Hamstring
Strain

What is a hamstring injury?

Hamstring injury is one of the most common injuries in sport, as the hamstring muscles are particularly susceptible to strains and tears.

Hamstring injuries are especially common in sports requiring high levels of acceleration, speed, power and agility, such as basketball, tennis and all codes of football.

Anatomy: The hamstring group, located at the back of the upper leg, consists of three muscles:

• Biceps femoris
• Semimembranosus
• Semitendinosus

These muscles originate at the lower part of the pelvis and insert onto the tibia and fibula just below the knee joint. The hamstrings act to flex (bend) the lower leg at the knee and extend (straighten) the upper leg at the hip.

Risk factors

Hamstring injuries may occur due to muscle imbalance or incoordination between the quadriceps (front thigh muscles) and the hamstrings (back thigh muscles). Quadriceps are strong muscles that assist in leg extension, and may overstretch the leg, placing excessive tension on the hamstrings.

Acute hamstring injuries can occur due to sudden movement or force. Athletes are usually immediately aware of the injury, and may report hearing a “pop”.

Proven risk factors:

• Previous hamstring injury
• Increasing age of the athlete
• Sudden changes in direction (acceleration or deceleration)

Suspected risk factors:

• Poor flexibility
• Poor strength
• Hamstring muscle fatigue
• Muscle imbalance between quadriceps and hamstrings
• Inadequate or no warm-up

Signs and symptoms

Hamstring injuries are classified as Grade 1–3 strains, depending on severity. A strain may occur in one or more of the three hamstring muscles.

Grade 1 (mild)

• Overstretching with minimal tearing of muscle or tendon fibres
• Symptoms may not appear until after activity
• Usually no loss of strength or flexibility
• Muscle tightness during stretch or full range of motion
• Pain may be felt while sitting, walking uphill or climbing stairs
• Weight-bearing and walking may be possible; swelling is usually minimal

Grade 2 (moderate)

• Partial tear in the muscle.
• Reduced strength and flexibility
• More immediate and severe pain than Grade 1
• Pain during stretch and contraction, and usually tenderness on touch
• Likely to limp when walking; occasional twinges during activity
• Pain when bending the knee against resistance; difficulty straightening the knee

Grade 3 (severe)

• Severe or complete rupture of the muscle. May be a large lump (of muscle tissue) above a depression where the tear is.
• Sudden, sharp pain in the back of the thigh.
• Walking is not possible without pain.
• After a few days, a large bruise may appear below the injury site caused by bleeding within the tissues.
• May require surgical repair.

Management

Immediate treatment should follow the RICER protocol – Rest, Ice, Compression, Elevation and Referral – for 48–72 hours. This helps reduce bleeding and muscle damage.

• Rest the muscle in an elevated position
• Apply ice for 20 minutes every two hours (never directly on skin)
• Apply a properly fitted compression bandage to control swelling and bleeding

The No HARM protocol should also be followed – No Heat, No Alcohol, No Running or activity, and No Massage – to reduce swelling and bleeding in the injured area.

Recovery time depends on the type and severity of the strain. As a general guide:

• Grade 1 strains: rest from sport for about 3 weeks
• Grade 2 strains: rest for at least 4 to 8 weeks
• Grade 3 ruptures: may require surgery and around 3 months of rehabilitation

Premature return to sport and inadequate rehabilitation increase the risk of reinjury. Athletes should regain full range of motion and strength, and complete full-speed sport-specific drills (accelerating, twisting, jumping, changing direction) before returning to play.

Ways to help prevent hamstring strain include:

• Completing a full warm-up, including sport-specific stretching and skill drills
• Including appropriate speed work in training to prepare the hamstrings for high acceleration
• Maintaining cardiovascular fitness and muscular endurance to minimise fatigue
• Stretching and cooling down after training and games
• Including regular stretching and strengthening in training programs
• Undertaking training prior to competition to ensure readiness to play
• Gradually increasing the intensity and duration of training
• Allowing adequate recovery time between sessions
• Wearing appropriate footwear and protective equipment
• Checking the sporting environment for hazards
• Staying hydrated before, during and after play
• Avoiding activities that cause pain. If pain occurs, stop immediately and commence RICER