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Research ArticleOpen Access

Reliability of Mechanical and EMG Variables Assessed During Concentric Bench Press Exercise Against Different Submaximal Loads

Volume 9 - Issue 3

Juan Manuel Yáñez García1, David Rodríguez Rosell1*, Ricardo Mora Custodio1, Antonio G Ravelo García2, Juan Ribas Serna3 and Juan José González Badillo1

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    • 1Physical Performance & Sports Research Center, Pablo de Olavide University, Seville, Spain
    • 2Institute for Technological Development and Innovation in Communications, Universidad de Las Palmas de Gran Canaria, Spain
    • 3Department of Medical Physiology and Biophysics, University of Seville, Spain

    *Corresponding author: David Rodríguez Rosell, Physical Performance & Sports Research Center, Pablo de Olavide University, Seville, Spain

Received: September 21, 2018;   Published: September 27, 2018

DOI: 10.26717/BJSTR.2018.09.001798

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Abstract

Background: Purpose: To analyze the intrasession reliability of different kinetic, kinematic and surface electromyography (EMG) variables obtained during concentric phase of the bench press exercise against four different submaximal loads: 50%, 60%, 70% and 80% 1RM.

Methods: Twelve physical active men performed four testing sessions (one with each load magnitude) in a random order and separated by a time period of 3-4 days. In each session, participants were required to perform 3 sets of 2 repetitions each (3-min interset rests). The fastest repetition of each set was considered for subsequent reliability analysis. All data were analyzed using the intraclass correlation coefficient (ICC) and the coefficient of variation (CV).

Results: Variables related to force, velocity, power and acceleration presented high reliability scores (ICC: 0.920-0.997, CV: 1.22-8.87%) against all load magnitudes used. The maximal rate of force development (MRFD) showed a high reproducibility, whereas the time taken to achieve the MRFD, time needed to attain different fractions of peak force and RFD quantify in different time bands (0-25, 0-50, 0-75ms) resulted in low to high relative reliability (ICC: 0.550-0.978) and moderate to poor absolute reliability (CV: 11.60-52.68%). Absolute (CV: 3.59-57.52%) and relative (ICC: 0.703-0.995) reproducibility for EMG variables related to signal amplitude and frequency of the power spectrum was fair to good, independent of load magnitude used and muscle assessed.

Conclusion: Overall, these results suggest that the reliability of the mechanical and EMG measures varied depending on the variable used to assess the performance during a concentric BP exercise.

Keywords: Force Time Curve; Reproducibility; Power Spectrum EMG Variables; Dynamic Muscle Activation; Rate of Force Development

Abbreviations: 1RM: One Repetition Maximum; ANOVA: Analysis of Variance; BP: The Bench Press (BP) exercise; CI: Confidence Interval; CV: Coefficient of Variation; EMG: Electromyography; FInsm5: Dimitrov Index; Fmax: Maximal Frequency; Fmean: Mean Frequency; Fmed: Median Frequency; ICC: Intraclass Correlation Coefficient; iEMG: Integrated EMG; MPF: Mean Propulsive Force; MPV: Mean Propulsive Velocity; MRFD: Maximal RFD; MV: Mean Velocity; PA: Peak Acceleration; PF: Peak Force; PM: Pectoralis Major; PP: Peak Power; PV: Peak Velocity; RFD: Rate of Force Development; RFDAV: Average Rate of Force Development; RMS: Root Mean Square; rRFD: RFD Normalized Relative to Maximum Peak Force; SD: Standard Deviations; SEM: Standard Error of Measurement; T_MRFD: Time From Force Onset to The Instant of Reaching MRFD T25%, 50%, 75% and 100% Time taken to the Attainment of 25%, 50%, 75% and 100% of the PF; TB: Triceps Brachii

Abstract | Introduction | Materials and Methods | Results | Discussion | Conclusion | Practical Applications | Acknowledgement| References|