跑 is a foot ⻊ with 包 lending sound — a late, practical character for a motion as old as legs. The foot radical carries a whole gym: 跳 jump, 踢 kick, 跑 run.
跑步 'run-steps' is jogging, China's dawn ritual in every park. 跑 also means to flee or to slip away: 别跑! 'don't run!' works for children, dogs, and thieves alike. A busy errand-runner 跑来跑去 — runs here and there all day.
Foot ⻊ wrapped 包 in motion — RUN!
跑龙套 'running the dragon-costume parts' means playing bit roles — from opera extras who sprinted across the stage carrying flags to make armies look bigger.