Several American runners can break the two-hour marathon mark just by improving their stride efficiency. In this video, we measure their bounce, stride angle, overstride angle, toe lift angle, and crossover angles and compare them to African runners who are more efficient.
Since runners take 1,000 strides per mile, any small problem in stride mechanics will be amplified 26,200 times during the marathon. A 4" bounce, for instance, results in running 3.3 vertical miles during the race.
Bouncing up and down, overstriding, crossing the legs over toward the midline and lifting the toes all over-stress the legs, increase injury and fatigue, and slow the runner down.
The myth persists that African runners win because they are genetically superior, run to school as kids, and live and train at high altitude. But video analysis of their stride shows that they win because they run more efficiently.