Insight
Why Do Muscle Injuries Keep Coming Back?
Sport and Exercise Physician | Managing Director
Published
September 1, 2026
Sport and Exercise Physician | Managing Director
Published
September 1, 2026
Muscle injuries tend to be prominent across the NRL and other professional competitions. Hamstring muscle injuries generally receive most of the attention, but recurrent calf, quadriceps and adductors injuries can be equally frustrating. This is not just an elite-sport problem. At Axis, most of the people we see are recreational athletes trying to return to running, club sport, work or regular exercise.
I have some personal experience too. Despite regularly advising others about progressive loading and sensible return-to-running programmes, I keep tearing my own calf. It is an uncomfortable case of "do as I say, not as I do", but it illustrates how easily rehabilitation can stop once the pain settles.
Across professional football studies, approximately 16% of muscle injuries are reinjuries. In one large study, recurrence rates were approximately 30% for hamstring injuries, 29% for adductor injuries and 21% for quadriceps and calf injuries. This is a problem, partly because it is very frustrating but also because these second injuries also tend to cause longer absences that then original injury.
The risk of recurrent hamstring injury is highest during the first two weeks after returning to sport, and more than half occur within the first month.
While time is definitely an important part of a good treatment plan, this is a resource that is generally in short supply in elite sport. Athletes need to know that pain settles long before strength and load tolerance have fully recovered. They may be able to jog, complete a gym session or sprint but this does not automatically mean that they are prepared for the demands of competition.
Building strength is a key goal of a successful rehabilitation programme. This should begin early and remain a priority throughout an athlete's recovery. Initial isometric and controlled resistance exercises can be introduced within the limits of pain before progressing to heavier loading through a greater range. Being able to tolerate substantial eccentric loading in the clinic or gym is a critical phase of recovery because muscle must absorb high forces as they lengthen during running and sport.
Hamstring rehabilitation should combine knee-dominant exercises, such as curls and Nordics, with hip-dominant exercises, such as Romanian deadlift and long-lever bridges. Programmes incorporating Nordic hamstring exercise can approximately halve hamstring injury rates with completed consistently. Calf rehabilitation should target both the gastrocnemius and soleus through straight-knee and bent-knee loading before progressing to heavier resistance and explosive work. The same principles apply to quadriceps and adductor injuries.
Restoring eccentric strength is an important rehabilitation goal, but it is not the only goal. Rehabilitation must also restore mobility, balance, coordination, power and overall lower-limb function. Gym-based loading should be combined with progressive running, acceleration, deceleration and change-of-direction drills. To complete successful rehabilitation the final stages, need to reproduce the speeds, fatigue and sport-specific tasks the athlete will encounter when they return.
Running should be introduced alongside the later stages of strength rehabilitation, rather than waiting until all gym work is complete. Unfortunately, there is no single test that proves someone is ready, but the muscle should be able to tolerate meaningful resistance and eccentric loading.
Following a calf injury, a recreational runner should generally be able to walk briskly, climb stairs and hop without pain or altered movement. A useful target is 25 to 30 good-quality single-leg calf raises, using both straight-knee and bent-knee variations, with less than approximately 10% difference between sides. This is a guide rather than a guarantee, and experienced runners or professional athletes will require greater capacity.
The first run should be deliberately easy. Alternating one minute of running with one minute of walking for 15 to 20 minutes is often better than starting with a continuous run. Early runs should be separated by 24 - 48 hours, with progression guided by symptoms during the run and the response later that day and the following morning. It is a good idea to increase one main variable at a time: duration, frequency, speed or hills. The traditional advice to increase weekly distance by no more than 10% is not strongly validated, is pretty conservative but does feel sensible. A recent study of more than 5,000 recreational runners found that the length of an individual run relative to the longest run during the previous 30 days may be more important. Sudden increases in load are not sensible. Based on this data someone whole longest recent run is 3km should not attempt 6km simple because their total weekly volume remains low.
For field-sport athletes, drilling or easy running must progress to high-speed and repeated sprinting before full return. An NRL player also needs to sprint after contact, get repeatedly off the ground and maintain performance under fatigue. Reaching a target speed once is not enough; the player needs to tolerate these demands repeatedly and across successive training sessions.
Most recurrent muscle strains are not caused by an unusual structural abnormality. More commonly, rehabilitation has ended too early or has not adequately restored strength, speed and load tolerance. This does not necessarily mean that anyone has done a poor job.
The missing element may not become apparent when the person returns to their full activity.
If you keep injuring the same calk, hamstring, quadriceps or adductor, repeatedly resting until the pain settles is unlikely to solve the problem. A sport and physician or physiotherapist can review the diagnosis, identify what has been missed and develop a structured strength and return-to0running programme matched to the demands you need to tolerate.
