Trainee: Hold the legs of the standing partner in a supine position. Extend the legs vertically upwards and when the partner wants to push the legs towards the floor, hold against them/brake the downward movement so that the legs never touch the floor.
Partner: Hold the trainee's legs in a high position and push them towards the floor.
Attention:
Always listen to/respond to your partner (adjust pressure/intensity). Keep your back in constant contact with the floor (no hollow back, consciously tense your stomach), do not put your legs down, keep your legs as straight as possible.
Lighten:
Just hold the position (legs stretched out in extension of the upper body), raise and lower your legs without additional impulse from your partner.
Harden:
Increased impulse from the partner; additional weight for the legs.
Variant:
The partner pushes the legs not only straight towards the floor but also to the side (direction known to the exerciser or arbitrarily defined by the partner).
