Leg Extension
The leg extension is a seated machine exercise where you straighten your knees against a padded lever. It isolates the quadriceps, including the rectus femoris that squats train less. Use it to add quad volume without loading your back, or to finish your legs after heavier compound lifts.
Muscles worked
The leg extension trains the quadriceps.
Primary
Weekly sets for quadriceps
Hard sets per week that Swole.fit plans for quadriceps, counting every exercise that trains it. Start a cycle near the growth line and climb toward the recovery limit before a deload.
How to do the leg extension
- 01Adjust the back pad so your knees line up with the machine's pivot point.
- 02Set the shin pad just above your ankles, resting on the lower shin.
- 03Sit back, grab the side handles, and keep your hips pressed into the seat.
- 04Extend your knees until your legs are straight and squeeze your quads at the top.
- 05Lower slowly until your knees reach about 90 degrees or a little deeper, then repeat.
Coaching cues
- Knees in line with the pivot
- Squeeze hard at the top
- Hips stay in the seat
Common mistakes
- Misaligning your knee with the pivot makes the pad slide and loads the joint awkwardly, so adjust the backrest first.
- Swinging the weight up and dropping it wastes the eccentric, so control the lowering for two to three seconds.
- Lifting your hips off the seat to finish reps takes tension off the quads, so hold the handles and stay down.
How Swole.fit programs it
Log it once and the app plans the next session for you.
- Most sets land between 8 and 15 reps, the range the plan steers isolation work toward for size.
- Week one starts around 2 to 3 reps in reserve. Each week you train a little closer to failure, ending around 0 to 1 in reserve before a deload week.
- Hit the top of the range on every set and the next session adds the smallest real jump in weight, rounded to the plates, dumbbells or stack you actually have.
- Sets for this exercise count toward your weekly volume for every muscle it trains: a full set for the primary muscles, half a set for the helpers.
The full method, with the maths, is in how mesocycles work.
Leg Extension alternatives
Same muscles, different tool. Swap in one of these when the equipment is taken or your joints want a change.
Free programs that use it
Ready-made splits from the Swole.fit library. Pick one and the app runs the progression.
- Core Four3 days a week, chest, back, shoulders, quadriceps
- Leg Destroyer3 days a week, quadriceps, hamstrings, glutes
- Pump & Circumstance3 days a week, chest, back, shoulders, biceps, triceps
- Leg Specialization4 days a week, quadriceps, hamstrings, glutes
- Powerbuilder Classic4 days a week, chest, back, quadriceps, shoulders
- Squat Science4 days a week, quadriceps, glutes, hamstrings
Log it. Let the app plan the next one.
Track your leg extension free. Swole.fit picks the next weight, counts your weekly sets and tells you when to deload.