A runner exercises before a race to prevent his muscles from tensing up.
A runner exercises before a race to prevent his muscles from tensing up.
赛跑运动员在比赛前要活动活动，以放松肌肉。
A runner exercises before a race to prevent his muscles from tensing up.
赛跑运动员在比赛前要活动活动，以放松肌肉。