Muscle AtrophyNCT06631053
FIT Exercise in 30d of ULLS-induced Muscle Disuse
A study testing velocity-based FIT (VBFIT) and No Exercise in people with Muscle Atrophy and Muscle Weakness, run by Lance Bollinger at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 35 to 45 yearsHealthy volunteers can take part
- Conditions the study is for
- Muscle Atrophy, Muscle Weakness
- What is being tested?
- velocity-based FIT (VBFIT) and No Exercise
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 29 participants
- Where
- 1 siteUnited States
- Study dates
- 23 Oct 2024to 31 Aug 2026
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 35 to 45 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- 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)
Who cannot join
- Waist circumference < 55cm or > 90cm (F) and < 75cm or > 100cm (M)
- Body mass index < 18.5 or > 29.9
- Not regularly engaging in exercise for previous 12 months
- Tobacco use within previous 6 months
- Blood clotting disorder
- Implanted device which could negatively be affected by electrical impulse or strong magnetic field such as pacemaker, internal defibrillator, or cochlear implant
Show all 13Show fewer
- Diagnosed cardiovascular, pulmonary, renal, or metabolic disease
- Pregnancy (within previous 6 months)
- High resting blood pressure (>140 systolic and/or > 90 diastolic)
- 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)
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Use of Velocity Monitoring to Prescribe Appropriate Flywheel-based Inertial Training (FIT) Workloads for Exercise in Space Flight
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.
Read the detailed description
The primary objectives of this project are:
- 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.
- 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:
- To assess impact of ULLS with and without FIT on aerobic capacity
- 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 upright squats (four sets of 3 min).
Before and after the intervention, subjects will complete a series of tests including:
- Body Composition - height, weight, waist circumference, and tetrapolar bioelectrical impedance analysis will be conducted.
- 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.
- 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.
- 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.
- 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
- Conditions
- Muscle Atrophy, Muscle Weakness
- Being tested
- velocity-based FIT (VBFIT), No Exercise
- Keywords
- spaceflight, unweighting, disuse, exercise
- Medical subject headings
- Muscular Atrophy, Muscle Weakness, Motor Activity
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
velocity-based FIT (VBFIT)Other
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 ExerciseOther
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.
| Study group | Role | What they receive |
|---|---|---|
| No Exercise | Active comparator | Participants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) without exercise Receives: Other: No Exercise |
| velocity-based FIT (VBFIT) | Experimental | Participants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) with exercise Receives: Other: velocity-based FIT (VBFIT) |
What is being measured
The primary outcome is the main question the study is designed to answer.
Voluntary activation
Voluntary activation of the quadriceps will be assessed with electrical stimulation of the femoral nerve before, during, and after a maximal voluntary isometric contraction (MVIC) using the interpolated twitch technique.
Measured: Baseline, day 13, and day 30
Twitch Properties-Electromechanical Delay
Electromechanical delay will be calculated as the time difference between the onset of electrical impulse and onset of torque development during femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Measured: Baseline, day 13, and day 30
Twitch Properties-Rate of Torque Development
Rate of Torque Development will be calculated as the change in torque divided by the change in time in the linear phase between 20 and 80% of peak twitch torque during femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Measured: Baseline, day 13, and day 30
Twitch Properties-Time to peak Tension
Time to peak tension will be calculated as the time difference between the onset of electrical impulse and peak twitch torque during femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Measured: Baseline, day 13, and day 30
Twitch Properties-Peak Twitch Torque
Peak twitch torque during femoral nerve stimulation will be calculated as the highest torque output immediately (approximately 200ms) following femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Measured: Baseline, day 13, and day 30
Twitch Properties-Relaxation Rate
Relaxation rate will be calculated as the change in torque divided by the change in time during the relaxation phase of twitch following femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Measured: Baseline, day 13, and day 30
Post activation Potentiation
Post-activation will be calculated as the percentage difference in peak twitch torque in femoral nerve stimulation before and after a maximal voluntary isometric contraction.
Measured: Baseline, day 13, and day 30
Motor unit action potential train (MUAPT) firing rate
Firing rate of individual motor units of the vastus lateralis (VL) will be assessed with high density surface electromyography (EMG) using four-pin high density surface electromyography electrodes. Firing rate at 30, 60, and 90% MVIC will be reported. Motor unit firing rate will also be reported during static stance.
