Single-leg Leg Extension

How to perform it

1. 1Preparation and positioning. Adjust the seat/back pad and roller so the machine axis approximates the knee axis and the pad contacts the lower leg without pressing on the joint. Select the range and load before entering.
2. 2Starting position. Sit fully against the support, secure the restraint as provided, keep the pelvis still, and align the working knee. Keep the non-working leg clear of the lever.
3. 3Concentric phase. Extend the knee smoothly without kicking the roller or lifting the hips from the seat.
4. 4End position. Reach controlled extension without snapping or forcefully hyperextending the knee.
5. 5Eccentric phase. Return the lever slowly to the same start marker while keeping the pelvis and machine stack controlled.
6. 6Breathing and bracing. Exhale through the shortening phase and inhale during the return; maintain light trunk bracing against the pad.
7. 7Valid rep. A rep uses the same seat, axis, range, and side-specific standard, keeps the stack from touching down between reps unless intended, and contains no kick or pelvic lift.

Common mistakes

• Changing the setup between reps

  Fix: Fix stance, grip, support, and range before the set and keep them constant.

• Using momentum

  Fix: Reduce load or leverage and make both directions visibly controlled.

• Shortening the difficult range

  Fix: Use the same start and end markers on every valid rep.

• Continuing after technique loss

  Fix: End the set at the first persistent breakdown rather than rehearsing compensation.

Safety

• Current hip, knee, ankle, or tendon symptoms call for an individually tolerated range and load; pain is not a cue to force alignment or depth.
• Adjust the machine to the user, verify the selector pin/attachment and safety stops, and keep hands, clothing, and other people clear of the moving lever, cable, and stack.

Progressions & alternatives

• regressionLeg Extension— Reduce strength, balance, or coordination demand while rehearsing the key pattern before returning to Single-leg Leg Extension.
• progressionSingle-leg Leg Extension through a longer controlled range— Increase load, range, instability, or skill demand after Single-leg Leg Extension is repeatable through the planned volume with reserve and no technique drift.
• alternativeGoblet Squat— Train a similar primary pattern with a different stability, equipment, or joint-loading profile when Single-leg Leg Extension is impractical or poorly tolerated.