Your hamstring muscle rehabilitation guide
Hamstring injuries are one of the most common soft tissue injuries, particularly in athletes and active individuals.
Understanding the mechanics of the hamstring muscles, the causes of injury and the rehabilitation process is crucial for recovery.
Below we will look at the role of the hamstrings in movement, common injury mechanisms and key recovery pathways and rehabilitation exercises.
The role of the hamstring muscles
The hamstring group consists of three muscles, each with slightly different functions. They are located at the back of the thigh: the biceps femoris, semitendinosus and semimembranosus.
These muscles span from the pelvis to the tibia and fibula, playing a vital role in knee flexion, hip extension and overall lower body mobility.
When you walk, run or jump your hamstrings work to decelerate the leg as it swings forward.
These muscles also help stabilise the pelvis during movements like bending forward or lifting, contributing to the body's overall balance and posture.
Common hamstring injuries
Hamstring injuries typically occur due to overstretching or sudden acceleration, often seen in activities that involve sprinting or quick directional changes.
Hamstring strains are classified based on severity:
Grade 1 (mild): minor muscle fibre damage with a slight loss of strength. Symptoms include tightness in the back of the thigh but no significant pain or loss of function.
Grade 2 (moderate): partial muscle tear with more noticeable pain, swelling and loss of strength. Patients may have difficulty walking and a limited range of motion.
Grade 3 (severe): more than half of the muscle fibres torn to a complete muscle tear that results in severe pain, swelling, bruising and an inability to walk without assistance.
Hamstring strains present as pain in the posterior thigh, however if this pain is proximal to the pelvic bones or the back of the knee, the injury may be to the hamstring tendon, which will need alternative management.
The bicep femoris (the long muscle at the back of the thigh), is the most commonly injured hamstring muscle.
Sprinting-related activities, where the muscle rapidly transitions from eccentric (lengthening) to concentric (shortening) contraction, are the primary causes of this injury.
Occasionally, sciatica can be misinterpreted as a hamstring strain, particularly if the onset of pain is during sport or a run. Clinicians will help to differentiate between the two, and an important part of hamstring rehabilitation is ensuring the patient has sufficient sciatic nerve flexibility.
Hamstring strain symptoms
A sudden pain in the back of the thigh, without direct external contact (i.e. contusion) is a common symptom of a hamstring injury.
This is common during explosive movements (sprinting or jumping), and in contact sports with a running component, such as the football codes.
Acute hamstring strains are very common, however overuse strains can also occur.
Recurrent strains are also common due to return to play after inadequate healing or reconditioning.
There are also predisposing factors that can lead to a hamstring injury. These include:
Limited hamstring flexibility
Poor lower body maximal strength
Poor hamstring eccentric strength
Inadequate velocity exposure
Fatigue
Previous calf injury
Previous substantial knee injury
Osteitis pubis
Rehabilitation for hamstring injuries
Rehabilitation of hamstring injuries should be individualised, focusing on restoring strength, flexibility and function while preventing re-injury.
Historically, muscle strains were managed in the context of a recovery timeframe, such that rehab may progress every two weeks or so with the understanding that the muscle has become healthier due to time and the exercises being performed.
Though we can still be guided by timeframes, there is a way of progressing athletes more effectively through rehab by using sets of criteria that allow them to pass to the next stage.
In many cases, this allows an individual to return to play sooner than expected.
For example, rather than waiting two weeks to progress to phase two of the rehab program, an individual may demonstrate sufficient function after 4-5 days of early-stage rehab, allowing them to enter phase two.
This doesn’t mean that we rush rehabilitation unnecessarily, however we do tend to see exercise introduced from day one, and progress sooner than in the past.
In professional sports settings, this has resulted in less time lost to injury for professional athletes.
Early-stage (phase 1) hamstring rehabilitation
The early stage of rehabilitation involves both isometric contractions of the hamstring and early-stage eccentric exercises.
Isometric contractions: are those that generate force without a change in muscle length (i.e. you will see effort but no joint movement). The length the muscle is positioned in, as well as the force of contraction, can be adjusted to suit the muscle’s current capacity.
Eccentric contractions: are those that see the muscle lengthen while generating force (i.e. a braking force). Repeating a movement involves alternating concentric (shortening) and eccentric (lengthening) muscle contractions, and at times a muscle may be injured during its eccentric (lengthening) phase of contraction.
The inclusion of eccentric-based exercises in hamstring rehabilitation is protective against future injury and can be included in the early stages of rehabilitation.
Here are some key exercises that can be incorporated into phase 1 of a hamstring rehabilitation program:
Isometric contractions (0 degrees, 45 degrees, 90 degrees)
Isometric double leg bridge
Isometric single leg bridge
Isometric double leg bridge with weight
Assisted eccentrics
Swiss ball eccentric slide outs
Phase 2 hamstring rehabilitation
Phase 2 of hamstring recovery incorporates some rehabilitation exercises with increasing complexity to challenge the hamstring muscle to aid in the healing process.
These exercises aim to strengthen and restore mobility. But, to progress to this new phase of rehabilitation, certain achievements should be reached.
In relation to the exercises outlined below, here is a guide to suggest you can move onto the phase 2 exercises:
Pain-free knee extension stretch
Less than 3/10 pain with isometric contraction
Ability to perform >10 single leg hip thrusters
Ability to perform >10 swiss ball sliders
Isometric contractions don’t feature in this phase of rehab. The eccentric exercises are progressed, and weighted exercises such as a hip thrust (bridge) and RDL are introduced.
Phase 2 exercises:
TRX slide-out
Bridges (double, single and weighted)
Assisted eccentrics (single and double)
RDL with long eccentric phase
Band-assisted Nordics
Phase 3 hamstring rehabilitation
Phase 3 of hamstring recovery bridges the gap between rehabilitation and full function - or return to play.
This phase involves higher loading of eccentric exercises, in particular bodyweight or weighted nordic curls.
The strength program should start to resemble what the individual was capable of prior to injury. There is also the inclusion of plyometric exercises to expose the hamstring tissue to higher velocity contractions.
For those playing sports or returning to running, the rehabilitation will involve running at max speed by the end of phase 3.
To enter phase 3, an individual should be able to demonstrate:
A symmetrical active straight leg raise test.
Pain free isometric contraction of the hamstring in prone lying position.
>15 single leg hamstring bridges (depending on ability to do so beforehand).
Ability to run at moderate speed
For some, we will also test their capacity to perform single leg eccentric sliders.
Here are the exercises we suggest in the third phase of a hamstring rehabilitation program:
Single leg RDL (landmine)
Bodyweight Nordics
Tantrums (with swiss ball)
Kettlebell swing
DB step-up
Conclusion
In our experience, rehab will not always neatly progress from one stage to the next, and the exercises provided here may overlap across the course of a rehab program.
A final consideration is when someone should return to normal training, or ‘return to play’.
There are differing opinions on what the ‘return to play’ criteria should look like, and each case needs to be considered individually, but here is a basic guide:
Symmetrical active straight leg raise (ASLR)
Strength testing <10% limb symmetry index (LSI)
Specific strength loads of greater than 90% of pre-injury capacity
Ability to sprint or run at max speed
Rehabilitating hamstring injuries requires a comprehensive approach that includes both therapeutic exercises and professional care.
By understanding the mechanics of the hamstring muscles and the principles of effective rehabilitation, patients can recover more effectively and return to their normal activities with reduced risk of re-injury.