CHRONIC CALF INJURIES IN THE ENDURANCE ATHLETE

One of the injuries endurance athletes face is the chronic calf injury.  It is predominantly gastrocnemius muscle crossing both the knee and ankle and usually at the junction between muscle and tendon or medial head of the muscle on the inner aspect of the calf.  On occasion it may involve soleus, the short calf muscle.  This can be considered a little better as it is a less ballistic muscle but is involved in endurance sport to a greater level than tennis or other sports requiring rapid changes of direction.

Calf tears are not usually related to warm up but are fatigue related ie later in the run or end of second set at tennis.  This makes the notion of good strength accompanied by endurance critical in managing these injuries.

Control and stability around the pelvis can contribute to micro-trauma of the calf and subsequent injury.  For instance medial drift of the knee in stance (when standing on that side running) may load the medial calf to a greater degree creating micro tears in the medial head of the long calf muscle.  There are some indications that footwear contributes with pronation perhaps loading the medial calf again although there is some debate around this still.

How does the calf injury present?

Often we hear the story about an onset of calf pain running that was mild but restricted normal running. This may be followed by a short rest then a return to activity.  Then the patient had a sudden onset of acute calf pain as the muscle fatigued and the initial tear worsened.

The initial tear had not had sufficient time to consolidate its healing and as the surrounding muscle fibres fatigued they were unable to support and unload the torn fibres.  The result is further tearing of the already damaged fibres.

Why does it become Chronic?

If we consider the torn fibres a weak link due to the fact they are non contractile we want to keep this scar size to a minimum to limit its influence on the remainder of the muscle.

With repeated micro-tears at one site the scar size may increase since it is continually being pulled away and more collagen is laid down to repair it. 

This requires time to consolidate the healing process and gain enough strength and endurance to enable loading in sport without further tearing at the site.

Chronic calf tears can usually be related to either insufficient healing time post injury before return to sport or faulty mechanics with increased loading and subsequent micro tears at a site within the calf (usually medially).

Management

The first recommendation for calf injury is sufficient recovery time prior to return to activity.  As a guide most muscle injuries require 3- 5 weeks before being adequately healed to allow loading in sport (they will recover to allow day to day loading earlier).  Initially this means rest from activity requiring aggressive calf contraction to allow the muscle fibre to begin growing back in the correct architecture. Managed loading on the bike is well tolerated after the first week on most occasions.

Once through the first week post injury the strengthening phase must start again.  By definition the muscle fibres are torn due to insufficient strength for the activity undertaken.  If you were unlucky enough to fall from a height and tear the calf on landing you could argue it wasn’t a normal training stimulus so won’t have to get stronger than you were initially to prevent recurrence.  However if you were merely running and suffered a calf injury you may not have had sufficient muscle strength to tolerate that level of load.  In this case you will require a level of strength and endurance that exceeds your pre injury level.

The strength exercise that we use is simple enough with it being a single leg calf raise but how you progress it is important.  Begin the exercise with the foot flat on the floor before rising up onto the toes reaching the highest point over 2 seconds, then lower until the heel just comes into contact with the floor again before repeating.  By beginning the first progression on the floor you avoid outer range muscle work by the calf and lessen the risk of re-injury during your rehab.

Progress this to doing it on a stair to allow the heel to pass lower than the toes at the lowest point to make the exercise more functional.

How many?

Again there are no scientific studies to back this up but from experience we find that 3 sets of 45 reps of single leg calf raises with 90 seconds rest between sets is a manageable number that diminishes the risk of calf injury.  For the first 3 weeks of the strengthening regime this is undertaken 5 days a week and then 3 days a week following this.  The risk of re-injury is attached to the run rather than the calf raises so when you reach the point of returning to run complete the run first and calf raises second if you are contemplating doing them both in the same session.  Separating them into 2 sessions allowing recovery between would be preferable.

When do you stop your strengthening regime?

This is pretty imprecise.  Once you have achieved the 45 reps it could be argued that you could stop at this point.  However it is likely there will be a decline in strength with only bike and run as the training stimulus.  If you are prone to chronic calf injuries we would encourage you to continue the strength exercises and include them in your core workouts which would ideally be twice per week.

Return to running can usually be negotiated at some time after weeks 3-5 once you have sufficient strength to hop pain free repeated times.  We use a figure of a dozen hops in the clinic.  Not because it is anything scientific but because it gives us a realistic idea without subjecting the patient to unreasonable risk of tearing again by hopping through to fatigue.

Where does stretching fit with calf injury?

There is an ideal length for any muscle that allows it the best mechanical environment to work in.  Stretching a muscle past this point is likely to upset this length / tension relationship.  As a quick guide if you stand with your foot facing a wall and bend the knee forwards as far as you can with the heel on the floor the toes should be between 5 and 8 cm from the wall.  With a straight knee but a similar stance bending the ankle forward this should be a little less.

Stretching can be part of your warm-up to run and something to be undertaken when you have particular stiffness in a muscle.  However not everyone requires regular muscle stretching to maintain the optimum muscle length.

This isn’t intended to replace sound medical advice but to give you a working model of chronic calf tears to assist recovery and avoid further injury.  Many other things can reproduce calf pain but be remote from the site so your chronic calf may not in fact be a calf injury at all but be lumbar spine, compartment syndrome, the popliteal artery to name a few.