Participants will use a screen displaying real-time torque output. Participants will voluntarily increase torque (5 seconds), hold at a pre-determined torque level (10 seconds), and gradually reduce force back to resting (5 seconds) with the knee held in a fixed position. This test will be completed with a 10s isometric hold at 30, 60, and 90% of maximal voluntary isometric force.
Measured: Baseline, day 13, and day 30
Motor unit action potential train (MUAPT) recruitment threshold.
Recruitment threshold of individual motor units of the VL will be assessed with high density surface electromyography using four-pin high density surface electromyography electrodes. Recruitment threshold will be measured during isometric ramp contractions of the quadriceps
Participants will use a screen displaying real-time torque output. Participants will voluntarily increase torque (5 seconds), hold at a pre-determined torque level (10 seconds), and gradually reduce force back to resting (5 seconds) with the knee held in a fixed position. This test will be completed with a 10s isometric hold at 30, 60, and 90% of maximal voluntary isometric force.
Measured: Baseline, day 13, and day 30
Motor unit action potential train (MUAPT) de-recruitment threshold.
De-recruitment threshold of individual motor units f the VL will be assessed with high density surface electromyography using four-pin high density surface electromyography electrodes. Recruitment threshold will be measured during isometric ramp contractions of the quadriceps
Participants will use a screen displaying real-time torque output. Participants will voluntarily increase torque (5 seconds), hold at a pre-determined torque level (10 seconds), and gradually reduce force back to resting (5 seconds) with the knee held in a fixed position. This test will be completed with a 10s isometric hold at 30, 60, and 90% of maximal voluntary isometric force.
Measured: Baseline, day 13, and day 30
Muscle size
Muscle size will be measured by MRI. Anatomical MRI scans will allow for assessment of anatomical cross sectional area.
Measured: Baseline and day 30
Muscle Physiological cross-sectional area
Diffusion tensor imaging (DTI) will be used to assess muscle volume and fascicle length. Physiological cross-sectional area will be calculated as Muscle volume divided by fascicle length.
Measured: Baseline and day 30
Muscle Fractional Anisotropy
Diffusion tensor imaging (DTI) will be used to assess anisotropic measures. A ratio of the diffusivity in the principal planes will be used to calculate fractional anisotropy.
Measured: Baseline and day 30
Muscle Diffusion properties
Diffusion tensor imaging (DTI) will be used to assess rate of water diffusion in three principal planes. We will report rates of water diffusion in three ways: 1) mean diffusivity (average rate in all three plane), 2) axial diffusivity (rate of diffusion along primary axis), and 3) radial diffusivity (rate of diffusion perpendicular to the primary axis).
Measured: Baseline and day 30
Muscle cross-sectional area (Ultrasound)
cross-sectional area of the vastus lateralis and rectus femoris will be measured by ultrasonography
Measured: Baseline, day 13, and day 30
Fascicle length
Panoramic views of the mid-portion of the VL will be measured by ultrasonography
Measured: Baseline, day 13, and day 30
Pennation angle
Pennation angle of the mid-portion of the vastus lateralis will be assessed by ultrasonography
Measured: Baseline, day 13, and day 30
Voluntary Isokinetic Muscle Strength
Maximal voluntary isokinetic concentric strength of the knee extensors/flexors and ankle dorsi-/plantar-flexors will be assessed at 60 deg/s
Measured: Baseline, day 13, and day 30
Voluntary Isometric Muscle Strength
Maximal voluntary isometric strength of the knee extensors/flexors and ankle dorsi-/plantar-flexors will be assessed during a (10 seconds) maximal effort contraction.
Measured: Baseline, day 13, and day 30
Secondary outcomes (11)
Aerobic Capacity
Subjects will complete a VO2max exercise test on a stationary bicycle. Gas exchange and heart rate data will be collected continuously. Initial workload will be set at approximately 2 METS. Every three minutes, we will add more resistance to the pedals (~1.5 METS). Subjects will continue to pedal until they can either not maintain pedal speed (50RPM) or until a plateau in VO2 occurs. Pedal force for each limb will be assessed.
