AMPLIFI: Adaptive Modulation of Plasticity Through Lactate and Fitness Interventions (AMPLIFI)

April 16, 2026 updated by: Keith McGregor, University of Alabama at Birmingham

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

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.

Study Type

Interventional

Enrollment (Estimated)

48

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Keith M McGregor, PhD
  • Phone Number: ‪(205) 693-9997‬
  • Email: kmmcgreg@uab.edu

Study Contact Backup

Study Locations

  • United States
    • Alabama
      • Birmingham, Alabama, United States, 35233
        • CH19 933 19th St S
        • Contact:
          • Keith M McGregor, PhD
          • Phone Number: ‪(205) 693-9997‬
          • Email: kmmcgreg@uab.edu
        • Principal Investigator:
          • Keith M McGregor, PhD
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

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

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Aerobic Exercise at Lactate Threshold
Participants complete a 20-minute aerobic cycling session at individually prescribed intensity to achieve lactate threshold, based on VO2 max and blood lactate data. This condition is designed to induce metabolic stress and engage neuromodulatory pathways related to cortical plasticity. Participants complete TMS and motor learning tasks before and after the intervention.
Behavioral: High intensity cycling
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
Active Comparator: Low-Intensity Aerobic Exercise
Participants complete a 20-minute cycling session at a light workload, below lactate threshold. This condition controls for movement and engagement without significant metabolic challenge. TMS and motor learning outcomes are assessed pre- and post-intervention.
Behavioral: Low-intensity cycling
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
Placebo Comparator: Education Control
Participants engage in a 20-minute health education session instead of exercise. This arm serves as a non-exercise control to isolate the effects of physical exertion on neuroplasticity. All outcome measures are collected similarly to the exercise groups.
Behavioral: Health education session
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
Active Comparator: Active Comparator: Moderate-Intensity Aerobic Exercise
Arm Description: Participants complete a 20-minute cycling session at a moderate workload, surrounding lactate threshold. This condition controls for movement and engagement without advanced metabolic challenge. TMS and motor learning outcomes are assessed pre- and post-intervention.
Behavioral: Moderate Intensity Aerobic Exercise
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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Baseline, Day 2, Day 3, Day 4, and Day 5

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Long-Interval Intracortical Inhibition (LICI)
Time Frame: Baseline, Day 5
LICI is measured using a 100 ms interstimulus interval to assess GABAB-mediated inhibition. Recorded before and after each intervention session.
Baseline, Day 5
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.
Baseline, Day 5
Change in Blood Lactate Concentration
Time Frame: Day 2, Day 3, Day 4
Measured via fingerstick blood samples pre-, mid-, and post-exercise.
Day 2, Day 3, Day 4
Change in Executive Function (D-KEFS Verbal Fluency and Stroop Tests)
Time Frame: Day 1 and Day 5
Executive function neuropsychological tests.
Day 1 and Day 5

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Alabama at Birmingham

Investigators

  • Principal Investigator: Keith McGregor, PhD, Keith McGregor

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

May 14, 2026

Primary Completion (Estimated)

September 1, 2029

Study Completion (Estimated)

January 1, 2030

Study Registration Dates

First Submitted

April 3, 2025

First Submitted That Met QC Criteria

April 22, 2025

First Posted (Actual)

April 29, 2025

Study Record Updates

Last Update Posted (Actual)

April 17, 2026

Last Update Submitted That Met QC Criteria

April 16, 2026

Last Verified

April 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB-300014361

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

No, not beyond the original research team.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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