The effect of biting tasks on human balance- and posture control during the performance of gross motor tasks

流行病学研究表明，颌面疼痛与颈部和背部疼痛的合并症很高，这对卫生保健系统构成了巨大的经济负担。假设列出的症状与颅下颌功能障碍（CMD）的症状复合物有关。到目前为止，关于颅下颚系统（CMS）与人体其他运动亚段之间的神经肌肉相互作用的证据很少。在我们之前的工作中，初步发现CMS对颈部肌肉和习惯性站立姿势的身体姿势的影响。本实验随机化研究旨在了解受控咬咬对健康受试者在执行简单和复杂运动任务时动态平衡和姿势的影响。为此，进行了复杂的生物力学运动分析。除咬合力外，还同步记录运动的运动学、动力学和肌电图特征。红外摄像机捕捉到片段的运动。测力板用于测量地面反作用力和足部压力。一个遥测的16通道肌电图装置被用来测量下肢的肌肉活动。根据处理后的运动学数据，通过模型计算可以计算出关节角度、关节力矩曲线和重心。对于静态运动任务的分析，可以分析身体的重心位置和压力中心（COP）在支撑基座上的位置。对于动态运动任务，采用von Hof数学模型确定其动态稳定性。为了阐明咬人与不咬人时稳定性参数可能存在的差异，采用经典的孤立自由度离散参数对被试的运动协调进行了分析。用连续相对相位角和正交参考函数的相位角相似度来检验不同自由度之间的协调性。基于这些数据和结果，对肌肉骨骼亚段复杂相互作用的更深入的神经生物学理解应该有助于揭示CMS与人类肌肉骨骼系统之间可能的功能和病理生理相互作用。这些知识可能有助于制定优化的、降低成本的治疗策略。

Epidemiological studies reveal a high comorbidity of pain in the maxillofacial area with pain in the neck and back which represent an extraordinary financial burden on the health care system. It is assumed that the listed symptoms are associated with the symptom complex of craniomandibular dysfunction (CMD). So far there is a low level of evidence for the neuromuscular interactions between the craniomandibular system (CMS) and other motor sub-segments of the human body.In our previous work, initial findings of the impact of the CMS on the neck muscles and the body posture in the habitual standing position are detected. The planned experimental randomized study will provide information about the effect of a controlled biting task on the dynamic balance and posture in healthy subjects during the performance of simple and complex motion tasks. For this purpose, a complex biomechanical motion analysis is performed. Besides the bite forces, kinematic, dynamic and electromyographic characteristics of the movements are recorded synchronously. The segment movements are captured with infrared cameras. Forceplates are used to measure ground reaction forces and the foot pressure. A telemetric 16-channel EMG device is used to measure the muscle activity of the lower extremities. Based on the processed kinematic data, the joint angle and joint torque curves and the center of gravity can be calculated by means of model calculation. For analysis of the static motion tasks, the position of the body´s center of gravity and the position of the center of pressure (COP) over the support base can be analyzed. For the dynamic movement tasks, the mathematical model of von Hof is used to determine the dynamic stability. To elucidate possible differences in the stability parameters between the conditions biting and not biting, the coordination of movements of the subjects are analyzed by using classical discrete parameter of isolated degrees of freedom. The coordination between different degrees of freedom is tested by means of continuous relative phase angle and the similarity of the phase angle by means of orthogonal reference functions.On the basis of the data and results, a deeper neurobiological understanding of the complex interaction of musculoskeletal sub-segments should help to reveal possible functional and pathophysiological interaction between the CMS and the human musculoskeletal system. This knowledge may help to develop optimized, cost-cutting treatment strategies.