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Objective:The aim of this study was to explore the associations of muscle size and density with handgrip strength(HGS)and the Timed Up and Go(TUG)test.Methods:Totally 301 participants living in the Xinjiekou community near Beijing Jishuitan Hospital were recruited for CT imaging of the hip and a 1-cm slice of the mid-thigh.The cross-sectional area and density of the gluteus maximus and the mid-thigh muscles were estimated by the Osirix viewer based on CT images.HGS and TUG were also performed in these subjects.Logistic regression analysis was used to evaluate the correlations of muscle density and size with TUG and grip strength.Results:In women, after adjustment for age and BMI, the density of the gluteus maximus was negatively correlated with TUG( P trend=0.0366), while the size of the gluteus maximus and the mid-thigh muscles was not correlated with TUG.In men, the density or size of these muscles was not correlated with TUG.After adjustment for age and BMI, the density of the gluteus maximus was positively correlated with grip strength( P trend=0.0334)and the size of the mid-thigh muscles was also positively correlated with grip strength( P trend=0.0155)in men, but they were not correlated with grip strength in women. Conclusions:There were sex differences in the relationship between muscle size or density and grip strength or timed up and go.The density of the gluteus maximus is associated with muscle strength and physical performance while the size of the mid-thigh muscles is correlated with muscle strength.
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Objective:To find out the characteristic topog ra phic distribution of the muscle spindles in human masseter.Methods: The muscle spindles of masseter on both sides of 5 human corpses fixed in for malin for more than 1 year were observed by histological technique and quantitat ively analyzed by picture analysis equipment.Results: The muscle spindles were maldistributed and the spindles were commonly clustered in some i ndividual portions,and the muscle spindles figures of the masseter were diversif orm,which were predominantly composed of the spindle simple and spindle complexe s. The spindle complexes in the deep portion was obviously more than that in the superficial. The muscle spindles in the muscle close to the temporomandibular j oint and muscle tendon in the deep portion were more than that in the other port ions.Conclusion:The distribution of muscle spindles in the masse ter is heterogeneous,muscle spindle density in the deep portion is greater than that in the superficial.