The Side Everyone Attacks
Opponents find your backhand early and keep going there. That makes it the shot under the most pressure and the one most often hit while stretched, late, or off balance — conditions that expose small technical faults which never surface during a comfortable warm-up rally.
It is also the harder side to feel accurately. On the forehand your dominant arm gives you a reasonable sense of where the racket is. On the backhand — particularly one-handed — that feedback is weaker, so the gap between what you think you did and what you actually did tends to be wider.
The result is a stroke that gets diagnosed by outcome. The ball floats, so you are told to swing harder. But floating usually comes from late preparation or contact too close to the body, and swinging harder makes both worse.
One-Handed and Two-Handed
The analysis does not require you to declare which backhand you hit. Phase detection and joint-angle measurement work from the pose data itself, so the same six phases and the same measurements apply whether you hit with one hand or two.
What differs is how you read the results. A one-hander depends more on early preparation and a contact point well in front, so shoulder rotation and contact extension carry more weight. A two-hander is more forgiving on contact position but more dependent on a stable base, which makes knee bend and rotation through the forward swing the numbers to watch.
The Six Phases of a Backhand
Every backhand is segmented automatically from the pose data — nothing is marked by hand, and the boundaries reflect what your body actually did rather than a fixed time slice.
Ready
Split-step and neutral position before the ball is read, establishing the baseline for the rest of the stroke.
Preparation
The turn away from the net. On the backhand side this happens under more time pressure, which is why late preparation is the most common fault.
Backswing
The racket travels back and down. Shape here determines whether you can drive through the ball or end up steering it.
Forward Swing
The chain unwinds toward the ball. Stability through this phase separates a backhand that holds up under pace from one that breaks down.
Contact
The decisive frame. Contact position and arm extension are measured precisely here.
Follow Through
Deceleration and finish. A short or blocked finish usually points to a problem earlier in the swing.
What Gets Measured
Pose estimation tracks 33 body landmarks on every frame, and the measurements below are derived from them:
Shoulder rotation
Peak rotation between preparation and contact. On the backhand this is the clearest signal of whether you turned early enough or reached for the ball with your arms.
Knee bend
Average bend on your hitting-side leg through preparation. The backhand depends heavily on a stable, loaded base.
Arm extension at contact
Elbow angle on the exact contact frame. Contact too close to the body is the classic backhand breakdown, and it shows up here as a sharply bent elbow.
Swing path
Trajectory angle through the hitting zone. A negative value means a high-to-low path, which flattens the ball out and costs margin over the net.
Separation (X-factor)
Shoulder-to-hip separation, reported only when you film from behind. A side view cannot recover this angle.
Filming a Backhand That Analyses Well
A phone is enough, and handedness and camera view are both detected automatically. Film from the side for swing path, contact position, and extension; film from behind for rotation and separation.
Keep your entire body in frame for the whole stroke, feet included. Landmarks that leave the frame cannot be measured, and on the backhand side players often drift out of frame during the follow-through.
Capture a few repetitions rather than one perfect swing. The backhand you hit under pressure is the one worth measuring, and a single rehearsed stroke tends to flatter you.
Turning It Into Practice
Each analysis returns a score per area of the stroke alongside written feedback explaining what the numbers mean and what to work on — in plain language, not joint-angle notation.
The comparison that matters most is against your own earlier uploads. Six weeks of work on early preparation should show up as a measurable change in peak shoulder rotation, not just a feeling that things are going better.
The same pipeline handles your forehand and your serve. To see the output format first, the sample analysis walks through a complete annotated breakdown.