Isolation exercises aren't typically regarded as huge mass builders, but a leg extension done to the point of exhaustion is excellent for stimulating hypertrophy and also bringing out more muscle shape and definition.
- 1Sit on the leg extensions machine
- 2Get your legs under the pads right above the ankles
- 3Grab the handles and rest your back and head
- 4Extend the legs up, contracting the quads
- 5After a brief pause at the peak contraction, go back down slowly
- 6Repeat the movement pattern
Do this one for high reps and it'll certainly have your muscles screaming.
The leg extension is going to strictly target the quad muscles while all the other lower body muscles get to have a rest.
Because this exercise is less demanding on your central nervous system compared to the other compound moves, you can add some intensity building techniques into the protocol.
For instance, try a T30-45 set, meaning you’ll ditch counting reps and instead, do as many as you can in 30 or 45 seconds. Beware you will feel the lactic acid burn with this protocol.
Or, you can try a mirror rep drop set. Do your first set, drop the weight by 30% and then do a second set after that. Aim for 8-10 reps per set when doing this set-up.
You can also change the direction you're pointing your toes in order to change the nature of the stimulus on the muscle tissue.
Point the toes out to work the inner quad, in to work the outer quad, or straight to work the quad head on.