Muscle outlines from Body Muscles by Ivan Vulović, Apache 2.0 — regrouped and recoloured for Muscle Train.
Lie on your back, legs extended, arms by your sides. Place hands lightly behind your head, elbows wide. Engage your core, lift knees to chest while curling your upper body off the mat. Hold briefly, squeezing your abs. Slowly lower back down, maintaining control. Repeat.
Control movements to maximize core engagement. Keep lower back pressed against the mat. Exhale during the crunch, inhale on the descent. Use hands for light support only; avoid neck strain. Start with fewer reps and increase gradually.
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