This action primarily recruits transverse abdominus. Be careful not to hold your breath – you should be able to breathe evenly while bracing.

需要注意的是，进行练习时不要摒住呼吸----要保持呼吸均匀。

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These are propellers mounted in transverse tunnels in the hull, to help position the craft and hold her stable while alongside a rig.

ECONOMIST: Marine technology: A voyage of discovery | The