This week, a couple bloggers I follow posted some interesting things that I definitely would like to comment on.
Shoes and forces of running
First, Pete Larson at Runblogger had this interesting post about a study of rocker-soled shoes and forefoot pain.
I'd especially like to focus on what Pete says here:
I’m a believer that different shoes modify how forces during running are applied to the body...
This is a very important point that I think often goes unmentioned and even ignored. People talk about cushioned shoes absorbing impact for you or minimal shoes changing your stride in a way that reduces impact. I admit I've probably oversimplified and said these things at times myself. However, I don't think these claims are sound. Regardless of how much cushioning you have between yourself and the ground, at some point your foot is going to come to a stop and has to support the weight of your body. Regardless of what part of the foot comes into contact with the ground first, some part has to absorb that impact.
While some might say a higher stride rate means the impact forces are lower, I'd point out that unless you are running faster a higher stride rate also means you're going to be coming into contact with the ground more times per mile. So are you really reducing forces or just spreading them out over more impacts? I'm not sure about that answer but simple math suggests it's not as simple as some try to make it, that it's at least closer to a zero sum game than most people realize.
As for what to take with this information, I think the key point is to consider what gives you problems. If minimal shoes give you forefoot problems, consider shoes such as those with a rocker design or more cushioning that may shift some of the forces off the forefoot. If you have knee problems, consider shoes that will allow your foot to take more of the forces.
As usual, I'll say there is no right shoe for everyone. There is almost surely one right type of shoe (most likely available from more than one manufacturer in more than one model so you can find all the details that will work just right for you) for you but that may not be the right shoe for me or for your cousin who is asking for shoe advice. This is why I dislike shoe advice. When asked, I usually suggest going to a good shoe store instead of offering a specific model as some people seem to expect.
How to fend off age related decline?
There has been a lot of research recently on age related performance decline. Well, Alex Hutchinson at the Runner's World Sweat Science blog posts about another one.
In this case, runners were split into three different groups with average ages of 26, 61 and 78. Then average power at ankle, knee and hip were compared while walking, running and sprinting.
Interestingly, no significant differences were found at the knee and hip but there were some found at the ankle. A possible answer given is that we are using much stronger muscles to control the knee and hip than to control the ankle. As a result, as we lose muscle while we age, we can still maintain the same power output in those stronger muscles because they have more reserve power available. In the lower leg muscles, primarily the muscles making up the calf, we're already using a higher percentage of total capacity in our youth. As we age and lose power, we reach maximal power output and can't maintain.
So what does this mean? Well, it's obviously too early to make any definitive statements. However, it suggests that maybe strength work for the lower legs would help reduce age related performance declines. Given the fact that there's little downside I can see to doing some lower leg strengthening, I'd consider this another reason to in fact do what we should already be doing. That said, I am looking forward to more research to confirm this result and test the theory that strengthening the lower legs might help mitigate age related performance declines.