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| ID | Type | Description | Link |
|---|---|---|---|
| 80NSSC20M004 | Other Grant/Funding Number | NASA Kentucky |
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| Name | Class |
|---|---|
| National Aeronautics and Space Administration (NASA) | FED |
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The goal of this trial is to learn about how restricted sleep and not bearing weight on the leg affects muscle strength and posture control. Participants will walk exclusively on one leg, sleep at differing intervals, and complete posture tests, muscle strength tests, and muscle imaging. Researchers will compare adequate sleep and restricted sleep to see if muscle strength and posture are affected.
During space flight, astronauts experience multiple physiological stimuli (such as microgravity and altered sleep cycles) which independently impair balance and strength. The goal of this project is to determine how these stimuli interact to affect static single-leg balance, balance during dynamic tasks, and muscle recruitment, strength, and remodeling.
Subjects (healthy adults age 18-50) will complete 13 days of unilateral lower limb suspension (ULLS, the gold standard analog for measuring space flight in ambulatory subjects). For the final three days of the study, subjects will be randomly assigned (via a matched pairs approach) to either normal sleep (7-9 hours per night) or restricted sleep (5 hours per night). Before and after the study, subjects will complete balance assessments and measures of muscle strength and recruitment. At the end of the study, subjects will also undergo diffusion tensor imaging for the thighs.
Balance testing will be conducted by examining sway in center of gravity during single leg stance and when stepping down from a box. Muscle strength and recruitment will be assessed via submaximal and maximal voluntary isometric contractions. Additionally, an interpolated twitch experiment will be performed to assess muscle recruitment and twitch properties. Diffusion Tensor imaging will be used to quantify muscle size and structure.
As prophylactic treatment against deep vein thrombosis (the major risk of ULLS), subjects will take an aspirin (81mg daily), wear compression stockings, complete passive range of motion exercises, and use intermittent pneumatic compression devices during sedentary times.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Sleep Restriction (SR) | Experimental | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SR group will sleep only 5 hours for three consecutive nights. |
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| Sleep Adequate (SA) | Active Comparator | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SA group will sleep for 9 hours for three consecutive nights. |
|
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Sleep Restriction | Behavioral | 5 hours of sleep for 3 days |
| |
| Measure | Description | Time Frame |
|---|---|---|
| Change in Percentage in Interpolated Twitch Torque of the Loaded and Unloaded Leg | Subjects will sit upright in an isokinetic dynamometer with the knee at 60° flexion. Gel electrode pads will be placed over the femoral nerve and just proximal to the patellar tendon. Square wave, constant current, doublet pulses from an electrical stimulator will be used to evoke twitches prior to, during, and following a maximal voluntary isometric contraction (MVIC). Twitch torque will be measured in Newton-meters (Nm). Outcome data are reported as the percentage change in voluntary activation from baseline. | Baseline and study completion, approximately 14 days |
| Percent Change in Single Leg Stand (SLS) | Balance will be assessed using a dual force plate system. Participants will be asked to stand on one leg and maintain their balance for 15 seconds. Specific outcome measures include percentage change in center of pressure 95% ellipse area (sq. mm) compared to baseline. | Baseline and study completion, approximately 14 days |
| Muscle Volume | Diffusion Tensor Imaging (DTI) will be used to quantify muscle volume of the loaded and unloaded leg. Subjects will lay supine, and slightly flex the knee (~10°) to elongate and straighten the quadriceps. A spine array coil will be placed on the MR-scanner table and a flexible body coil wrapped around the upper thigh and centered over mid-thigh of the dominant leg. Multiple images will be taken. DSI Studio program will be used to analyze raw images. | Post-intervention, approximately 14 days after start of study |
| Percent Change in Center of Pressure Velocity During Single Leg Stance | Balance will be assessed using a dual force plate system. Participants will stand on one leg on a stable force deck for 15 seconds. The mean Center of Pressure (CoP) velocity will be measured in millimeters per second (mm/s) for loaded and unloaded limbs. Outcomes are reported as the percentage change in mean velocity compared to pre-intervention. |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Lance Bollinger, PhD | University of Kentucky | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Kentucky | Lexington | Kentucky | 40506 | United States |
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| ID | Title | Description |
|---|---|---|
| FG000 | Sleep Restriction (SR) | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SR group will sleep only 5 hours for three consecutive nights. |
| FG001 | Sleep Adequate (SA) | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SA group will sleep for 9 hours for three consecutive nights. |
| Title | Milestones | Reasons Not Completed | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Overall Study |
|
|
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| ID | Title | Description |
|---|---|---|
| BG000 | Sleep Restriction (SR) | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SR group will sleep only 5 hours for three consecutive nights. |
| Units | Counts |
|---|---|
| Participants |
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| Title | Description | Population Description | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Denominator Units Selected | Denominators | Classes |
|---|---|---|---|---|---|---|---|---|---|
| Age, Continuous | Mean |
| Type | Title | Description | Population Description | Reporting Status | Anticipated Posting Date | Parameter Type | Dispersion Type | Unit of Measure | Calculate Percentage | Time Frame | Units Analyzed | Denominator Units Selected | Arm/Group Information | Denominators | Classes | Analyses | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Primary | Change in Percentage in Interpolated Twitch Torque of the Loaded and Unloaded Leg | Subjects will sit upright in an isokinetic dynamometer with the knee at 60° flexion. Gel electrode pads will be placed over the femoral nerve and just proximal to the patellar tendon. Square wave, constant current, doublet pulses from an electrical stimulator will be used to evoke twitches prior to, during, and following a maximal voluntary isometric contraction (MVIC). Twitch torque will be measured in Newton-meters (Nm). Outcome data are reported as the percentage change in voluntary activation from baseline. | Posted | Mean | Standard Deviation | Percent change in voluntary activation | Baseline and study completion, approximately 14 days |
|
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Death, serious adverse events and other (non-serious adverse events) were not assessed for this study.
