Skip to main content
OpenTrials
Active, Not Recruiting

NCT Number: NCT06950060

AMPLIFI: Adaptive Modulation of Plasticity Through Lactate and Fitness Interventions

The AMPLIFI study (Adaptive Modulation of Plasticity through Lactate and Fitness Interventions) investigates how short-term aerobic exercise influences brain plasticity and learning in older adults and stroke survivors. The study compares three groups: one performing aerobic cycling at an intensity that elevates lactate levels, one performing low-intensity exercise, and one receiving health education without exercise.

All participants will complete motor learning tasks and undergo brain-stimulation testing using transcranial magnetic stimulation (TMS) to assess how well the brain responds to training. The goal is to understand whether different types of exercise can improve brain function, movement, and memory, and how the body's response to exercise (like lactate levels) might support brain health.

This research may help identify low-cost, non-invasive interventions-such as targeted exercise-that improve motor and cognitive outcomes in aging and stroke recovery.

Active, Not Recruiting

This study is active but is not currently recruiting participants.

Key information

Conditions

Stroke, Chronic Aging Brain Diseases Bronchial Diseases Bronchiolitis Bronchiolitis Obliterans Bronchiolitis Obliterans Syndrome Bronchitis Cardiovascular Diseases Central Nervous System Diseases Cerebrovascular Disorders Cognition Disorders Cognitive Decline Cognitive Dysfunction Graft vs Host Disease Immune System Diseases Lung Diseases Lung Diseases, Obstructive Mental Disorders Motor Dysfunction Nervous System Diseases Neurocognitive Disorders Neurologic Manifestations Neuroplasticity Organizing Pneumonia Pathological Conditions, Signs and Symptoms Respiratory Tract Diseases Signs and Symptoms Stroke Vascular Diseases

Age range

18 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

CH19 933 19th St S

Birmingham, Alabama, 35233, United States

About this study

The AMPLIFI study is a mechanistic clinical trial designed to investigate the neurophysiological effects of acute aerobic exercise on cortical plasticity and motor learning in older adults and individuals with chronic stroke. Participants are randomized into one of three groups: (1) moderate-to-high intensity aerobic exercise at lactate threshold, (2) moderate intensity aerobic exercise, (3) low-intensity aerobic exercise, or (4) education-only control.

The primary outcome measure is cortical inhibition, assessed using transcranial magnetic stimulation (TMS) measures including short-interval intracortical inhibition (SICI), long-interval intracortical inhibition (LICI), and intracortical facilitation (ICF). Secondary outcomes include performance on upper extremity motor tasks, measures of verbal and executive function, and blood lactate levels.

Participants complete three sessions over 2-3 weeks, including baseline assessments, VO2 max testing, multiple blood draws, and cognitive and motor testing. The exercise intervention is delivered via stationary cycling at intensities tailored using individual VO2 max data and lactate monitoring. Genetic and biochemical assays will be performed on blood samples to explore associations between metabolic and neural response.

This study will clarify how lactate-related exercise intensity impacts cortical inhibition and whether those effects support improvements in motor learning. Findings may help define the mechanisms by which exercise promotes neuroplasticity and support individualized rehabilitation strategies for aging and post-stroke populations.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

For All Participants:

  • Able to provide informed consent
  • Right-handed (for TMS consistency)
  • English-speaking
  • Clearance for moderate-intensity aerobic exercise
  • Able to safely sit and pedal a stationary cycle ergometer
  • No contraindications to TMS (e.g., no metal in skull, pacemakers, or seizure history)

Younger Adults (18-35):

  • No history of neurological or psychiatric conditions
  • Not currently on medications that affect the central nervous system

Older Adults (60-85):

  • No diagnosis of dementia
  • Independent in activities of daily living
  • No stroke history

Stroke Survivors (40-85):

  • At least 6 months post-stroke (chronic phase)
  • Medically stable and cleared for aerobic exercise
  • Able to engage in motor learning task (with or without hemiparetic adaptations)

Exclusion criteria

  • History of epilepsy or seizures
  • Current substance abuse or uncontrolled psychiatric disorder
  • Severe cardiovascular disease or unstable medical condition
  • Pregnancy
  • Contraindications to TMS or exercise testing (e.g., implanted neurostimulators, severe hypertension)
  • Participation in another interventional trial within the past 30 days

Treatment and study plan

High intensity cycling

Behavioral

Participants cycle on a stationary ergometer at an intensity prescribed to reach their lactate threshold, guided by VO2 max results and lactate sampling. The session lasts approximately 20 minutes and is preceded and followed by TMS assessments and a structured motor learning task. This condition is designed to evaluate the effect of exercise-induced metabolic stress on cortical inhibition and motor learning.

Other names: HIIT

Low-intensity cycling

Behavioral

Participants perform 20 minutes of cycling at a light workload below their lactate threshold. Exercise intensity is individualized using heart rate and perceived exertion (Borg RPE scale), avoiding significant metabolic activation. TMS and motor learning are assessed pre- and post-exercise. This condition serves as an active comparator to assess the impact of exercise intensity.

Other names: MICT

Health education session

Behavioral

Participants receive a 20-minute session of health education content (e.g., wellness, healthy aging). No exercise is performed. Participants undergo TMS and motor learning testing before and after the session. This condition is used to control for attention and cognitive engagement without physical activity.

Other names: Education

Moderate Intensity Aerobic Exercise

Behavioral

Participants cycle on a stationary ergometer at an intensity prescribed to surround, but not exceed their lactate threshold, guided by VO2 max results and lactate sampling. The session lasts approximately 20 minutes and is preceded and followed by TMS assessments and a structured motor learning task. This condition is designed to evaluate the effect of moderate exercise-induced metabolic stress on cortical inhibition and motor learning.

Primary outcomes

  1. Motor Learning Performance (12-Digit Serial Reaction Time Task)

    Time frame: Baseline, Day 2, Day 3, Day 4, and Day 5

    Motor learning is assessed using the 12-digit Serial Reaction Time Task (SRTT), a computer-based measure of implicit motor sequence learning. Participants respond to visual cues by pressing buttons in a fixed or random sequence. Learning is quantified by changes in reaction time and accuracy across structured and unstructured trials. A learning index is derived by comparing performance between patterned (learning) and random sequences.

Secondary outcomes

  1. Change in Long-Interval Intracortical Inhibition (LICI)

    Time frame: Baseline, Day 5

    LICI is measured using a 100 ms interstimulus interval to assess GABA<sub>B</sub>-mediated inhibition. Recorded before and after each intervention session.

  2. Change in Intracortical Facilitation (ICF)

    Time frame: Baseline, Day 5

    ICF is assessed using paired-pulse TMS with a 10-15 ms interstimulus interval to evaluate cortical excitability.

  3. Change in Blood Lactate Concentration

    Time frame: Day 2, Day 3, Day 4

    Measured via fingerstick blood samples pre-, mid-, and post-exercise.

  4. Change in Executive Function (D-KEFS Verbal Fluency and Stroop Tests)

    Time frame: Day 1 and Day 5

    Executive function neuropsychological tests.

Sponsors and collaborators

Lead sponsor

University of Alabama at Birmingham

Other

Registry information

Acronym: AMPLIFI

Important dates

Study start
2026
Primary completion
2029
Study completion
2030
First posted
Apr 29, 2025
Registry last updated
Jul 17, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.