Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Downward dog: hands shoulder-width, V-shape body, feet hip-width. Bend elbows, lower chest to floor (low plank). Straighten arms, lift torso (upward dog). Lower torso, lift hips (back to downward dog). Repeat.
Engage core, relax spine/neck, open shoulders; fluid motion. Inhale down dog to up dog (elbows close). Exhale to down dog.
MuscleTrain is actively being built. If something looks broken, or you have a suggestion, let us know — it really helps shape the app.