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| ID | Title | Description | Deaths (Affected) | Deaths (At Risk) | Serious Events (Affected) | Serious Events (At Risk) | Other Events (Affected) | Other Events (At Risk) |
|---|---|---|---|---|---|---|---|---|
| EG000 | Sleep Restriction (SR) | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SR group will sleep only 5 hours for three consecutive nights. |
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| Title | Organization | Phone | Extension | |
|---|---|---|---|---|
| Dr. Lance Bollinger | University of Kentucky | 859-257-7904 | lance.bollinger@uky.edu |
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| Type | Includes Protocol | Includes SAP | Includes ICF | Document Label | Document Date | Document Uploaded Date | Document File Name |
|---|---|---|---|---|---|---|---|
| Prot_SAP | Yes | Yes | No | Study Protocol and Statistical Analysis Plan | Nov 14, 2025 | Apr 2, 2026 | Prot_SAP_001.pdf |
| ICF | No | No | Yes | Informed Consent Form | Apr 24, 2024 | Mar 19, 2025 | ICF_000.pdf |
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| ID | Term |
|---|---|
| D018908 | Muscle Weakness |
| D020447 | Parasomnias |
| ID | Term |
|---|---|
| D009135 | Muscular Diseases |
| D009140 | Musculoskeletal Diseases |
| D020879 | Neuromuscular Manifestations |
| D009461 | Neurologic Manifestations |
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Subjects will be randomized to different arms via a matched-pairs design using the following criteria: age, sex, and race. Within each arm, the loaded limb will serve as an internal control to assess effects of unloading.
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| Sleep Adequate |
| Behavioral |
9 hours of sleep for 3 days |
|
| Baseline and study completion, approximately 14 days |
| BG001 | Sleep Adequate (SA) | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SA group will sleep for 9 hours for three consecutive nights. |
| BG002 | Total | Total of all reporting groups |
| Year |
|
| Sex: Female, Male | Count of Participants | Participants |
|
| Race (NIH/OMB) | Count of Participants | Participants |
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| Ethnicity (NIH/OMB) | Count of Participants | Participants |
|
| Region of Enrollment | Count of Participants | Participants |
|
| OG001 | Sleep Adequate (SA) | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SA group will sleep for 9 hours for three consecutive nights. |
|
|
| Primary | Percent Change in Single Leg Stand (SLS) | Balance will be assessed using a dual force plate system. Participants will be asked to stand on one leg and maintain their balance for 15 seconds. Specific outcome measures include percentage change in center of pressure 95% ellipse area (sq. mm) compared to baseline. | Data unavailable for one subject. | Posted | Mean | Standard Deviation | Percent change in COP ellipse area | Baseline and study completion, approximately 14 days |
|
|
|
| Primary | Muscle Volume | Diffusion Tensor Imaging (DTI) will be used to quantify muscle volume of the loaded and unloaded leg. Subjects will lay supine, and slightly flex the knee (~10°) to elongate and straighten the quadriceps. A spine array coil will be placed on the MR-scanner table and a flexible body coil wrapped around the upper thigh and centered over mid-thigh of the dominant leg. Multiple images will be taken. DSI Studio program will be used to analyze raw images. | Posted | Mean | Standard Deviation | Centimeters cubed | Post-intervention, approximately 14 days after start of study |
|
|
|
| Primary | Percent Change in Center of Pressure Velocity During Single Leg Stance | Balance will be assessed using a dual force plate system. Participants will stand on one leg on a stable force deck for 15 seconds. The mean Center of Pressure (CoP) velocity will be measured in millimeters per second (mm/s) for loaded and unloaded limbs. Outcomes are reported as the percentage change in mean velocity compared to pre-intervention. | Posted | Mean | Standard Deviation | Percent change | Baseline and study completion, approximately 14 days |
|
|
|
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| 0 |
| EG001 | Sleep Adequate (SA) | The research team will provide participants with a pair of shoes to wear throughout the study. The right shoe will be modified to include a 5cm (approximately 2") rocker-style platform which will keep the left leg suspended during walking. Participants will also be provided with a pair of short crutches to assist with walking. Participants in the SA group will sleep for 9 hours for three consecutive nights. | 0 | 0 | 0 | 0 | 0 | 0 |
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| D009422 | Nervous System Diseases |
| D010335 | Pathologic Processes |
| D013568 | Pathological Conditions, Signs and Symptoms |
| D012816 | Signs and Symptoms |
| D012893 | Sleep Wake Disorders |
| D001523 | Mental Disorders |