Sports Medical Research Group, Department of Orthopaedics, Balgrist University Hospital, University of Zurich, Zurich, SWITZERLAND.
Faculty of Sports Science, Human Movement Science, Ruhr University Bochum, Bochum, GERMANY.
Med Sci Sports Exerc. 2020 Jan;52(1):233-243. doi: 10.1249/MSS.0000000000002123.
This study aimed to compare biceps femoris long head (BFlh) fascicle length (Lf) obtained with different ultrasound-based approaches: 1) single ultrasound images and linear Lf extrapolation, 2) single ultrasound images and one of two different trigonometric equations (termed equations A and B), and 3) extended field of view (EFOV) ultrasound images.
Thirty-seven elite alpine skiers (21.7 ± 2.8 yr) without a previous history of hamstring strain injury were tested. Single ultrasound images were collected with a 5-cm linear transducer from BFlh at 50% femur length and were compared with whole muscle scans acquired by EFOV ultrasound.
The intrasession reliability (intraclass correlation coefficient [ICC3,k]) of Lf measurements was very high for both single ultrasound images (i.e., Lf estimated by linear extrapolation; ICC3,k = 0.96-0.99, SEM = 0.18 cm) and EFOV scans (ICC3,k = 0.91-0.98, SEM = 0.19 cm). Although extrapolation methods showed cases of Lf overestimation and underestimation when compared with EFOV scans, mean Lf measured from EFOV scans (8.07 ± 1.36 cm) was significantly shorter than Lf estimated by trigonometric equations A (9.98 ± 2.12 cm, P < 0.01) and B (8.57 ± 1.59 cm, P = 0.03), but not significantly different from Lf estimated with manual linear extrapolation (8.40 ± 1.68 cm, P = 0.13). Bland-Altman analyses revealed mean differences in Lf obtained from EFOV scans and those estimated from equation A, equation B, and manual linear extrapolation of 1.91 ± 2.1, 0.50 ± 1.0, and 0.33 ± 1.0 cm, respectively.
The typical extrapolation methods used for estimating Lf from single ultrasound images are reliable within the same session, but not accurate for estimating BFlh Lf at rest with a 5-cm field of view. We recommend that EFOV scans are implemented to accurately determine intervention-related Lf changes in BFlh.
本研究旨在比较使用不同超声方法测量的股二头肌长头（BFlh）肌束长度（Lf）：1）单张超声图像和直线 Lf 外推法，2）单张超声图像和两种不同三角方程之一（分别称为方程 A 和 B），以及 3）扩展视野（EFOV）超声图像。
对 37 名无腘绳肌拉伤史的精英高山滑雪运动员（21.7±2.8 岁）进行了测试。在股骨长度的 50%处，使用 5cm 线性换能器采集 BFlh 的单张超声图像，并与 EFOV 超声获得的整个肌肉扫描进行比较。
单次超声图像（即通过线性外推法估计的 Lf）和 EFOV 扫描的 Lf 测量的内部分组可靠性（组内相关系数[ICC3，k]）均非常高（分别为 0.96-0.99，SEM=0.18cm）。尽管外推方法与 EFOV 扫描相比存在 Lf 高估和低估的情况，但从 EFOV 扫描测量的平均 Lf（8.07±1.36cm）明显短于通过三角方程 A（9.98±2.12cm，P<0.01）和 B（8.57±1.59cm，P=0.03）估计的 Lf，但与手动线性外推法（8.40±1.68cm，P=0.13）测量的 Lf 无显著差异。Bland-Altman 分析显示，EFOV 扫描与方程 A、方程 B 和手动线性外推法测量的 Lf 的平均差异分别为 1.91±2.1、0.50±1.0 和 0.33±1.0cm。
在同一时段内，用于从单张超声图像估计 Lf 的典型外推方法是可靠的，但在 5cm 视野下不能准确估计休息时 BFlh 的 Lf。我们建议使用 EFOV 扫描来准确确定 BFlh 干预相关的 Lf 变化。
