Relationships between skinfold thickness and electromyographic and mechanomyographic amplitude recorded during voluntary and non-voluntary muscle actions

Influence of subcutaneous fat on mechanomyographic signals at three levels of voluntary effort

“…First, asepsis and shaving were performed at the medial point of the dominant thigh (muscle rectus femoris belly) for positioning of the MMG Although the difference, and at the same point three measurements of ST were carried out using an adipometer (Lang  ) for estimation of localized fat (Cooper and Herda, 2014). Three submaximal contractions were performed as located warm-up, as well as stretching of the lower muscle group (quadriceps) 5 min prior to the beginning of the tests (Baptista et al, 2009).…”

“…MMG is used in many applications, including: prostheses control (Orizio et al, 2003); indication of muscle activation degree (Scheeren et al, 2010); monitoring of muscle fatigue (Orizio et al, 2003;Tarata, 2003); neuromuscular diseases diagnosis (Hu et al, 2007); obtainment of signals for the study of muscle strength gradation mechanisms (Akataki et al, 2001;Matta et al, 2005;Madeleine et al, 2001;Nogueira-Neto et al, 2013); evaluation of respiratory muscle work (Sarlabous et al, 2014); changes in MU activation strategies, which can occur with aging, neuromuscular diseases, endurance training programs, and care of injuries (Cooper et al, 2014); and Parkinson's disease (Marusiak et al, 2009;Malek and Coburn, 2012). In applications with comparisons between the MMG signal and the force response the biceps brachii (Orizio et al, 1989) and rectus femoris (Krueger et al, 2016;Shin et al, 2016) are the muscles more used due its easy accessibility and comparison capability.…”

“…However, signals generated by the muscle may suffer attenuation when propagated through tissues such as subcutaneous fat, thus hindering signal acquisition (Baars et al, 2007;Herda et al, 2010;Herda et al, 2011;Jaskólska et al, 2003;Yoshitake et al, 2002) and possibly attenuating signals as a low-pass filter (Cooper and Herda, 2014). Interferences in signal acquisition are found in studies that verified the influence of different skinfold thicknesses (ST) on the acquisition of MMG where the MMG signals were attenuated in muscles covered with high percentages of subcutaneous fat (Cooper et al, 2014;Herda et al, 2010;Herda et al, 2011;Trevino and Herda, 2015).…”

“…Interferences in signal acquisition are found in studies that verified the influence of different skinfold thicknesses (ST) on the acquisition of MMG where the MMG signals were attenuated in muscles covered with high percentages of subcutaneous fat (Cooper et al, 2014;Herda et al, 2010;Herda et al, 2011;Trevino and Herda, 2015). Volume 32, Number 4, p. 307-317, 2016 For example, Cooper et al (2014) observed correlations (p<0.05) between skinfold thicknesses and MMG signal for the muscles rectus femoris and vastus lateralis with r = -0.376 and -0.484, respectively. Similarly, the amplitude of electromyography (EMG) and MMG signals showed a reduction in the entire force spectrum in muscles with greater ST during progressive isometric muscle actions (Cooper et al, 2013;Herda et al, 2010;Herda et al, 2011).…”

“…Studies with different force levels (Cochrane et al, 2015;Cooper et al, 2014;Jaskólska et al, 2003;Polato et al, 2008) reported significant differences when evaluating different intensities of isometric force with ST in larger and smaller fat layers. However, those researchers did not show if there is a trend related to different force levels or if this influence occurs in all (three) accelerometers axes.…”