Longer repetition duration increases muscle activation and blood lactate response in matched resistance training protocols

Hugo Cesar Martins-Costa,Rafael Silva Valle de Almeida,André Gustavo Pereira de Andrade,Mauro Heleno Chagas,Fernando Vitor Lima,Sandra Carvalho Machado,Rodrigo Cesar Ribeiro Diniz

doi:10.1590/s1980-65742016000100005

Abstract

This study analyzed the effect of different repetition durations on electromyographic and blood lactate responses of the bench press exercise. Fifteen recreationally trained male volunteers completed two training protocols, matched for intensity (% one-repetition maximum; 1RM), number of sets, number of repetitions, and rest intervals. One of the protocols was performed with a repetition duration of 4 s (2 s concentric: 2 s eccentric; 2:2 protocol), whereas the second protocol had a repetition duration of 6 s (2 s concentric: 4 s eccentric; 2:4 protocol). The results showed higher normalized integrated electromyography (pectoralis major and triceps brachii) for the 2:4 protocol. Blood lactate concentration was also higher in the 2:4 protocol across all sets. These results show that adding 2 s to the eccentric action in matched training protocols increases muscle activation and blood lactate response, which reinforces the notion that increasing repetition duration is an alternative load progression in resistance training.

Highlights

Repetition duration, defined as the time spent performing the concentric and eccentric muscle actions during a repetition, should be considered when prescribing a resistance training program (American College of Sports Medicine [ACSM], 2009; Bird, Tarpenning, & Marino, 2005)
The amplitude of the electromyographic signal has often been measured in resistance training protocols (Burd et al, 2012; Eckhardt, Wollny, Müller, Bärtsch, & Friedmann-Bette, 2011; Lacerda et al, 2016; Sakamoto & Sinclair, 2012; Sampson, Donohoe, & Groeller, 2014; Smilios, Häkkinen, & Tokmakidis, 2010; Takarada, Takazawa, Sato, Takebayashi, Tanaka, & Ishii, 2000; Walker, Taipale, Nyman, Kraemer, & Häkkinen, 2011), since it represents the degree of muscle activation and, at least in part, the recruitment of motor units during the training session (Hunter, Duchateau, & Enoka, 2004; Suzuki, Conwit, Stashuk, Santarsiero, & Metter, 2002)
Results indicate that blood lactate concentrations increased for both protocols throughout the sets, and blood lactate concentration was higher in the 2:4 protocol than the 2:2 protocol for all sets, except during rest measurement

Summary

Introduction

Repetition duration, defined as the time spent performing the concentric and eccentric muscle actions during a repetition, should be considered when prescribing a resistance training program (American College of Sports Medicine [ACSM], 2009; Bird, Tarpenning, & Marino, 2005). The amplitude of the electromyographic signal has often been measured in resistance training protocols (Burd et al, 2012; Eckhardt, Wollny, Müller, Bärtsch, & Friedmann-Bette, 2011; Lacerda et al, 2016; Sakamoto & Sinclair, 2012; Sampson, Donohoe, & Groeller, 2014; Smilios, Häkkinen, & Tokmakidis, 2010; Takarada, Takazawa, Sato, Takebayashi, Tanaka, & Ishii, 2000; Walker, Taipale, Nyman, Kraemer, & Häkkinen, 2011), since it represents the degree of muscle activation and, at least in part, the recruitment of motor units during the training session (Hunter, Duchateau, & Enoka, 2004; Suzuki, Conwit, Stashuk, Santarsiero, & Metter, 2002) Some of these studies have measured the concentration of blood lactate (Eckhardt et al, 2011; Lacerda et al, 2016; Smilios et al, 2010; Takarada et al, 2000; Walker et al, 2011) because the augmented lactate response has been associated with an increased recruitment of fast-twitch motor units (Gladden, 2004; Moritani, Tanaka, Yoshida, Ishii, Yoshida, & Shindo, 1984). Given the expectation that the activated muscle fibers are those that adapt to training (Spiering et al, 2008; Wakahara, Fukutani, Kawakami, & Yanai, 2013), protocols which show higher electromyographic amplitude would present greater potential to promote increases in strength and muscle hypertrophy (Takarada et al.; 2000; Watanabe, Madarame, Ogasawara, Nakazato, & Ishii, 2014)

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