By Sue Humphrey
Sue Humphrey is a highly respected track and field coach, with decades of experience at the collegiate, national, and Olympic levels. A trailblazer in coaching, she has served on 3 USA Olympic Staffs, including as the 2004 Olympic Women’s Head Coach. Specializing in high jump and athlete development, Humphrey coached 1996 Olympic Champion and American recordholder, Charles Austin and Coleen Rienstra Sommer, the first woman to jump 2.00 meters indoors. She continues to impact the track and field community through coaching education and leadership through the Gold Medal Coaches Summits.
Defying gravity with every leap, high jumpers push the limits of human biomechanics, seamlessly converting speed and power into breathtaking vertical elevations. Every movement leading up to takeoff plays a critical role in determining an athlete’s ability to successfully clear the bar. What separates good high jumpers from great ones is the precision of technique and the mastery of takeoff mechanics.
The key biomechanical factors include rhythm and acceleration, proper foot placement at takeoff, a slight lowering of the center of gravity, a powerful takeoff using the entire foot and opposite free knee drive, and the hinge moment.
Influencing these biomechanical factors and jump performance are the eccentric and concentric muscle actions during takeoff. The eccentric phase, characterized by controlled muscle lengthening, is essential for storing elastic energy and preparing the jumper for an explosive lift-off. This is followed by the concentric phase, during which muscle shortening generates the vertical force needed to propel the athlete upward.
Understanding the interplay between these biomechanical principles enables the optimization of technique, enhancement of performance, and injury risk minimization in high jumpers. In preparing for these muscle actions, the hinge moment will put the body in the best possible position through the final steps of the approach.
Eccentric muscle actions play a crucial role in high jump performance, particularly in the penultimate step and takeoff phase. During the penultimate step, the athlete’s center of gravity is lowered, and the four quadriceps muscles (rectus femoris, vastus intermedius, vastus medialis, vastus lateralis), along with the gluteus maximus, lengthen under tension, store elastic energy, and absorb impact. This eccentric loading enables high jumpers to generate a rather large ground reaction force at takeoff, up to 4 to 5 times their body weight. At the same time, the three hamstrings muscles (biceps femoris, semimembranosus, semitendinosus) co-contract with the quadriceps muscles to stabilize the knee joint. The calf muscles (gastrocnemius, soleus) stretch slightly to absorb horizontal momentum and set the athlete up for a powerful, vertical takeoff. The core muscles (rectus abdominis, obliques, transversus admininis) work together with the leg muscles to maintain posture and prevent unnecessary loss of energy. The eccentrically contracted muscles then release the elastic energy for the ensuing explosive takeoff, as the athlete’s quadriceps extend the knee, propelling the athlete upwards, the gluteus maximus extends the hip, providing additional power for vertical lift, and the calf muscles plantarflex the foot, enabling an effective push-off. The hamstrings assist in knee flexion and contribute to hip extension, which helps optimize takeoff mechanics.
This rapid sequence of active muscle lengthening (eccentric) immediately followed by muscle shortening (concentric) is called the stretch-shortening cycle (SSC) and is fundamental to an efficient energy transfer in the high jump. Research since the 1960s has shown that greater muscular forces can be generated during a concentric muscle action when that action is immediately preceded by a quick eccentric action (Bosco & Komi, 1979; Cavagna et al., 1968; Komi, 1984; Thys et al., 1972). The stored potential energy during the eccentric muscle action rapidly converts into kinetic energy during the concentric action, generating the necessary vertical force for lift-off. Although a brief transition phase occurs between eccentric and concentric actions (i.e., an isometric muscle action), this phase should be noticeably short to maximize the elastic energy transfer from eccentric to concentric for the explosive takeoff.
Elite jumpers maximize SSC efficiency by reducing ground contact time (approximately 0.12 to 0.14 second) while maintaining high force output (Dapena, 1980; Dapena & Chung, 1988). Spending too much time on the ground at takeoff creates too much downward velocity and loss of potential elastic energy to convert into effective vertical lift. Therefore, the jumper should minimize the time it takes for the final two steps while maintaining ideal body positions.
The high jump takeoff angle (approximately 40 to 50 degrees) is influenced by the timing and coordination of concentric actions. If the concentric force is applied too early or too late, the jump will be inefficient, either losing height or sacrificing momentum.
Eccentric Strength
Athletes with greater eccentric strength can manage higher loads and produce greater vertical lift. Eccentric strength training helps prevent knee, Achilles tendon, and hamstring injuries, which are common in jumpers due to the high forces involved. To enhance eccentric strength, high jumpers should incorporate depth jumps (eccentric loading followed by explosive takeoff), slow eccentric squats (with about a 4- to 6-second lowering phase), Nordic hamstring curls and single-leg eccentric exercises (e.g., Bulgarian split squats) in their training.
Concentric Strength
To improve concentric strength, high jumpers should focus on including Olympic lifts (power cleans, snatches) for explosive strength, squat variations (box squats, Bulgarian split squats) for lower-body force production, plyometrics (depth jumps, bounding drills) to enhance SSC efficiency, and concentric- and isometric-only exercises (trap bar deadlifts, sled pushes) for force application specificity.
