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Smith Machine Sit-Up
A guided resistance sit-up using a Smith machine that targets the rectus abdominis and obliques to build core strength and hypertrophy, with added weight for progressive overload.
About Exercise
Equipment
Smith Machine
Difficulty
2/5 • Beginner
Primary Muscle Groups
Abs
Secondary Muscles
Hip Flexors
Popularity Score
5
Goals
Training Style
Setup Requirements
Requires Rack
No
Requires Bench
Yes
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
Programming
Typical Rep Range
10-25 reps
Rest Between Sets
30-60 seconds
How to Perform
Place a flat bench under the Smith machine bar adjusted to align over your upper chest when lying down. Lie supine with knees bent, feet flat, and grip the unlocked bar with extended arms.
- Engage core and curl torso upward toward knees.
- Push bar vertically with straight arms as you rise.
- Squeeze abs at the top of the movement.
- Slowly lower torso back to start, resisting the bar's weight.
- Keep back rounded and neck neutral throughout.
Coaching Tips
Form Cues
- Curl from abs, not arms.
- Keep bar at arm's length.
- Neck neutral.
- Ribs toward knees.
- Control the descent.
Breathing
Inhale as you lower, exhale forcefully as you curl up and brace core.
Tempo
3-1-2
Range of Motion
From upper back flat on bench to torso upright with shoulders past hips, maintaining spinal flexion without hyperextension.
Safety
Safety Notes
- Set safeties at chest level.
- Start with light weight or bar only.
- Avoid if acute back or neck pain.
- Warm up spine and core first.
- Stop if sharp pain occurs.
Spotting
Spotting not typically needed due to guided path; use safeties and self-spot if adding heavy weight.
Common Mistakes
- Pulling with arms or neck.
- Using momentum or jerking.
- Arching lower back.
- Incomplete range, not squeezing top.
- Too much hip flexor drive.
When to Avoid
- Acute lower back pain
- Neck strain or injury
- Recent abdominal surgery
Flexibility Needed
- Adequate spinal flexion
- Hip flexion range
Build Up First
- Basic bodyweight sit-up form
- Core bracing technique
Also known as
Smith Machine Crunch, Guided Abdominal Sit-Up, Machine Core Flexion
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