Why do muscles grow after lifting weights?
Show answer & explanation
Answer: Muscle fibers repair bigger
Bones push muscles outward — Wrong. Bones don't push muscles. Muscle growth happens when individual muscle fibers thicken through protein synthesis.
Muscle fibers repair bigger ✓ — Correct! Weight training creates tiny tears in muscle fibers. Your body repairs these tears with extra protein, making fibers thicker and stronger. This is why rest days and protein are important!
Muscles absorb air during exercise — Wrong. Muscles can't absorb air—they don't work like balloons. Real muscle growth comes from protein building thicker fibers over time during rest and recovery.