Table 3 Loaded power, plyometrics and ballistic exercises, and running rehabilitation after a calf muscle strain injury

Loaded power, plyometrics and ballistic exercises

 Once load tolerance has been shown during strengthening, begin rehabilitating dynamic muscle–tendon unit actions

“Isolated strength progressions will overlap and entwine with slowly getting them moving more dynamically. So getting them started a couple of days after you start loading them with decent single leg strength work. Once they start adding good loads then they can definitely start to add in more advanced dynamic work.” Expert 11

 Use mixed approaches (loaded and unloaded) to restore elastic function prior to running

“You think: ‘Gee this guy looks good,’ and then they go out and start running, and we have even manipulated their running depending on what tissue they have injured, but then they break down. I think it’s perhaps because we have restored strength, length, endurance, but we haven’t considered ground contact times in rehab with plyometrics and explosive exercises,” Expert 1

‘ Power-endurance’ is often an important attribute at RTP: build both instantaneous and repeated power capacities

“I think you really need to respect running for what it is: how much repeated force goes through your body, the elastic properties you need to run. And I think people might take that for granted—these abilities you need to develop in rehab before you can tolerate running demands.” Expert 1

 Dynamic loading can bridge calf capacities developed during heavy strengthening and field-based activities, as well as re-exposure to the mechanism of injury (if any)

“If you can’t hop well then you can’t sprint. It is just that simple. You don’t have the tissue capacity. You don’t have the elastic properties…it just means that their risk of injury is probably higher, in my experience, of re-injuring that calf.” Expert 2

“The issue with calves is that they’re the first point of loading in our kinetic chain, and this is the thing that’s often lost in rehab, you know. So whereas you can accommodate stuff more proximally, there is nowhere to hide with the calf… that is why the problematic ones are really problematic.” Expert 13

Running rehabilitation

 Begin the path to running reconditioning early using low-load walking drills and exercises

“As soon as they are tolerating isolated calf work, I will start to add in some more dynamic work. So I might do things like a toe walk or a ballet walk up on their toes, and you can add in a couple of kettle bells or dumbbells into their hands. And then start progressing into some more dynamic movements. So before I start adding in true foot stiffness, advanced plyometric type drills, I will often get them to do some ladder-based drills, maybe ‘under-overs’, so there is less vertical explosive force. Something like an ‘ecky-shuffle’; side skips, grapevine on their toes…” Expert 3

 Gradually rehabilitate locomotive capacity—CMSI are unforgiving

“There’s no warning often with a calf in terms of a recurrence, and so there is a bit of risk-aversion to how to deal with calves in rehab. Whereas a hamstring, generally they have a little bit of ‘awareness’ or a little bit of tightness and you can pull back from there. Calves in my experience feel ‘good, good, good’ and then ‘no good.’ And so there’s no warning. There’s no ability to modify the session. So I think you almost need more confidence that its ready to go before you start exposing them,” Expert 16

 In the lead up to running emphasise run drilling and technique to smooth the transition and to ensure coordinated use of strength and power

“focus on, or use imagery, to minimize their time on the ground. And just put them in better positions….I think a lot of people who run ‘out the back’ have a lot of calf-Achilles issues.” Expert 1

“Lots of ‘pitter-patter,’ jump-land-react…it’s all the A-skips, the B-skips. I think you are teaching the coordination of the muscle again too because I think, when you see calves ‘go’ they often ‘go’ at low level, or stride pace, barely changing direction, it can’ t always be ‘we have exceeded the tissue capacity of the calf.’ Part of it has to be: ‘if it tries to fire at the wrong moment, when I put 90 kg and the rest through it, it re-injures.’ So there’s a lot of timing drills, and patterning and so on, in early rehab for us.” Expert 15

 Capacity must be high prior to running, accept a slight delay in return to running for CMSI compared to other muscle strains

“The loads in the calves are poorly understood—the very fact that running is essentially hopping from one leg to another, and I think that’s really poorly conceptualized by clinicians. So once they do all the slow training, and then go to run, bugger me they fail! So I think really getting the message out about how much load the calves absorb during normal running, I think that’s a ‘biggie.’ In fact I think it is one of the ‘biggies’ to be honest…how long do we wait before we start mobilizing? I think of the calf and our perfusion below the knee is less than what it is in other tissues. That’s something that the plastics guys talk about, and the orthopaedic surgeons talk about it too. We, you know, depending on the severity, but anything grade 3 then I am generally waiting 7 days or so before starting to load them, 5 to 7 days before doing too much. But mind you, once they can walk, I’d put them in a heel lift, and just start walking. But for some I’d extend that out to 7 to 10 days for a grade 3.” Expert 13

