A hamstring strain is a tear in one or more of the hamstring muscles. The hamstring group is made up of three muscles, the semimebranosus, semitendinosus and biceps femoris. Their main function is to bend your knee and extend your hip, and contribute to the position of your pelvis.
The most commonly strained hamstring muscle tends to be the biceps femoris.
Like most muscle strains, a tear is likely to occur at the musculotendinous junction.
Signs & Symptoms
A sudden sharp pain or pull at the back of the thigh during exercise – most probably during sprinting or high velocity movement
Pain on stretching your hamstring
Pain on contracting your hamstring (knee flexion or hip extension)
Possible swelling and/or bruising
What Causes It?
Hamstring strains are extremely common in sports involving sprinting, sudden acceleration/deceleration, hurdling, and kicking.
When you are sprinting and stride out, the hamstring muscle is in a lengthened position, but also at the point where it generating most of its power. This position is therefore the point at which strains often occur. Other contributing factors include:
Decreased flexibility of the hamstring group
Poor hamstring strength
Poor core stability leading to increased reliance on the hamstring group as a pelvis stabilizer
Weak glute strength, resulting on an increased reliance on the hamstrings to generate power
The presence of trigger points in the glutes and hamstrings which refer pain and affect length and function of the hamstring muscles.
Lumbar degeneration, affecting nerve supply to the hamstring muscles
How to Self Manage
Cease activity immediately to prevent damage
Apply the R.I.C.E.R. principles
During this phase, do not run or exercise, do not stretch the injured area, do not consume alcohol, do not apply heat and do not massage the area.
It is advisable that you seek treatment for this injury, because if scar tissue forms then this will form a point of weakness in the muscle and could increase the likelihood of reinjury.
Hamstring injuries will be graded by your physio from grades 1-3 depending on the severity of the injury. The recovery time also depends on the degree of the tear.
A strain to the hamstring typically occurs from overload or excessive stretch to the muscle. Muscle strains can be categorized in to three grades
Grade I – damage to a few muscle fibers (<30%), localized pain, normal strength
Grade II – damage to more muscle fibers (30-80%), localized pain, swelling, and pain reproduction on power testing of the muscle
Grade III – damage to >80% of fibers or complete rupture. Most commonly occurs at the musculotendinous junction.
How Physio Helps
Your physiotherapist will:
Assess the length and strength of your hamstring to determine the degree of strain (see soft tissue healing and management for details).
Assess the length and strength of your core and lower limb muscles to check for any imbalances
Assess your thoracic and lumbar spine for any restrictions
Provide manual treatment to promote healing and reduce scar by using massage, deep transverse frictions, joint mobilization, stretching of the muscles and nerves, ultrasound, and acupuncture.
Prescribe a relevant rehabilitation program including progressive strengthening, as well as agility and sports specific exercises where needed.