Reliability and Comparison of Sonographic Methods for In Vivo Measurement of Human Biceps Femoris Long-Head Architecture

Comparison of manual and semi-automated algorithm for measuring architectural features during different isometric knee extension intensities: a reliability and comparative study in novice raters

Introduction

Ultrasound is a cost-effective and reliable method to determine skeletal muscle architecture. However, manual analysis of fascicle length (FL) and pennation angle (PA) can be arduous and subjective among raters, particularly among novice raters. Alternatives to manual processing have been proposed that expedite the evaluation of muscle architecture and afford more consistency. While using algorithms has provided dependable results of muscle architecture, it has often focused on variables of passive range of motion and submaximal contractions. To fully understand the impact of muscle architecture using semi-automated analysis, an investigation of a broad range of contraction intensities is needed. The purpose of this study was to develop and determine the intra-rater and inter-rater reliability of a custom, semi-automated algorithm to extract measures of muscle thickness, pennation angle, and fascicle length, and second to compare the semi-automated measures to measures extracted manually from the same novice raters while accounting for differences between contraction intensities.

Methods

Fifteen resistance-trained individuals (male: n = 6, female: n = 9) completed this study. Images were collected during four contraction intensities relative to maximal voluntary isometric contractions (MVIC) (at rest, 30%, 70%, and MVIC) and analyzed by three novice raters to compare the semi-automated algorithm and manual measurement in the vastus lateralis.

Results

Intra-rater reliability for manual measures was poor for FL (ICCs: 0-0.30), poor to good for PA (ICCs: 0.46-0.77), and moderate to good for muscle thickness (MT) (ICCs: 0.55-0.84). For the semi-automated algorithm, the intra-rater reliability was good to excellent for FL (range: 0.90-0.99), PA (range: 0.88-0.99), and MT (range: 0.996-0.999) across all contraction intensities.

Discussion

The findings of this study suggest that the reliability of manual measurement is lower when novice raters perform image analyses compared to the semi-automated method. Therefore, careful consideration and training should be provided when considering manual assessment of muscle architecture values, and standardized identification methods and features in algorithm development may be a better method for reproducibility.

Examiner experience moderates reliability of human lower extremity muscle ultrasound measurement - a double blinded measurement error study

Structural muscle properties are critical in health and athletic settings, with magnetic resonance imaging considered the gold standard assessment procedure under static conditions due to its reliability and objectivity. Practical limitations, including cost and accessibility, have led to the increasing use of ultrasound as an alternative for skeletal muscle morphological parameters. However, ultrasound measurements are sensitive to evaluation conditions and assessor experience, which has not been sufficiently explored, yet. Therefore, this study investigated the influence of assessor experience on the reliability of ultrasound measurements. A double-blind design was used, involving an experienced assessor (> 12,000 images for several years) and multiple inexperienced assessors (< 100 images) to collect data from 39 recreationally active participants. Measurements of muscle architecture were conducted in the leg muscles over two consecutive days, generating 1,248 ultrasound images. Relative and absolute reliability were analyzed using intraclass correlation coefficients (ICCs), standard error of measurement, minimal detectable change, mean absolute error (MAE), mean absolute percentage error (MAPE) and Bland-Altman analyses. Relative reliability was good to excellent in all measurement spots and time-points for muscle thickness (ICC = 0.76-0.98) irrespective of assessor experience, except for the inter-day comparison for the gastrocnemius lateralis by the inexperienced assessors, (ICC = 0.58). The pennation angle assessment ranged from insufficient to excellent reliability (ICC = 0.18-0.94) and experience contributed greatly to better results. The random error for the inexperienced assessors was reflected in two- to three-times higher MAEs/MAPEs and limits of agreement in the Bland-Altman analyses, respectively. The findings emphasize the importance of experience and standardization in achieving reliable ultrasound data, particularly for (a) sensitive parameters like the pennation angle and/or (b) inter-day, intra-subject comparisons.

