The effects of varying time under tension and volume load on acute neuromuscular responses

Abstract

The purpose of this study was to examine the effects of different methods of measuring training volume, controlled in different ways, on selected variables that reflect acute neuromuscular responses. Eighteen resistance-trained males performed three fatiguing protocols of dynamic constant external resistance exercise, involving elbow flexors, that manipulated either time-under-tension (TUT) or volume load (VL), defined as the product of training load and repetitions. Protocol A provided a standard for TUT and VL. Protocol B involved the same VL as Protocol A but only 40% concentric TUT; Protocol C was equated to Protocol A for TUT but only involved 50% VL. Fatigue was assessed by changes in maximum voluntary isometric contraction (MVIC), interpolated doublet (ID), muscle twitch characteristics (peak twitch, time to peak twitch, 0.5 relaxation time, and mean rates of force development and twitch relaxation). All protocols produced significant changes (P <or= 0.05) in the measures considered to reflect neuromuscular fatigue, with the exception of ID. Fatigue was related to an increase in either TUT or VL with greater fatigue, as reflected by MVIC and peripheral measures, being associated with differences in TUT. The lack of change in ID suggests that fatigue was more related to peripheral than central mechanisms. It was concluded that the load and contraction velocities of the repetitions have different effects on acute neuromuscular responses and should, therefore, be clearly calculated when describing training volume for dynamic constant external resistance exercise training.

Can the efficacy of electrically stimulated pedaling using a commercially available ergometer BE improved by minimizing the muscle stress–time integral?

“…In addition, it has been demonstrated that a reduction of the forcetime integral for a single muscle group leads to an increase in the duration of the force-generating capacity of the muscle group. 29,30 Because a reduction in the force-time integral increases the endurance for a single muscle group, it is reasonable to consider that a similar outcome would be observed for multiple muscle groups. Accordingly, there has been a long-held association between the reduction of the muscle stress-time integral and the increased endurance of multiple muscles working together to perform a gross motor task such as walking or pedaling.…”

“…45 The one-tailed analysis was performed because the dependent variable (i.e., mechanical work) was expected to increase due to previous results with the parameters tested (i.e., stress-time integral). 30 A second set of analyses was performed to determine whether differences in the electrical stimulation applied to the muscles could have influenced the mechanical work performed. Two-factor, repeated-measures, one-tailed ANOVA was performed to identify whether there were differences in the electrical stimulation (i.e., current-time integral) delivered to the muscle groups (QUADS, HAMS, and GMAX) when pedaling with Stim3 and StimErg.…”

“…A relationship exists between the endurance of a muscle and the muscle force-time integral, which reflects the interaction between force amplitude, duration of contraction, and rest interval between contractions. [29][30][31][32] Bigland-Ritchie et al 31 and Thomas et al 32 used reduction in the force-time integral as a measure of muscle fatigue. In addition, it has been demonstrated that a reduction of the forcetime integral for a single muscle group leads to an increase in the duration of the force-generating capacity of the muscle group.…”

A mathematical model of neuromuscular adaptation to resistance training and its application in a computer simulation of accommodating loads

“…Clearly, the rate of strength decrease is dependent on the magnitude of force applied and its duration (Tran et al 2006). Considering that in this paper we are interested in the performance of skilled athletes, it will be assumed that the lifter is continuously applying the maximal possible force at every point during the lift.…”

Os efeitos do exercício resistido no metabolismo da lipoproteína de baixa densidade (LDL) e da lipoproteína de alta densidade (HDL), utilizando uma nanoemulsão semelhante a LDL

“…O volume de treinamento é a soma do número total de repetições realizadas durante uma sessão de treinamento, multiplicado pela resistência utilizada (kg) e é um reflexo da duração com que os músculos estão sendo estressados (Tran et al, 2006). Enquanto que, para indivíduos iniciantes, recomenda-se 1 a 3 séries de exercícios (Rataness et al, 2009;Peterson et al, 2005) em 2-3 dias por semana (Rataness 2009; Rhea et al, 2003), para indivíduos intermediários e avançados, estudos indicam que múltiplas séries podem ser utilizadas com sistemática variação de volume e intensidade (Rataness et al, 2009;Kemmler et al, 2004), sendo, para indivíduos intermediários, 3-4 dias por semana, dependendo da divisão dos grupos musculares e para indivíduos avançados, 4-6 dias por semana.…”