Traditional 動 put strength 力 behind 重 'heavy' — moving is applying force to what resists. Simplified 动 swapped in 云 cloud for sound: now it's strength moving clouds, which is somehow better.
运动 sports and exercise, 动物 animals ('moving things' — the zoo is 动物园), 感动 to be moved emotionally, 动手 to get hands moving (to start — or to start a fight). 别动! 'don't move!' is what every parent, photographer, and police drama says.
Strength 力 enough to move clouds 云 — MOVE.
动车 'moving car' is the D-class bullet train — in a country with 40,000 km of high-speed rail, 动 is the first character on most tickets.