Neural Adaptations to Metronome-Paced Strength Training
NCT Number: NCT06532786
Status: RECRUITING
Study Type: INTERVENTIONAL
Phases: NA
Conditions: Healthy
Interventions: OTHER: Fractal Paced|OTHER: Isochronous Paced|OTHER: Self Paced
Sponsor: Egas Moniz - Cooperativa de Ensino Superior, CRL
Collaborators: Fundação para a Ciência e a Tecnologia
Sex: MALE
Age: ADULT
Enrollment: 60
Study Design: Allocation: RANDOMIZED|Intervention Model: PARALLEL|Masking: SINGLE (PARTICIPANT)|Primary Purpose: BASIC_SCIENCE
Start Date: 2024-09-15
Completion Date: 2025-12-31
Locations: Egas Moniz School of Health & Science, Almada, Monte De Caparica, 2829-699, Portugal

Summary:
The aim of the study is to investigate the effects of incorporating variability within 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. It is also known that conditions such as ageing and injury have a negative impact on neural drive to the muscles with consequences at motor control level that are not addressed by traditional RT. 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.

Primary Outcome Measures: Corticospinal Excitability (CSE) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, 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 (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Short-interval Intracortical Inhibition (SICI) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, 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 (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Corticospinal Silent Period (CSP) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, 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 (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Intracortical Facilitation (ICF) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, 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 (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Lumbar Evoked Potentials (LEP) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, 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 (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Maximal Compound Action Potentials (Mmax) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, Mmax is a measure assessed through peripheral nerve stimulation and represents the maximal capacity of recruit the motoneurons that innerve a muscle., PRE (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|StartReact Gain changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, StartReact gain is a measure that is calculated following the StartReact protocol. It consists in measuring the participants' reaction times in response to visual stimuli (visual reaction time \[VRT\]), visual stimuli combined with a quiet sound (visual auditory reaction time \[VART\]) and visual startling stimuli (visual startling reaction time \[VSRT\]) and, then, apply the following formula: StartReact gain = (\[VRT - VSRT\]/\[VRT - VART\])., PRE (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)
Secondary Outcome Measures: Single leg extension 1RM changes after 4-weeks intervention (PRE to POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, Single leg 1RM is defined as the maximal load that each participant mobilized in a single maximum dynamic knee extension., PRE (baseline), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Maximal Voluntary Isometric Contraction (MVIC) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, MVIC is defined as the maximal force an individual can produce against an immovable resistance, PRE (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Sample Entropy (SampEn) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, 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 (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Coefficient ov variation (CV) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, 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 (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Motor Unit Action Potentials (MUAP) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, MUAP is obtained through the decomposition of electromyographic (EMG) signals collected using High-density surface EMG electrodes and is an index of motor unit recruitment., PRE (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)|Firing Rate (FR) changes across the 4-weeks intervention (PRE to Week1, Week 2, Week 3, POST and follow-up) both within and between Fractal paced, Isochronus Paced and Self paced groups, FR is obtained through the decomposition of electromyographic (EMG) signals collected using High-density surface EMG electrodes and is a measure of intramuscular coordination, PRE (baseline), W1 (week 1), W2 (week 2), W3 (week 3), POST (week 4), FUP (follow-up 4 weeks after the end of intervention)