Measured: Baseline and day 30
Ventilatory Threshold
Gas exchange data from the aerobic capacity test (VO2, ventilation; VE, and VCO2) will be used to calculate ventilatory threshold during exercise
Measured: Baseline and day 30
Substrate utilization
Gas exchange data from the aerobic capacity test (VO2, respiratory exchange ratio; RER, and VCO2) will be used to calculate substrate utilization (energy expenditure, carbohydrate use, and fatty acid oxidation) at varying exercise intensities
Measured: Baseline and day 30
Body Composition
Bioelectrical Impedance Analysis (BIA) will be used to assess body composition. Subjects will lie supine and have small adhesive electrodes placed on the right hand, wrist, ankle, and foot. A small (imperceptible) electrical current will be delivered to one electrode and the amount of resistance to the electrical current will be used to measure body composition. Percent body fat will be measured. Muscle mass will be calculated using previously established formulae.
Measured: Baseline and day 30
Postural sway area
Subjects will complete a series of balance assessments while standing on one leg using a dual force plate system. Subjects will stand still on one leg for 15 seconds with hands on hips. This will be repeated on both legs with eyes open and with eyes closed in the shod and unshod conditions in random order. Postural sway area will be calculated as an index of postural control.
Measured: Baseline, day 13, and day 30
Postural Sway Velocity
Subjects will complete a series of balance assessments while standing on one leg using a dual force plate system. Subjects will stand still on one leg for 15 seconds with hands on hips. This will be repeated on both legs with eyes open and with eyes closed in the shod and unshod conditions in random order. Mean Postural sway velocity will be calculated as an index of postural control.
Measured: Baseline, day 13, and day 30
Motor unit firing rate - single leg stance
Subjects will complete a series of balance assessments while standing on one leg using a dual force plate system. Subjects will stand still on one leg for 15 seconds with hands on hips. This will be repeated on both legs with eyes open and with eyes closed in the shod and unshod conditions in random order.
High density surface EMG sensors will be adhered to the skin over the tibialis anterior and soleus muscles with double-sided tape. Exponential functions will be fit to describe the relationship between motor unit firing rate and action potential amplitude on an individual manner to determine how firing rates of various motor unit pools relate to postural control.
Measured: Baseline, day 13, and day 30
Change in heart rate at rest
heart rate measured
Measured: Baseline and day 30
Change in blood pressure at rest
blood pressure measured at the arm
Measured: Baseline and day 30
Change in heart rate variability
for 20 minutes electrodes will be placed on the skin of the chest and a respiratory belt will be wrapped around the chest and blood pressure will be taken at the arm. During the final 10 minutes, 5 minutes of regular breathing (minutes 11-15), and 5 minutes of controlled breathing at a rate of 12 breaths per minute will be done. Resting heart rate (throughout), respiratory rate (throughout) and blood pressure (min 15 and 20) will be collected.
Measured: Baseline and day 30
Change in heart rate recovery after exercise
a maximal-effort exercise test on a stationary bicycle will be done. Immediately upon finishing the cycling, participants will rest on the bike for 5 minutes while remaining as still as possible. Heart rate will be collected throughout the this time to give a measure of heart rate recovery
Measured: Baseline and day 30
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted8 Oct 2024
- Study start23 Oct 2024
- Primary completion31 Aug 2026
- Study completion31 Aug 2026
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Muscle AtrophyStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- 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.
- Masking
- None (open label)
- Enrolment
- 29 participants (actual)
Sponsor and investigators
- Lead sponsor
- Lance Bollinger
- Sponsor type
- University, hospital or other
- Collaborators
- University of Louisville, National Aeronautics and Space Administration (NASA)
- Responsible party
- Sponsor-investigator, Lance Bollinger, University of Kentucky
- Investigators
- Lance Bollinger, PhD, Principal investigator, University of Kentucky
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06631053
- Sponsor's protocol ID
- 97289
- Other IDs
- 80NSSC24M0149
- Status last verified
- Oct 2026
- First submitted
- 24 Sep 2024
- Last updated
- 6 Nov 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 6 Nov 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Use of Velocity Monitoring to Prescribe Appropriate Flywheel-based Inertial Training (FIT) Workloads for Exercise in Space Flight
- ClinicalTrials.gov ID
- NCT06631053
- Acronym / sponsor ID
- 97289
- Conditions
- Muscle Atrophy, Muscle Weakness
- Keywords
- spaceflight, unweighting, disuse, exercise
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 29 participants (actual)
- Lead sponsor
- Lance BollingerUniversity, hospital or other
- Collaborators
- University of Louisville, National Aeronautics and Space Administration (NASA)
- Study start
- 23 Oct 2024 (actual)
- Primary completion
- 31 Aug 2026 (actual)
- Study completion
- 31 Aug 2026 (actual)
- First posted
- 8 Oct 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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.
