Most players eventually want more than one serve, and the three that matter are flat, slice, and kick. Understanding what actually changes between them — and, just as importantly, what a form analysis can and can't tell about which one you hit — will save you a lot of confusion when you read your feedback.
The three serves, briefly
Flat is the fastest and lowest-margin — struck cleanly with little spin, tossed out in front, the first-serve bomb. Slice brushes the side of the ball, curving it and staying low, tossed a touch more to the side; a reliable, angle-creating serve. Kick brushes up and across the back of the ball to make it jump — tossed more overhead and slightly behind you, with a bigger upward-and-over cartwheel of the shoulders, waiting a beat longer, and typically finishing out on the hitting side rather than crossing the body. It's the go-to second serve because its heavy margin and jump make it safe.
The headline: these serves legitimately look different in the body. A kick serve's more-overhead toss and its finish out to the side aren't faults — they're the design.
Why the camera is serve-type blind
Here's the honest and important part. CoachVision measures your body, not your intent. It has no idea whether you meant to hit a flat, slice, or kick serve — the ball, the spin, and the racquet are all invisible to the tracker. The only way it knows is if you tell it, through the serve-type note when you film. Be precise about where that note lands, though: it reaches the coach writing your feedback, so the words come back in the language of the serve you meant. It does not move the measuring stick.
Take the cross-body finish. On a flat serve, the hitting arm usually whips across the body to the tossing side — a full throw. On a kick serve, the arm finishes out on the hitting side by design, so a reading that would look short on a flat serve is exactly right on a kick. CoachVision only reads that finish from behind the baseline — film the sideline view we recommend and it isn't measured at all — and when it is read, the band is deliberately wide for exactly this reason: one band has to cover all four serve types at once. The same goes for a high toss-arm reach and a longer wait before contact: on a kick or second serve, those are the serve type working, not a problem. What the app can't do is grade a kick on a kick's own scale, because it only has the one scale. So when your serve type puts a reading near the edge of its band, that's the job to weigh it — read the number, not the grade.
What this means for reading your feedback
The measurement bands are deliberately generous and serve-type-agnostic — they're built to span flat, slice, kick, and second serves without punishing any of them. So a value sitting just outside a band on a serve whose shape looks strong is usually the serve type showing through, not a fault to chase. What the numbers really measure is the shape underneath all three: did the racquet drop, did the legs load and fire, did the body stack under the ball, did contact happen high. That shape is the engine every serve type shares.
The practical takeaway: pick your serve type before you film and tell the app. A kick serve described as a flat one gets coaching notes written for the wrong serve — it'll read as finishing wrong and tossing too far back, when really it's doing its job. Give the app your intent and the notes come back for the serve you actually hit; the numbers underneath are the same either way, and interpreting them for your serve type stays your job. Master the shared shape first; the three flavors are variations on the one engine, not three different machines.