Cervical Spine Musculotendon Lengths When Reading a Tablet in Three Seated Positions
Cervical Spine Musculotendon Lengths When Reading a Tablet in Three Seated Positions
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以三个坐姿阅读平板电脑时的颈椎肌肉肌腱长度
DOI：
10.1123/jab.2020-0062
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发表时间：
2021
影响因子：
1.4
通讯作者：
Douglas, Ethan C.
中科院分区：
文献类型：
--
作者：
Gallagher, Kaitlin M.;Vasavada, Anita N.;Fischer, Leah;Douglas, Ethan C.
使用无线技术的一种流行姿势是斜坐，躯干向后旋转到臀部。这个位置降低了头部的重力矩;然而，头部相对于躯干的角度与在膝盖上使用平板电脑时直立坐着的角度相似。本研究比较了在使用片剂时，3种常见坐姿和最大颈部屈曲之间的颈部伸肌肌腱长度从中立位置的变化。21名参与者在膝上放置平板电脑的情况下以中立、全屈曲、直立、半斜躺和斜躺姿势拍摄X线片。一个生物力学模型被用来计算受试者特定的标准化肌肉肌腱长度为27颈部肌肉肌腱节段。下颈椎在斜坐时更屈曲，但颅骨在直立时更屈曲。对于C4-C6/7（深）和C2-C6/7（浅）多裂肌、颈半棘肌（C2-C7）和头夹肌（颅骨-C7），与直立坐姿相比，斜倚时的标准化肌肉肌腱长度增加。枕下（R2= 0.19 - 0.71）和头半棘肌节段长度变化与颅骨-C1角（0.24-0.51）显著相关。半躺阅读姿势可能是一种理想的坐姿，可以减少头部的重力力臂，而不会过度拉伸评估的肌肉。
A popular posture for using wireless technology is reclined sitting, with the trunk rotated posteriorly to the hips. This position decreases the head’s gravitational moment; however, the head angle relative to the trunk is similar to that of upright sitting when using a tablet in the lap. This study compared cervical extensor musculotendon length changes from neutral among 3 common sitting postures and maximum neck flexion while using a tablet. Twenty-one participants had radiographs taken in neutral, full-flexion, and upright, semireclined, and reclined postures with a tablet in their lap. A biomechanical model was used to calculate subject-specific normalized musculotendon lengths for 27 cervical musculotendon segments. The lower cervical spine was more flexed during reclined sitting, but the skull was more flexed during upright sitting. Normalized musculotendon length increased in the reclined compared with an upright sitting position for the C4-C6/7 (deep) and C2-C6/7 (superficial) multifidi, semispinalis cervicis (C2-C7), and splenius capitis (Skull-C7). The suboccipital (R2= .19–.71) and semispinalis capitis segment length changes were significantly correlated with the Skull-C1 angle (0.24–0.51). A semireclined reading position may be an ideal sitting posture to reduce the head’s gravitational moment arm without overstretching the assessed muscles.