Single-Leg Back Extension

Unilateral posterior chain power — builds glute and hamstring strength one leg at a time while exposing and correcting side-to-side imbalances

⚡ Quick Reference

Aspect	Details
Pattern	Hinge (Posterior Chain, Unilateral)
Primary Muscles	Glutes, Hamstrings, Erectors
Secondary Muscles	Core, Lats
Equipment	Back Extension Bench or GHD
Difficulty	⭐⭐ Intermediate
Priority	🟡 Supplementary

Movement Summary

🎯 Setup

Starting Position

Pad height: Adjust so pad is at hip crease (not waist or thighs)
Working leg: One foot/ankle secured on pad or foot platform
Non-working leg: Extended straight back in line with body OR bent at knee
Upper body: Start in neutral alignment with hips and legs
Arms: Crossed over chest OR behind head (harder)
Core: Braced and engaged
Head: Neutral, following spine

Leg Position Options

Position	Setup	When to Use
Straight Back	Non-working leg extended straight	Standard, more stability challenge
Bent Knee	Non-working leg bent at 90°	Easier balance, reduces hamstring cramping
Alternating	Switch legs each set	Equal work both sides

Setup Cue

"One leg on the pad, other leg extends back — you're a straight line from head to heel before you even start"

🔄 Execution

The Movement

🔝 Starting Position
⬇️ Lowering
⏸️ Bottom Position
⬆️ Raising

What's happening: Body straight and aligned, one leg loaded on pad

One leg secured on pad/platform
Other leg extended back (or bent)
Body in straight line from head to heel
Arms crossed at chest
Core braced
Ready to hinge

Feel: Working leg engaged, core tight, balance maintained

Key Cues

Primary Cues

"Stay square" — don't let hips rotate
"Straight line from head to heel" — entire body moves as one unit
"Squeeze the glute" — working side drives the movement
"Don't hyperextend" — stop at neutral, don't arch back

Tempo Guide

Goal	Tempo	Example
Strength	3-1-2-0	3s down, 1s pause, 2s up
Hypertrophy	3-2-2-0	3s down, 2s pause, 2s up
Endurance	2-0-1-0	2s down, no pause, 1s up

💪 Muscles Worked

Activation Overview

Primary Movers

Muscle	Action	Activation
Glutes (working side)	Hip extension — driving torso up from hinged position	`█████████░` 85%
Hamstrings (working side)	Hip extension — assisting glutes, controlling descent	`████████░░` 80%
Erectors	Maintains spinal position throughout movement	`███████░░░` 70%

Secondary Muscles

Muscle	Action	Activation
Core & Obliques	Prevents rotation, maintains stability	`███████░░░` 65%
Lats	Stabilizes torso position	`█████░░░░░` 50%

Stabilizers

Muscle	Role
Hip Stabilizers	Keeps hips level and square, prevents rotation
Upper Back	Maintains upper body position

Unique Benefit

Unilateral loading exposes imbalances — you can't compensate with your stronger side, making this excellent for identifying and correcting left-right strength differences in the posterior chain.

⚠️ Common Mistakes

Mistake	What Happens	Why It's Bad	Fix
Hips rotating	One hip drops/rotates	Uneven loading, poor pattern	Brace obliques, keep hips square
Hyperextending	Arching back past neutral	Lower back strain	Stop at neutral alignment
Rounding spine	Back rounds at bottom	Disc stress, injury risk	Reduce depth, brace core
Going too deep	Over-flexing hips	Can cause rounding	Stop at 60-90° hip flexion
Swinging/momentum	Using momentum to rise	Less muscle activation	Controlled tempo, squeeze glute

Most Common Error

Hips rotating or dropping to one side — this defeats the purpose of single-leg training. Keep your hips perfectly level and square throughout the entire movement.

Self-Check Checklist

Hips stay level and square (no rotation)
Body moves as one straight line
Stop at neutral, don't hyperextend
Controlled tempo both up and down
Working glute is driving the movement
No lower back pain or strain

🔀 Variations

By Equipment

By Bench Type
By Loading

Variation	How	When to Use
45-Degree	Angled bench	Most common, easier
Horizontal	Flat bench	Harder, more ROM
GHD	Glute-ham developer	Advanced, full ROM

Variation	How	Emphasis
Bodyweight	No added load	Learning pattern, endurance
Holding Plate	Plate at chest	More resistance
Weighted	Weight plate or dumbbell	Strength, hypertrophy

By Leg Position

Target	Variation	Change
More Stability	Bent knee (non-working)	Easier balance
More Challenge	Straight leg (non-working)	Harder stability
Isolation Focus	Slow tempo	More time under tension

📊 Programming

Rep Ranges by Goal

Goal	Sets	Reps per Leg	Rest	Notes
Strength	3-4	8-12	60-90s	Add weight if needed
Hypertrophy	3-4	12-15	45-60s	Focus on squeeze
Endurance	2-3	15-20+	30-45s	Bodyweight, higher volume

Workout Placement

Program Type	Placement	Rationale
Leg day	Accessory	After main lifts (squats/deadlifts)
Posterior chain	Secondary	Unilateral work after bilateral
Glute/hamstring day	Primary or secondary	Direct glute work
Prehab/rehab	Primary	Correcting imbalances

Progression Scheme

How to Progress

Master bodyweight first — 3x12 per leg with perfect control and no rotation. Then add 5-10 lbs and rebuild. Focus on quality over quantity.

