MEASUREMENT OF THE EMG-FORCE RELATIONSHIP IN A HUMAN UPPER AIRWAY MUSCLE
MEASUREMENT OF THE EMG-FORCE RELATIONSHIP IN A HUMAN UPPER AIRWAY MUSCLE
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DOI：
10.1152/jappl.1995.79.1.270
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发表时间：
1995-07-01
影响因子：
3.3
通讯作者：
FREGOSI, RF
中科院分区：
文献类型：
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作者：
FULLER, D;SULLIVAN, J;FREGOSI, RF
上呼吸道肌肉在呼吸、吞咽和说话中发挥着重要作用，但人们对这些肌肉的肌电图 (EMG) 与力的关系知之甚少。我们使用通过前额和上唇安装的定制耳机测量了人鼻扩张器肌肉 (NDM) 的峰值综合肌电图活动 (iEMG) 和力量。头件包含一个显微操作器，该操作器固定一根杆，杆尖安装有测力传感器。通过在 13 名受试者的两个不同场合的多次试验中测量 NDM 的横向力或“张开”力来检查力测量的再现性。在这些研究中，受试者被指示进行最大自主收缩（MVC）。日内比较的重测重现性平均为 8.3%（变异系数），日间比较的重现性平均为 13.7%。我们还在 9 名受试者的增量运动测试中测量了 iEMG 和 NDM 力；他们被要求在休息时和每次工作时在 30 秒的时间里用鼻呼吸。峰值运动 (175-275 W) 期间的 iEMG 和力量平均分别为 81 +/- 26% (SD) MVC 和 235 +/- 127 mN（类似于 75% MVC）。增量运动期间的 iEMG 与峰值力呈线性相关（r = 0.90，P < 0.001）。通过对面神经施加单次超最大电击（0.1 毫秒脉冲），测量了 7 名受试者的收缩特性。抽搐力平均为 9 +/- 6% MVC，达到峰值力的时间为 62 +/- 13 毫秒，这比人类隔膜或肘屈肌的时间要快得多。得出以下结论：1）我们的方法对于在自愿、非自愿和电诱发收缩期间进行 NDM 力的可重复测量很有用； 2) 使用该系统测量的力与 NDM 的神经驱动 (iEMG) 非常相似； 3) NDM在鼻呼吸峰值运动期间（即75% MVC）的力量输出很大； 4)人类NDM具有相对快速的收缩特性。
The upper airway muscles play an important role in breathing, swallowing, and speaking, but Little is known about the electromyogram (EMG)-force relationship of these muscles. We have measured the peak integrated EMG activity (iEMG) and force of human nasal dilator muscles (NDM) with a custom-designed headpiece that was attached via the forehead and upper lip. The headpiece contains a micromanipulator that holds a rod with a load cell mounted on its tip. The reproducibility of the force measurements was examined by measuring the lateral or ''flaring'' force of the NDM in multiple trials on two separate occasions in 13 subjects. For these studies the subjects were instructed to perform maximal voluntary contractions (MVCs). Test-retest reproducibility averaged 8.3% (coefficient of variation) for within-day comparisons and 13.7% between days. We also measured iEMG and NDM force during an incremental exercise test in nine of the subjects; they were instructed to breathe nasally throughout one 30-s epoch at rest and at each workload. The iEMG and force during peak exercise (175-275 W) averaged 81 +/- 26% (SD) MVC and 235 +/- 127 mN (similar to 75% MVC), respectively. The iEMG during incremental exercise was linearly related to the peak force (r = 0.90, P < 0.001). Contractile properties were measured in seven of the subjects by application of single supramaximal shocks (0.1-ms pulse) to the facial nerve. Twitch force averaged 9 +/- 6% MVC, and the time to peak force was 62 +/- 13 ms, which is considerably faster than that in human diaphragm or elbow flexors. The following conclusions were made: 1) our method is useful for making reproducible measurements of NDM force during voluntary, involuntary, and electrically evoked contractions; 2) the force measured with this system closely parallels the neural drive (iEMG) to the NDM; 3) the force output of the NDM during peak exercise with nasal breathing (i.e., 75% MVC) is substantial; and 4) human NDM have relatively rapid contractile properties.