Leg extension

Why it's here

The leg extension works the quadriceps on their own, with nothing else limiting the set. How you use its range matters: in a twelve-week trial, training the knee-bent part of the movement grew parts of the quadriceps more than full-range training, while training only the straight-legged end did least ^[1].

The evidence

• Training study Forty-five untrained women trained the leg extension for twelve weeks in one of four ranges. Training only the knee-bent range (100° to 65° of knee bend) produced greater relative growth than every other condition at one measured site, and more than full-range training at two others; training only the straight-legged range (65° to 30°) did no better than not training at two sites ^[1].
• Training study The same trial found no range beat varied-range training for strength. Its participants were untrained, so whether the knee-bent advantage holds for experienced lifters is less certain ^[1].

How to do it

1. Set the seat so your knees line up with the machine's pivot and the pad rests on your lower shins.
2. Start with your knees well bent and straighten them under control.
3. Lower slowly all the way back to the bent position. Don't cut the bottom short — that knee-bent range is where the trial above found the most growth ^[1].

Stop an exercise that causes significant or unusual pain and have it assessed. This page describes the movement; it is not rehabilitation advice.

Making it harder over time

This is a isolation exercise in the Progressive Overload Calculator, which adds weight in steps of 2%–5% once every set reaches the top of your rep range, and adds reps until then.

Alternatives

• Leg press — Heavy quadriceps work with nothing to balance, so sets can go close to failure and the load can rise in small steps.
• Smith machine squat — A squat with the bar on a fixed track. Machine training built muscle and strength about as well as free weights.