5 Freestyle Swimming Mistakes That Slow You Down

Why Swimming Technique Is So Hard to Self-Correct

Swimming technique is uniquely difficult to self-correct because you cannot see yourself swim. Unlike land-based sports where mirrors and video are easily accessible, swimmers must rely on feel — a notoriously unreliable guide to technique.

Research published in the International Journal of Sports Physiology and Performance found that technique improvements in freestyle swimming produce greater speed gains than fitness improvements in recreational swimmers. A 10% improvement in stroke efficiency produces the same speed gain as a 15% improvement in aerobic capacity.

AI pose estimation tracks body position, stroke mechanics, and kick pattern throughout freestyle swimming, identifying the 5 errors that most reduce swimming efficiency.

Mistake 1: Head Position Too High

What it is: In freestyle, the head should be in a neutral position — the waterline at the hairline, eyes looking forward and slightly down. Head position too high (looking forward rather than down) causes the hips to drop, increasing drag dramatically.

Why coaches miss it: Head position is easy to assess from the pool deck but difficult to correct because it feels natural to look forward. Swimmers who look forward believe they are swimming correctly because they can see where they are going.

What AI measures: AI measures the angle of the head relative to the spine, flagging head elevation greater than 15° above neutral. Hip drop caused by high head position is also measured as a secondary indicator.

The fix: The "look at the bottom" cue — focus your eyes on the bottom of the pool, not the far wall. The waterline should be at your hairline. This naturally lowers the hips and reduces drag.

Mistake 2: Crossover Entry

What it is: In freestyle, each hand should enter the water in line with its own shoulder — not crossing over the midline of the body. Crossover entry (the hand entering past the midline) causes the body to snake from side to side, wasting energy and reducing forward propulsion.

Why coaches miss it: Crossover entry is visible from above but difficult to assess from the pool deck at water level. Coaches watching from the side cannot assess hand entry position relative to the midline.

What AI measures: AI measures the horizontal position of each hand at entry relative to the shoulder landmarks, flagging entry more than 5 cm past the midline as crossover.

The fix: The "shoulder-width entry" drill — enter each hand in line with its own shoulder. A useful cue: imagine two parallel lanes, one for each hand. Each hand should enter in its own lane.

Mistake 3: Dropped Elbow in the Pull Phase

What it is: In the underwater pull phase, the elbow should remain high (pointing toward the surface) while the forearm and hand sweep backward. A dropped elbow (elbow pointing toward the bottom) reduces the surface area pushing backward and dramatically reduces propulsion.

Why coaches miss it: The underwater pull phase is invisible from the pool deck without underwater video. Coaches watching from above cannot assess elbow position during the pull.

What AI measures: AI measures the angle of the elbow relative to the shoulder during the pull phase, flagging elbow drop greater than 30° below the shoulder plane.

The fix: The "high elbow catch" drill — focus on keeping the elbow pointing toward the surface as the hand enters and begins the pull. The forearm should be vertical (pointing toward the bottom) at the catch, with the elbow high. This maximises the propulsive surface area.

Mistake 4: Insufficient Body Rotation

What it is: In freestyle, the body should rotate 45–60° to each side with each stroke. Insufficient body rotation (less than 30°) reduces stroke length, reduces the power available from the core and back muscles, and increases shoulder impingement risk.

Why coaches miss it: Body rotation is partially visible from the pool deck but difficult to quantify. Coaches can identify swimmers who are not rotating but cannot measure whether the rotation is sufficient.

What AI measures: AI measures the rotation of the shoulder line relative to the horizontal throughout each stroke cycle, flagging rotation less than 35° as insufficient.

The fix: The "side kick" drill — kick on your side for 25 metres, then switch sides. This builds proprioceptive awareness of body rotation and strengthens the rotational muscles. Progress to full freestyle with a focus on rotating to each side with every stroke.

Mistake 5: Two-Beat Kick Timing Error

What it is: In a two-beat kick (one kick per arm stroke), the kick should be timed to the opposite arm entry — left kick as the right hand enters, right kick as the left hand enters. Incorrect kick timing (kicking with the same side as the entering arm) disrupts body rotation and reduces efficiency.

Why coaches miss it: Kick timing is a coordination error that requires watching the relationship between the arms and legs simultaneously. Coaches focused on arm mechanics often miss kick timing.

What AI measures: AI measures the timing of each kick relative to the opposite arm entry, flagging kick timing errors greater than 0.1 seconds from the correct timing.

The fix: The "opposite arm-leg" drill — in slow motion, practice the coordination of left kick with right arm entry and right kick with left arm entry. Use a kickboard to isolate the kick timing before integrating with the full stroke.

Using AI to Swim Faster

SportsReflector's swimming analysis tracks all 5 of these errors simultaneously, providing a technique score (0–100) with specific feedback on head position, hand entry, elbow mechanics, body rotation, and kick timing.

Download SportsReflector and find out which technique error is costing you the most time in the water.