Neural Adaptations to a Single Session of Metronome-Paced Strength Training

Neural Adaptations to a Single Session Metronome-Paced Strength Training: Insights From Neuroscience and Human Movement Variability

The aim of the study is to investigate the effects of incorporating variability within a single session of Resistance Training (RT) methods on the neural adaptations along the corticospinal tract and on neuromuscular function. The literature suggests that RTis one of the most common modalities to enhance and restore muscle function and its practice results in adaptation in neural and morphological adaptations. Moreover, it is also known that muscle contraction relies on the coordination and regulation of the descending neural drive from the motor cortex to the motoneurons and from the motoneurons to the muscles. However, traditional RT programs tend not to address this motor control dimension. Recent approaches such as metronome paced strength training have been used to cover this motor control dimension through a greater control and consciousness of movement. However, this methodology tends not to incorporate the inherent variability and complex, fractal-like fluctuations that characterize human movement. The investigators propose that incorporating variability through a fractal-like metronome approach will speed up the neural adaptations which will be useful in injury rehab

Study Overview

• Status: Completed
• Conditions: Healthy
• Intervention / Treatment: Other: Fractal Paced; Other: Isochronus Paced; Other: Self Paced

• Study Type: Interventional
• Enrollment (Actual): 30
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Portugal
  • Monte de Caparica
    • Almada, Monte de Caparica, Portugal, 2829-699
      • Egas Moniz School of Health & Science

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• healthy males
• aged between 18 and 40 years

Exclusion Criteria:

• Neurologic conditions;
• Lower limb disabilities or disease;
• Not able to provide informed consent;
• Have an implanted device (e.g. pacemakers) or any metal in the body;
• Medication advised against the application of Transcranial Magnetic Stimulation;
• History/family history of seizures, brain lesions or head trauma, neurological or psychiatric diseases, epilepsy, migraine

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Fractal Paced; Strength training in single leg extension machine, synchronizing each repetition with a fractal-like visual metronome, i.e., a metronome presenting visual external cues with variability within its temporal structure.	Other: Fractal Paced; The intervention consists in a single session of metronome paced strength training composed by 4 sets of 15 repetitions at 65% of the one-repetition maximal (1RM) in single leg extension machine, synchronizing each repetition with fractal external cues presented by a visual metronome. The rest between sets will be set at 2 minutes of rest between sets.
Experimental: Isochronous Paced; Strength training in single leg extension machine, synchronizing each repetition with a isochronus visual metronome, i.e., a metronome presenting visual external cues withthe same pace in each repetition (without variability)	Other: Isochronus Paced; The intervention consists in a single session of metronome paced strength training composed by 4 sets of 15 repetitions at 65% of the one-repetition maximal (1RM) in single leg extension machine, synchronizing each repetition with isochronus external cues presented by a visual metronome. The rest between sets will be set at 2 minutes of rest between sets.
Experimental: Self Paced; Strength training in single leg extension machine at participants self pace.	Other: Self Paced; The intervention consists in a single session of strength training composed by 4 sets of 15 repetitions at 65% of the one-repetition maximal (1RM) in single leg extension machine, at at participants' own self pace (with no metronome). The rest between sets will be set at 2 minutes of rest between sets.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Corticospinal Excitability (CSE) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	CSE is a parameter extracted through the application of Transcranial Magnetic Stimulation (TMS). This parameter provides information regarding the level of excitability of the corticospinal tract.	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)
Short-Interval Intracortical Inhibition (SICI) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	SICI is a parameter extracted through the application of Transcranial Magnetic Stimulation (TMS). This parameter provides information regarding the level of inhibition within the motor cortex.	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)
Corticospinal Silent Period (CSP) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	CSP is a parameter extracted through the application of Transcranial Magnetic Stimulation (TMS). This parameter provides information regarding the level of inhibition along the corticospinal tract.	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)
Intracortical Facilitation (ICF) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	ICF is a parameter extracted through the application of Transcranial Magnetic Stimulation (TMS). This parameter provides information regarding the level of facilitation within the motor cortex.	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)
Lumbar Evoked Potentials (LEP) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	LEP is a measure extracted through the aplication of Lumbar stimulation. This measure allow to distinguish the adaptations that occur at spinal level as a result of strength training.	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)
Maximal Compound Action Potentials (Mmax) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	Mmax is a measure assessed through peripheral nerve stimulation and represents the maximal capacity of recruit the motoneurons that innerve a muscle	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal Voluntary Isometric Contraction (MVIC) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	MVIC is defined as the maximal force an individual can produce against an immovable resistance	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)
Sample Entropy (SampEn) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	SampEn is a non-linear measure of the temporal structure of force output, being an indicator of the regularity of this physiological output. It is obtained from sustained submaximal isometric contractions and it has been proposed as an indirect index of the capacity of the neuromuscular system to adapt the force output to changes in environment, i.e., its adaptability.	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)
Coefficient ov variation (CV) changes Pre-to-Post intervention both within and between Fractal paced, Isochronus Paced and Self paced conditions	CV is a common linear measure that translates the amount of variability within the signal and is calculated through the standard deviation normalised to the mean of a time series	PRE (before intervention), POST (immediately after the intervention) and POST 60 (60 minutes after the intervention)

Collaborators and Investigators

• Sponsor: Egas Moniz - Cooperativa de Ensino Superior, CRL
• Collaborators: Fundação para a Ciência e a Tecnologia; University of Essex

Study record dates

Study Major Dates

• Study Start (Actual): July 22, 2024
• Primary Completion (Actual): June 30, 2025
• Study Completion (Actual): July 31, 2025

Study Registration Dates

• First Submitted: July 29, 2024
• First Submitted That Met QC Criteria: August 1, 2024
• First Posted (Actual): August 6, 2024

Study Record Updates

• Last Update Posted (Estimated): January 16, 2026
• Last Update Submitted That Met QC Criteria: January 14, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Transcranial Magnetic Stimulation; Neuroscience; Motor Control; Neural Adapatations; Dynamic Systems; Metronome Paced Strength Training
• Other Study ID Numbers: AcuteMETROTRAIN - 1404

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No