achieved by using the correct take-off technique during each phase. Triple jumpers face the difficulty in maintaining the propulsive force during the take- off and landing in the phases. This is supported by Newton’s First Law, an object at rest will stay at rest, and an object in motion will stay in motion, unless acted upon by another force (Blazevich, A. 2010). The athlete starts at a 45-degree angle to the ground so they can push themselves forward.  The first 6 strides of the triple jump involve maximal effort in order to reach maximum speed. The power is driven from the legs and hips which is influenced by Newton’s Third Law. For every reaction, there is an equal and opposite reaction (Blazevich, A. 2010). The athletes’ foot is the action force and the movement down the runway in the reaction force. It is beneficial for athletes to attain a high speed, as they need to carry this speed with them throughout the rest of the movement phases. After the initial 6 strides, the athletes posture will become tall and erect, which the hips beneath, similar to the posture of a sprinter (Blazevich, A. 2010). This is an ideal technique as in this position, the body can generate force for the next skip, hop and jump phases (Blazevich, A. 2010).

An elite triple jumper will show many characteristics similar to a great sprinter. In the moment prior to one foot touching the ground, it is already extended and the other knee is directly in line with the extended knee. More time can be used to produce a propulsive impulse as there is a large distance between each point of contact with the ground (Blazevich, A. 2010). Angular momentum is a function of moment of inertia and angular velocity. The moment of inertia is a product of the distribution of weight in the leg away from the primary point of torque production (hips). The greater the moment of inertia, the greater the force needed to move the leg. The moment of inertia can be manipulated to help minimize the force needed to move the leg (Blazevich, A. 2010). This is done by the jumpers having large powerful quadriceps but minimal the weight in their calves. The leg muscles hold greater mass in jumpers as they create the velocity used for the jump. In triple jump, mass is used particularly in the hop, skip and jump phases (Blazevich, A. 2010).

Hop phase- The hop phase is the continuation of the movement pattern showed during the run up. The arms are slightly slower and the legs are slightly slower and elongated, but the speed remains the same. The take-off for the hop and step phases are taken from the safe foot, consequently it is argued that the optimal body positions are the same or similar (WU, W., WU, J., LIN, H., & WANG, G. 2003). To propel the jumper, a vertical ground reaction force is created. Wu et al (2003) states that the angular momentum of the athlete at the take off point should be zero. The optimal trajectory is relative to personal characteristics of the athlete and also the speed in which they take off. This articulates the importance of maintaining speed from the last steps of the approach phase into the hop phase. The rowing of the arms helps to reduce the amount of momentum and to keep it consistent. It also helps to rotate the body rotate back to a neutral position so the athlete is ready for landing. Jumpers are unable to look down at the board prior the jump as this interferes with the body position. If this occurs, the jump will be shorter or the athlete may fall over. The foot should land slightly in front of the jumpers centre of mass. Excessive front-side placement of the foot produces deceleration or even injury (Blazevich, A. 2010).

The ground reaction force is when a person applies on the ground, the ground applies a force of the same intensity and opposite direction on the person. An example of this is when gymnasts land after their routine. Their body needs to be able to absorb the force the ground has given back once they land (Blazevich, A. 2010).

In the hop phase, there are two technical components, the hop leg cycle and the free leg cycle. The hop leg cycle is the action of the leg that executes the take-off from the board and take off into the step phase. The free leg cycle is the movement of the other leg during the flight phase of the hop. Novice athletes aggressively pull the leg forward, destroying the reflexive nature of the movement. This evokes the body’s flexion reflex and produces forward tilt of the pelvis. This technique will negatively affect results as velocity is lost through the hips and resulting in a lower angle of take-off (Blazevich, A. 2010).

At the completion of the hop, a small amount of front side distance is needed to create proper lift into the step phase. The front side distance at the hop landing is be excessive, correct or insufficient. Premature planting of the foot is a strategy used by jumpers to overcome instability (Blazevich, A. 2010).

Skip/step phase- After the landing of the hop phase, the step phase involves the athlete taking an elongated step. This requires the athlete to take off at the optimal angle, thrust both arms forward and holding their posture and position at the top of the step. Angular motion is a mass moving at an angular velocity (Blazevich, A. 2010). Within the skip phase, angular momentum is evident in both the swinging of the arms and legs. The legs need to swing back quickly in order to increase torque developed by the hip muscles which makes the jumper move forwards. The time in which muscle force is developed allows higher velocities due to the change in angular momentum of the leg being greater. The body is propelled in a forward manner by swinging both arms forward as this results in greater angular momentum (Blazevich, A. 2010).

Posture and swing elements are critical in “holding the step”. Holding the step is when athletes keep their legs and powerfully explode them outsides to maintain momentum.
The sequence of skills; tall and neutral body posture, pelvis posture, the thrusting of the free legs and arms, and a strong lift of the swing leg, collaboratively allow the desired distance of the step phase to be achieved (Blazevich, A. 2010). A tall and upright position will mean that a longer jump can be performed as the centre of mass is in the correct position. Before the landing, the support foot extends to maximum length to increase the distance acquired in the step. The swing leg moves at the same time as support/take-off foot lands in preparation for the jump phase. The arms swing forward simultaneously towards the swing leg to reduce momentum lost (Blazevich, A. 2010). Upon impact with the sand, the ground applies an equal and opposite force against the jumper after the foot applied a forward force in a downward motion. Breaking force needs to be minimised in order to prevent the loss of speed. This can be done by the forward directed force of the foot off the ground providing a propulsive impulse. This maximises propulsion and minimising the breaking forces (Blazevich, A. 2010).

Jump / landing phase-The aim of an effective take-off is the cooperation between a good gain in vertical velocity and a minimal loss of horizontal velocity. Maintaining velocity can be achieved by rotating the core and hips, maintaining wider angles between knees and legs and keeping legs lifted (Blazevich, A. 2010). Athletes aim to reduce any non-essential time their foot spends touching the ground. Triple jumpers strike the ground with a fore-foot/mid-foot strike which reduces the power and amount of force lost. Any additional time or body part that impacts the ground, if velocity lost which results in a shorter flight time (Blazevich, A. 2010). The following steps assume the jumper has landed the step phase correctly in an upright position with an extended leg to increase the distance of the step. The athlete will swing their arms and free leg whist rolling and thrusting their body(Blazevich, A. 2010).Their chest, knees and arms will be moving in an upward and forward motion to reach an optimum maximum height. Reaching the optimum maximum height will mean the athlete maintains a central centre of gravity (Blazevich, A. 2010). This will make the jump more stable and produce the most amount of velocity to propel them forward. The next sequence of movements sees the knees being pulled in closer to the chest and the arms being swung down similar to a paddling motion (Blazevich, A. 2010). This will further propel the jumper forward whilst the body position is kept upright, legs outstretched and feet flexed to avoid touching the sand. Once ground contact is established, the jumper rolls their body forward even more to ensure their core touches the contact site of the feet. Rolling the body forward results in no ground being lost from the landing so the full jump can be measured (Blazevich, A. 2010).