About this trial
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.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
Able to provide informed consent
Right-handed (for TMS consistency)
English-speaking
Clearance for moderate-intensity aerobic exercise
Disqualifiers
History of epilepsy or seizures
Current substance abuse or uncontrolled psychiatric disorder
Severe cardiovascular disease or unstable medical condition
Pregnancy
Trial design
Parallel
Treatments tested in this trial
High intensity cycling
BehavioralParticipants 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.
Low-intensity cycling
BehavioralParticipants 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.
Health education session
BehavioralParticipants 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.
Moderate Intensity Aerobic Exercise
BehavioralParticipants 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.
Treatment groups
Trial outcomes
Primary outcomes
Motor Learning Performance (12-Digit Serial Reaction Time Task)
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
Change in Long-Interval Intracortical Inhibition (LICI)
LICI is measured using a 100 ms interstimulus interval to assess GABA\<sub\>B\</sub\>-mediated inhibition. Recorded before and after each intervention session.
Change in Intracortical Facilitation (ICF)
ICF is assessed using paired-pulse TMS with a 10-15 ms interstimulus interval to evaluate cortical excitability.
Change in Blood Lactate Concentration
Measured via fingerstick blood samples pre-, mid-, and post-exercise.
Change in Executive Function (D-KEFS Verbal Fluency and Stroop Tests)
Executive function neuropsychological tests.
Sponsors and contacts
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