Analysis of the three-dimensional scapular kinematics and associated scapular muscle activity during scapular muscle exercises.

OBJECTIVE: To compare scapular kinematics and muscle activity among various scapular muscle exercises. DESIGN: A cross-sectional study. SETTING: A university research laboratory. PARTICIPANTS: Eighteen healthy men participated in this study. MAIN OUTCOME MEASURES: Three-dimensional scapular kinematics was measured with an electromagnetic motion capture system. Activities of the upper trapezius (UT), lower trapezius (LT), and serratus anterior (SA) were measured by using surface electromyography (EMG). In addition, the ratio of LT to the UT (LT/UT) and SA to the UT (SA/UT) was calculated. A repeated one-way analysis of variance and Shaffer's post-hoc analysis were used to detect the differences in each outcome during five exercises. RESULTS: The scapula was rotated upwardly during all exercises except push-up plus. The LT/UT ratio during side-lying external rotation and side-lying flexion were significantly higher than that for scapular plane elevation (P < .05), although the highest activity of the lower trapezius was produced during scapular plane elevation. The activities of the serratus anterior and SA/UT ratio during horizontal adducted elevation and push-up plus were significantly higher than that during scapular plane elevation (P < .05). CONCLUSION: Horizontal adducted elevation might be more appropriate for increasing scapular upward rotation with high serratus anterior activity and SA/UT ratio than push-up plus.

Comparisons of hamstring flexibility between individuals with and without low back pain: systematic review with meta-analysis.

Background: There is no robust evidence on the contribution of reduced hamstring flexibility to the development of low back pain (LBP) in cohort studies.Purpose: To investigate whether individuals with LBP have impaired hamstring flexibility and stiffness and what measures have been used to compare hamstring flexibility and stiffness between individuals with and without LBP.Methods: A systematic literature search was undertaken in PubMed, EMBASE, MEDLINE, CINAHL, SCOPUS, and Cochrane databases from inception to April 2018. The GRADE system was used to determine the quality of evidence for each measure evaluated in meta-analysis.Results: Respectively, seventeen and two studies having acceptable methodological quality were analyzed with regard to hamstring flexibility and stiffness. Four measures were identified for hamstring flexibility and five for stiffness. Meta-analyses were undertaken in straight leg raising (SLR), sit and reach and knee extension in 90° hip flexion for hamstring flexibility and for hamstring stiffness measures of stiffness at 50° SLR and gradient of stiffness from 20° to 50° SLR (Me-grad). Significantly reduced hamstring flexibility or increased stiffness (P < .05) was detected in SLR, 90/90 knee extension and Me-grad. However, the validity of measures for hamstring flexibility was problematic and GRADE scores for all measures in the meta-analyses were very low.Conclusion: There have been four measures for hamstring flexibility and five for stiffness to evaluate individuals with and without LBP. It was impossible to conclude whether individuals with LBP have impaired hamstring flexibility and stiffness due to very low quality of evidence for meta-analyses.

Comparison of Features by Simultaneous Measurement of Blood Pressure Pulse Wave and Electrocardiogram.

In this study, we report features related between an electrocardiogram (ECG) and a blood pressure pulse wave measured by the fabricated wearable device. The device consists of MEMS 3-axis force sensors, an electrocardiograph, a signal processing board and a fixed band. This device measures blood pressure using force sensors that are placed on the surface of the skin over a blood vessel. During experimentation, blood pressure was varied by breath holding while simultaneously measuring the blood pressure pulse wave and the ECG. Furthermore, features derived from the blood pressure pulse wave, its differential waveforms, such as the acceleration pulse wave, and the ECG were compared. The correlation coefficient between the pulse pressure of the blood pressure pulse wave and the P wave amplitude of the ECG associated with hypertension was 0.976. Moreover, the correlation coefficient between the augmentation index of the blood pressure pulse wave and the ST segment elevation of the ECG, which is used for diagnosis of myocardial infarction, was 0.915.

The Calibration Method for Blood Pressure Pulse Wave Measurement Based on Arterial Tonometry Method.

In this study, we report a method to accurately calibrate the forces measured by a wearable device for measuring blood pressure pulse waves by the arterial tonometry method to obtain blood pressure measurements. A device based on the arterial tonometry method and a commercially available manometer was used for this research. The force and the blood pressure were simultaneously measured at three measurement heights using the arterial tonometry device and the manometer. The proposed calibration was found to reduce the influence of the inclination of the lower arm. As a result, the average coefficient of determination of the regression equations between the force and the blood pressure was 0.96. Thus, it was concluded that the proposed method can be used to accurately calibrate the measured forces to obtain blood pressure measurements with a high coefficient of determination.

Three-Axis Ground Reaction Force Distribution during Straight Walking.

We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.