Day 7 puts your legs and hands in the same room. The Practice structure runs 10 seconds of squats, 20 seconds of side kicks, 10 seconds of squat hold punches and 20 seconds of punches, for 5, 10 or 15 rounds. Half the round happens below parallel, and the other half is powered by what you built there.
Squats and kicks are the same muscles doing different jobs, which is why they lead into each other here. The squat loads the quads, glutes and hips; the side kick spends that strength one leg at a time. Then comes the interesting part: punching from a held squat. The legs work isometrically while the torso rotates and strikes, teaching the single most important power lesson in striking - punches are thrown with the legs, and the arms just deliver the mail.
Squat to parallel with the weight in your heels and the chest up. In the squat hold, find a depth you can defend for the full 10 seconds and stay there - thighs burning, guard up, punches turning from the hips even though the legs cannot move. When you rise for the standing punches, notice how much easier rotation feels with the legs free again: that contrast is the lesson.
Ten seconds in a squat with your fists flying - the shortest interval on the card and somehow the longest.
Make it Harder: Sink the squat hold deeper and refuse to rise even a centimetre until the interval ends.
Make it Easier: Take the squat hold a few inches higher - a position you can punch from beats one you abandon.
