Total strides and thus average stride length may not change but the distribution of stride length will change as performance rises, as pointed out on the forum content:
1: Start stride length may shrink as the foot must land quicker and sooner when the athlete is driven out at a lower, more aggressive angle.
2: Mid strides get longer with more power.
3: Last few strides get significantly shorter as they change from freewheeling, slow bounds to power strokes closer in length to those of mid-race (at a much higher rate)
4: Average rate and specific point rate increase with performance.