Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Begin in standard push-up position. Slowly lower body until chest nearly touches floor. Keep descent slow and controlled. Press up to start at normal pace.
Bottom: upper body "A-shape" (arms/spine)—no elbow flare ("w"). Neutral neck—no chin tuck. Squeeze glutes/engage abs for rigid spine.
MuscleTrain is actively being built. If something looks broken, or you have a suggestion, let us know — it really helps shape the app.