🔄 Alternatives & Progressions

Exercise Progression Path

Regressions (Easier)

Exercise	When to Use
Bodyweight Back Extension (both legs)	Build base strength first
45-Degree Back Extension	Master bilateral before unilateral

Progressions (Harder)

Exercise	When Ready
Weighted Single-Leg Back Extension	Bodyweight is too easy
Single-Leg GHD	Want more ROM and challenge

Similar Exercises

Alternative	When to Use
Single-Leg RDL	Want to load heavier
Back Extension (Bodyweight)	Bilateral version
Romanian Deadlift	Bilateral loaded hinge

🛡️ Safety & Contraindications

Who Should Be Careful

Condition	Risk	Modification
Lower back issues	Load on spine in flexed position	Reduce depth, lighter load
Disc herniation	Flexion under load	Avoid or get medical clearance
Hamstring injury	Stretch and load on hamstrings	Wait for recovery
Hip impingement	Deep hip flexion	Reduce ROM

Stop Immediately If

Sharp pain in lower back
Pain radiating down legs
Inability to keep hips level
Cramping in hamstrings
Dizziness or lightheadedness

Safety Tips

Master bilateral back extensions before trying single-leg
Start with bodyweight only
Don't hyperextend — stop at neutral
Keep hips square and level at all times
If one side feels significantly weaker, focus extra volume there

🦴 Joints Involved

Joint	Action	ROM Required	Stress Level
Hip	Flexion/extension	High hip flexion ROM	🟡 Moderate
Knee	Minimal movement	Low	🟢 Low
Spine	Neutral position maintained	N/A	🟡 Moderate

Hip Mobility

This exercise requires good hip flexion mobility. If you can't reach 90° without rounding your back, reduce the ROM.

❓ Common Questions

How is this different from regular back extensions?

Single-leg forces each side to work independently, exposing strength imbalances and requiring much more core stability. It's harder and more effective for identifying weaknesses.

Which leg should I start with?

Start with your weaker leg first (usually the non-dominant leg). This ensures you don't fatigue your weak side and reinforces balanced development.

Should I keep my non-working leg straight or bent?

Either works. Bent knee is easier for balance; straight leg is harder and challenges stability more. Try both and see which feels better.

My hips keep rotating. How do I fix this?

Brace your obliques hard, focus on keeping both hip bones pointing down at the floor. You may need to reduce depth or slow down the tempo to maintain control.

How far should I lower down?

Lower to 60-90° of hip flexion OR until you can no longer maintain a neutral spine — whichever comes first. There's no need to go super deep.

📚 Sources

Biomechanics & Muscle Activation:

ExRx.net — Tier C
NSCA Essentials — Tier A

Programming & Unilateral Training:

Practical Programming for Strength Training — Tier B
Athletic Body in Balance (Gray Cook) — Tier B

For Mo

When to recommend this exercise:

User has access to back extension bench or GHD
User wants to address left-right strength imbalances
User is looking for posterior chain isolation work
User wants glute and hamstring work without heavy loading
User complains one side feels weaker in deadlifts or squats

Who should NOT do this exercise:

Acute lower back injury → Wait for recovery
Disc herniation without medical clearance → Avoid
Cannot maintain neutral spine even on bilateral back extensions → Build base strength first

Key coaching cues to emphasize:

"Keep your hips perfectly square and level — no rotation"
"Stop at neutral — don't arch your back at the top"
"Squeeze your glute to lift, not your lower back"

Common issues to watch for in user feedback:

"My hips keep rotating" → Reduce depth, slow tempo, brace obliques harder
"I feel it all in my lower back" → Cue to drive with glutes, reduce hyperextension
"One side is way weaker" → Good! That's the point. Focus extra volume on weak side
"My hamstring cramps" → Bend non-working leg, reduce depth

Programming guidance:

For strength: 3-4 sets of 8-12 per leg after main lifts
For hypertrophy: 3-4 sets of 12-15 per leg with slower tempo
For correcting imbalances: Extra set on weaker side
Progress when: Can do 3x12 per leg with perfect control, no rotation

Last updated: December 2024

⚡ Quick Reference​

Movement Summary​

🎯 Setup​

Starting Position​

Leg Position Options​

🔄 Execution​

The Movement​

Key Cues​

Tempo Guide​

💪 Muscles Worked​

Activation Overview​

Primary Movers​

Secondary Muscles​

Stabilizers​

⚠️ Common Mistakes​

Self-Check Checklist​

🔀 Variations​

By Equipment​

By Leg Position​

📊 Programming​

Rep Ranges by Goal​

Workout Placement​

Progression Scheme​

🔄 Alternatives & Progressions​

Exercise Progression Path​

Regressions (Easier)​

Progressions (Harder)​

Similar Exercises​

🛡️ Safety & Contraindications​

Who Should Be Careful​

Safety Tips​

🦴 Joints Involved​

❓ Common Questions​

📚 Sources​