So yesterday, I was helping out a friend in jump starting his car when I had the urge to go visit the "rest" room. Anyway, I did a quick hopstep to jog back to the house, and in so doing, I felt and heard a painful pop coming from the calf of my "good" leg (my left knee and ankle are caput for running, so my right leg is my good leg). I hit the ground and couldn't support myself much less walk normally. Luckily a couple of ex-physical therapy nurses were around and they diagnosed me with a minor muscle tear (aka a pull) in my calf and put me on a regimen of ibuprofin, ice and walking. All I did was an easy hop step to start a slow 100 foot jog. Of course, I had toddlers the day before jumping on my calves while I was their "horse" (something I've done for years). I'm 31 now and am discovering that I get injured like that much easier. I can only attribute this to age. BTW, I'm walking without crutches today, but it's more like a slow hobble. I was just getting the hang of my new MTB build too!