How to perform it

Mark two turnaround lines with clear stopping space before either wall. Follow the prescribed distance and work-rest intervals; build up from an easy rehearsal.
Accelerate with short, purposeful steps. Keep your head up so you can judge the approaching line.
Begin braking before the line: shorten the final steps and lower through the hips and knees. If a hand touch is prescribed, reach only as low as you can while staying balanced.
Plant the turning foot securely, with the knee following the toes. Push back along the route without wrenching the knee over a fixed foot.
Alternate the turning side across repetitions. Keep the turns controlled throughout the set, rather than winning the first sprint and losing your braking technique.

Common mistakes

Leaving all the braking to one overlong step at the line.
Touching the floor by rounding the back and dropping the head instead of bending the legs.
Letting the turning knee collapse inward or twisting on a foot that cannot turn with the body.
Always turning on the same leg, or placing the turnaround so close to a wall that there is no stopping space.

Skip or adapt this movement if any of these apply — and check with a professional when in doubt.