Hinge Moment
The hinge moment, which is the biomechanical action occurring at the hip joint during the final steps of the takeoff phase, is one of the most crucial yet often overlooked elements of the high jump. It is essential in converting horizontal velocity into vertical lift, ensuring an optimal flight path over the bar. Incorporating a refined hinge moment into a jumper’s technique can significantly enhance performance, providing the necessary efficiency to reach new heights, while maintaining control throughout the jump.
The fundamental principle of the hinge moment follows Newton’s first law of motion: an object in motion continues in motion unless acted upon by an external force. This explains why a high jumper must maintain an erect posture through the curve while keeping the shoulders slightly behind the hips in the penultimate and final takeoff steps.
Throughout the curved approach, athletes must maintain an upright posture to optimize their takeoff mechanics. When an athlete fully understands and applies the hinge moment principle, he or she will adopt a more pronounced hip-led posture, maintaining slight shoulder displacement behind the hips through the final strides. This positioning effectively sets up the body for an optimal takeoff by maximizing vertical force application.
Upon ground contact of the takeoff foot, the torso remains upright while the hip joint functions as a pivot point, facilitating a natural transition into a more vertical orientation while the foot is still in contact with the ground. This strategic positioning ensures an efficient transfer of horizontal velocity into vertical lift. It’s during this part of the jump that the heel spikes of the athlete’s shoe become more important than the spikes of the forefoot.
Coaching the hinge moment can be enforced by running circles, repeated take offs, and curved runs using a “lead with your hips” cue. High jump running posture is altered through the final steps to keep the jumper in the correct position, with shoulders slightly over and behind the hips. In this position, when the jumper plants at takeoff, all body parts above the planted foot are accelerated forward. When the active free knee and arm action contribute to this conversion from horizontal to vertical, a more effective takeoff is executed. If the jumper is out of this hip position and the shoulders are too far forward when the foot is planted, vertical lift is compromised and the jumper has limited conversion.
The hinge moment in the high jump heavily involves multiple muscle groups working together to generate power, control rotation, and optimize takeoff. The primary muscle groups that play a role are also involved in the eccentric-concentric process discussed above. While the gluteus maximus provides the explosive push needed at takeoff, the gluteus medius and minimus help stabilize the hips, and the hamstrings assist in hip extension and help control knee flexion during takeoff. The eccentric loading in the penultimate step actively stretches the hamstrings, allowing for a powerful recoil during takeoff. The quadriceps are crucial for knee extension, allowing the jumper to push off forcefully from the ground and absorbing much of the impact during the penultimate step, preventing excessive knee collapse. Finally, the hip flexors (iliopsoas, rectus femoris, sartorius), especially during the free-leg drive, contribute to upward lift and proper body positioning at takeoff by aiding in the transition from horizontal to vertical motion at foot plant.
Other muscle groups provide overall support to the jumper’s body positions through the approach and actual jump. The core muscles stabilize the upper body during the hinge moment, the calf muscles contribute to ankle plantarflexion at the final push against the ground at takeoff, and the adductors and abductors assist in lateral stability and control to prevent the knee and hip from collapsing inward during takeoff.
To develop an effective hinge moment, high jumpers should focus on hip mobility, explosive power drills, and proper takeoff mechanics. Strength training exercises such as single-leg squats, step-ups, and plyometric drills help reinforce this movement pattern.
Optimizing Hip Positioning
Ensuring correct hip positioning in the final strides is paramount for maximizing vertical displacement. Poor hip alignment results in excessive horizontal momentum retention, reducing the effectiveness of vertical force application. Additionally, improper force absorption can increase stress on the knee and ankle joints, increasing the risk of injury. Athletes often describe a properly executed takeoff as feeling effortless, a direct result of optimal biomechanical alignment and force application efficiency.
By emphasizing tall posture through the curve, controlled backward lean in the final strides, and proper hip articulation at takeoff, coaches can help athletes achieve a more efficient and mechanically sound high jump performance.
Teaching eccentric-concentric actions to young high jumpers requires simple explanations, visual examples, and drills to help them feel the movement. The key is to show them how muscles absorb force (eccentric) and then explode (concentric) for a powerful takeoff.
Before having them do any drills, have them jump without first bending their knees to see how little rebound they get from not preloading. Then, have them flex their knees and quickly jump up. They will feel the springy lifting effect of how important the eccentric preloading phase is.
References
Bosco, C. and Komi, P.V. Potentiation of the mechanical behavior of human skeletal muscle through prestretching. Acta Physiologica Scandinavica, 106:467-472, 1979.
Cavagna, G.A., Dusman, B., and Margaria, R. Positive work done by a previously stretched muscle. Journal of Applied Physiology, 24:21-32, 1968.
Dapena, J. Mechanics of rotation in the Fosbury-flop. Medicine and Science in Sports and Exercise, 12(1):45-53, 1980.
Dapena, J. and Chung, C.S. Vertical and radial motions of the body during the take-off phase of high jumping. Medicine and Science in Sports and Exercise, 20(3):290-302, 1988.
Komi, P.V. Physiological and biomechanical correlates of muscle function: effects of muscle structure and stretch-shortening cycle on force and speed. In: Terjung, R.L. (ed.). Exercise and Sport Sciences Reviews. Lexington, MA: Collamore, 12:81-121, 1984.
Thys, H., Faraggiana, T., and Margaria, R. Utilization of muscle elasticity in exercise. Journal of Applied Physiology, 32:491-494, 1972.
