Kunita K, Fujiwara K
Graduate School of Natural Science and Technology, Kanazawa University, Japan.
Eur J Appl Physiol Occup Physiol. 1996;74(6):553-7. doi: 10.1007/BF02376772.
This study investigated the relationship between the reaction time of eye movement (RTEM) and activity of the superficial neck extensor muscles when the shoulder girdle elevator muscles contracted isometrically. The results were compared with those of a previous study in which the subjects's head was fixed and loaded with the neck flexed. When the shoulder girdle elevator muscles contracted isometrically, RTEM decreased significantly in comparison to RTEM at rest. This demonstrated that the reaction time significantly decreased not only as a result of the neck in flexion, which activated the deep and superficial neck extensor muscles, but also from contraction of the shoulder girdle elevator muscles which mainly activated the superficial extensor muscles. The relationship between RTEM and relative muscle load of the shoulder girdle elevator muscles showed that RTEM decreased up to 30% loading, and with loading above 40% the RTEM was longer than with 30%. The relative muscle load for the shortest RTEM demonstrated a subject-to-subject variance ranging from 24.7% to 49.6%. The difference between RTEM at rest and at their shortest reaction time was approximately 20 ms, which was consistent with the data for the neck in flexion. However, the relative muscle load for the shortest RTEM differed between the current and previous studies. The parameters obtained in this study were higher than for those in the previous study.
本研究调查了在肩胛带提升肌等长收缩时，眼球运动反应时间（RTEM）与颈部浅层伸肌活动之间的关系。将结果与之前一项研究的结果进行了比较，在之前的研究中，受试者头部固定且颈部处于屈曲状态并加载负荷。当肩胛带提升肌等长收缩时，与静息时的RTEM相比，RTEM显著缩短。这表明反应时间显著缩短不仅是由于颈部屈曲激活了颈部深层和浅层伸肌，还由于主要激活浅层伸肌的肩胛带提升肌收缩。RTEM与肩胛带提升肌相对肌肉负荷之间的关系表明，在负荷达到30%时RTEM缩短，而负荷超过40%时，RTEM比30%负荷时更长。最短RTEM时的相对肌肉负荷在受试者之间存在差异，范围为24.7%至49.6%。静息时与最短反应时间时的RTEM差异约为20毫秒，这与颈部屈曲时的数据一致。然而，本研究与之前研究中最短RTEM时的相对肌肉负荷有所不同。本研究获得的参数高于之前的研究。
