Physioball Leg Curl

Stability meets strength — builds hamstring and glute power while challenging core stability on an unstable surface

⚡ Quick Reference

Aspect	Details
Pattern	Hinge (Hip Extension + Knee Flexion)
Primary Muscles	Hamstrings
Secondary Muscles	Glutes, Core, Calves
Equipment	Stability ball
Difficulty	⭐⭐ Intermediate
Priority	🟡 Supplementary

Movement Summary

🎯 Setup

Starting Position

Ball size: 55cm (shorter people), 65cm (average), 75cm (taller people)
Starting position: Lying on back, feet on ball
Foot position: Heels or calves on top of ball
Hips: Elevated in bridge position
Arms: On floor at sides, palms down for stability
Core: Braced tight, ribs down
Head: Resting on floor, neck relaxed

Ball Size Guide

Height	Ball Size	Notes
Under 5'4"	55cm	Smaller ball, higher difficulty
5'4" - 5'10"	65cm	Most common size
Over 5'10"	75cm	Larger ball, more stable

Foot Placement Options

Position	Difficulty	Emphasis
Calves on ball	Easier	More stable, easier to balance
Heels on ball	Standard	Good balance of challenge
Just toes on ball	Harder	Maximum instability

Setup Cue

"Feet on ball, bridge hips up, arms wide for stability, ready to roll ball away and curl it back"

🔄 Execution

The Movement

🔝 Starting Position
⬇️ Rolling Out
⏸️ Extended Position
⬆️ Curling In

What's happening: Bridge position with feet on ball, knees bent

Lying on back, feet on stability ball
Hips elevated in bridge
Knees bent, ball close to butt
Hamstrings and glutes engaged
Core braced for stability
Arms on floor for balance

Feel: Already challenging to maintain balance, hamstrings and glutes engaged

Key Cues

Primary Cues

"Hips stay high" — don't let them drop at any point
"Control the ball" — smooth rolling motion
"Pull with hamstrings" — drive feet into ball and curl
"Brace your core" — essential for maintaining balance

Tempo Guide

Goal	Tempo	Example
Strength	3-1-2-1	3s out, 1s pause, 2s curl, 1s squeeze
Hypertrophy	2-1-2-1	2s out, 1s pause, 2s curl, 1s squeeze
Stability	2-2-2-2	Slow throughout with pauses

💪 Muscles Worked

Activation Overview

Primary Movers

Muscle	Action	Activation
Hamstrings	Knee flexion — curling ball toward butt	`█████████░` 85%
Glutes	Hip extension — maintaining elevated bridge	`████████░░` 75%

Secondary Muscles

Muscle	Action	Activation
Core	Maintains stable bridge on unstable surface	`████████░░` 75%
Gastrocnemius	Assists knee flexion, helps control ball	`██████░░░░` 55%

Stabilizers

Muscle	Role
Hip Stabilizers	Prevents hips from shifting side to side
Adductors	Keeps legs aligned on ball
Entire Core	Maintains rigid torso during instability

Unique Benefit

Exceptional core and stability demand — the unstable ball requires constant micro-adjustments, building core strength and neuromuscular control beyond what stable surface exercises provide.

⚠️ Common Mistakes

Mistake	What Happens	Why It's Bad	Fix
Hips sagging	Hips drop during extension	Loses hamstring/glute tension	Squeeze glutes, brace core harder
Ball rolling sideways	Unstable, wobbling motion	Inefficient, loss of control	Keep core tight, legs aligned
Arms doing too much	Pushing hard with arms	Reduces hamstring work	Use arms for balance only
Rushing the reps	Fast, uncontrolled rolling	Less muscle activation, harder to balance	Slow, controlled tempo
Feet placement inconsistent	Foot position shifts on ball	Reduces effectiveness	Maintain consistent contact point

Most Common Error

Losing balance and letting the ball roll sideways — this usually means core isn't braced enough. Squeeze everything tight and move slowly and deliberately.

