Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.
Center of Sport Medicine, IRCCS Don Gnocchi Foundation, Milan, Italy.
J Strength Cond Res. 2018 Jan;32(1):230-236. doi: 10.1519/JSC.0000000000002178.
Limonta, E, Arienti, C, Rampichini, S, Venturelli, M, Cè, E, Veicsteinas, A, and Esposito, F. Effects of two different self-adapted occlusal splints on electromyographic and force parameters during elbow flexors isometric contraction. J Strength Cond Res 32(1): 230-236, 2018-The study was aimed at determining the acute effects of 2 types of occlusal splints on maximum isometric strength and fatigue of the elbow flexors muscles. The hypothesis was that splint-induced masticatory muscle repositioning might improve primary muscles recruitment by stretching masticatory muscles especially with the thicker splint. On 9 physically active volunteers with no temporomandibular joint and masticatory muscles disorders, we assessed maximum voluntary contraction (MVC) of the elbow flexors with diurnal (OSD, 1-mm thick) and sport (OSSP, 3-mm thick) splints, and without splint (control, Ctrl). On different days, participants performed 60 seconds of isometric contraction at 100% MVC (100%60s) and 80% MVC contraction until exhaustion (80%exh) under OSD, OSSP, and Ctrl in random order. Time of force output within target (t-target), force distance from target (ΔF), and force coefficient of variation were calculated. Percentage of force decay (ΔFi-Fe) was determined during 100%60s. From the electromyographic (EMG) signal, root mean square (EMG RMS) and mean frequency (EMG MF) were determined. Neuromuscular efficiency (NE) was calculated as the ratio between force and EMG RMS. MVC contraction and NE were significantly higher in OSSP and OSD than in Ctrl. During MVC, EMG MF was significantly lower in both splint conditions, and EMG RMS showed a nonstatistical tendency to lower values under both splint conditions. During 80%exh, t-target was longer in OSD and OSSP (+7.8% and +5.2%, respectively) than in Ctrl. ΔFi-Fe was lower in OSSP than in Ctrl and OSD. These results support the hypothesis of a NE improvement of the elbow flexors possibly induced by acute, splint-induced masticatory muscles repositioning.
利蒙塔、阿里恩蒂、兰皮奇尼、文特雷利、切、维切斯坦纳斯和埃斯波西托。两种不同自适应性咬合垫对口轮匝肌等长收缩时肌电图和力参数的影响。《力量与调节研究杂志》32（1）：230-236，2018-本研究旨在确定 2 种咬合垫对口轮匝肌最大等长收缩力量和疲劳的急性影响。假设是咬合垫引起的咀嚼肌重定位可能通过拉伸咀嚼肌来改善主要肌肉募集，特别是使用更厚的咬合垫。在 9 名无颞下颌关节和咀嚼肌疾病的活跃志愿者中，我们评估了口轮匝肌最大自主收缩（EMG），并在日间（OSD，1 毫米厚）和运动（OSSP，3 毫米厚）咬合垫和无咬合垫（对照，Ctrl）的情况下进行评估。在不同的日子里，参与者在 OSD、OSSP 和 Ctrl 下以 100%最大自主收缩（100%60s）和 80%最大自主收缩（直到衰竭）进行 60 秒的等长收缩。计算力输出在目标内的时间（t-target）、力与目标的距离（ΔF）和力变异系数。在 100%60s 期间确定力衰减百分比（ΔFi-Fe）。从肌电图（EMG）信号中，确定均方根（EMG RMS）和平均频率（EMG MF）。神经肌肉效率（NE）定义为力与 EMG RMS 的比值。OSSP 和 OSD 中的最大自主收缩和 NE 均显著高于 Ctrl。在最大自主收缩期间，两种咬合垫条件下的 EMG MF 均显著降低，而 EMG RMS 显示出在两种咬合垫条件下值降低的非统计学趋势。在 80%衰竭期间，OSD 和 OSSP 的 t-target 均长于 Ctrl（分别为+7.8%和+5.2%）。OSSP 的ΔFi-Fe 低于 Ctrl 和 OSD。这些结果支持了这样一种假设，即急性、咬合垫诱导的咀嚼肌重定位可能改善肘部屈肌的 NE。
