We have talked about step with hundreds of times it seems. We get asked all the time about optimal or proper step width in our runners, especially the ones that have a tendency to drop into the higher risk category of "cross over" gait. We like to refer them to our standard reply, "many good things happen with increasing your step width, but there is no need to go beyond the hip distance width, no wider than the hips. You should find more gluteal activation there. However, this is less economical than a narrower step width. But, the narrower the step width, you are juggling the increased economy with increased liability (for injury) and riskier biomechanics. One must earn their way into the higher economy narrow step width with gaining durability in these potentially riskier narrow step with mechanics. Failure to do so is a choice taken at your own risk." This article suggest costly risks to a narrow step width as well.
From the Shorter Abstract
"Humans tend to walk economically, with preferred step width and length corresponding to an energetic optimum. In the case of step width, it is costlier to walk with either wider or narrower steps than normally preferred. Wider steps require more mechanical work to redirect the body's motion laterally with each step, but the cost for narrower steps remains unexplained. Here we show that narrow steps are costly because they require the swing leg to be circumducted around the stance leg. And, we could not agree more. There is definitely a sweet spot for every runner, finding it, and earning the durability required to fend off injury is where the magic lies. RAther than tell your runners where to place their feet , thus you defining their step width, give your clients the appropriate hip and frontal plane stability work to find their low risk sweet spot. After all, most of the foot posturing placement is dictated from the hip and pelvis mechanics, as we have written about extensively previously.
Gait Posture. 2017 Mar 23;54:265-270. doi: 10.1016/j.gaitpost.2017.03.021.
The high cost of swing leg circumduction during human walking.
Shorter KA1, Wu AR2, Kuo AD3.