- EquipmentMachine
- PatternIsolation
- Reps10 to 20 reps
- Joint loadKnee
Sit in the machine with your knees in line with its pivot and the pad resting on the front of your lower shins. Hold the handles.
First cueLine the knee up with the pivot.
How to do the Leg Extension
Set up. Sit in the machine with your knees in line with its pivot and the pad resting on the front of your lower shins. Hold the handles.
- Straighten your knees to lift the pad.
- Squeeze the thighs at the top.
- Lower under control.
Form cues
- Line the knee up with the pivot.
- Keep your hips on the seat.
- Lower slowly.
Common mistakes
- Swinging the weight up.
- Lifting the hips off the seat.
Muscles worked
Main target: Quads. The quadriceps are four muscles at the front of the thigh. They straighten the knee: squats, lunges, leg presses and every stair.
The catalog names no other muscle it works on the way.
Its other side: Hamstrings and Glutes, in the knees and hips pattern.
What to pair it with
Movements that round out a workout with the Leg Extension, from the same catalog the StatBlockFit app logs.
- Seated Leg Curl Superset partner: it trains the other side of the knees and hips pattern, so the two can alternate.
- Cable Pull-Through Same legs session: it trains the glutes.
- Seated Calf Raise Same legs session: it trains the calves.
- Hip Abduction Often left out: it trains the abductors, a job the moves above leave undone.
A complete workout around it
5 movements, the Leg Extension first, at the catalog's rep ranges. Load it into the workout builder to change the sets, reps and weights, then bookmark it or download it.
- Leg Extension 3 × 10 to 20 reps
- Seated Leg Curl 3 × 10 to 20 reps
- Cable Pull-Through 3 × 10 to 20 reps
- Seated Calf Raise 3 × 10 to 25 reps
- Hip Abduction 3 × 12 to 25 reps
Alternatives and swaps
The same main muscle with other equipment: a swap never changes the muscle a workout trains.
Home or dumbbell swap
Heel-Elevated Goblet Squat
Kettlebell
Gym or cable swap
Smith Machine Squat
Smith machine
Less load on the knee
Terminal Knee Extension
From the app's workaround table: less deep knee bend under load.
A swap describes the movement, not your body: if a joint hurts, ask a professional before you train it.
Working weight and 1RM calculator
Enter a set you did: the weight, the reps and how many more reps you had left in you. The estimate is the formula the StatBlockFit app uses for its records, weight × (1 + (reps + reps in reserve) ÷ 30); above 12 reps it is rough.
Training zones
| Zone | Share of 1RM | Usual reps |
|---|---|---|
| Strength | 85 to 90 % | 3 to 6 |
| Muscle growth | 70 to 80 % | 6 to 12 |
| Endurance | 60 to 65 % | 15 to 20 |
A warm-up before the working sets: 50 % for 5, 70 % for 3 and 85 % for 1, each rounded down to a plate.
Common starting points, not a prescription: the right weight is the one you can lift with good form for the reps you planned.
Variations and preparation
Its variations: Terminal Knee Extension.
Do before it: Terminal Knee Extension (same movement, lighter).
Track it in StatBlockFit
In the StatBlockFit app the Leg Extension is logged set by set: the app suggests your next weight after each session, times your rests, keeps your records and shows the 72-hour recovery of every muscle on its training map. The training guide explains how.
Questions
How do you do the Leg Extension?
Set up: Sit in the machine with your knees in line with its pivot and the pad resting on the front of your lower shins. Hold the handles. Steps: 1. Straighten your knees to lift the pad. 2. Squeeze the thighs at the top. 3. Lower under control. Form cues: Line the knee up with the pivot. Keep your hips on the seat. Lower slowly. Common mistakes: Swinging the weight up. Lifting the hips off the seat.
What muscles does the Leg Extension work?
It trains the quads; the catalog names no other muscle it works on the way.
What can I do instead of the Leg Extension?
At home: Heel-Elevated Goblet Squat. In a gym: Smith Machine Squat. With less load on the knee: Terminal Knee Extension. Each trains the same main muscle.
What should I pair the Leg Extension with?
Good partners in the same workout are Seated Leg Curl, Cable Pull-Through, Seated Calf Raise and Hip Abduction.
How heavy should the Leg Extension be?
Pick a weight you can lift for the planned reps with one or two left in reserve. As a common starting point, sets of 3 to 6 reps use about 85 to 90 percent of your one-rep max and sets of 6 to 12 reps about 70 to 80 percent; the calculator on this page does the arithmetic.