We investigated the relationship between impedance parameters and skeletal muscle function in the lower extremities, as well as the effectiveness of impedance parameters in evaluating muscle quality. Lower extremity impedance of 19 healthy men (aged 23–31 years) measured using the direct segmental multi-frequency bioelectrical impedance analysis were arc-optimized using the Cole–Cole model, following which phase angle (PA), $${R}_{i}/{R}_{e}$$ R i / R e , and β were estimated. Skeletal muscle function was assessed by muscle thickness, muscle intensity, and isometric knee extension force (IKEF). IKEF was positively correlated with PA (r = 0.58, p < 0.01) and β (r = 0.34, p < 0.05) was negatively correlated with $${R}_{i}/{R}_{e}$$ R i / R e (r = − 0.43, p < 0.01). Stepwise multiple regression analysis results revealed that PA, β, and $${R}_{i}/{R}_{e}$$ R i / R e were correlated with IKEF independently of muscle thickness. This study suggests that arc-optimized impedance parameters are effective for evaluating muscle quality and prediction of muscle strength.

Objectives The aim of this study was to clarify changes in the lactate threshold (LT) in the acute period after cerebral infarction.Methods Cerebral infarction was induced by the injection of microspheres (MS) into the right internal carotid artery. To estimate the degree of neurological deficit caused by surgery, the behaviors of all rats were evaluated in terms of typical symptoms of stroke in rats. A rotarod test was used to evaluate equilibrium function. Rats were forced to perform stepwise treadmill exercises and serial changes in the blood lactate concentration were measured for determination of the LT. ResultsThe average treadmill speed at the LT and rotarod performance in MS rats was significantly lower than those in sham-operated rats on the 2 nd days after surgery.However, while neurological deficits disappeared on the 7 th days after surgery in MS rats, the LT and rotarod performance were significantly lower than those in shamoperated rats. ConclusionThese results suggest that the decrease in the LT in the acute period following cerebral infarction may be induced by impairment of the equilibrium function.Other possibilities are also discussed.

[Purpose] Many patients receive intermittent cervical traction in a daily treatment setting. However, unified settings for traction force, duration, and direction have yet to be determined. Therefore, an objective index is required to determine changes in traction conditions or to indicate its effectiveness. [Subjects] Fifteen healthy males volunteers participated in this study. [Methods] The thickness of the trapezius and splenius capitis muscles before and during traction were measured using ultrasonography at three traction forces: 5, 8 and 11 kg. [Results] Significant differences in muscle thickness were observed at 11 kg in the trapezius, and at 8 kg and 11 kg in the splenius capitis muscles. The muscle thickness ratio of the trapezius muscle showed a significant difference between 11 kg and 5 and 8 kg, and between 5 kg and 8 and 11 kg, as well as between 8 kg and 11 kg for the splenius capitis muscles. [Conclusion] Differences in muscle direction between the trapezius and splenius capitis muscles may account for the contrasting results obtained at the 8 kg traction force. This finding suggests that cervical traction must be performed considering the effects on different neck regions.

Verification of the accuracy of measuring the muscle cross-sectional area and muscle intensity of the rectus femoris using ultrasonography. Jpn J Compr Rehabil Sci 2018; 9: 66-72.Objective: This study aimed to establish ultrasonography as a method of measuring the muscle cross-sectional area and muscle intensity of the rectus femoris and to assess its measurement accuracy. Methods: Three testers measured the muscle crosssectional area and muscle intensity of the rectus femoris using ultrasonography in 16 healthy male volunteers. Intra-rater and inter-rater reliabilities were evaluated using the intraclass correlation coefficient (ICC), and Bland-Altman (B-A) analysis was used to confirm the systematic error and measure the minimum detectable change. Results: Intra-tester and inter-tester ICCs of the muscle cross-sectional area and muscle intensity were ≥0.9 and ≥0.7, respectively. On B-A analysis, no systematic error was observed in each measurement. The minimum testable changes were 0.39 cm 2 for the intra-tester cross-sectional area, 0.15 cm 2 for the intertester cross-sectional area, 6.77 for the intra-tester intensity, and 4.47 for the inter-tester intensity. Conclusion:The muscle cross-sectional area and muscle intensity of the rectus femoris can be measured with high accuracy using this measurement method. In addition, changes larger than the minimum detectable change can be used as a true change in clinical efficacy assessments.

Purpose Type 2 diabetes mellitus (T2DM) and concomitant diabetic polyneuropathy (DPN) induce muscle weakness. Muscle weakness in the foot is associated with foot deformities and falls. However, factors affecting toe grip strength (TGS) are not well known. Therefore, the present study investigated factors related to TGS in patients with T2DM. Methods This was a cross-sectional study involving 100 patients with T2DM who were hospitalized for the treatment of T2DM and 50 healthy adults. The subjects were divided into three groups: a group of healthy subjects, a group of T2DM patients without DPN, and a group of T2DM patients with DPN. Hierarchical multiple regression analysis was performed with TGS and the TGS-to-weight ratio (TGS/Wt%) as dependent variables and with age, the presence of T2DM, and DPN as independent variables, and sex and BMI as confounders. Results There were no significant differences in age or sex among the three groups. In the final regression analysis, age and presence of T2DM and DPN were associated in both models with TGS and TGS/Wt% as dependent variables. Conclusion DPN, T2DM, and age were found to be related to TGS. The findings of this study could contribute to healthcare providers developing foot care and rehabilitation programs for diabetic patients. Trial registration This study was registered with UMIN-CTR (UMIN000034320) on 1 November 2018.