One of the most important parts of muscle injury rehabilitation is not just choosing exercises, but understanding why we have chosen specific exercises.
That may sound obvious, but in practice it is where rehabilitation can become surprisingly unclear. There are countless exercise options available, and the literature on muscle injury (particularly hamstring injury) has expanded rapidly. We now have studies investigating fascicle length, muscle size, eccentric strength, activation patterns, varied joint angles, muscle lengths, tendon behaviour etc etc.
While these studies are undoubtably valuable, it can be difficult to see the wood through the trees. And it’s easy to get drawn towards whichever exercise is currently fashionable, or which study appears to give the answer we want to hear.
So how do I approach rehab?
When I’m selecting exercises targeting the injured area, I typically programme 1–3 key exercises, and I prioritise them in the following way:
1. Structural adaptation of the injured tissue
Hamstring and Calf muscle injuries are not all the same. We call these “muscle injuries” but the reality is we may be dealing with a variety of tissue structures; some are predominantly myofibrillar while others involve the myo-aponeurotic complex, intramuscular tendon, or free tendon. These tissues may not respond in the same way to loading. Therefore, my key consideration is:
What structural quality am I trying to restore, and what loading stimulus will drive that adaptation?
For example: muscle tissue (strength and hypertrophy etc) will adapt across a range of loading conditions, while tendon and aponeurotic tissue likely require higher mechanical strain; with aponeurotic tissue responding to both longitudinal strain achieved in long length contractions and transverse strain through muscle bulging. Additionally, I may want to consider structural adaptations such as increasing fascicle length or physiological cross-sectional area. All of which will benefit from different loading stimuli.
Therefore, when selecting an exercise I would always consider:
- The exercise: what tissue am I trying to “bias”?
- Position: long length or short length? How does this influence strain?
- Load / intensity: is this sufficient to stress the tissue appropriately?
- Reps/ sets: how much is too much? And how does this impact intensity?
Hamstring muscles do not operate uniformly across all positions. Their ability to generate force changes with hip and knee angle, and different exercises will expose the tissue to very different mechanical environments. If those variables are not aligned with the target adaptation, it is very easy to undercook the injured tissue!
2. Functional adaptation (force, RFD and SSC)
Once the tissue is being exposed to an appropriate structural stimulus, I want to know whether it can also meet the functional demands of the sport.
Sprinting for example, places very large demands on the hamstrings; especially in late swing, where they are required to tolerate high loads under very short time periods with high strain on elastic tissues. These tissue qualities should be restored within our rehab process if we are to prepare the athlete for the sport demands we aim to return them to. And each are developed through variances in how we program exercises.
For me, exercises targeting functional adaptations would typically be placed early in the session, where fatigue is low and the quality you want to develop (rapid force, elastic/ reactive strength) can be expressed appropriately without fatigue.
3. Addressing synergists and specific deficits
This is the part that is often missed when rehabilitation becomes too “injury-site” focused. It is easy to think that if the injured structure is the biceps femoris long head, then all exercise selection should focus on loading the biceps femoris long head. But movement is not isolated.
The hamstrings operate as a group, and there are meaningful differences between the medial and lateral hamstrings in architecture, moment arms and likely functional contributions. Furthermore, surrounding function of the trunk and lower limb may all influence mechanical patterns and the loading demands placed on the hamstring.
Therefore, appropriate assessment of the hamstrings through different ranges and positions, along with system level/ surrounding joint/ tissue function, can help us to identify further functional deficits which may influence the initial injury. Through assessing and addressing these deficits we can aim to restore balanced contribution across the whole system, not just in one isolated structure.
Final Thoughts
This is just my personal framework on how I select exercises in hamstring and calf muscle rehab. It does not touch on wider considerations such as movement patterns, sprint exposure and global/ system level tissue qualities. But at a local tissue level; the exercise, joint angle, sets, reps and intensity are often far more meaningful than people consider.
Get the exercise prescription right, and you give the tissue the best possible chance to adapt. Get it wrong, and rehabilitation can quickly become non-specific with poor outcomes.