 Monitor functional milestones to determine readiness to run, and then use the first runs to test the waters—taking care to avoid too much “plodding”

“If you can’t do 20 repetitions of single leg hopping without having symptoms there is no way you should go running,” Expert 10; “Usually do 8 × 80 m and get them to sit or stand between reps. I don’t get them to walk back between reps because that is ‘time on the legs’. And then we will try to aim for 2 to 3 blocks of that, with enough rest between sets that they feel like they can run again.” Expert 1

“We start at about 60%, so that’s 4 or 5 m per second. The really slow running is effectively all calf work, whereas once you get your pace up a bit, you are starting to get some contribution from the more proximal regions. And again, you can mine from Tim Dorn’s paper [39] how long their contact times are as their pace increases, and so I think you try to keep their contact times not too slow.” Expert 13

 Progressing running volume requires the most careful attention for sports involving large running workloads and for ‘problem calves’ involving soleus

“For the calf it is probably more overall volume and what’s in that volume, and how that plays a role. Whether its high ‘accel-decels’, or high ‘B3’ or moderate speed running. So early on…our running would maybe just tick over on the edge of the 18 km/hr, but not try to give them too much in that 18 to 24 dose in the first one or two sessions, and then introduce that from there. But just always keep an eye on the overall volumes of it.” Expert 12

“Why can soleus be difficult? I guess it has a slightly different role to gastrocs. It is a lot deeper and you can't poke it or feel it as easily, or as obviously, as some particular issues. I think maybe it has a slightly different action. I think it is ‘on’ more often—so it might be prone to fatigue, so endurance might be an issue. Strength-endurance might be and issue with it. Often you can do ok for a short period of time, and also in terms of the speed of running. I know as speeds increase loads exponentially do as well and at higher speeds…so again unless you’re going full gas for a long time you can often compensate and get by. So I think that is a problem because people cannot go full gas in training and in ‘game sims’, and they don’t get anywhere near the same level of fatigue, or the same kind of uncoordinated desperation in running, particularly with defensive running, that, once you get on the field, and you’ve got to do some defensive running late in the game and you’re knackered, you can’ t’ pull up, you can’ t go 90%, you go full gas and then ‘bang’….” Expert 16

 Address the range of running capacities needed to perform in the sport at RTP, and to be resilient to recurrent CMSI

“Acceleration is probably the big one, and then high-speed running. So, you know, your calf work plateaus at about 7 m per second, so once you can sort of build up to that speed, running faster doesn’t actually make any more work on your calf. But going from standing still to as fast as you can in a few steps—that’s the thing that really loads it up. So we will gradually build up speed, but the thing we are probably most careful on is max accelerations. Now we will start, once you can get through the first session of running, we’ll start accelerations but, you know, it will be from a standing start to a jog over 5 or 10 m, so it’s not explosive accelerations. Slowly, slowly, increase the velocities. Once the velocities are higher we will decrease the distances.” Expert 12

“We have some timed agility grids we progress through. Some ‘random’, so uncontrolled, unplanned agility type work, and that’s a conditioning thread that works through the rehab plan as well, because obviously we are not dealing with a linear sport.” Expert 16

 While volumes and intensity are built, running attributes can be fast-tracked using reconditioning methods

“I see their reconditioning as moving loads through range, so making it a bit more functional, rather than just doing a calf raise up and down. I’d use banded catch ups or Prowler, or Prowler catch-ups, or some sled walks….it is important because you are training your acceleration or your horizontal velocity movements. You are applying greater force through the ground in probably more, for want of a better word, ‘functional’ based positions where you’re bringing in extension or triple extension positions, rather than what we find with seated calf raise and these sorts of things. It is a nice load progression that replicates closer to where they are going with what they do in the game… and it gives me greater confidence if they can push greater load through in those sort of ranges and positions, that they are going to tolerate greater loads and forces that matches up with their match-like movements.” Expert 11

 Devote time to building tolerance of and exposure to the mechanism of injury during field-based rehabilitation

“Bear in mind how it happened too. If you’ve got a guy that has told you, quite specifically, that they were jogging backwards and they’ve gone to suddenly explode forwards as hard as they can and felt a grab in their calf—if that’s the mechanism of injury, that might be something you’d wait a little bit till toward the back end of the rehab process, and also include it as a key focus point in your functional rehab progressions versus a jump-land guy who, you know, say a ruckman who felt a grab in his calf landing from, or taking off for, a contest or something. And maybe the jump-land activities is a focus point for you when you rehab, and perhaps it is something you introduce towards the back end of the process.” Expert 18