山姆只接触到PRI的“90/90 Breathing with Posterior Tilt”动作，以此动作做分享。您可以在动态热身前，进行5~10次的练习，其动作的要点：

● 腹式呼吸：吸气：透过鼻子（３秒），从腹部先扩张，接着是胸腔；吐气：透过嘴巴（１０秒），从胸腔收缩，接着腹部收缩。
● 躺在地上，背贴平，膝盖及屁股呈现９０度。
● 大腿夹住一个滚桶或小药球。（约用50%的力量）
● 勾脚掌，骨盆后倾，让尾骨离开地面。

影片网址：https://youtu.be/xilrUEE8F8o

吐气为什么持续要吐10秒呢？强迫把吐气延长是为了强迫核心的用力，但强迫吐气可能会造成过度换气的症状或不适感。关于这部份，山姆问了MBSC的教练Brendon Rearick：

Some people say, if they force themselves to exhale out (I mean, to send all the air out from the lungs), it will cause hyperventilation syndrome and make them feel uncomfortable.
And it is difficult for them to exhale little and strongly, when they do it intently, their breath will become very fast and the body will be stiff.

Do you have similar experience or could you give some suggestions for teaching PRI breath?

Brendon Rearick 的回答：

I have never heard of this but I could see the exhale part of things causing someone anxiety who had never done it before. I would tell them to take deep natural breaths for the first week or two then start focusing on the forced exhales as they get more comfortable. We’ve also had good success of coaching the exhale stuff using straws.

以上分享。