## 4 Discussion
Although speculative, it is possible MMGMDF is more sensitive than MMGMPF at lower contraction intensities, as the authors reported no differences in \(b\) terms between muscle actions or among training statuses (sedentary, chronic aerobically- and resistance-trained) during contractions at 50% and 60% MVC. Future research should compare the sensitivity of MMG mean- and median-power frequency among contraction intensities and training statuses, and between muscle actions. Following 10 weeks of training, the \(b\) terms were not different between muscle actions for POST\({}_{\text{ABS}}\). Although the training did not result in any longitudinal changes for the \(b\) terms during the increasing or decreasing segments, the linearity of the relationships was altered. For example, the 95% CIs around the \(b\) terms during the linearly increasing segment were >0 for PRE; however, they included zero for POST\({}_{\text{ABS}}\) (Figure 3). Recently, it was reported that 5 weeks of high-intensity continuous cycling decreased MVC of the knee extensors and resulted in a larger percentage of higher-threshold MUs being recruited to match a 40% targeted torque relative to pre-training MVC [9]. Therefore, the change in the linearity of the \(b\) terms during the linearly increasing muscle action following training for the current study may reflect an accelerated activation of higher threshold MUs [11; 29], which exhibit lower firing frequencies [28; 30], to modulate torque for POST\({}_{\text{ABS}}\). It has been reported that endurance training increases fatigue resistance [18] but is reported to have no effect on MU potentiation [31] and may explain the similar \(b\) terms between both segments for POST\({}_{\text{ABS}}\), as MUs would be recruited and derecruited at the same relative torque (% MVC) during both muscle actions, respectively. The isometric trapezoidal template also allows the examination of MU behavior during steady torque, similar to a step contraction [6]. For the current study, sex-related differences were observed independent of training. For example, males exhibited greater MMGMDF values before and after training. However, it should be noted that sFAT was correlated (\(p=0.002\)) with MMGMDF during steady torque at PRE (\(r=-0.609\)) and POST\({}_{\text{ABS}}\) (\(r=-0.599\)). It has been reported that the MMG signal can be low-pass filtered by fat tissue, thereby attenuating the higher frequencies [27]. Subsequently, we performed a secondary analysis examining MMGMDF between a subset of males and females matched for sFAT, which indicated no sex-related differences (\(p=0.395\)). Thus, the physiological interpretation for the greater MMGMDF values exhibited by the males during steady torque for the overall cohort is unclear. Consequently, investigating log-transformed MMGMDF-torque relationships with an isometric trapezoidal template may provide the most relevant physiological information to examine changes in MU behavior, as sFAT did not influence the \(b\) terms for this study and numerous investigations [11; 16; 26; 27; 32; 33]. Although high-intensity cycling training has previously increased cardiorespiratory fitness, it has been associated with maximal strength decreases [9; 11]. In addition, it has been reported that solely engaging in cycling training can have deleterious effects on bone mineral density [34]. Thus, it has been suggested that individuals include resistance and aerobic training in their exercise routines throughout the lifespan to improve bone health and muscular strength [35; 36; 37].