Within- and between-session reliability of medial gastrocnemius architectural properties

Abstract

This study aimed to determine the within- and between-session reliability of medial gastrocnemius (MG) architecture (e.g. muscle thickness (MT), fascicle length (FL) and pennation angle (PA)), as derived via ultrasonography followed by manual digitization. A single rater recorded three ultrasound images of the relaxed MG muscle belly for both legs of 16 resistance trained males, who were positioned in a pronated position with their knees fully extended and the ankles in a neutral (e.g. 90°) position. A subset of participants (n = 11) were retested under the same conditions ~48-72 hours after baseline testing. The same rater manually digitized each ultrasound image on three occasions to determine MG MT, FL and PA before pooling the data accordingly to allow for within-image (n = 96), between-image (n = 32) and between-session reliability (n = 22) to be determined. Intraclass correlation coefficients (ICCs) demonstrated excellent within-image (ICCs = 0.99-1.00, P < 0.001) and very good between-image (ICCs = 0.83-0.95, P < 0.001) and between-session (ICCs = 0.89-0.95, P < 0.001) reliability for MT, FL and PA. Between-session coefficient of variation was low (≤ 3.6%) for each architectural parameter and smallest detectible difference values of 10.6%, 11.4% and 9.8% were attained for MT, FL and PA, respectively. Manually digitizing ultrasound images of the MG muscle at rest yields highly reliable measurements of its architectural properties. Furthermore, changes in MG MT, FL and PA of ≥ 10.6%, 11.4% and 9.8% respectively, as brought about by any form of intervention, should be considered meaningful.

Information from dynamic length changes improves reliability of static ultrasound fascicle length measurements

“…As this cannot be done on single-image fascicle lengths, our results suggest that it is worthwhile to record image sequences with fascicle movement, even for studies interested in single-image analyses. SEM values between different raters remain rather high (4.15 and 4.29 mm for DIT and UFI respectively) for both strategies, especially compared to intra-rater SEM values (average of 2.59 ± 1.56 mm), but are within the range reported in other studies ( König et al, 2014 ; McMahon, Turner & Comfort, 2016 ).…”

“…This has the potential to result in low reliability and low repeatability because of the subjective nature of this analysis. Studies on the reliability of fascicle identification from ultrasound images during a wide range of tasks, including measurements of muscle in a relaxed and contracted state, during walking, running and jumping, have reported standard error of measurement (SEM) percentages of 4.3–14.2% for inter-session ( Kwah et al, 2013 ), 0.0–8.3% for inter-image ( Kwah et al, 2013 ) and 3.8–7.5% for inter-rater ( König et al, 2014 ; McMahon, Turner & Comfort, 2016 ) analyses. Overall, these values remain rather high, considering the effect sizes generally reported in cross-sectional or longitudinal training studies (10–19%) ( Abe, Kumagai & Brechue, 2000 ; Fukutani & Kurihara, 2015 ; Timmins et al, 2016 ) and in studies that compare fascicle length changes between various conditions within similar dynamic tasks (9–14%) ( Lichtwark & Wilson, 2006 ; Farris & Sawicki, 2012 ; Brennan et al, 2017 ).…”

Triceps Surae Muscle Architecture Adaptations to Eccentric Training

“…The absence of a change in PA post-eccentric training might be due to measurement errors in US image analysis (Baroni et al, 2013b). While eccentric training and conventional resistance training seem to increase plantar flexor PA by around 1.2–4.0° (Morse et al, 2007; Duclay et al, 2009; Vieillevoye et al, 2010; Sanz-Lopez et al, 2016), ultrasonographic analyses have shown a TE of 0.15–3.7 (de Boer et al, 2008; Padhiar et al, 2008; Martins et al, 2012; McMahon et al, 2016). Reported PA adaptive responses to strength training are close to the measurement error in US analysis, which could explain results from studies that found an increase in muscle hypertrophy without concomitant changes in PA (Reeves et al, 2009; Raj et al, 2012; Baroni et al, 2013b; Fouré et al, 2013).…”

Age- and muscle-specific reliability of muscle architecture measurements assessed by two-dimensional panoramic ultrasound

“…A second source of inconsistency is the use of reliability estimates of MA parameters that are not comparable between studies [ 16 , 17 , 19 ]. It is also often the case that due to a large number of images, two or more raters determine MA, however the reliability between raters analyzing the same image is scarcely reported [ 20 ]. Furthermore, reliability of US estimates of MA has only been scarcely examined in the older population.…”