This one has me intrigued and is a good example of how agendas can interfere with the management of clinical problems.
Severs disease or calcaneal apophysitis is an overuse injury that occurs to the growth plate at the back of the calcaneus or heel bone that is more common between the ages of 10 to 14 years. It is by far the most common cause of heel pain in kids and is more common in those kids involved in athletic activity. The most common symptom is pain on activity and pain at the edges around the back of the heel bone, especially if squeezed by the hands. The growth plate merges with the rest of the heel bone around the mid-teenage years, so ceases to be a problem after that age.
The exact cause of Severs disease is not clear, though overuse is the obvious factor. The reason that it is not clear are that there are two loads on the growth plate. One of those loads is from the calf muscles as the Achilles tendon inserts into the growth plate, so if this load is a factor in the condition, then forefoot striking is going to increase the load on the growth plate. The other load is the growth plate is the part of the calcaneus that contacts the ground first during gait, so if this load is a factor in the condition, then heel striking is going to increase the load on the growth plate.
There is not one piece of evidence that shows or even hints at which of these two causes of the load (or a combination of them) is the predominant risk factor for Severs disease. I have specifically asked two people who did their PhD’s on Severs disease (and there is probably no one that knows more about this condition than these two) which one of the two loads, in the absence of evidence, did they think was the problem. Was it the pull from the Achilles tendon or was it the impact on the ground? Neither of them had any idea which was more important. So we have no evidence and the experts agree that we do not know.
For this reason, the most common first line approach to its management is to use some sort of cushioned heel raise. This will have the effect of reducing the impact load on the growth plate as well as reduce the pull from the Achilles tendon, so both bases are covered. Combined with a short to medium term reduction in activity levels, using ice after activity, doing calf muscle stretching and a dose of commonsense, this generally works pretty well in the majority of cases.
The reason that this one intrigues me is that if you hang out on the barefoot or minimalist running forums and websites you sometimes see a parent asking about the Severs disease that their kid has and wants some advice on what they should do. The uniform advice is to go minimalist and forefoot strike as heel striking is the cause of Severs disease. We have no evidence that this is the case, the experts do not know if it is and if the pull from the Achilles tendon really is the problem, then this is really bad and potentially detrimental advice.
Why is it that those with no clinical experience and totally unfamiliar with the evidence, have such strong opinions on clinical conditions and give such bad advice and not be held legally accountable for that advice?
I go where the evidence takes me until convinced otherwise.