Detailed description
The primary objectives of this project are:
- 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.
- 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:
- To assess impact of ULLS with and without FIT on aerobic capacity
- 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 upright squats (four sets of 3 min).
Before and after the intervention, subjects will complete a series of tests including:
- Body Composition - height, weight, waist circumference, and tetrapolar bioelectrical impedance analysis will be conducted.
- 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.
- 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.
- 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.
- 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
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- 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.
| Arm | Type | Receives |
|---|---|---|
| No Exercise | Active comparator | Other: No ExerciseParticipants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) without exercise |
| velocity-based FIT (VBFIT) | Experimental | Other: velocity-based FIT (VBFIT)Participants will undergo a 30d Unilateral Lower Limb Suspension (ULLS) with exercise |
Who may qualify
- Ages
- 35 to 45 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- 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)
Key exclusion criteria (13 listed)
- Waist circumference < 55cm or > 90cm (F) and < 75cm or > 100cm (M)
- Body mass index < 18.5 or > 29.9
- Not regularly engaging in exercise for previous 12 months
- Tobacco use within previous 6 months
- Blood clotting disorder
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| 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 | Other | velocity-based FIT (VBFIT) |
| No ExerciseParticipants 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. | Other | No Exercise |
Primary outcome
Voluntary activation
Time frame: Baseline, day 13, and day 30
Voluntary activation of the quadriceps will be assessed with electrical stimulation of the femoral nerve before, during, and after a maximal voluntary isometric contraction (MVIC) using the interpolated twitch technique.
Twitch Properties-Electromechanical Delay
Time frame: Baseline, day 13, and day 30
Electromechanical delay will be calculated as the time difference between the onset of electrical impulse and onset of torque development during femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Twitch Properties-Rate of Torque Development
Time frame: Baseline, day 13, and day 30
Rate of Torque Development will be calculated as the change in torque divided by the change in time in the linear phase between 20 and 80% of peak twitch torque during femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Twitch Properties-Time to peak Tension
Time frame: Baseline, day 13, and day 30
Time to peak tension will be calculated as the time difference between the onset of electrical impulse and peak twitch torque during femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Twitch Properties-Peak Twitch Torque
Time frame: Baseline, day 13, and day 30
Peak twitch torque during femoral nerve stimulation will be calculated as the highest torque output immediately (approximately 200ms) following femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Twitch Properties-Relaxation Rate
Time frame: Baseline, day 13, and day 30
Relaxation rate will be calculated as the change in torque divided by the change in time during the relaxation phase of twitch following femoral nerve stimulation. This will be measured before and after a maximal voluntary isometric contraction.
Post activation Potentiation
Time frame: Baseline, day 13, and day 30
Post-activation will be calculated as the percentage difference in peak twitch torque in femoral nerve stimulation before and after a maximal voluntary isometric contraction.
Motor unit action potential train (MUAPT) firing rate
Time frame: Baseline, day 13, and day 30
Firing rate of individual motor units of the vastus lateralis (VL) will be assessed with high density surface electromyography (EMG) using four-pin high density surface electromyography electrodes. Firing rate at 30, 60, and 90% MVIC will be reported. Motor unit firing rate will also be reported during static stance. Participants will use a screen displaying real-time torque output. Participants will voluntarily increase torque (5 seconds), hold at a pre-determined torque level (10 seconds), and gradually reduce force back to resting (5 seconds) with the knee held in a fixed position. This test will be completed with a 10s isometric hold at 30, 60, and 90% of maximal voluntary isometric force.
Motor unit action potential train (MUAPT) recruitment threshold.
