Recruiting

FIT with VBT & HIIT

Sponsor:

Lance Bollinger

Code:

NCT06631053

Conditions

Muscle Atrophy

Muscle Weakness

Eligibility Criteria

Sex: All

Age: 35 - 45

Healthy Volunteers: Accepted

Interventions

velocity-based FIT (VBFIT)

No Exercise

Study Details

Brief summary:

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

Study ID

NCT06631053

Start date

Oct 23, 2024

Status verified date

Sep, 2025

Completion date

Sep 1, 2026

Anticipated

Primary completion date

Sep 1, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 35 - 45

Healthy Volunteers: Accepted

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

Enrollment

16 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

active comparator: No Exercise

Participants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) without exercise

experimental: velocity-based FIT (VBFIT)

Participants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) with exercise

Interventions

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

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.

Primary outcome measure

  • Voluntary activation [ Time Frame: Baseline, day 13, and day 30 ]
  • Twitch Properties-Electromechanical Delay [ Time Frame: Baseline, day 13, and day 30 ]
  • Twitch Properties-Rate of Torque Development [ Time Frame: Baseline, day 13, and day 30 ]
  • Twitch Properties-Time to peak Tension [ Time Frame: Baseline, day 13, and day 30 ]
  • Twitch Properties-Peak Twitch Torque [ Time Frame: Baseline, day 13, and day 30 ]
  • Twitch Properties-Relaxation Rate [ Time Frame: Baseline, day 13, and day 30 ]
  • Post activation Potentiation [ Time Frame: Baseline, day 13, and day 30 ]
  • Motor unit action potential train (MUAPT) firing rate [ Time Frame: Baseline, day 13, and day 30 ]
  • Motor unit action potential train (MUAPT) recruitment threshold. [ Time Frame: Baseline, day 13, and day 30 ]
  • Motor unit action potential train (MUAPT) de-recruitment threshold. [ Time Frame: Baseline, day 13, and day 30 ]
  • Muscle size [ Time Frame: Baseline and day 30 ]
  • Muscle Physiological cross-sectional area [ Time Frame: Baseline and day 30 ]
  • Muscle Fractional Anisotropy [ Time Frame: Baseline and day 30 ]
  • Muscle Diffusion properties [ Time Frame: Baseline and day 30 ]
  • Muscle cross-sectional area (Ultrasound) [ Time Frame: Baseline, day 13, and day 30 ]
  • Fascicle length [ Time Frame: Baseline, day 13, and day 30 ]
  • Pennation angle [ Time Frame: Baseline, day 13, and day 30 ]
  • Voluntary Isokinetic Muscle Strength [ Time Frame: Baseline, day 13, and day 30 ]
  • Voluntary Isometric Muscle Strength [ Time Frame: Baseline, day 13, and day 30 ]

Central Contacts and Locations

Central contacts

Lance Bollinger, PhD

8592577904lance.bollinger@uky.edu

Locations

University of Kentucky

Recruiting

Lexington, Kentucky, United States, 40506

More Information

Sponsor

Lance Bollinger

Last update posted

Oct 24, 2025

Last verified

Sep, 2025

Keywords

  • spaceflight
  • unweighting
  • disuse
  • exercise

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by Lance Bollinger on 2025-10-24.