Day 45 pairs the fastest standing exercise in the program with one of the slowest floor ones. Four 15-second intervals - high knees, plank leg raises, high knees, plank leg raises - three to seven sets, one minute of rest.
A plank leg raise holds the high plank position and lifts one straight leg off the floor, then lowers it and alternates. It looks minor and it is anything but: the moment a foot leaves the ground your base drops to three points, your hips want to tilt, and the glute of the lifting leg has to work while the whole core fights to keep everything level. After fifteen seconds of high knees, arriving at an exercise whose entire success criterion is stillness is a genuine change of gear.
Lift the leg from the glute rather than by arching your lower back, and stop when the foot is a hand's width off the floor - height is not the point, control is. Keep the hips square and the plank line intact. On high knees, drive the pace and use the arms.
Legs everywhere for fifteen seconds, then one leg moving and everything else forbidden to.
Make it Harder: Hold each leg at the top for two seconds before lowering, and keep the hips from dipping while you do it.
Make it Easier: Take the plank from your knees and lift one lower leg at a time rather than the whole leg.
