Sore Calf Muscles From Running in Vibram Five Fingers
This story starts with a very interesting (brutal) workout at my local CrossFit gym. It was five rounds for time, of running 400 meters followed by 10 squat thrusters (a front squat into an overhead push press) at the prescribed weight of 135 pounds.
Combining the short 400m run with the thrusters basically prevents you from catching your breath, and turns this into a monster metabolic conditioning workout. The total 2km of running was actually the most I'd done in a while since busting up my knees.
They had been healing nicely, so I figured it would be a good opportunity to work on my barefoot running form in my Vibram Five Fingers.
Be prepared for sore calf muscles. It's going to to happen, but it will pass.
I soldiered through the workout and was pretty happy with my performance, but the running really did a number on my calves. Up until then, I had mainly been wearing my Vibram Five Fingers for weight lifting and indoors training. Because this was my first time running in my barefoot shoes, I inadvertently made a rookie mistake in regard to my form.
I purposefully (and wrongly) avoided letting my heel strike the ground.
I focused on landing on the balls of my feet, which is an important component of a proper running form, but only half of the formula. By the end of the workout my calves were so tight I had trouble walking to my car. After three days I was still walking down the front steps to my apartment sideways!
After some advice from one of my trainers and from the website of "Barefoot" Ken Bob, I later realized how essential it is to let the heel "kiss" the ground to some extent after initially planting with the ball of my foot. This brief period of heel touch allows the calf muscles to temporarily relax (something they didn't experience during my workout). Here is an excerpt from Ken Bob's website:
"Letting the heel touch allows the calf muscles to relax. Do relax! Don’t fight to keep the heel off the ground, otherwise, you will end up with extremely sore calves and achilles tendons. You probably will have sore calves, and possibly sore achilles tendons, too, at first anyway. Especially if you are new to running, or have been a chronic heel striker (over striding)."
Along with this critical mistake in my form, I also neglected to realize that years of wearing shoes had affected the conditioning of my leg muscles. Not only are very few of the leg's muscles activated while running in shoes, but the calf muscle becomes shorter in relation to the amount of cushioning between the heel and the ground.
When switching from my old sneakers to Vibram Five Fingers, that change amounted to a difference from 25mm to 6mm! After taking shoes out of the picture, the lever action between the foot and the leg increases significantly.
Even when using proper form, new barefoot or minimalist runners will notice that their calf muscles are very sore and tight in the beginning. When allowing the heel to kiss the ground in the middle phase of the forefoot landing stride, the calf muscles do a lot of work towards controlling the heel's descent.
"Controlled descent" is key here because it insinuates that your heel is safely and softly touching, instead of banging and driving into the ground like in the typical heel strike landing. If this sounds complicated remember, it isn't rocket science. Just relax and let your body do what it needs to in order to prevent you from hurting yourself and causing pain. You don't need to force something your body was naturally engineered to do!
In fact, a body composition test I had done revealed that during one period of my training my calf muscles grew faster than any of the other major areas of my body.
Be sensible about your training and don't do any hard running if your legs are already really sore. Just get plenty of rest and keep working at it! Focus on running with good form and with a light step, rather than trying to reclaim your previous mileage as fast as possible.
I've also made this video to help explain some of the issues that contribute to muscle soreness from barefoot running.
If you want to learn more about the muscles and soft tissue which interact during human running, you should check out the book Running Anatomy. It offers an intriguing inside look into what the human body is doing while you're tearing it up out on the track.