Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Plank: hands under shoulders, straight body (core tight, pelvis tucked, hips level with shoulders). Triceps back (elbows to knees), neutral head/spine. Lift one hand, tap opposite shoulder; return. Alternate controlled, steady. Keep body still (no hip sway/dip; even weight). Finish reps, lower knees. Modify if back/shoulders hurt.
Keep hips steady (fight gravity; recruit opposite side). If struggling, practice with light weight (water bottle/cushion) on back.
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