The 'hamstrings' or 'hamstring muscles' are the muscles at the back of the thigh - semimembranosus, semitendinosus and biceps femoris.
Page updated July 2024 by Dr Sheila Strover (Clinical Editor)
Side view of the tendons on the medial side of the knee - showing the semitendinosus - where it can be harvested for cruciate ligament reconstructions. The semimembranosus lies behind it.
View from the back of the two heads of the biceps femoris component of the hamstrings inserting on the lateral side of the knee.
Why are they called the 'hamstrings'?
They are so called because in pigs they are the muscles used to make ham, and the hams were strung up using hooks through the long string-like tendons.
What do the hamstrings muscles do?
The hamstrings muscles' main function is to bend the knee but they also work to straighten the hip.
One can check hamstrings function and strength by letting the patient lie on their tummy on an examination table with the hips bent and the lower limbs hanging over the end. If the hamstrings are weak then the patient will have difficulty bending the bad knee as much as the opposite side, especially if an observer applies a bit of extension force.
What is a hamstrings strain?
Hamstrings injuries are very common in athletes.
Problems can range from a muscle sprain, through chronic tendinopathy to actual rupture of the hamstrings tendon.
-
Quote from peer-reviewed paper:
"....Acute hamstring strains can occur with high-speed running or with excessive hamstring lengthening. Athletes with proximal hamstring tendinopathy often do not report a specific inciting event; instead they develop the pathology from chronic overuse...."
Citation: Chu SK, Rho ME. Hamstring Injuries in the Athlete: Diagnosis, Treatment, and Return to Play. Curr Sports Med Rep. 2016 May-Jun;15(3):184-90. doi: 10.1249/JSR.0000000000000264. PMID: 27172083; PMCID: PMC5003616.
The hamstrings as a graft material for cruciate ligament reconstruction
During cruciate ligament reconstruction the surgeon may choose to take the tendon of the semitendinosis and that of the gracilis as a graft material.
-
Quote from peer-reviewed paper:
"There is variable hamstring regeneration after harvest...Although overall functional deficits have been reported to be minimal, a definite change in the anatomy of the medial hamstrings is a factor..."
Citation: Dhillon MS, Rajnish RK, Dhillon S, Kumar P. Is there significant regeneration of the hamstring tendons after harvest for ACL reconstruction? A systematic review of literature. J Clin Orthop Trauma. 2021 Feb 17;16:208-218. doi: 10.1016/j.jcot.2021.02.011. PMID: 33680834; PMCID: PMC7919951.
Forum discussions
- weak hamstring??
ACL reconstruction patients discuss problems with weak hamstrings after surgery.
Relevant material -
2008 - Primer -