Neuromuscular Adaptations in Endurance-Trained Male Adolescents Versus Untrained Peers: A 9-Month Longitudinal Study

BACKGROUND

Neuromuscular function is considered as a determinant factor of endurance performance during adulthood. However, whether endurance training triggers further neuromuscular adaptations exceeding those of growth and maturation alone over the rapid adolescent growth period is yet to be determined.

OBJECTIVE

The present study investigated the concurrent role of growth, maturation, and endurance training on neuromuscular function through a 9-month training period in adolescent triathletes.

METHODS

Thirty-eight 13- to 15-year-old males (23 triathletes [~6 h/week endurance training] and 15 untrained [<2 h/week endurance activity]) were evaluated before and after a 9-month triathlon training season. Maximal oxygen uptake (V̇O2max) and power at V̇O2max were assessed during incremental cycling. Knee extensor maximal voluntary isometric contraction torque (MVCISO) was measured and the voluntary activation level (VAL) was determined using the twitch interpolation technique. Knee extensor doublet peak torque (T100Hz) and normalized vastus lateralis (VL) electromyographic activity (EMG/M-wave) were also determined. VL and rectus femoris (RF) muscle architecture was assessed using ultrasonography.

RESULTS

Absolute V̇O2max increased similarly in both groups but power at V̇O2max only significantly increased in triathletes (+13.8%). MVCISO (+14.4%), VL (+4.4%), and RF (+15.8%) muscle thicknesses and RF pennation angle (+22.1%) increased over the 9-month period in both groups similarly (p < 0.01), although no changes were observed in T100Hz, VAL, or VL EMG/M-wave. No changes were detected in any neuromuscular variables, except for coactivation.

CONCLUSION

Endurance training did not induce detectible, additional neuromuscular adaptations. However, the training-specific cycling power improvement in triathletes may reflect continued skill enhancement over the training period.

Three-dimensional mapping of ultrasound-derived skeletal muscle shear wave velocity

Introduction: The mechanical properties of skeletal muscle are indicative of its capacity to perform physical work, state of disease, or risk of injury. Ultrasound shear wave elastography conducts a quantitative analysis of a tissue's shear stiffness, but current implementations only provide two-dimensional measurements with limited spatial extent. We propose and assess a framework to overcome this inherent limitation by acquiring numerous and contiguous measurements while tracking the probe position to create a volumetric scan of the muscle. This volume reconstruction is then mapped into a parameterized representation in reference to geometric and anatomical properties of the muscle. Such an approach allows to quantify regional differences in muscle stiffness to be identified across the entire muscle volume assessed, which could be linked to functional implications. Methods: We performed shear wave elastography measurements on the vastus lateralis (VL) and the biceps femoris long head (BFlh) muscle of 16 healthy volunteers. We assessed test-retest reliability, explored the potential of the proposed framework in aggregating measurements of multiple subjects, and studied the acute effects of muscular contraction on the regional shear wave velocity post-measured at rest. Results: The proposed approach yielded moderate to good reliability (ICC between 0.578 and 0.801). Aggregation of multiple subject measurements revealed considerable but consistent regional variations in shear wave velocity. As a result of muscle contraction, the shear wave velocity was elevated in various regions of the muscle; showing pre-to-post regional differences for the radial assessement of VL and longitudinally for BFlh. Post-contraction shear wave velocity was associated with maximum eccentric hamstring strength produced during six Nordic hamstring exercise repetitions. Discussion and Conclusion: The presented approach provides reliable, spatially resolved representations of skeletal muscle shear wave velocity and is capable of detecting changes in three-dimensional shear wave velocity patterns, such as those induced by muscle contraction. The observed systematic inter-subject variations in shear wave velocity throughout skeletal muscle additionally underline the necessity of accurate spatial referencing of measurements. Short high-effort exercise bouts increase muscle shear wave velocity. Further studies should investigate the potential of shear wave elastography in predicting the muscle's capacity to perform work.