That's, like, more than 30% of the applications. Wow. You have to figure that pent up demand, then, will carry into 2022+.
As to your other comment about messing with stride length, cadence, foot strike: I would disagree on the latter (foot strike) for sure. Changing to a mid/forefoot strike many years ago had a very positive effect on my running. An inefficient/ineffective foot strike is an element that should be fixed by many runners...along with that comes the issue of contact time as runners roll through from heel to toe. I would speculate that a better foot strike will also naturally improve cadence due to the contact issue. Improvement in stride length probably becomes a natural function of strength and flexibility rather than active alterations during the run.