STARTING FROM SCRATCH?
Prep your middle pre-jackknife with these simple – but super – progressions
1 HALF HOLLOW HOLD
Lying on your back, extend your arms straight past your head and bend your knees. Raise your feet and shoulders a couple of inches, keeping your lower back glued to the floor.
2 HOLLOW HOLD
Like the half hold, but keep your legs straight and raise your arms and legs higher to create a V shape.
3 BENT-KNEE JACKKNIFE
Start on your back with your legs slightly bent, arms extended past your head and lower back glued to the floor. Without arching your back, contract your abs to raise your torso and legs simultaneously, bending your knees and swinging your arms so they meet in the middle.