Ab Crunch Machine
The Ab Crunch Machine is a resistance-based exercise that isolates the abdominal muscles through controlled spinal flexion. It allows for safe, adjustable loading to build core strength and definition while minimizing lower back strain.
Because abdominal training often involves high repetitions, it is easy to plateau by lifting the same weight indefinitely; the AI analyzes your RPE and performance trends to prescribe incremental load increases specifically when your recovery data indicates readiness. If you report lower back sensitivity, the app can instantly recommend stability-focused alternatives like Dead Bugs to maintain training volume safely. Additionally, by monitoring your daily HRV and sleep, the system can adjust the session intensity to prevent overtraining the central nervous system on isolation days.
Form Cues
- Exhale deeply as you crunch forward to maximize contraction
- Keep your lower back pressed firmly against the seat support
- Initiate the movement specifically with your abs
- Control the return phase slowly to keep tension on the muscles
- Don't pull the handles down using your arm strength
- Don't let the weight stack slam down between repetitions
- Don't hold your breath during the crunch
- Don't use momentum to jerk your torso forward
Common Mistakes
- Pulling with arms instead of abs
- Using excessive momentum
- Lifting hips off the seat
- Performing reps too quickly
- Incomplete range of motion
Muscles Worked
This exercise primarily targets the rectus abdominis, effectively isolating the 'six-pack' muscles through loaded spinal flexion. It also engages the external obliques to a lesser degree to assist in stabilizing the torso throughout the movement range.
Primary
Secondary
Get Personalized Coaching for Ab Crunch Machine
Don't guess your way through weights or workouts. Download Iridium for automatic, AI-powered coaching that adapts to your recovery and goals.