Related Experiment Video
Updated: Jan 3, 2026

Muscle Imbalances: Testing and Training Functional Eccentric Hamstring Strength in Athletic Populations
Published on: May 1, 2018
Hamstring muscle-tendon unit lengthening and activation in instep and cut-off kicking
Liwen Zhang1, Hanjun Li1, William E Garrett2
1Biomechanics Laboratory, School of Sport Science, Beijing Sport University, Beijing, China.
Abstract:
Hamstring muscle strain injury is one of the most common injuries in sports involving sprinting and kicking. Studies examining hamstring kinematics and activations are rich for sprinting but lacking for kicking. The purpose of this study was to examine kinematics and activations of hamstring muscles in instep and cut-off kicking tasks frequently performed in soccer. Videographic and electromyographic (EMG) data were collected for 11 male soccer-majored college students performing the two kicking tasks. Peak hamstring muscle-tendon unit lengths, elongation velocities, and maximum linear envelop EMG data were identified and compared among hamstring muscles and between kicking tasks. Hamstring muscles exhibited activated elongations before and after the contact of the kicking foot with the ball. The muscle-tendon unit lengths peaked in the follow-through phase. The peak elongation velocity of the semimembranosus was significantly greater than that of the semitendinosus and biceps femoris (p = 0.001). The maximum linear envelop EMG of the biceps femoris was significantly greater than that of the semimembranosus (p = 0.026). The potential for hamstring injury exists in the follow-through phase of each kicking task. The increased hamstring muscle-tendon unit elongation velocities in kicking tasks may explain the more severe hamstring injuries in kicking compared to sprinting.
More Related Videos
Related Concept Videos
Muscles of the Leg that Move the Foot and Toes
Anterior Compartment
The anterior compartment includes muscles that contribute to the dorsiflexion of the foot. This compartment houses the tibialis anterior, extensor hallucis longus, and extensor digitorum longus muscles....
Muscles that Move the Leg
Anterior Compartment
The quadriceps femoris, the most visible muscle of the anterior compartment, is integral for leg extension and thigh flexion. It is formed by merging four distinct muscles — the vastus lateralis, vastus medialis, vastus intermedius, and rectus femoris. The quadriceps tendon, a shared tendon of the four quadriceps muscles, is affixed...
Excitation-Contraction Coupling in Skeletal Muscles
When an action...
Muscles that Move the Thigh
Three other significant muscles are the gluteus maximus, gluteus medius, and gluteus minimus. The gluteus maximus originates from the posterior surface of the ilium, sacrum, and coccyx, and the thoracolumbar...
Bones of the Lower Limb: Femur and Patella
Motor Unit Stimulation
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...

