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Balance Trainer Single Leg Crunches
A core crunch on an unstable balance trainer with one leg extended, targeting rectus abdominis and obliques to build stability and coordination; enhances balance and core strength.
About Exercise
Equipment
Balance Trainer
Difficulty
3/5 • Intermediate
Primary Muscle Groups
Abs
Secondary Muscles
Hip Flexors, Lower Back
Popularity Score
5
Goals
Training Style
Setup Requirements
Requires Rack
No
Requires Bench
No
Requires Spotter
No
Space Needed
Small
Noise Level
Low
Muscle Breakdown
View Muscle MapAbs
10/10Rectus Abdominis
Obliques
7/10External Obliques, Internal Obliques
Hip Flexors
5/10Iliopsoas
Lower Back
3/10Erector Spinae
Programming
Typical Rep Range
10-20 reps
Rest Between Sets
30-60 seconds
How to Perform
Place balance trainer dome-side up on a stable surface. Sit on the dome and recline back until your lower back is supported, with one knee bent foot flat and the other leg extended hovering above ground.
- Brace your core and draw belly button to spine.
- Exhale and curl torso upward, lifting head, neck, and shoulders off the dome.
- Reach rib cage toward hips or extended leg.
- Squeeze abs at the top and hold briefly.
- Inhale and lower upper body slowly with control.
- Switch legs after reps on one side.
Coaching Tips
Form Cues
- Eyes to ceiling
- Use core, not neck
- Keep hips stable
- Elbows wide open
- Hover leg steady
Breathing
Exhale as you crunch up and engage abs; inhale as you lower back down.
Tempo
2-1-2
Range of Motion
Lift shoulders off dome until rib cage nears hips; avoid full spinal extension on descent.
Safety
Safety Notes
- Avoid if acute neck or lower back pain
- Master standard crunches first
- Ensure trainer is secure
- Stop on sharp pain
- Maintain natural spine curve
Spotting
No spotting needed; perform in controlled environment with space to fall safely.
Common Mistakes
- Pulling on neck
- Using momentum
- Arching lower back
- Dropping head too low
- Uneven leg balance
When to Avoid
- Acute neck strain
- Lower back injury
- Recent abdominal surgery
Flexibility Needed
- Adequate shoulder flexion
- Hip mobility for leg extension
Build Up First
- Master standard crunches
- Basic balance on unstable surface
Also known as
BOSU Single Leg Crunches, Stability Ball Single Leg Crunch
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