Crunches (Bodyweight)
Crunches are a foundational core exercise that targets the upper abdominal muscles by flexing the spine while lying on the floor. This beginner-friendly bodyweight movement strengthens the rectus abdominis without requiring any equipment.
Because core exercises are often performed with high volume, the AI analyzes your RPE and set duration to ensure you are maintaining effective tension rather than relying on momentum or rushing reps. It tracks your abdominal recovery status from previous sessions to prevent overtraining, and if you report neck strain or lower back pain, the system can instantly suggest ergonomic alternatives like dead bugs to keep you training safely.
Form Cues
- Press your lower back firmly into the floor throughout the set
- Exhale sharply as you curl your shoulder blades off the ground
- Imagine holding an apple between your chin and chest to protect your neck
- Squeeze your abs at the top of the movement for a one-second pause
- Lower your torso slowly to maintain constant tension
- Don't pull on your head or neck with your hands
- Don't lift your lower back off the floor
- Don't use momentum to swing your torso upward
- Don't tuck your chin completely into your chest
- Don't hold your breath during the contraction
Common Mistakes
- Yanking on the neck
- Lifting the lower back
- Using hip momentum
- Limited range of motion
- Rushing the lowering phase
Muscles Worked
This exercise primarily targets the rectus abdominis, specifically emphasizing the upper region, by flexing the thoracic spine against gravity. Unlike full sit-ups, crunches minimize hip flexor involvement, keeping the metabolic stress and tension focused purely on the abdominal wall.
Primary
Secondary
Get Personalized Coaching for Crunches (Bodyweight)
Don't guess your way through weights or workouts. Download Iridium for automatic, AI-powered coaching that adapts to your recovery and goals.