Lie on your back with your legs straight; place your arms at your sides or under your bottom for stability; engage your core and press your lower back gently into the floor. From this position, lift your legs upwards in a controlled manner (until your hips form an angle of approximately 90° or until your legs are vertical). Slowly lower the legs back to the starting position, stopping just before they touch the floor, without letting the back arch. The movement comes from the hips, not from momentum.
Attention:
Do not arch your lower back; do not swing your legs up or down; do not lower them too quickly; do not let your hip flexors do all the work (abdominal muscles not sufficiently engaged); do not tense your neck or lift your head (unnecessary additional tension).
Lighten:
Keep your knees bent rather than straightening your legs; lift one leg at a time (for better control); use a smaller range of motion; place your hands under your bottom for support; vary the movement: bend your legs, stretch them upwards, lower your straight legs in a controlled manner.
Harden:
Straight legs + slower eccentric phase (more core tension); stop legs just above the floor (hover hold); weight on the feet; hanging leg raises as a progression whilst hanging, toes to bar as an explosive variation, or V-ups.
Variation I:
Alternately lift and lower your legs.
Variation II:
Bend your legs together (keeping them straight or turning them out to the side) and then straighten them.
