Left foot radical (Kangxi #157) — the seven-stroke pictograph of a leg-and-foot in compressed left-side form (the bottom
止 'foot' is squashed). Anchors
跳 in the moving-on-feet family alongside
跑 (run),
踢 (kick),
踩 (step on),
跌 (stumble),
蹲 (squat),
跨 (stride). Tells the reader: this character names something the foot does — here, leaving the ground.