By Jeff Kipp, M.S., C.S.C.S
The sport of track and field places heavy demands on the core musculature of its athletes. An athlete with de-conditioned or weak "trunk" muscles will have decreased efficiency, power output and performance. The core musculature connects the upper and lower extremities and acts as a link between them during movement, as well as postural and stabilization support. Regardless of the event, a well conditioned trunk will create fatigue resistance and movement efficiency, allowing an athlete to maintain proper posture and technique. Furthermore, increasing core muscle strength can help track and field athletes effectively resist applied external forces (e.g. pole vault and inertia in sprints), as well as apply force to implements (e.g. javelin, shot put and discus). Increasing core muscle strength and power also contributes to greater whole body balance and stability. With each step, jump or glide, the maintenance of whole body balance and stability can be attributed to how quickly the core musculature reacts to the downward pull of gravity
When the core musculature is weak or deconditioned, forces are not effectively transferred through the body, resulting in inefficient movement and energy absorption during sprinting, jumping, pole vaulting or throwing events. Energy leaks may occur as a sprinter leaves the blocks, continuing with each step of acceleration, or for a jumper during the approach, take-off preparation and take-off in both the horizontal and vertical events. Energy leaks may also be detrimental to throwing performance for the shot put, weight throw, javelin, or discus events, as less of the ground reaction force is ultimately transferred to the implement. For the pole vault, the energy leaks may occur during the approach, the plant and take-off, as well as the swing up, extension and turn decreasing the force transferred through the pole that propells the athlete over the bar.
An analogy to illustrate the leakage of energy is the function of a pogo stick. The shaft of a pogo stick is straight and made out of a rigid material that provides the desired reaction (bouncing or energy return). The shaft is strong enough to allow even a full grown man to bounce around like a child. The shaft is made straight and rigid for a reason. When force is applied down the shaft of the pogo stick, the force is immediately returned back up the shaft, resulting in the desired bouncing effect (i.e. lift off from the ground). If the shaft of the pogo stick becomes dented or bent, energy is lost at that spot, resulting in a reduced response or the pogo stick could break. Additionally, if a pogo stick were made of a less rigid material, more energy would be lost with a related decrease in the bouncing effect.
A second analogy used to illustrate the need for cylindrical strength in the core muscles is one of a soda can or pop can. Given that the sides of the can do not have any weaknesses (deformities or dents); a person may apply force to the top of the can without crushing it. However, if one or both sides of the can were dented, the can will collapse. The sides of the cylinder work as a unit to resist the forces being applied from top to bottom or bottom to top. Thus, small weaknesses in the integrity of the core musculature can cause a decreased reactivity to the external forces that are applied to the body and likewise a decreased transfer of force from one segment of the body to the other. Conditioning the athletic cylinder (i.e. core musculature) also provides the necessary stiffness to affectively apply forces that are transferred distally to the upper and lower extremities.
The exercises used to train the core musculature for the track and field athlete will start out early in the off-season with low intensity, higher volume basic movements or isometric holds. Over the course of the off-season and into the pre-season the exercises will become more dynamic and increasingly unstable with greater specificity to each event. Loads for the weighted exercises begin early in the off-season with low loads and high volumes. With increases in strength, the loads get higher as the overall volume will decrease. When using the body weight exercises, the volume will increase over the course of the program. Recovery intervals will be longer for the throwing athletes, where higher loads are used and complete recovery is necessary for higher power output. Pole vault and sprint events utilize shorter rest intervals, higher volumes and circuit or superset style core training programs to promote some fatigue resistance in addition the strength and power gains. Distance runners will primarily use isometric holds, full range of motion and stability exercises and short (if any) rest intervals to promote muscular endurance and efficiency even when fatigued.