Self-Check Checklist

Hips stay elevated throughout entire rep
Ball rolls in straight line (not side to side)
Controlled tempo both directions
Core stays maximally braced
Full range of motion while maintaining control

🔀 Variations

By Difficulty

Easier (Regressions)
Standard
Harder (Progressions)

Variation	How	When to Use
Bridge Hold Only	Just hold bridge on ball, no curling	Learning to balance on ball
Partial ROM	Only roll ball partway out	Building strength and control
Calves on Ball	Position calves on ball instead of heels	More stable surface contact
Arms Wide	Spread arms wider for more balance	Need more stability support

Variation	How	Emphasis
Standard Bilateral	Both feet, full ROM	Balanced development
Heels on Ball	Standard foot position	Good challenge level
Narrow Arm Position	Arms closer to body	More core challenge
Pause at Extension	2-3s hold when extended	Isometric strength

Variation	How	When to Use
Single-Leg	One leg at a time	Significant difficulty increase
Marching	Alternate lifting one foot while holding	Extreme stability challenge
Arms Crossed	Arms on chest instead of floor	Remove stability aid
Toes Only	Just toes on ball	Maximum instability

By Target

Target	Variation	Change
Hamstrings	Focus on powerful curl motion	Drive heels into ball
Glutes	Emphasis on hip height	Squeeze glutes maximally
Core/Stability	Reduce arm support, slower tempo	Remove stability aids
Eccentric Strength	5-second roll-out phase	Super slow extension
Unilateral	Single-leg version	One leg at a time

📊 Programming

Rep Ranges by Goal

Goal	Sets	Reps	Rest	Notes
Strength	3-4	8-12	90s	Slow tempo, full ROM
Hypertrophy	3-4	12-15	60s	Moderate tempo, constant tension
Stability	2-3	10-15	60s	Focus on control and balance

Workout Placement

Program Type	Placement	Rationale
Lower body	After main lifts	Accessory hamstring/glute work
Home workout	Primary posterior chain	Excellent with one piece of equipment
Core training	Integrated exercise	Combines hamstring and core
Rehab/Prehab	Stability work	Builds control and coordination

Progression Scheme

How to Progress

Master bridge holds first, then add partial curls, build to full ROM 3x12-15, then progress to single-leg or transition to slider curls for more difficulty.

🔄 Alternatives & Progressions

Exercise Progression Path

Regressions (Easier)

Exercise	When to Use
Glute Bridge	Learning hip extension pattern
Ball Bridge Hold	Can't control the curling motion yet
Partial ROM Version	Full ROM too challenging

Progressions (Harder)

Exercise	When Ready
Single-Leg Physioball Curl	Can do 12+ bilateral reps
Slider Leg Curl	Want more hamstring emphasis
Kneeling Leg Curl	Ready for elite hamstring challenge

Alternatives

Alternative	When to Use
Slider Leg Curl	Similar difficulty, different stability challenge
Lying Leg Curl	Have access to machine
Romanian Deadlift	Want loaded hip hinge pattern

🛡️ Safety & Contraindications

Who Should Be Careful

Condition	Risk	Modification
Hamstring injury history	Re-injury if progressed too fast	Start with partial ROM and bridge holds
Poor balance	Risk of falling off ball	Start with just holding bridge
Lower back pain	Bridge can aggravate	Reduce ROM, focus on core bracing
Neck issues	Lying position can be problematic	Use small towel under head for support

Stop Immediately If

Sharp pain in hamstring
Lower back pain during movement
Loss of control leading to instability
Neck pain or discomfort

Safety Tips

Start with bridge holds before attempting curls
Use partially deflated ball for more stability initially
Clear space around you in case you lose balance
Start with arms wide for maximum stability
Progress slowly — stability takes time to develop
Keep ball properly inflated (firm but with slight give)

🦴 Joints Involved

Joint	Action	ROM Required	Stress Level
Knee	Flexion/extension	0-90°+	🟡 Moderate
Hip	Extension maintained throughout	Isometric hip extension	🟢 Low
Ankle	Dorsiflexion, adjustments for balance	Variable	🟢 Low
Spine	Neutral position maintenance	Stability challenge	🟢 Low

Joint-Friendly

Low joint stress overall. The ball provides a cushioned surface and the movement is controlled and smooth.

