Logan Steele
Hamstrings are a group of muscles that run along the back of the thigh. They are often injured in sports and professional dancing, with an average of two injuries per 1000 hours of performance. The hamstring muscles cross two joints – the hip and the knee – and are therefore known as biarticulate or biaxial muscles. The three 'true' hamstrings are the semitendinosus, semimembranosus, and biceps femoris. They are involved in knee flexion and hip extension.
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What You'll Learn
Hamstrings are biarticulate or biaxial muscles
The three 'true' hamstrings cross both the hip and the knee joint and are therefore involved in knee flexion and hip extension. The short head of the biceps femoris is a single-joint muscle that only crosses the knee and is therefore not involved in hip extension.
The hamstrings play a crucial role in many daily activities such as walking, running, jumping, and controlling some movement in the gluteus. They are most important in walking as an antagonist to the quadriceps in the deceleration of knee extension.
The function of biarticular muscles is complex and depends on both their anatomy and the activity of other muscles at the joints in question. Their role in movement is not yet fully understood. These muscles can transfer mechanical power between distal and proximal joints, and the direction and magnitude of this transfer vary with anatomy, muscle activity level, and joint angles.
Biarticular muscles can also be found in the arm and the shin. For example, the biceps are most powerful in elbow flexion and are assistants in shoulder joint flexion. The gastrocnemius is most powerful in ankle extension and a strong assistant in the leg curl exercise.
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They cross the hip and knee joints
The hamstrings are biarticulate or biaxial muscles, which means they are two-jointed muscles that cross two joints – the hip and the knee. They are involved in knee flexion (heel to buttocks) and hip extension (extending the thigh backward).
The three 'true' hamstrings cross both the hip and the knee joint and are therefore involved in knee flexion and hip extension. These are the semitendinosus, semimembranosus, and the long head of the biceps femoris. The short head of the biceps femoris is a single-joint muscle that only crosses the knee joint and is therefore not involved in hip extension.
The hamstrings play a crucial role in many daily activities such as walking, running, and jumping. They are important in controlling some movement in the gluteus and act as an antagonist to the quadriceps in the deceleration of knee extension.
The hamstrings can be targeted in their hip extension role by removing them from their role as knee flexors. This can be done through exercises such as straight leg pulldowns on a pulley or with Active Cords in the pawback. To maximally target the hamstrings in their knee flexion role, they need to be removed from their role as hip extensors. This can be achieved through exercises such as leg curls, either with a machine or free weights.
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They have an action at each joint
The hamstrings are an example of a two-jointed muscle, also known as a biarticulate or biaxial muscle. These muscles cross two joints and have an action at each joint. The hamstrings cross the hip and the knee joints. At the hip joint, the hamstrings are involved in hip extension, which is seen in straight leg pulldowns. The upper hamstrings, which are attached to the pelvis, are involved in this action.
At the knee joint, the hamstrings are involved in knee flexion (heel to buttocks), which is seen in the leg curl exercise. The leg curl exercise develops mainly the mid to lower hamstrings. The hamstrings are also involved in knee flexion during the swing phase of walking and running. During this phase, the hamstrings coordinate with the rectus femoris to reduce muscle fatigue.
The hamstrings play a crucial role in many daily activities such as walking, running, jumping, and controlling some movement in the gluteus. For example, in walking, the hamstrings are important as an antagonist to the quadriceps in the deceleration of knee extension.
The hamstrings can be injured during sports or dance activities, with an overall incidence of about two injuries per 1000 hours of performance. The biceps femoris is the most commonly injured hamstring, followed by semitendinosus.
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Hamstrings are involved in knee flexion and hip extension
The hamstrings are a group of three muscles: the biceps femoris, semitendinosus, and semimembranosus. They are two-joint muscles, crossing both the hip and the knee joints. They originate at the pelvis and insert at the tibia or fibula.
The hamstrings are involved in knee flexion and hip extension. Knee flexion is the movement of the heel towards the buttocks. Hip extension is the movement of extending the thigh backward.
The hamstrings' role in knee flexion can be maximally targeted through specific exercises. For example, a seated leg curl machine allows for effective hamstring work by flexing the hip joint. To further maximise the role of the hamstrings in hip extension, their function as knee flexors must be removed. This can be achieved by performing exercises with a slight knee flexion, such as lowering the resistance by pushing the buttocks backward while keeping the barbell, dumbbell, or machine arms near the thighs.
The force generated by the hamstrings during hip extension and knee flexion exercises increases when the muscles are in a lengthened condition. The peak torque of knee flexion is also greater with an increased hip flexion angle. Additionally, the hamstrings' activity as knee flexors is higher than their activity as hip extensors. The semitendinosus, in particular, is more involved in knee flexion than in hip extension.
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They are crucial for daily activities like walking, running and jumping
Hamstring muscles are crucial for daily activities like walking, running, and jumping. They are a group of three muscles (except the short head of the biceps femoris) that cross two joints – the hip and the knee. They originate at the pelvis and insert into the tibia (semitendinosus and semimembranosus) and fibula (biceps femoris long head).
Hamstrings assist with knee flexion (heel to buttocks) and hip extension (extending the thigh backward). This dual functionality at the hip and knee joints is essential for walking and running. During the swing phase of walking and running, the hamstrings and rectus femoris muscles work together to reduce muscle fatigue.
The hamstrings are also vital for jumping. They help stabilize the knee, which is crucial for preventing injuries. Hamstring flexibility is a key factor in jumping, and tight hamstrings can negatively impact performance in sports that involve jumping.
Overall, the hamstrings' role in knee and hip movement, along with their contribution to stability and flexibility, makes them essential for daily activities such as walking, running, and jumping.
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Frequently asked questions
Yes, the hamstrings cross and act upon two joints – the hip and the knee.
Two-joint muscles, also known as biarticulate or biaxial muscles, cross two joints and have an action at each of the joints.
The hamstrings are the three posterior thigh muscles in human anatomy: the semimembranosus, semitendinosus, and biceps femoris.
The hamstrings are involved in knee flexion and hip extension. They play a crucial role in many daily activities such as walking, running, and jumping.
The overall incidence of a hamstring injury in sports and professional dancers is about two per 1000 hours of performance. In some sports, a hamstring injury occurs at a rate of 19% of all sports injuries.
