Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Lie on your back and grip a stable bar behind your head. Lift your body into a straight line with your core and glutes engaged, then lower yourself slowly over 3–6 seconds while keeping your body rigid. Reset to the starting position and repeat with controlled form.
Keep your body straight from shoulders to feet: don't bend at the hips on the way down. Rest your weight on your upper back, not your neck. If your hips bend or your lower back arches, stop and bring your legs back up. If a straight body is too hard, start with your knees bent.
Muscle Train is actively being built. If something looks broken, or you have a suggestion, let us know — it really helps shape the app.