Sprint power cutoff?

I’m not the strongest sprinter, so I’m hardly surprised to be passed by many fellow racers on the final effort to the line - but I’m wondering if my abilities are the only factor holding me back. On my harder sprint efforts, I often notice that the power trend shown at bottom of Zwift screen is flat-topped, as if my power was cut off at a certain limit. The screenshot here shows today’s example. Examination in Strava shows that my actual power during the interval ranged from 627 to 674W, while the power in the previous harder effort also shown (and not subject to limit) was around 570W. So it seems like Zwift cuts off my power around 600W - at least in the display, I don’t know if it also affect in-game speed calculation. I use a left-pedal Stages powermeter as my power source. Any thoughts?

Completely normal - the graph cuts off there, Zwift does not cap your power.

First, the good news: Zwift is not capping your power, Yay. The graph simply cuts off for presentation purposes. Imagine the big power monsters pushing 1500-2000w (they are out there!), the graph would cover half the screen.

Second, the bad news: Losing sprints is all down to your ability. Those beating you to the line are positioning themselves better, timing their sprint better and delivering their power more efficiently (perhaps in bigger doses too).

Keep riding, keep training, keep improving. Ride On!