❓ Common Questions

I keep losing balance and the ball rolls sideways. What's wrong?

This is normal when learning the exercise. Focus on: (1) bracing core harder, (2) moving slower and more deliberately, (3) keeping legs aligned, and (4) using wider arm position for more stability. It gets easier with practice.

What size ball should I use?

General guideline: 55cm if you're under 5'4", 65cm for 5'4"-5'10", 75cm if over 5'10". When you sit on the ball, your thighs should be parallel to the floor or knees slightly lower than hips.

My hamstrings cramp during this. Is that normal?

Yes, cramping is common initially. The hamstrings are working hard in an unfamiliar pattern. Take breaks between reps, reduce range of motion, and build up gradually. Stay hydrated and consider supplementing with electrolytes.

Should I do this or slider leg curls?

Both are excellent. The ball emphasizes stability and core engagement more. Sliders often allow for more hamstring strength focus. Try both and see which you prefer, or alternate them in your training.

Can I do this if I don't have space for a big ball?

You need enough space to lie down and extend your legs. If space is limited, slider leg curls might be a better option as they require less vertical clearance.

📚 Sources

Biomechanics & Muscle Activation:

Marshall, P.W., & Murphy, B.A. (2006). Core stability ball training — Tier A
Escamilla, R.F., et al. (2010). Stability ball exercises — Tier A
ExRx.net — Tier C

Programming:

NSCA Essentials — Tier A
Physical therapy protocols — Tier B

For Mo

When to recommend this exercise:

User has access to stability ball
User wants hamstring training with core/stability benefits
User is working out at home or gym
User is building toward more advanced hamstring exercises
User enjoys stability/balance challenges

Who should NOT do this exercise:

Acute hamstring injury → Wait for recovery
Severe balance impairment → Use stable surface exercises
No access to properly sized stability ball → Use slider curls instead

Key coaching cues to emphasize:

"Hips stay high — squeeze your glutes the entire time"
"Control the ball — smooth, straight rolling motion"
"Brace your core hard to maintain balance"
"Pull with your hamstrings, drive feet into ball"

Common issues to watch for in user feedback:

"I keep losing balance" → Normal, practice bridge holds first, move slower
"Ball rolls sideways" → Core not braced enough, legs not aligned
"I can't curl it back" → Reduce ROM, build strength progressively
"My hamstrings cramp" → Common, reduce volume, stay hydrated
"I don't feel it in hamstrings" → Check foot position, drive heels into ball

Programming guidance:

For beginners: Start with bridge holds, then partial ROM, build to 3x10
For intermediate: Build to 3x12-15 full ROM with control
For advanced: Progress to single-leg or move to slider/kneeling curls
Progress when: Can do 12-15 reps with perfect form and control

Ball size recommendations:

Under 5'4": 55cm ball
5'4" to 5'10": 65cm ball (most common)
Over 5'10": 75cm ball

Last updated: December 2024

⚡ Quick Reference​

Movement Summary​

🎯 Setup​

Starting Position​

Ball Size Guide​

Foot Placement Options​

🔄 Execution​

The Movement​

Key Cues​

Tempo Guide​

💪 Muscles Worked​

Activation Overview​

Primary Movers​

Secondary Muscles​

Stabilizers​

⚠️ Common Mistakes​

Self-Check Checklist​

🔀 Variations​

By Difficulty​

By Target​

📊 Programming​

Rep Ranges by Goal​

Workout Placement​

Progression Scheme​

🔄 Alternatives & Progressions​

Exercise Progression Path​

Regressions (Easier)​

Progressions (Harder)​

Alternatives​

🛡️ Safety & Contraindications​

Who Should Be Careful​

Safety Tips​

🦴 Joints Involved​

❓ Common Questions​

📚 Sources​