QUAD EXERCISE: LEG EXTENSION5-6 sets (1-2 warmups and 4 working sets), 12-15 reps, up to full stackPHIL'S TAKE “This is a good warmup, and it’s a pre-exhaustion move to target my quads before squats and the other compound exercises. (In those latter moves) the muscles will then be pushed to their limits faster.”DO IT RIGHT Phil adjusts the seat for his prodigious frame, then sits, tucking the crook between his feet and lower leg underneath the pads. With his head focused forward, he grasps both handles for stability, then powerfully flexes his quadriceps to straighten his legs. Squeezing hard at the top, he bends his knees to lower the weight, stopping before the stack touches down and initiating the next rep.ERRORS & OMISSIONS One key with leg extensions is walking the line between an “explosive rep” and doing your sets in a sloppy fashion. “You don’t want to hyperextend your knees at the top,” Heath warns. “Think of repping with controlled explosiveness.”INTENSITY TIP “I don’t do much out of the ordinary for these, but you can hold the peak contraction for 1–2 seconds at the top of each rep for extra emphasis.” HAMSTRINGS EXERCISE: STANDING SINGLE-LEG CURL5 sets, 10–15 reps, various weightsPHIL’S TAKE “I’ll do this one because it can help even out imbalances. Like your biceps, your hamstrings might not always develop at an even pace, so I can give extra reps to one or the other as needed.”DO IT RIGHT Taking position on a standing leg curl machine, Phil places the working leg so that the pad sits in the area of the Achilles, then grasps both handles while keeping his non-working leg anchored. Flexing at just his knee joint, he brings the weight up as far as he can, envisioning his hamstring flexing like his aforementioned biceps muscle, then slowly releasing. He is sure not to let the weight stack touch down between reps, which would dissipate the muscle tension.ERRORS & OMISSIONS If your body is sliding and you’re moving around in an effort to gain leverage as you lift, you’re going too heavy. Knock the weight back, and concentrate on the hamstrings taking on all of the efort.INTENSITY TIP “You might have a tendency to ‘kick up’ the weight, but instead, keep the contraction deliberate and under control. Tempo is important on this exercise,make sure it’s steady and not a sudden, out-of- control burst to finish the lift.” FLEXOnline breaks down Phil Heath's leg routine, exercise by exercise. Click "Next Page" for: Hack Squat!