Muscle Architecture Assessment: Strengths, Shortcomings and New Frontiers of in Vivo Imaging Techniques

Does stretch training induce muscle hypertrophy in humans? A review of the literature

“…In both the works of Akagi and Takahashi (2014) (Franchi, Raiteri, et al, 2018;Franchi, Ruoss, et al, 2018;Simpson et al, 2017), this may at least in part help to explain such differences. Additionally, in the study of Mizuno (2019), the stretch was carried out at an ankle angle whereby the calf muscles were fully stretched, while the stretch in Akagi and Takahashi (2014) was performed with a ~10% reduction in this angle and intensity.…”

“…Moreover, Akagi and Takahashi () used a convex probe to measure the MT of the ankle flexors (from the adipose tissue–muscle interface of the posterior lower leg to the muscle–bone interface), whereas Mizuno () used a linear probe and measured only the lateral gastrocnemius. Considering that muscle portions may respond non‐uniformly to the muscle lengthening (Franchi, Raiteri, et al, ; Franchi, Ruoss, et al, ; Simpson et al, ), this may at least in part help to explain such differences. Additionally, in the study of Mizuno (), the stretch was carried out at an ankle angle whereby the calf muscles were fully stretched, while the stretch in Akagi and Takahashi () was performed with a ~10% reduction in this angle and intensity.…”

“…It is customary to use equations for estimating the FL when analysing muscles that are large in length or when using a probe with a small width or field of view, as employed in some studies included herein (Freitas & Mil-Homens, 2015;Lima et al, 2015;Nakamura et al, 2012). However, some equations display better validity than others (Kumagai et al, 2000;Noorkoiv, Stavnsbo, Aagaard, & Blazevich, 2010;Potier, Alexander, & Seynnes, 2009); thus, extrapolation of FL results should be made with caution (Ando et al, 2014;Franchi, Raiteri, et al, 2018), as well as the comparison of findings between studies that employ this procedure but use different equations. Future studies should consider the use of appropriate measurement techniques depending on the size of the muscle to be analysed (Franchi, Raiteri, et al, 2018).…”

“…However, some equations display better validity than others (Kumagai et al, 2000;Noorkoiv, Stavnsbo, Aagaard, & Blazevich, 2010;Potier, Alexander, & Seynnes, 2009); thus, extrapolation of FL results should be made with caution (Ando et al, 2014;Franchi, Raiteri, et al, 2018), as well as the comparison of findings between studies that employ this procedure but use different equations. Future studies should consider the use of appropriate measurement techniques depending on the size of the muscle to be analysed (Franchi, Raiteri, et al, 2018). reported that the content of activated costamere-associated proteins increased more prominently at the distal site.…”

Sprint versus isolated eccentric training: Comparative effects on hamstring architecture and performance in soccer players

“…Furthermore, the same group of authors recently reported that soccer players with shorter biceps femoris long head (BFlh) fascicles (<10.56 cm on average) were at fourfold greater risk of hamstring strain injury than players with longer fascicles [11]. It is however important to keep in mind that clear methodological limitations are associated with ultrasound methodology to infer muscle fascicle lengths [12,13] as will be discussed below. Given the effectiveness of the predominantly eccentric NHE in increasing eccentric hamstring strength when added to soccer training [14], it is important to examine the impact of this single exercise on BFlh fascicle lengths concomitantly to real soccer practice and not only in isolated conditions.…”