Swimmer Kicks V. 2 (male)

Lie face down on a mat with your arms extended overhead.

Engage your core and lift your chest and legs off the ground simultaneously.

Kick your legs up and down in a fluttering motion, as if you were swimming.

Continue kicking for the desired number of repetitions.

Lower your chest and legs back down to the starting position.

Losing tension in the core or lower back partway through the movement — because Swimmer Kicks V. 2 (male) loads multiple joints at once, a small breakdown in bracing at the hips or spine compounds through the whole chain.

Flaring the elbows too wide or letting the hips sag/pike, which shifts load off Glutes and stresses the shoulder joint.

Rushing through reps using momentum rather than controlling both the lifting and lowering phase, which is especially important since there's no external load to force good tempo.

Skipping a warm-up set at lighter load/intensity — even "beginner" exercises benefit from a rehearsal set to groove the movement pattern before working sets.