Neuromuscular Efficiency of the Rectus Abdominis Differs With Gender and Sport Practice

Abstract

The purpose of this investigation was to distinguish the abilities of the rectus abdominis (RA) muscle according to gender and sport training by means of neuromuscular parameters extracted from electromyography (EMG)-torque relationships. Thirty-eight healthy students, divided into 4 groups (i.e., 8 male runners, 10 female gymnasts, 12 male controls, and 8 female controls) were asked to perform 6 seconds of isometric trunk flexions at 20%, 25%, 75%, and 100% of their maximal voluntary contraction. Flexion torque and surface EMG of the RA muscle were recorded simultaneously to construct a EMG-torque relationship. Under maximal and submaximal conditions, an index of neuromuscular efficiency (NME) was determined to characterize the capacity of the RA muscle to develop a torque. At each level of contraction, the area of data scattering (ADS), reflecting torque and EMG fluctuations, was computed to express the capacity to maintain a constant target torque. Flexion torque, NME, and ADS values differed significantly between genders, but when data were related to anthropometric characteristics, no difference was observed. Although runners were not distinguished from male controls, gymnasts had higher flexion torque, higher NME, and lower ADS values than female controls had. These differences should reflect neural and muscular adaptations linked to the specificity of gymnastic training. These findings revealed different functional abilities of the RA muscle, according to gender and sport practices. The indices of neuromuscular capacities used in this study could constitute complementary tools to athletic trainers and professionals in sports medicine for evaluating and following, during sport-specific training programs, the abdominal muscle performance implied in force transfers with a lower cost and lower risks of back pain.

Effects of Low-Dose Creatine Monohydrate on Muscle Strength and Endurance

“…This finding could be attributed to the characteristics of the muscle group, mainly consisting of type 2 muscle fibers, which are naturally oxidative and resistant to fatigue (27,28). Moreover, our sample was composed of individuals with at least 6 months of previous training; thus, most likely, the muscle group already had high fatigue resistance.…”

Gender Differences in the Curl-up and the Double-leg-lower Tests

“…This result is not surprising and is to be expected due to the lower absolute muscle strength of females. 29) , height and lean body weight 8) , or muscle mass 30) . On the other hand, other researchers have found higher strength values for males compared to females, even when the muscle strength or torque production were normalized to body mass 7) .…”

“…Previous studies using large sample sizes and utilizing surface electromyography (sEMG) [6][7][8][9] , ultrasound imaging 10,11) , and computed tomography scanning 12) , have reported gender differences 13) . Although these studies have hinted at a relationship between musculoskeletal injury rate and gender difference 14) , to the best of our knowledge, most have only examined limb musculature.…”

“…Although these studies have hinted at a relationship between musculoskeletal injury rate and gender difference 14) , to the best of our knowledge, most have only examined limb musculature. Studies of gender differences in trunk muscle activity are scarce 8) .…”

Proposta e análise de indicadores eletromiográficos espectrais e temporais em protocolos dinâmicos com indução de fadiga muscular localizada

“…Suas recorrentes aplicações incluem a monitoração da fadiga muscular (DeLuca, 1984) e da recuperação muscular após a fadiga localizada (Larivière et al, 2002), treinamento associado à eletroestimulação (Molina et al, 1997), avaliação das capacidades motoras (Larivière et al, 2008(Larivière et al, e 2009, quantificação da eficiência neuromuscular (Milner et al, 1986;David et al, 2008;Arabadzhiev et al, 2010), aplicações diversas à neurologia (Zwarts et al, 2004), observação de padrões e diferenças entre os gêneros durante exercícios fatigantes (Clark et al, 2005), técnicas não invasivas e automação de sistemas para predição e detecção da fadiga muscular localizada (Al-Mulla et al, 2011ae 2011b, controle de próteses , neurorreabilitação (Jiang et al, 2010), reabilitação motora , monitoração indireta de parâmetros biomecânicos (Cifrek et al, 2009), ergonomia (Hägg et al, 2004), detecção automática de zonas de inervação utilizando eletromiografia de superfície (EMG-S) (Ullah et al, 2014), estudo de relações entre funções neuromusculares e postura (Boyas et al, 2013), de padrões de recrutamento de unidades motoras em diferentes fases da contração muscular (Kay et al, 2000), de biofeedback (Cram, 2004), de parâmetros associados às lesões musculares (Thiebaud et al, 2013), de causas de distúrbios associados ao controle motor (Bottas et al, 2005), da fisiologia do exercício (Felici et al, 2004), dos efeitos da fadiga sobre as ações agonista e antagonista na ação motora (Hassani et al, 2006), da fadiga de longo prazo após esforços prolongados (Søgaard et al, 2003), análise de postura e movimento (Frigo e Shiavi, 2004), entre outras.…”