Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Lie on your back, arms extended overhead, legs straight. Hold a weight plate or dumbbell above your chest. Engage your core, lift shoulders and legs off the ground into a 'hollow' body position. Keep your lower back pressed to the floor. Hold, then slowly lower back down.
Maintain lower back contact with the floor. Start with a lighter weight. Breathe steadily. Tuck your chin if you feel neck strain. Keep your core engaged. Adjust leg height to modify difficulty.
MuscleTrain is actively being built. If something looks broken, or you have a suggestion, let us know — it really helps shape the app.