Decline Crunch vs Seated Knee Up
Which one fits your Core workout plan?
Contents
Planfit users log Seated Knee Up more often — 9,913 sessions vs 2,842. Compare Core form, muscles worked, and when to use each.
Compare the benefits of Decline Crunch and Seated Knee Up and pick the one that fits your Core workout.
Decline Crunch vs Seated Knee Up: Which Do Planfit Users Choose?
Based on randomly selected data from 1 million completed workouts, Planfit users log Seated Knee Up more often — 9,913 sessions compared to 2,842 for Decline Crunch.
What most people do isn't always what fits you. Decline Crunch and Seated Knee Up differ in the muscles they work, the equipment they need, and how hard they are to learn — the comparison below covers each.
How Decline Crunch and Seated Knee Up Differ
| What differs | Decline Crunch | Seated Knee Up |
|---|---|---|
| Difficulty | 3 of 5 | 2 of 5 |
| Sessions logged by Planfit users | 2,842 sessions | 9,913 sessions |
How to Do Decline Crunch
Decline Crunch Muscles Worked: Core
Form
- 1. Please lift your upper body while keeping your back straight.
- 2. Slowly return to the starting position.
Coach's Tips
- 1. If you lift your upper body excessively, it can strain your lower back, so please lift your upper body without letting your back rise.
- 2. If your neck hurts, support your head with your hands and relax your neck while proceeding.
For a full Decline Crunch guide with alternatives and benefits, see the Decline Crunch exercise guide.
How to Do Seated Knee Up
Seated Knee Up Muscles Worked: Core
Form
- 1. Lift your lower body so that your knees and chest come closer together.
- 2. Allow your upper body to naturally lean forward so that your core can contract.
- 3. Slowly return to the starting position.
Coach's Tips
- If it's too difficult, try proceeding with your knees bent.
For a full Seated Knee Up guide with alternatives and benefits, see the Seated Knee Up exercise guide.
Frequently Asked Questions
Which is better for Core, Decline Crunch or Seated Knee Up?
Planfit users log Seated Knee Up more often — 9,913 sessions against 2,842 for Decline Crunch. Both train Core, so pick the one that matches the equipment you have and the muscles you want to load.
What equipment do Decline Crunch and Seated Knee Up need?
Decline Crunch needs bodyweight only, and Seated Knee Up needs bodyweight only.
Which is easier to start with?
Seated Knee Up is the easier place to start. Move to Decline Crunch once your form holds up.
Stop Guessing Which One to Do
AI picks your workouts based on your goals, body type, and experience.

