GHD Sit-Up

The extreme ROM ab destroyer — full spinal extension to full flexion on GHD machine, famously brutal for building core strength and causing legendary soreness

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⚡ Quick Reference

Aspect	Details
Pattern	Core (Spinal Flexion + Extension)
Primary Muscles	Abs (entire rectus abdominis)
Secondary Muscles	Hip Flexors, Obliques
Equipment	GHD machine
Difficulty	⭐⭐⭐ Advanced
Priority	🟡 Supplementary

Movement Summary

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🎯 Setup

Starting Position

1. GHD adjustment: Set footplate so your hips are just past the edge of the pad when seated
2. Feet position: Lock ankles/feet securely under the foot pads
3. Hip placement: Sit with hips slightly past the pad edge — not fully on pad
4. Starting position: Lean back until torso is parallel to ground or slightly below
5. Arms: Crossed at chest or extended overhead (harder)
6. Head: Neutral, looking forward or slightly up

GHD Setup Guide

Setting	Effect	When to Use
Hips on pad	Easier, less ROM	First time trying
Hips past pad	Standard, full ROM	Most common
Hips far past pad	Harder, deeper extension	Advanced

Setup Cue

"Hips just past the pad, feet locked, ready to extend all the way back"

Critical Warning

Start with LOW REPS your first time (5-10 max). GHD sit-ups cause EXTREME delayed-onset muscle soreness (DOMS) if you're not adapted. Many people can't walk or sit properly for days after overdoing it the first time.

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🔄 Execution

The Movement

🔝 Starting Position

What's happening: Extended back, parallel to ground or lower

1. Leaning back, torso parallel to ground
2. Feet locked securely under pads
3. Hips past the pad edge
4. Arms crossed at chest or overhead
5. Core engaged, ready to curl up

Feel: Stretch through abs, weight pulling you backward

⬇️ Extension (Bottom)

What's happening: Lowering into full hyperextension

1. From parallel, can lower further into extension (optional)
2. This stretches abs under load
3. Only go as far as comfortable — full extension is advanced
4. Keep feet locked, don't let hips slide

Tempo: 2-3 seconds (controlled)

Feel: Deep stretch through entire front of torso

Note: Many people start from parallel and skip deep extension until adapted.

⬆️ Curl Up

What's happening: Explosive spinal flexion to sitting upright

1. Curl spine to pull yourself up
2. Think "roll up vertebra by vertebra"
3. Continue curling until chest touches thighs
4. This is a HUGE range of motion — from extended to fully flexed
5. Exhale forcefully as you come up

Tempo: 1-2 seconds

Feel: Abs contracting powerfully through full ROM

⏸️ Top Position

What's happening: Full flexion, chest to thighs

1. Torso vertical or curled forward
2. Chest near or touching thighs
3. Full spinal flexion
4. Brief pause

Common error here: Not completing full ROM — go all the way up to thighs.

⬇️ Lower

What's happening: Controlled descent back to extension

1. Lower yourself back down with control
2. Unroll spine gradually
3. Return to parallel (or full extension if doing deep ROM)
4. Inhale as you lower

Tempo: 2-3 seconds

Feel: Eccentric loading through abs — this is where soreness comes from

Key Cues

Primary Cues

• "Extend back, curl all the way up" — full ROM both directions
• "Roll through the spine" — sequential flexion
• "Exhale hard on the way up" — assists contraction
• "Control the descent" — don't just drop back

Tempo Guide

Goal	Tempo	Example
Strength	2-1-2-0	2s up, 1s pause, 2s down
Hypertrophy	2-2-3-0	2s up, 2s pause, 3s down
Endurance	1-0-2-0	Continuous, controlled

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💪 Muscles Worked

Activation Overview

Primary Movers

Muscle	Action	Activation
Rectus Abdominis	Spinal flexion through EXTREME ROM	█████████░ 90%

Secondary Muscles

Muscle	Action	Activation
Hip Flexors	Hip flexion, pulling torso to thighs	████████░░ 75%
Obliques	Stabilization, assists flexion	███████░░░ 65%

Stabilizers

Muscle	Role
Lower Back	Eccentric control during extension
Glutes/Hamstrings	Stabilize lower body on GHD

Unique Benefit

The extreme range of motion — going from hyperextension to full flexion — creates eccentric loading and muscle damage unlike any other ab exercise. This is why GHD sit-ups are notoriously effective but also cause legendary soreness.

