1. Poor Body Position

• Your head or hips may be too high or too low.

• If your head lifts to breathe or if your kick pushes your chest upward, it causes your body to seesaw—hips drop, chest rises, and vice versa.

2. Inconsistent Kick Timing

• An unsteady or overly powerful kick can create upward and downward thrust rather than driving you forward.

• If you’re “bicycle kicking” or not using a compact flutter kick, it adds vertical motion.

3. Pressing Down with the Hand

• During the catch, if you press down on the water instead of pressing back, your upper body lifts.

• This throws off balance and rhythm.

4. Core Not Engaged

• A soft or loose core can’t hold a stable, horizontal line in the water.

• You end up flopping or bouncing instead of gliding.

5. Breathing Mistakes

• Lifting your head to breathe instead of rotating your body causes a spike in vertical motion.

• You might also “pause” your stroke to breathe, which creates a stop-start rhythm that looks like bouncing