Le 5 juillet 2016, 03:50 dans Humeurs • 0
How running shoes can have a detrimental effect on our feet and lower extremity? To be clear, I am not arguing that it is unnatural or wrong to heel strike. On the contrary, there are several reasons why barefoot and shod people sometimes prefer to heel strike, especially on soft surfaces. Womens Nike Casual Shoes Heel striking allows you to lengthen your stride easily, and it requires much less strength in your calf muscles (which have to contract forcefully while they lengthen to help bring down your heel gently when you forefoot strike). Heel striking is also easier on the Achilles tendon. The thick heels on many shoes also make it difficult not to heel strike. My point is that when you heel strike in a cushioned shoe, your body no longer gets the sensory feedback it expects to help modulate your gait to change the impact.
As a result, if you run in cushioned shoes with poor form, it is easy to be a thumper, hitting the ground hard with every step.12 Thanks to the shoe’s cushioned heel, these impact peaks don’t hurt. But if you run 40 kilometers (25 miles) a week this way, each leg experiences about a million forceful impacts per year. These impacts, in turn, may be damaging. Studies by Irene Davis and others have shown that runners who generate higher, more rapid impact peaks are significantly more likely to accumulate repetitive stress injuries in their feet, shins, knees, and lower back.13 My students and I found that members of the Harvard cross country team who heel strike are injured more than twice as frequently as those who forefoot strike.14 The bottom line is that whether you forefoot strike or heel strike, you should do so gently, and being barefoot gives you less choice.
“Shoes have other features designed to increase comfort that also affect your body. Many shoes, including running shoes, have an arch support, which props up the arch of the foot. A normal foot arch looks like a half dome and naturally flattens a little when you walk, stretching to help stiffen the foot and transfer your weight to the ball of the big toe. Nike KD Shoes When you run, the arch collapses much more, acting like a giant spring that stores and releases energy, helping push you into the air (see chapter 4). Your foot has about a dozen ligaments and four layers of muscles that hold the arch’s bones together.