The Assessment, Management and Prevention of Calf Muscle Strain Injuries: A Qualitative Study of the Practices and Perspectives of 20 Expert Sports Clinicians
This paper aimed to evaluate the current practices regarding assessment, management and prevention of calf muscle injuries. This was done through interviews with 20 expert clinicians who either work in elite sport or were researchers in the relevant field.
The first portion of the interviews focused on evaluating injury characteristics and in particular differentiating gastrocnemius strains from soleus strains. There was a consensus that soleus injuries can be an accumulation of symptoms that tend to present as a gradual onset, whether gastrocnemius injuries have a distinct mechanism. Soleus injuries are more common in steady state running whether gastrocnemius injuries tend to involve acceleration, jumping, landing or sprinting. Low grade soleus injuries can be more difficult to localise the source of pain, with focal pain being more common in injuries involving gastrocnemius (or severe soleus injuries).
Risk factors including past history of calf strain or previous lower limb soft tissue injury as well as recent interruptions to or sudden increases in running workloads, this is particularly relevant in soleus injuries. This was noted more often in the pre-season period as athletes were re-introduced to running workloads and higher intensity. In objective testing changing knee position can help differentiate muscle involvement for stretch and strength testing (flexed for soleus and extended for gastrocnemius) however in severe injuries symptoms will present similarly regardless of knee position. Appropriate loading during your examination from low load (isometrics) through to concentric (double and single leg) and plyometric if able assisted in grading the injury severity.
After assessment for injury severity and pathology, experts then looked at rehabilitation. Initial goals were normalising gait pattern and appropriate early loading. Once able to demonstrate single leg calf raise capacity athletes should then be progressed to loaded strengthening, commonly this involved smith machine calf raises, and seated calf raises. These should be set up with parameter reflecting the sport (eg: strength endurance in runners or force generation capacity in rugby or sprinters) and progress through range of motion as the athlete tolerates initially starting on flat then moving to an incline. Experts also advised to strongly considered soleus capacity in all calf injuries and athletes regardless of the pathology involved prior to introducing dynamic exercise.
The next step is to introduce plyometric/ballistic exercises. Two main exercise streams were identified: (1) repeated stretch-shortening cycle’s (SSC) over small length-excursions associated with a rhythmic muscle tendon unit (MTU) action (e.g. skipping or single leg pogos), and (2) single or several SSCs over larger length excursions (e.g. single leg countermovement jump, forward hopping) associated with an accelerative MTU action. These should be prescribed first in the vertical plane and then in the horizontal plane due to increased tissue demands required in the latter. Plyometric exercise selection should reflect the sporting demands and with sports such as AFL or soccer there may be a need to develop both rhythmic and accelerative plyometrics.
Determining readiness to run was another topic discussed throughout the paper with experts reporting that gait re-training drills were initiated as soon as practical with examples such as stair ascents, bear crawls or wall A-drills used. To be cleared for return to running 3 checkpoints were required, firstly achieving appropriate tissue strength capacity (eg: single leg calf raise endurance or loaded calf strength), secondly the ability to tolerate repeat hopping and finally the absence of any clinical signs or symptoms (pain on stretch, reduced ROM etc). Six recommendations were identified from information provided by experts to guide running rehabilitation: (1) initially run on alternate days, (2) avoid “plodding” early, (3) do not progress volume and intensity on consecutive running days, (4) schedule off-field exercises (e.g. loaded strengthening) after running, (5) shape running progressions to meet the demands of the sport—don’t overshoot with excessive volume, (6) avoid sudden changes in conditions, such as the surface and footwear. The reasoning to avoid plodding during early running rehabilitation was that it had been found to predispose to recurrence for injury involving soleus. Endurance capacity does need to be ticked off however the recommendation was to check this off last once higher speeds and change of direction loads had been hit.
A return to play checklist is detailed below, in terms of strength tests Smith machine raises (extended knee) at least 1 x bodyweight for 5 repetitions and seated calf raises 1.5 x bodyweight for 5 repetitions were recommended. For vertical hop tests a countermovement or depth jump was used and for horizontal capacity a single hop and triple hop test were used with an asymmetry of <10% compared to the unaffected side. Once the athlete has returned to sport, these tests can also be used as a monitoring criteria in regards to injury prevention. It was found the risk of recurrence was due to four main factors: (1) Increased chronological age, (2) previous calf muscle injury, (3) previous lower limb injury and (4) exposure/loading history. Experts agreed that the best way to mitigate risk was to ensure uninterrupted sports exposure whilst monitoring player training loads and continuing to hit strength benchmarks.