# Sit-Up with Knee Tuck

A sit-up with the hands behind your head in which the feet lift slightly off the floor as the torso rises, knees staying bent. Trains the abs and obliques through a full trunk curl.

- Beginner · Isolation
- Equipment: 
- HD video: https://media.seto.fit/exercises/crunch-leg-raise/video/male.mp4
- HTML: https://seto.fit/exercises/sit-up-with-knee-tuck/

## Muscles worked

- Abs: 9/10
- Obliques: 5/10

## How to do the Sit-Up with Knee Tuck

1. Lie on your back, knees bent, hands behind your head.
2. Curl up while your feet lift slightly off the floor.
3. Rise until your torso is near upright.
4. Lower your torso and feet back down under control.

### Full technique — 7 steps

1. Lie on your back with knees bent and feet flat on the floor.
2. Place your hands lightly behind your head with elbows pointing out to the sides.
3. Press your lower back into the floor and keep your ribs pulled down.
4. Exhale and curl your torso up, letting your feet lift slightly off the floor with your knees staying bent.
5. Continue rising until your torso is near upright and close to your knees.
6. Lower your torso and feet under control until your upper back and feet return to the floor.
7. Reset the bottom position before starting the next repetition.

## Common mistakes

- Pulling the head with hands
- Swinging knees for momentum
- Stopping at a crunch
- Dropping back without control
- Letting lower back arch

## Form cues

- Hands stay by head
- Curl, don't yank up
- Keep the knee bend fixed
- Exhale on the way up
- Lead with your ribs

## How much to do

- **Strength**: 3 sets of 8–12 reps · rest 1 min 15 s · 3 reps in reserve · lower 2 s, lift 1 s, pause 1 s
- **Muscle growth** (good fit): 3–4 sets of 12–20 reps · rest 1 min · 2–3 reps in reserve · lower 2 s, lift 1 s, pause 1 s
- **Endurance** (best fit): 2–3 sets of 20–30 reps · rest 45 s · 3–4 reps in reserve · lower 1 s, lift 1 s

Reps in reserve: how many more you could still do when you end the set.

## Substitutes by equipment

Same muscles, same movement — pick the version you have the gear for.

- **Dumbbells**: [Dumbbell Decline Sit-Up](https://seto.fit/exercises/dumbbell-decline-sit-up/), [Dumbbell Straight Arm Crunch](https://seto.fit/exercises/dumbbell-straight-arm-crunch/)
- **Resistance bands**: [Lying Resistance Band Crunch](https://seto.fit/exercises/lying-resistance-band-crunch/), [Lying Resistance Band Knee Tuck](https://seto.fit/exercises/lying-resistance-band-knee-tuck/)
- **Medicine ball**: [Medicine Ball Toe Touch Crunch](https://seto.fit/exercises/medicine-ball-toe-touch-crunch/), [Medicine Ball Straight Arm Crunch](https://seto.fit/exercises/medicine-ball-straight-arm-crunch/)
- **Suspension trainer**: [Suspension Trainer Hanging Knee Raise](https://seto.fit/exercises/suspension-trainer-hanging-knee-raise/), [Suspension Trainer Hanging Leg Raise](https://seto.fit/exercises/suspension-trainer-hanging-leg-raise/)

## Where to start and where to go next

Same muscles, same movement. Too hard for now — step down; once it gets easy — step up.

- Easier: [Reverse Crunch](https://seto.fit/exercises/reverse-crunch/) — 25% of bodyweight
- Easier: [Ab Wheel Pass Crunch](https://seto.fit/exercises/ab-wheel-crunch/) — 30% of bodyweight
- **This exercise: Sit-Up with Knee Tuck — 35% of bodyweight**
- Harder: [Ab Wheel Half Rollout](https://seto.fit/exercises/ab-wheel-half-rollout/) — 40% of bodyweight
- Harder: [Ab Wheel Knee Tuck](https://seto.fit/exercises/ab-wheel-knee-tuck/) — 60% of bodyweight

## Quick answers

### What muscles does the Sit-Up with Knee Tuck work?

Primary: Abs 9/10. Also works: Obliques 5/10.

### When should I do the Sit-Up with Knee Tuck in a workout?

Finisher. Goes last, once the heavy work is done. ≈ 5 min with rest.

### How many sets and reps of the Sit-Up with Knee Tuck?

Strength: 3 sets of 8–12 reps, rest 1 min 15 s, 3 reps in reserve. Muscle growth: 3–4 sets of 12–20 reps, rest 1 min, 2–3 reps in reserve. Endurance: 2–3 sets of 20–30 reps, rest 45 s, 3–4 reps in reserve.

### What can I do instead of the Sit-Up with Knee Tuck?

Dumbbells: Dumbbell Decline Sit-Up, Dumbbell Straight Arm Crunch. Resistance bands: Lying Resistance Band Crunch, Lying Resistance Band Knee Tuck. Medicine ball: Medicine Ball Toe Touch Crunch, Medicine Ball Straight Arm Crunch. Suspension trainer: Suspension Trainer Hanging Knee Raise, Suspension Trainer Hanging Leg Raise.

### What is an easier version of the Sit-Up with Knee Tuck?

Ab Wheel Pass Crunch (30% of bodyweight), Reverse Crunch (25% of bodyweight).

### What is a harder version of the Sit-Up with Knee Tuck?

Ab Wheel Half Rollout (40% of bodyweight), Ab Wheel Knee Tuck (60% of bodyweight).

How we rate exercises: https://seto.fit/guides/methodology/

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