Impact of Duration of Eccentric Movement in the One-Repetition Maximum Test Result in the Bench Press among Women.

Author:Wilk, Michal

Introduction

Maximum strength is the maximum capability of a muscle or a muscle group to generate tension. It is often measured by the one repetition maximum test (1RM) (Seo et al., 2012). The 1RM test is defined as the maximal load that can be lifted once with a correct technique and over a specific range of motion. The 1RM test is relatively simple and requires inexpensive non-laboratory equipment (Kraemer et al., 2006). The 1RM test is considered the gold standard for assessing muscle strength under non-laboratory conditions (Levinger et al., 2009). Due to the wide use of 1RM tests, it is important that this test is a reliable measurement, however, it has not been established what effect different tempos of movement have on the results of the 1RM test as yet.

Training at a specific movement tempo is a concept in resistance training, where the duration of particular phases of movement is strictly controlled and manipulated (Wilk et al., 2018a). Since there is no standardized method within the scientific literature, in this paper we applied a unified description of the movement tempo using the following terms and three-digit combination: eccentric / isometric / concentric (e.g. 2/0/X), where each digit determined the duration [s] of a particular phase of the movement. "X" represented the maximum possible movement tempo during the concentric (CON) phase.

Previous research has shown that changes in movement tempo during resistance exercise have a significant impact on the number of performed repetitions, time under tension as well exercise intensity, and as a consequence influence adaptive changes related to strength, power and muscular hypertrophy (Hunter et al., 2003; Keeler et al., 2001; Wilk et al., 2018a; 2019). However, despite the fact that training with a controlled movement tempo influences acute responses (endocrine, metabolic, fatigue) and chronic changes (muscular strength and hypertrophy) following resistance exercise, only one study has examined the impact of different movement tempos on the maximal load lifted during 1RM testing (Headley et al., 2011). In the study of Headley et al. (2011) the participants reached 3.7% greater maximal loads during the 1RM test with the 2/0/2 tempo compared to the 4/0/2 tempo, what indicates that the tempo of movement affects 1RM test results. In addition to the tempo of movement used, other factors may affect the maximum amount of weight an individual can lift. Age, sex, limb lengths and circumferences, body mass, muscle mass, training routine and status, the rate of contractions, and the time distribution between eccentric and concentric phases could all possibly influence the maximal load able to be lifted in a specific exercise (Reynolds et al., 2006).

Considering that the extension of the eccentric (ECC) phase of movement by 2 s (2/0/2 vs. 4/0/2) caused a 3.7% decrease in results of the 1RM test (Headley et al., 2011), it can be hypothesized that an additional extension of the duration of the ECC phase would induce further decreases in 1RM testing performance compared to a faster movement tempo. However, there is limited available data that evaluates such differences, especially with slow tempos of movement.

Therefore, the aim of this study was to determine the effects of different movement tempos, with changes only in the duration of the ECC phase of movement during the bench press exercise (BP) on 1RM test results. Our initial hypothesis was that the movement tempo would have a significant impact on the maximal load lifted in the 1RM test.

Methods

The purpose of the study was to determine whether there was a significant difference in the maximal load obtained during the 1RM test using different movement tempos. All testing was performed in the Strength and Power Laboratory at the Jerzy Kukuczka Academy of Physical Education in Katowice. The experiment was conducted following a randomized crossover design, where each participant performed three familiarization sessions and three different testing protocols 7 days apart. During each experimental session, participants completed the 1RM test protocol using the bench press (BP) exercise with different tempos: 2/0/X eccentric fast tempo (ECCFAS), 4/0/X eccentric medium tempo (ECCMED) and 6/0/X eccentric slow tempo (ECCSLO). For example, the 2/0/X tempo denotes a 2 s ECC phase, no pause during the transition phase (0), "X" represents the maximum possible movement tempo during the CON phase. Participants were required to refrain from resistance training 72 hours prior to each experimental session, were familiarized with the exercise protocol and informed about the benefits and risks of the experiment before expressing their written consent for participation in the study.

Study participants

Twenty-one healthy strength trained females (age = 23.4 [+ or -] 2.2 years, body mass = 52.3 [+ or -] 6.7 kg), with a minimum one year of strength training experience (2.3 [+ or -] 1.47 years) took part in the research. Participants were free of any pathologies and injuries and were instructed to maintain their normal dietary habits over the entire study period and not to use any dietary supplements or stimulants for the duration of the study. In order to exclude the effect of motor learning, at least 3 weeks before the study, all participants practiced the bench press exercise with different movement tempos. Prior to study commencement, participants provided written informed consent; they were also allowed to withdraw from the experiment at any moment. This study was carried out in accordance with the recommendations of the ethical standards outlined in the Declaration of Helsinki, 2013. The protocol was approved by the Bioethics Committee for Scientific Research, at the Academy of Physical Education in Katowice, Poland (10/2018).

Procedures

Familiarization session

Three weeks before the...

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