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⚠️ Common Mistakes

Mistake	What Happens	Why It's Bad	Fix
Too many reps first time	Severe DOMS for days	Can't function normally	Start with 5-10 reps max
Going too deep too soon	Extreme soreness, injury risk	Overwhelming eccentric load	Start from parallel, progress slowly
Rushing the movement	Using momentum	Less muscle activation	Controlled tempo
Incomplete ROM at top	Not reaching thighs	Misses full contraction	Curl all the way to chest-to-thighs
Hips sliding forward	Losing position	Unsafe, less effective	Lock feet tighter, adjust pad

Most Critical Warning

DO NOT do high reps your first time. Even if you can physically do 30+ reps, your abs will be DESTROYED for days afterward. Start with 5-10 reps, then add 5 reps each session until adapted. This is not an exaggeration — GHD sit-up soreness is legendary in CrossFit gyms.

Self-Check Checklist

• Started with low reps (10 or less) if first time
• Controlled tempo both directions
• Full ROM — chest to thighs at top
• Feet stay locked, no sliding
• No momentum or jerking

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🔀 Variations

By Difficulty

Easier (Regressions)

Variation	How	When to Use
Partial ROM	Only go to parallel, not deep extension	First exposure
Hips on Pad	Sit fully on pad	Reduces ROM
Flat Sit-Up	On floor	No GHD available

Standard

Variation	How	Emphasis
Full ROM GHD	Parallel to full flexion	Standard version
Deep Extension	Go below parallel	Maximum stretch

Harder (Progressions)

Variation	How	When to Use
Weighted GHD Sit-Up	Hold plate at chest	Need more resistance
GHD Sit-Up + Twist	Rotate at top	Oblique emphasis
Arms Overhead	Extended arms	Longer lever arm

By Target

Target	Variation	Change
Full Abs	Standard version	Balanced approach
Obliques	Add twist at top	Rotate torso
Strength	Add weight	Hold plate (start 5-10 lbs)
Eccentric Focus	Slow descent (5s)	Maximize soreness (carefully)

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📊 Programming

Rep Ranges by Goal

Goal	Sets	Reps	Rest	Notes
First Time	1-2	5-10	N/A	DO NOT exceed this
Strength	3-4	10-15	90-120s	Once adapted
Hypertrophy	3-4	15-25	60-90s	Moderate pace
Endurance	2-3	25-50	60s	High volume

Adaptation Protocol

Workout Placement

Program Type	Placement	Rationale
CrossFit WOD	During or after	Common in metcons
Core day	Primary	Main ab exercise
Full body	Finisher	End of workout

Adaptation Strategy

Week 1: 2x5-10 reps (wait 3-5 days between sessions) Week 2: 2x10-15 reps (wait 2-3 days) Week 3+: Normal programming — 3-4 sets of 15-25 reps

This gradual approach prevents the crippling soreness.

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🔄 Alternatives & Progressions

Exercise Progression Path

Regressions (Easier)

Exercise	When to Use
Flat Sit-Up	Never done GHD before
Decline Sit-Up	Building up to GHD
Partial ROM GHD	First few GHD sessions

Progressions (Harder)

Exercise	When Ready
Weighted GHD Sit-Up	Can do 25+ reps easily
High-Rep GHD (50+)	Endurance training
Arms Overhead	Want more challenge

Alternatives

Alternative	When to Use
Decline Sit-Up	No GHD available
Weighted Sit-Up	Need external load
Ab Wheel	Different core angle

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🛡️ Safety & Contraindications

Who Should Be Careful

Condition	Risk	Modification
Lower back issues	Hyperextension under load	Avoid or use partial ROM only
Disc herniation	Flexion/extension stress	Avoid completely
First-timer	EXTREME soreness	Start 5-10 reps MAX
Rhabdomyolysis risk	Very high volume can cause rhabdo	Never exceed 50-100 reps total

Critical Safety Warnings

1. Rhabdomyolysis Risk: There have been documented cases of rhabdomyolysis (muscle breakdown releasing harmful proteins into blood) from excessive GHD sit-ups, especially in first-timers doing high-rep WODs. START LOW, PROGRESS SLOWLY.

