9 Ways to Track Your Arm Speed

The gold standard. Stalker radar guns are what MLB scouts and college recruiters point at pitchers, and for good reason — they read release or plate velocity within a tenth of a mile per hour from up to 300 feet away. If you need a number that goes on a recruiting profile, this is the number that counts. The tradeoff is price and portability: these are dedicated, standalone devices built for one job.

A pocket radar won't match a Stalker's precision, but it gets close enough for real training decisions at a fraction of the price and size. The Smart Coach fits in a back pocket, runs on AAA batteries for a season, and gives instant, no-guesswork mph readings — which is why it's become the default for youth and travel-ball coaches who need a real number but not a scouting-grade one.

These go beyond speed: spin rate, spin axis, movement profile, and release point on every single pitch. If a radar gun answers "how fast," a pitch-tracking system answers "how fast, and why does it move like that." That extra dimension is exactly why they cost as much as a used car and need real setup — they're built for programs optimizing pitch design, not for a quick bullpen check.

A sleeve-mounted sensor reads arm slot, forearm angular velocity, and elbow torque on every throw — not the ball's flight. That makes it a poor way to answer "how many mph did I just throw," but the best tool on this list for answering "is my arm getting overworked." Fatigue is the single biggest predictor of throwing injuries, and workload trends are what these sleeves are actually built to catch.

Swap "arm speed" for "clubhead speed" and the same accuracy-vs-convenience tradeoff plays out on the range. A $199 PRGR gives an accurate swing-speed reading with zero app or subscription; pricier options like the Rapsodo MLM2PRO add ball flight, carry distance, and video sync for players who want the full picture, not just a number.

These apps use your phone's camera and known throwing distance to calculate velocity, and some report accuracy close to a professional radar gun when the phone is positioned correctly. The catch is the setup: you need a tripod, a fixed distance, and consistent framing every time, which makes them better for a dedicated bullpen session than a quick check in the backyard.

Film the throw at your phone's highest frame rate, count frames from release to target, and do the distance-over-time math. It works, but it's tedious, one throw at a time, and it measures average flight speed rather than release speed — a ball loses roughly 7–8 mph to drag between the mound and the plate, so the number needs a correction factor to mean anything.

These apps read the acceleration of your iPhone or Apple Watch during the throw or swing itself, not the ball's flight — so they're a different tool than everything above, not a cheaper version of it. That's exactly why an app like Arm Speed Analyzer covers baseball throws and bat swings, golf swings, tennis and pickleball serves, and disc golf throws with the same setup: no tripod, no sleeve, no dedicated hardware, just your watch or phone. Where it doesn't compete is a certified mph number for a scout or a recruiting profile — for that, you still want a radar gun.

The most complete picture, and the least useful for an individual just trying to see a number after a bullpen. These platforms combine strength testing, throwing workload, and velocity history to flag fatigue before it becomes an injury — built for a pitching lab or a travel program with a roster to protect, not a single athlete training alone.