This study aims to apply a novel study methodology using high density electromyography (HDEMG) to know what are the mechanisms underlying the structural and functional changes obtained by two different training methods, commonly used, facilitating their understanding, study and subsequent application according to specific needs.
Different training methodologies have previously shown similar results in the improvement of structural or functional characteristics such as hypertrophy or strength. However, the different nature of their methods has suggested for years the possibility that different neuromuscular mechanisms could be behind these observed characteristics. The development of a new technology, such as high-density electromyography (HDEMG), capable of studying new properties previously hidden from assessment methods, such as the speed of nerve impulse propagation or the frequency of motor unit discharge, has allowed a more thorough study of the mechanisms. This study aims to apply this new study methodology to know what are the mechanisms underlying the changes at the structural and functional level obtained by two different training methods, commonly used, facilitating their understanding, study and subsequent application according to specific needs. For this reason, the main hypothesis is the generation of different neuromuscular mechanisms and adaptations by executing, for 4 weeks, two different training methodologies, obtaining a dissociation between the results obtained at the structural level (hypertrophy), functional (generation of strength) and HDEMG analysis of the central and peripheral characteristics of the neuromuscular system in each of the programs studied.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
OTHER
Masking
SINGLE
Enrollment
34
Strength training based on the control of speed loss in execution.
Strength training based on a protocol that includes reduced rest times between sets.
Health Science School , University of Malaga
Málaga, Spain
Change from Baseline Mean Discharge Rate of Brachialis Biceps Motor Units at 4 weeks
The mean discharge rate of the Brachialis Biceps motor units will be evaluated using a high density electromyography device (HDEMG). For this, the signal produced during isometric contractions at different submaximal force levels (10, 30, 50, and 70%) will be recorded, using an external analog to digital signal converter Sessantaquattro (64-channel EMG amplifier; OT Bioelettronica, Turin, Italy).
Time frame: Baseline and post-intervention (4 weeks after baseline)
Speed of propagation of Brachialis Biceps Motor Units
As a measure of evaluation of the peripheral characteristics of the neuromuscular system, the propagation speed of the action potentials produced by an HDEMG device will be evaluated. For this, the signal produced during isometric contractions at different submaximal force levels (10, 30, 50, and 70%) will be recorded, using the external analog to digital signal converter Sessantaquattro
Time frame: Baseline and post-intervention (4 weeks after baseline)
Isometric force of Brachialis Biceps using hand dynamometer
The isometric force at 0º, 45º and 90º will be evaluated during a maximum test of 5 seconds using a digital manual dynamometer. The peak force obtained will be obtained.
Time frame: Baseline and post-intervention (4 weeks after baseline)
Isometric force of Brachialis Biceps using s-beam load cell
The isometric force at 90º will also be evaluated through an S-type load cell (Biometrics Ltd., Newport, United Kingdom). In addition, the time needed to obtain the peak force achieved will be recorded.
Time frame: Baseline and post-intervention (4 weeks after baseline)
Muscle thickness (thickness) of the brachial biceps using ultrasound
Structural changes will be evaluated through an innocuous procedure such as ultrasound. To do this, ultrasound images will be recorded to measure the muscular and adipose thickness of the arm musculature.
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Time frame: Baseline and post-intervention (4 weeks after baseline)
Arm circumference
A variable related to structural changes such as arm circumference will also be evaluated. For this, the circumference will be recorded through a measuring tape at the average distance between the acromion and the olecranon.
Time frame: Baseline and post-intervention (4 weeks after baseline)