2. First-Timer Soreness: If you've never done GHD sit-ups, you WILL be extremely sore for 3-7 days even from just 10-15 reps. This is normal but can be debilitating. Plan accordingly — don't do them before an important event.

3. Stop If: Sharp back pain, dizziness, nausea, dark urine (sign of rhabdo), or inability to complete movement safely.

Safety Tips

• ALWAYS start with very low reps (5-10) your first time
• Progress reps by ~5 per session
• If doing a WOD with GHD sit-ups, scale the reps down
• Stay hydrated — dehydration increases rhabdo risk
• If you get dark urine or severe muscle pain, seek medical attention

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🦴 Joints Involved

Joint	Action	ROM Required	Stress Level
Spine	Extension + Flexion	EXTREME (hyperextension to full flexion)	🔴 High
Hip	Flexion	Full	🟡 Moderate

Joint Health

The extreme spinal ROM is what makes this exercise so effective but also so risky for people with back issues. If you have ANY lower back problems, avoid this exercise or stick to partial ROM.

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❓ Common Questions

How many should I do my first time?

5-10 reps maximum. Even if you feel like you can do more, DON'T. The soreness hits 24-48 hours later and can be debilitating. Trust the process and build up gradually.

Why do GHD sit-ups cause such extreme soreness?

The eccentric loading through extreme range of motion causes significant muscle damage. Your abs are stretched under load (hyperextension) then contract through a massive ROM. This combination creates legendary DOMS.

Are GHD sit-ups dangerous?

They can be if you do too many too soon. Rhabdomyolysis (muscle breakdown) has occurred in first-timers doing high-rep WODs. Start with low reps, build gradually, stay hydrated, and listen to your body.

How do I set up the GHD correctly?

Your hips should be just past the edge of the pad — not fully on it. Feet locked securely under pads. When seated, you should be able to lean back to parallel without your hips sliding forward.

What if I can't do a full GHD sit-up?

Start with partial ROM — only go down to parallel (horizontal), not into hyperextension. Build strength there before attempting full ROM.

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📚 Sources

Biomechanics & Muscle Activation:

• Escamilla, R.F., et al. (2006). Core muscle activation — Tier A
• ExRx.net — Tier C

Safety & Rhabdomyolysis:

• Makaryus, A.N., et al. (2010). Exercise-induced rhabdomyolysis — Tier A
• CrossFit Journal — Tier C

Programming:

• CrossFit Programming Guidelines — Tier C
• NSCA Essentials — Tier A

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For Mo

When to recommend this exercise:

• User has access to GHD machine
• User wants extremely effective ab work
• User is adapted to core training (not complete beginner)
• User understands the soreness warning

Who should NOT do this exercise:

• Disc herniation or acute back injury → Too much spinal stress
• Complete beginner to exercise → Too intense, start with basics
• Anyone who won't heed the low-rep warning → Injury risk
• Lower back issues → Hyperextension is risky

Key coaching cues to emphasize:

1. "Start with 5-10 reps MAXIMUM your first time"
2. "Full ROM — extend back, curl all the way to thighs"
3. "Control the descent — don't drop"

Common issues to watch for in user feedback:

• "I did 50 my first time and can't move" → This is why we warn people! Rest, hydrate, gentle movement
• "My back hurts" → Check setup, may need partial ROM only
• "Too easy" → After adaptation, add weight or increase reps
• "I'm not sore" → Some people adapt faster, this is fine

Programming guidance:

• For first-timers: 5-10 reps, wait 3-5 days, assess soreness
• For adapted athletes: 3-4 sets of 15-25 reps, 2-3x/week
• Progress when: Minimal soreness from current volume
• Advance by: Adding 5 reps per session, eventually add weight

Critical warning to always give: "GHD sit-ups cause EXTREME soreness if you're not adapted. Start with only 5-10 reps your first time, even if it feels easy. The soreness hits 24-48 hours later and can last a week. Build up gradually."

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Last updated: December 2024