The American Academy of Orthopaedic Surgeons writes that when fitting into an athletic shoe you should be able to freely wiggle all of your toes.

• 拿着一双穿旧丢的跑鞋，一个有素养的店员会检查你旧跑鞋的磨损情况，看出你脚的活动状况，从而决定哪一种跑鞋适合你。