Calcium Kinetic Responses to Exercise

December 20, 2022 updated by: United States Army Research Institute of Environmental Medicine

Skeletal Hormone and Calcium Kinetic Responses to Load Carriage Exercise in Females

This randomized cross-over study will identify physiological factors that underlie changes in bone metabolism that could affect skeletal injury risk, to include increases in parathyroid hormone (PTH) in response to militarily relevant exercise in females. The primary objective is to determine the hormone and calcium (Ca) response to multiple bouts of load carriage exercise in females. The investigators hypothesize that PTH will increase after multiple bouts of load carriage exercise and this increase will be due to disruption in Ca kinetics, specifically either a decrease in fractional intestinal Ca absorption (FCA) or changes in bone formation and/or resorption.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Completed

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

Initial military training (IMT) results in increased risk of stress fracture, particularly for females as up to 21% of females may sustain a stress fracture during IMT, an incidence that is approximately 4-fold higher than that for males. Young female adults will undergo two separate study periods in random order, one will include exercise and the other will not. Each study period will use dual stable Ca isotope methodology in order to determine Ca kinetic responses to a militarily relevant exercise, and dietary intake will be controlled. Kinetic analyses will include fractional intestinal Ca absorption (FCA), Ca flux into bone (Vo+) and out of bone (Vo-), as well as renal Ca handling. Serial blood samples collected during the study periods will also be used to determine hormonal responses to exercise. The treadmill exercise will consist of a 60 minute timed trial with load carriage (30% body weight) completed three times during the 6 day kinetic period. At the start of the study, blood will be collected for analysis of Ca and bone-related genetic markers, and habitual food intake and exercise will be assessed. The information gathered from this trial will be used to identify physiological responses that can be targeted by future interventions designed to improve bone responses to training and decrease injury risk in female Warriors.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
21

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • Massachusetts
      • Natick, Massachusetts, United States, 01760
        • United States Army Research Institute of Environmental Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

14 years to 38 years (Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • Women aged 18-42 years
  • No current or prior military service
  • Exercise 2-5 x/wk
  • Stable body weight for 2 months (±5 lbs)
  • Body mass index (BMI) between 19-26 kg/m2
  • VO2max between 35-50 ml·kg-1·min-1
  • Willing to discontinue use of dietary supplements and abstain from alcohol for the duration of the study
  • Have not donated blood within the last 8 weeks

Exclusion Criteria:

  • History of endocrine disorders (e.g., diabetes, uncontrolled thyroid dysfunction, hypoparathyroidism, or hyperparathyroidism)
  • History of bone-modifying disorders (e.g., osteogenesis imperfecta, osteopetrosis, or rickets)
  • History of cardiovascular or renal disease
  • Pregnancy or lactation in the last 6 months
  • Routine use of medications known to affect bone or calcium metabolism (e.g., thiazide diuretics, bisphosphonates, oral steroids)
  • A very restrictive diet or severe food allergies

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
No Intervention: Rest
Active Comparator: Exercise
Militarily relevant exercise
Behavioral: Exercise
Treadmill exercise for 60 minutes with load carriage (weighted vest, 30% body weight) completed three times during the 6 day kinetic period.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Hormone response and calcium kinetics
Time Frame: Exercise or rest will occur on days 0, 2, and 4 and measures will be taken daily days 0-4. After a washout period, measures will be repeated 1-4 weeks later on days 0, 2, and 4 with whichever intervention was not performed during the first study period.
After dosing with dual stable calcium isotopes, changes in calcium kinetics (isotopic rations) will be measured in response to multiple bouts of a militarily relevant load carriage exercise or no exercise (rest) in females.
Exercise or rest will occur on days 0, 2, and 4 and measures will be taken daily days 0-4. After a washout period, measures will be repeated 1-4 weeks later on days 0, 2, and 4 with whichever intervention was not performed during the first study period.

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Fractional calcium absorption
Time Frame: Bone measurement will be taken at baseline and FCA will be measured once during each intervention (exercise or rest) on day 0.
Determine whether fractional Ca absorption (FCA) is associated with bone microarchitecture and strength in females undergoing multiple bouts of a militarily relevant load carriage exercise
Bone measurement will be taken at baseline and FCA will be measured once during each intervention (exercise or rest) on day 0.
Single nucleotide polymorphisms
Time Frame: SNP measurement will be taken at baseline and calcium measurements will be taken daily on days 0-4 when undergoing exercise and daily on days 0-4 when there is no exercise (rest).
Evaluate whether single nucleotide polymorphisms (SNPs) previously identified to be associated with circulating 25OHD concentrations explain some of the variability in calcium kinetic responses to load carriage exercise.
SNP measurement will be taken at baseline and calcium measurements will be taken daily on days 0-4 when undergoing exercise and daily on days 0-4 when there is no exercise (rest).

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
United States Army Research Institute of Environmental Medicine

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
Cornell University

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Erin Gaffney-Stomberg, PhD, RD, United States Research Institute of Environmental Medicine

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
June 16, 2018

Primary Completion (Actual)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
March 18, 2020

Study Completion (Actual)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
March 18, 2020

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
August 10, 2017

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 20, 2017

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
September 26, 2017

Study Record Updates

Last Update Posted (Estimate)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
December 21, 2022

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
December 20, 2022

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
December 1, 2022

More Information

Terms related to this study

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 17-13-HC

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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