| 摘要 |
A head and neck exercise apparatus 110 may include a member operatively arranged with a valve mechanism 118 with a threshold pressure. The apparatus 110 may further include an acoustic apparatus, membrane 118, chromogenic material, or moveable element that may be configured to respond when the pressure within the member is greater in magnitude than the threshold pressure. The head and neck exercise apparatus 110 may also include a member operatively arranged with an acoustic apparatus, membrane, chromogenic material, or moveable element that may be configured, without a valve mechanism, to respond when the absolute pressure within the member is greater in magnitude than a threshold absolute pressure. |
