Swimming stroke analysis, one phase at a time

Practical guide · Updated August 8, 2026

Stroke changes are difficult to feel and difficult to explain from the pool deck. WithCoach aligns two recordings at a repeatable event such as hand entry, the start of the catch, wall contact, or breakout so the athlete can see the difference directly.

The app combines side-by-side playback, a shared sync point, individual frame steps, drawing annotations, and speeds down to 1/8x. Local comparisons are unlimited on the Free plan; exports and sharing include a WithCoach watermark.

How to record useful swimming video

Useful swimming footage depends on a clear phase of the stroke. Record from a stable poolside position, or import safely captured underwater footage after the session.

Side view: follow one lane while keeping the swimmer's entry, body line, kick, and exit in frame.
Front or rear view: record from a safe, permitted position to inspect alignment and symmetry.
For turns and starts, frame the wall, approach, contact, push-off, and breakout as one sequence.

Four moments worth comparing

Entry and extension

Compare hand placement, reach, body line, and whether the swimmer crosses the center line.

Catch

Align the start of pressure on the water to review elbow position, forearm direction, and body rotation.

Recovery and breathing

Inspect timing, head movement, shoulder rotation, and how quickly alignment returns.

Turn and breakout

Compare approach distance, wall contact, streamline, first kick, and the timing of the first stroke.

A repeatable analysis workflow

Choose two clips showing the same stroke, turn, or start from a similar angle.
Set a sync point at hand entry, catch initiation, wall contact, or breakout.
Use slow motion and frame steps to compare the full phase around that moment.
Draw a line for body alignment or an arrow for the intended hand and forearm path.
Share the short visual correction before the next pool session.

A useful review does not need dozens of marks. One clearly synchronized difference, one visual cue, and one new attempt give the athlete something concrete to act on. The next comparison then shows whether that change held.

Analyze your own swimming footage

Start with unlimited local comparisons on iPhone. No credit card is required for Free.

Download free on the App Store

Frequently asked questions

Can WithCoach use underwater swimming video?

Yes, if the footage is already available in a format the iPhone can import. Capture underwater video only with suitable equipment and in accordance with pool rules.

Where should I sync swimming stroke clips?

Choose a repeatable event tied to the question: hand entry for alignment, catch initiation for propulsion, breath timing for head movement, or wall contact for turns.

Can a swimmer review the coach's annotations later?

Yes. Reviews can be saved, exported, or shared according to the account's available plan and coaching access.