Hamstring injuries are common problems that affect a large number of athletes. These injuries can be slow to heal with a very high rate of re-occurrence. Hamstring injuries are often associated with sports that require fast acceleration and deceleration such as running (intervals), football, soccer, and rugby.
Among medical researchers, there is a considerable lack of consensus in regards to what precipitates a hamstring injury. Some of the more common theories are lack of strength, flexibility, muscle imbalances, and not warming up before an athletic event. However, it is agreed upon that hamstring injuries are usually not the result of a direct trauma, referred to as a “Non Contact Event”.
The hamstrings are called bi-articular muscles because they cross both the hip and knee joints. This is an important consideration because a hamstring injury can affect your hips, low back, knees, and the motion patterns of the entire lower extremity. If we consider fascial connections (posterior line), we will see that a hamstring injury can affect a very large area.
The hamstrings are composed of three muscles in the back of your thigh. They are called the:
- This muscle originates in the lower pelvis (ischial tuberosity) and runs down the back of the leg to an area just below the inside of the knee (Anterioromedial surface of the tibia, in an area called the Pes Anserinus).
- Three muscles insert into the pes anserinus: The Gracillis, Sartorius, and semiTendinosis (GST – Just remember sales tax). The pes anserinus is a common area to feel knee pain when the bursa that is under these muscles becomes inflamed.
- This muscle also originates in the lower pelvis (ischial tuberosity) and runs down the back of the leg to an area below the knee on the posterior medial side (posterior medial tibia).
- Inflammation of the Semimembranosis is often confused with an injury of the medial meniscus.
- Removing a restriction from the semimembranosus can have a positive effect on meniscus function.
- The biceps femoris has both a long and a short head. The long head originates in the lower pelvis (ischial tuberosity, common tendon of semitendinosus, and lower part of sacrotuberous ligament).
- It is easy to understand how low back pain can be also be referred from the hamstring with direct fascial attachments that run from the long head of the biceps femoris directly into the sacrotuberous ligament.
- The short head orginates on the outside and of the leg (posterolatera femur). Both heads insert just below the knee on the lateral side (head of fibula and lateral condyle of tibia).
- Numerous studies have shown that the biceps femoris is the most common site of hamstring injury (myotendinous junction).
In part two of Resolving Hamstring Injuries we review Hamstring Functional Actions, When the Hamstrings are Torn, and Grading a Hamstring Injury.