Pennation angle (PA) is an important property of human skeletal muscle that plays a significant role in determining the force contribution of fascicles to skeletal movement. Two-dimensional (2D) ultrasonography is the most common approach to measure PA. However, in principle, it is challenging to infer knowledge of three-dimensional (3D) architecture from 2D assessment. Furthermore, architectural complexity and variation impose more difficulties on reliable and consistent quantification of PA. Thus, the purpose of our study is to provide accurate insight into the correspondence between 2D assessment and the underlying 3D architecture. To this end, a 3D method was developed to directly quantify PA based on 3D architectural data that were acquired from cadaveric specimens through dissection and digitization. Those data were then assessed two-dimensionally by simulating ultrasound imaging. To achieve consistency over intermuscular variation, our proposed 3D method is based on the geometric analysis of fascicle attachment. Comparative results show a wide range of differences (1.1-47.1%) between 2D and 3D measurements. That is, ultrasound can under- or over-estimate PA, depending on the architecture.
The purpose of this study was to examine the effect of whole-body vibration (WBV) on calcaneal quantitative ultrasound (QUS) measurements; which has rarely been examined. We conducted a single-centre, 12-month, randomized controlled trial. 202 postmenopausal women with BMD T score between -1.0 and -2.5, not receiving bone medications, were asked to stand on a 0.3 g WBV platform oscillating at either 90- or 30-Hz for 20 consecutive minutes daily, or to serve as controls. Calcium and vitamin D was provided to all participants. Calcaneal broadband attenuation (BUA), speed of sound, and QUS index were obtained as pre-specified secondary endpoints at baseline and 12 months by using a Hologic Sahara Clinical Bone Sonometer. 12-months of WBV did not improve QUS parameters in any of our analyses. While most of our analyses showed no statistical differences between the WBV groups and the control group, mean calcaneal BUA decreased in the 90-Hz (-0.4 [95% CI -1.9 to 1.2] dB MHz(-1)) and 30-Hz (-0.7 [95% CI -2.3 to 0.8] dB MHz(-1)) WBV groups and increased in the control group (1.3 [95% CI 0.0-2.6] dB MHz(-1)). Decreases in BUA in the 90-, 30-Hz or combined WBV groups were statistically different from the control group in a few of the analyses including all randomized participants, as well as in analyses excluding participants who had missing QUS measurement and those who initiated hormone therapy or were <80% adherent. Although there are consistent trends, not all analyses reached statistical significance. 0.3 g WBV at 90 or 30 Hz prescribed for 20 min daily for 12 months did not improve any QUS parameters, but instead resulted in a statistically significant, yet small, decrease in calcaneal BUA in postmenopausal women in several analyses. These unexpected findings require further investigation.
This noninvasive, clinically feasible palpation/digitization protocol was reliable and repeatable in asymptomatic shoulders, and in a smaller sample of painful post-stroke shoulders. Implications for Rehabilitation In the clinical setting, a reliable and repeatable noninvasive method for assessment of three-dimensional (3D) clavicular/scapular/humeral joint orientation and range of motion (ROM) is currently required. The established reliability and repeatability of this proposed palpation/digitization protocol will enable comparative 3D ROM studies between asymptomatic and post-stroke shoulders, which will further inform treatment planning. Intra-rater test-retest repeatability, which is measured by the standard error of the measure, indicates the range of error associated with a single test measure. Therefore, clinicians can use the standard error of the measure to determine the "true" differences between pre-treatment and post-treatment test scores.
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