UK Center for Clinical and Translational Science

FIT Exercise in 30d of ULLS-induced Muscle Disuse

Purpose

This study aims to determine how flywheel-based inertial training (FIT) implemented according to principles of velocity-based training (VBT) and High-Intensity Interval Training (HIIT) affects disuse-induced physical de-conditioning including loss of voluntary muscle strength, aerobic capacity, and balance regulation.

Conditions

Muscle Atrophy
Muscle Weakness

Eligibility

Eligible Ages: Between 35 Years and 45 Years
Eligible Genders: All
Accepts Healthy Volunteers: Yes

Inclusion Criteria

Regularly engaging in aerobic exercise (> 150min/wk) and resistance exercise (>1 time per week) for the past 12 months - Education greater than or equal to bachelor's degree (any field)

Exclusion Criteria

Waist circumference < 55cm or > 90cm (F) and < 75cm or > 100cm (M) - Body mass index < 18.5 or > 29.9 - Shoe size < 25 or >29cm. - Not regularly engaging in exercise for previous 12 months - Tobacco use within previous 6 months - Blood clotting disorder - Heart arrhythmia - Implanted device which could negatively be affected by electrical impulse or strong magnetic field such as pacemaker, internal defibrillator, or cochlear implant - Diagnosed cardiovascular, pulmonary, renal, or metabolic disease - Pregnancy (within previous 6 months) - Oral contraceptive use (within previous three months) - High resting blood pressure (>140 systolic and/or > 90 diastolic) - Currently or previously undergone gender-affirming therapy (hormone therapy or sexual reassignment surgery) - Low back or leg injury in previous 6 months - Currently taking medication to assist with sleep - Muscle, bone, or joint injury that limits physical activity within previous 6 months - Neurological disorder which affects balance (such as multiple sclerosis or Parkinson's disease)

Study Design

Phase: N/A
Study Type: Interventional
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: ULLS is the gold standard for assessing muscle disuse in ambulatory subjects. Velocity based resistance training and High Intensity Interval Training are gold-standard exercise strategies in terrestrial settings which tend to out-perform other exercise interventions. However, these exercise paradigms have not be applied to those undergoing unloading such as astronauts in space flight. Here, we aim to adopt principles from these established exercise interventions to determine their effectiveness in preserving muscle and aerobic fitness during 30d ULLS.
Primary Purpose: Treatment
Masking: None (Open Label)
Masking Description: Participants are unable to be masked to their intervention (exercise v. non-exercise). Although other researchers from this team will be responsible for directly implementing exercise interventions, exercise sessions will be conducted in the same building as the PI's office. Therefore, it is likely that the PI will be aware of which subjects are completing exercise sessions. The PI and his team will be directly responsible for assessing primary and secondary research outcomes.

Arm Groups

Arm	Description	Assigned Intervention
Active Comparator No Exercise	Participants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) without exercise	Other: No Exercise Participants will ambulate unilaterally using a shoe modified with a 5cm rocker-style stack and forearm crutches for the duration of the study. All participants will complete two testing sessions prior to ULLS, one testing session at day 13, and two testing sessions at the end of the study.
Experimental velocity-based FIT (VBFIT)	Participants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) with exercise	Other: velocity-based FIT (VBFIT) Participants will ambulate unilaterally using a shoe modified with a 5cm rocker-style stack and forearm crutches for the duration of the study. All participants will complete two testing sessions prior to ULLS, one testing session at day 13, and two testing sessions at the end of the study. Those assigned to the exercise group will perform a both high-intensity resistance and aerobic exercise three times per week

Recruiting Locations

UK Center for Clinical and Translational Science and nearby locations

University of Kentucky
Lexington, Kentucky 40506

More Details

NCT ID: NCT06631053
Status: Recruiting
Sponsor: Lance Bollinger

Study Contact

Lance Bollinger, PhD
8592577904
lance.bollinger@uky.edu

Detailed Description

The primary objectives of this project are: 1. To assess how 30d of unilateral lower limb suspension (ULLS) with and without FIT exercise affects voluntary and electrically-evoked twitch force, motor unit recruitment, and anisotropic measures. 2. To determine how muscle anisotropy (assessed through diffusion tensor imaging) and motor unit action potential train (MUAPT) characteristics relate to contractile function in loaded and unloaded limbs Secondary objectives include: 1. To assess impact of ULLS with and without FIT on aerobic capacity 2. To assess impact of ULLS with and without FIT on balance regulation during single-leg stance This study aims to recruit 10 healthy, physically active participants (both male and female). Participants will undergo 30d of ULLS to unload the left limb during daily living activities. Subjects will wear a specially modified shoe with a 5cm rocker-style stack on the right leg and ambulate using crutches. Participants will be randomly assigned to either a control or exercise group. Those in the exercise group will perform Flywheel-based Inertial Training (FIT) leg press three times per week. Moment of inertia of the flywheel will be adjusted to elicit movement speeds of 0.4 m/s for resistance training (four sets of 10 repetitions). For High Intensity Interval Training, flywheel moment of inertia will be adjusted to elicit movement speed of 1.0m/s during leg press (four sets of 3 min). Before and after the intervention, subjects will complete a series of tests including: 1. Body Composition - height, weight, waist circumference, and tetrapolar bioelectrical impedance analysis will be conducted. 2. Balance assessment - center of pressure will be assessed using portable force decks during single leg stance with eyes open and closed. This test will be repeated in the shod and unshod conditions. MUAPT data (high density surface electromyography) will be collected for the soleus and tibialis anterior during this test. 3. Aerobic capacity test - VO2max will be determined during a graded exercise test on a cycle ergometer (3 min per stage). Gas exchange and heart rate data will be collected continuously throughout the test. Pedal force will also be assessed. Additional outcomes such as ventilatory threshold and substrate utilization will be assessed. 4. Muscle Imaging - Diffusion tensor imaging (DTI), a magnetic resonance technique will be used to assess anisotropic measures, muscle volume, fascicle length, and fascicle orientation of the mid-thigh. 5. Muscle strength testing - Maximal voluntary isometric and isokinetic strength of the knee extensors, flexors, and ankle plantar- and dorsi-flexors will be assessed. Interpolated twitch (electrical stimulation of the femoral nerve) will be used to assess twitch characteristics and voluntary activation of the quadriceps

Notice

Study information shown on this site is derived from ClinicalTrials.gov (a public registry operated by the National Institutes of Health). The listing of studies provided is not certain to be all studies for which you might be eligible. Furthermore, study eligibility requirements can be difficult to understand and may change over time, so it is wise to speak with your medical care provider and individual research study teams when making decisions related to participation.