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We studied the effects of emulsified oil impregnation on the texture of dried potato with convective drying using masseter muscle electromyography. Personal differences were defined as blocking factors by a randomized block design method, and a two-way analysis of variance was used for statistical analysis of the acquired electromyography data. The dried samples impregnated with emulsified oil had significantly smaller values for the five parameters than those without emulsified oil. The significantly different parameters were total duration, number of chews, total muscle activity, muscle activity per chew and duration per chew. The results suggested that the emulsified oil impregnation increased the crispy texture, made it easier to break the structure in t he early stages of mastication, and decreased the work for bolus formation with saliva before the first swallow. They also suggested that the randomized block design method enabled the analysis by subtracting personal differences from the effects of food processing. [ABSTRACT FROM AUTHOR]

Objective：The purpose of this study was to investigate whether archers clench their teeth when drawing and releasing a bow, and to clarify how clenching influences EMG activity and the release action in kyudo. Methods：The subjects were expert archers of kyudo. EMG activities of the masseter muscle, sternocleidomastoid muscle, trapezius and triceps muscle were simultaneously recorded with the output of a strain gauge on a bow and highspeed video images. EMG records for 1 second before and after release were used. The records of each subject were averaged, and the RMS was calculated for the following three sections：Section 1：1 second immediately before release, Section 2：Immediately after release until 0.25 seconds later, and Section 3：From 0.25 to 1 second after release. When masseter muscle activity exceeding 30％ MVC for 1 second or longer was measured, it was judged that there was clenching. The motion velocity of the right hand was calculated by measuring the distance that the base of the right thumb moved in 100 ms from the moment the string was released. Result and conclusion：Of the 19 subjects, two clenched their teeth while drawing and releasing the bow. Immediately after release, a transient increase in activity was observed in the left and right masseter muscles, sternocleidomastoid muscles and the left triceps muscle. This is thought to have responded to the vibration of the bow accompanying the shooting of the arrow. When the non-clenched subjects intentionally clenched, EMG activity did not change except for an increase of masseter muscle activity while drawing and releasing the bow. When intentionally clenched, the motion velocity of the right hand in the release action was significantly reduced. It is suggested that clenching may have a negative effect on the release action in kyudo. [ABSTRACT FROM AUTHOR]

It is known that tooth clenching is effective for increasing muscle strength. The purpose of this study was to investigate the influence of clenching on rugby scrum power. The subjects were 29 rugby players. EMG activities of the masseter muscle were simultaneously recorded with scrum power. A load cell was placed between a wire that connected a wall to a scrum machine on wheels, and the tension of the wire while the players pushed the machine was measured as an index of scrum power. Of the 29 rugby players, 13 clenched their teeth while pushing the scrum machine, whereas only 1 of 8 players clenched their teeth while pushing the scrum machine when only props were surveyed. There was no significant difference in scrum power between the clenching group and the non-clenching group. When the players of the clenching group pushed the scrum machine while purposely not clenching their teeth, the scrum power was significantly decreased. In contrast, when the players of the non-clenching group pushed the scrum machine while purposely clenching their teeth, the scrum power was increased as a value (area) integrated over the analysis period. EMG activities of the masseter muscle were nearly 50% of MVC during scrum machine pushing with clenching in both the clenching group and the non-clenching group, suggesting the need to protect the teeth, periodontal tissue and temporomandibular joint. [ABSTRACT FROM AUTHOR]

The article presents a study which analyzes the impact of bite force on masticatory function and occlusal contact area (OCA). The study recorded the temporal muscle activity, mandibular movement, and massetter during the mastication to analyze bilateral muscle activity ratio. It shows the increase of OCA in accord to the bite force of every position. It also reveals the significant correlation between bilateral masseter muscle activity ratio and the degree of increase of OCA.

The article presents a study regarding the analysis of peripheral feedback mechanism in chewing various types of food in Japan. The methods used in the study were ten healthy subjects that were asked to chew boiled fish paste, chewing gum and beef jerky. Results show that there were large variations among subjects and cycles wherein variations became small after the third cycle for chewing, gum, after the fourth cycle for fish paste and after the seventh cycle for beef jerky.

The article focuses on a study which assesses the influence of light and hard tensile force and unilateral clenching duration in static strain distribution on dry skull. The study employs an experimental model to simulate masseter and temporalis muscles. It shows that the influence of the tensile force of masticatory muscle and unilateral clenching duration was found on the frontal bone, parietal bone, temporal bone, and zygomatic process of temporal bone.

The article presents a study which aims to analyze the relationship between jaw displacement and non-chewing side contact area when clenching. Male volunteers were instructed to clench on a central bearing device where the linear variable transformers measured the vertical displacements of bilateral molars. The masseter and temporal muscles were also measured through electromyography. Results indicated that the contact area is larger on the area of the molar displacement.

The article presents a study which aims to analyze the activity of the medial pterygoid, the superficial masseter and the anterior temporal muscles during bite forces 49 Neuton and 147 Neuton on different teeth. Isometric muscle contractions which were performed by the subjects were recorded using subcutaneous needle electrodes. Results indicated that muscle activities were detected and registered.

The article presents a study on the reconstruction of tooth guidance which is under stomatognathic function. It states that the stomatognathic functions were assessed through clinical symptoms, mandibular movements and muscle activities as limitations of the scope of the study. The results reveal that the left and right masseter muscles, anterior temporal muscles and posterior temporal muscles appear to have normal activities.

A 38-year-old man diagnosed as esophageal achalasia developed masseter muscle rigidity after intravenous suxamethonium during anesthetic induction. Anesthesia was maintained with intravenous agents and epidural blockade, while the masseter muscle rigidity continued. After the surgery, his body temperature increased to 38.8 degrees C concomitantly with the appearance of myoglobinuria suggesting the occurrence of abortive malignant hyperthermia. These symptoms were dissolved by dantrolene administration. He was later proved to be negative with CICR test.