Jackknife Pull-Up
The jackknife pull-up is an assisted pull-up in which you sit under a low bar or rings with your legs straight out in front and push lightly through your heels to help you up. It trains the lats, biceps and upper back through the full pull-up range and is a step towards the unassisted pull-up.
Also called: Jackknife Pullups, Jackknife Pullup, Feet Assisted Pull-Up · Equipment: bodyweight · Pattern: pull
Step by step
- Sit under a secure low bar or a set of rings with your legs straight out in front of you and your heels on the floor.
- Grip the bar or rings at shoulder width with straight arms, so your seat sits just off the floor.
- Shift your torso slightly behind the bar so you can pull your chest up to it.
- Pull up until your chest touches the bar, or your hands reach your chest on rings, pushing through your heels only as much as you need.
- Keep your stomach and legs tense throughout so your hips stay up.
- Pause for a second at the top, then return to straight arms slowly and pause again.
- Over the weeks, keep your torso more upright and let your legs do less of the work.
- Chest to the bar
- Heels help only as much as needed
- Stomach and legs tight, no sagging
- Torso as upright as you can hold
- Pause at the top and bottom
In VALDA, these cues are one tap away on the exercise while you train.
What it trains
| Muscle | Role | Evidence |
|---|---|---|
| Latissimus dorsi | Prime mover | C |
| Biceps brachii | Secondary | C |
| Trapezius: lower | Secondary | C |
| Rhomboids | Secondary | D |
| Quadriceps | Stabiliser | D |
| Rectus abdominis | Stabiliser | D |
Evidence grades: A = strong research base · B = good · C = limited · D = coaching consensus.
What goes wrong, and the fix
Leaning far back
Fix: Keep your torso closer to upright as you pull.
Pushing hard with the legs
Fix: Press through your heels only enough to finish each rep.
Hips sagging
Fix: Keep your stomach and legs tense so your hips stay up.
Wrong seat position
Fix: Shift your body back slightly so your chest can reach the bar.
Dropping to the bottom
Fix: Return slowly and pause for a second at the bottom.
What the research says
General fitnessEndurance
- Muscles worked — EMG research on the pull-up finds the lats are the main movers with strong work from the biceps and the traps below the shoulder blades; this assisted version uses the same pull at a smaller load.
- Effort — A meta-analysis found training closer to failure brings a little more growth, with most of the benefit captured a few reps short of failure.
- Load range — Reviews find lighter loads with higher reps favour muscular endurance, while heavier loads favour strength. There is no direct research on jackknife pull-ups.
- Standards — Hybrid Calisthenics uses 2–3 sets of as many good reps as possible with 2–3 minutes' rest, moving on to the full pull-up after 3 sets of 20.
Log the jackknife pull-up in VALDA, with these cues one tap away while you train and your history for it in one place.
General information about exercise technique, not medical advice. If you have an injury or a health condition, your healthcare provider is the right person to ask.