Time frame: Baseline, day 13, and day 30
Recruitment threshold of individual motor units of the VL will be assessed with high density surface electromyography using four-pin high density surface electromyography electrodes. Recruitment threshold will be measured during isometric ramp contractions of the quadriceps Participants will use a screen displaying real-time torque output. Participants will voluntarily increase torque (5 seconds), hold at a pre-determined torque level (10 seconds), and gradually reduce force back to resting (5 seconds) with the knee held in a fixed position. This test will be completed with a 10s isometric hold at 30, 60, and 90% of maximal voluntary isometric force.
Motor unit action potential train (MUAPT) de-recruitment threshold.
Time frame: Baseline, day 13, and day 30
De-recruitment threshold of individual motor units f the VL will be assessed with high density surface electromyography using four-pin high density surface electromyography electrodes. Recruitment threshold will be measured during isometric ramp contractions of the quadriceps Participants will use a screen displaying real-time torque output. Participants will voluntarily increase torque (5 seconds), hold at a pre-determined torque level (10 seconds), and gradually reduce force back to resting (5 seconds) with the knee held in a fixed position. This test will be completed with a 10s isometric hold at 30, 60, and 90% of maximal voluntary isometric force.
Muscle size
Time frame: Baseline and day 30
Muscle size will be measured by MRI. Anatomical MRI scans will allow for assessment of anatomical cross sectional area.
Muscle Physiological cross-sectional area
Time frame: Baseline and day 30
Diffusion tensor imaging (DTI) will be used to assess muscle volume and fascicle length. Physiological cross-sectional area will be calculated as Muscle volume divided by fascicle length.
Muscle Fractional Anisotropy
Time frame: Baseline and day 30
Diffusion tensor imaging (DTI) will be used to assess anisotropic measures. A ratio of the diffusivity in the principal planes will be used to calculate fractional anisotropy.
Muscle Diffusion properties
Time frame: Baseline and day 30
Diffusion tensor imaging (DTI) will be used to assess rate of water diffusion in three principal planes. We will report rates of water diffusion in three ways: 1) mean diffusivity (average rate in all three plane), 2) axial diffusivity (rate of diffusion along primary axis), and 3) radial diffusivity (rate of diffusion perpendicular to the primary axis).
Muscle cross-sectional area (Ultrasound)
Time frame: Baseline, day 13, and day 30
cross-sectional area of the vastus lateralis and rectus femoris will be measured by ultrasonography
Fascicle length
Time frame: Baseline, day 13, and day 30
Panoramic views of the mid-portion of the VL will be measured by ultrasonography
Pennation angle
Time frame: Baseline, day 13, and day 30
Pennation angle of the mid-portion of the vastus lateralis will be assessed by ultrasonography
Voluntary Isokinetic Muscle Strength
Time frame: Baseline, day 13, and day 30
Maximal voluntary isokinetic concentric strength of the knee extensors/flexors and ankle dorsi-/plantar-flexors will be assessed at 60 deg/s
Voluntary Isometric Muscle Strength
Time frame: Baseline, day 13, and day 30
Maximal voluntary isometric strength of the knee extensors/flexors and ankle dorsi-/plantar-flexors will be assessed during a (10 seconds) maximal effort contraction.
11 secondary outcomes
Aerobic Capacity
Time frame: Baseline and day 30
Ventilatory Threshold
Time frame: Baseline and day 30
Substrate utilization
Time frame: Baseline and day 30
Body Composition
Time frame: Baseline and day 30
Postural sway area
Time frame: Baseline, day 13, and day 30
Postural Sway Velocity
Time frame: Baseline, day 13, and day 30
Motor unit firing rate - single leg stance
Time frame: Baseline, day 13, and day 30
Change in heart rate at rest
Time frame: Baseline and day 30
Change in blood pressure at rest
Time frame: Baseline and day 30
Change in heart rate variability
Time frame: Baseline and day 30
Change in heart rate recovery after exercise
Time frame: Baseline and day 30
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 6 Nov 2026.
- Individual participant dataSharing planned: No
Related trials for Muscle Atrophy
Enrolling by invitation
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A Study of Bimagrumab in Participants With HFpEF
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MF-300 for Treatment of Age-Related Sarcopenia
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Lance Bollinger, PhD principal investigator
University of Kentucky
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing velocity-based FIT (VBFIT) and No Exercise in people with Muscle Atrophy and Muscle Weakness, run by Lance Bollinger at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 6 Nov 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Voluntary activation (time frame: Baseline, day 13, and day 30). The study lists 19 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 6 Nov 2026.