Action – flexion of knee, extension of hip
medial rotation of knee (tibia) when knee is flexed
Origin – ischial tuberosity
Insertion – proximal anterior medial tibia (pes anserine)
Nerve – sciatic nerve, tibial division (L5, S1, S2)
Semitendinosus is one of three hamstring muscles. It is medial (towards the inside of your thigh) and lies on top of another hamstring muscle – semimembranosus. It has quite a long tendon to the insertion which can be easily felt when tensing the hamstrings, toward the inner part of the lower half on the back of the thigh.
Pes anserine is latin for goose foot. The area that semitendinosus inserts into is often called this because three muscles (semitendinosus, gracilis and sartorius) insert here together, in a way that resembles the shape of a goose’s foot.
The hamstring group are used when walking, running or lifting weight from the ground with straight legs.
Injury or dysfunction in the semitendinosus muscle can cause pain or discomfort in the back of the thigh, lower buttock or inner knee regions, and sometimes can be associated with low back pain. Common injuries include hamstring strains/tears, particularly when performing ballistic activity (sprinting, kicking, hurdling) without proper warm-up.
Symptoms may need to be differentiated from injury to the other hamstrings, hip or knee joint pain referral or nerve related pain (disc herniation, sciatica)
Standing upright with feet shoulder width apart, hold a barbell, kettlebell or pair of dumbbells of an appropriate weight with an overhand grip in front of your thighs with straight arms. With knees slightly bent and keeping a straight back, hinge forward at the hips and lower the weights while keeping them close to your legs until about the mid shin level. Pause, then squeeze your glutes to bring the hips forward and return to the starting upright position.
Sitting on the ground with one leg out in front and the other bent out to the side. With your foot on the inside of the straight legs knee. Lean forward (keeping a straight/neutral back) to feel a nice stretch down the back of the straight leg.
Rotate legs outwards to favour the medial hamstrings (semitendinosus and semimembranosus). You can use a towel to make the stretch stronger.
Sitting on a firm table or chair with your legs hanging off the edge. Place a ball under your right hamstring, where you feel it is tight. Slowly lift your foot, extending your knee a few times. Then move the ball onto the next tender spot along the muscle. Alternatively, not extending the knee, you can use your hands and body weight to push your thigh onto the ball with more pressure. When you feel the discomfort dissipate, move onto the next spot.