Effect of Intense Training on Ovarian Function and Bone Turnover

January 26, 2016 updated by: USDA, Western Human Nutrition Research Center

Impact of Intense Exercise Training on Energy Availability, Ovarian Function and Bone Turnover in Female Athletes

The investigators propose a prospective, longitudinal, department funded study protocol to evaluate whether changes in energy availability, during a period of highly intensified exercise training, will increase bone turnover markers and decrease ovarian function and exercise performance, in a dose-dependent fashion in competitive female athletes.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Female athletes participating in sports which emphasize leanness as a factor to success, while also imposing large exercise training loads, present a high prevalence of endocrine and metabolic alterations linked to low energy stores, including suppressed ovarian function and bone loss. Increased bone turnover resulting from low energy stores and suppressed estrogen production may hold the most adverse consequences for long term health, increasing the risk of premature osteopenia, while increasing the risk of stress fractures in the short term. Chronically low energy stores may also contribute to the development of overreaching and overtraining syndromes, characterized by excessive, lasting fatigue and long-term decreases in performance, which can compromise these athletes' health and athletic career. The investigators propose the first longitudinal study aiming to demonstrate the link between low energy status, impaired ovarian function, bone turnover and decreased performance in free-living, competitive female athletes. After a 4-week baseline period of habitual training, athletes will undergo 4 weeks of intensified training (IT), during which the exercise load is increased by 30% from their individual baseline load in order to sharply increase energy expenditure. As athletes will be let to freely adjust their food intake, the investigators aim to test the hypothesis that athletes will fail to adjust food intake sufficiently to match energy expenditure, and that the resulting decrease in energy availability (EA, energy intake - energy expenditure from exercise) will influence, in a dose-dependent fashion, the suppression of estrogen production, the increase in bone turnover and the severity of performance decrement. The IT period will then be followed by a 2-week taper (REC), in which exercise training volume will be reduced by 50% from baseline. The investigators will assess whether EA returns to baseline values, and characterize changes in bone turnover during this recovery period. It is hypothesized that any improvements in exercise performance resulting from IT + REC will occur in athletes who were able to remain closest to a balanced energy state during IT. Concretely linking EA to both performance and bone health may incentivize female athletes to adopt more adequate feeding behaviors for their activity level.

Study Type

Interventional

Enrollment (Actual)

18

Phase

  • 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
    • California
      • Davis, California, United States, 95616
        • USDA Western Human Nutrition Research Center

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

Ages Eligible for Study

18 years to 40 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  • competitive endurance runners (racing in events ranging from 10km to ultra-marathons)
  • training at least 5 days per week over the past 12 months, and more than 30 miles per week
  • regular menstrual cycles (24-35 days) over the past 6 months
  • maximal oxygen consumption (VO2max) > 50ml/kg/min
  • English speaking

Exclusion Criteria:

  • smoker
  • amenorrhea
  • pregnant or lactating in the past 2 years
  • chronic disease that will affect bone health, metabolism or the cardiorespiratory system
  • take medications that have cardiovascular or metabolic effects
  • present any contra-indication to exercise testing (cardiovascular abnormalities)
  • report any major illness or injury preventing training for more than 4 weeks over the past 3 months
  • a history of clinical anorexia nervosa or bulimia nervosa

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Intensified training
Volunteers will increase exercise training by 30% from baseline
Behavioral: Intensified Training
Volunteers will increase exercise training by 30% from baseline

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in energy availability (energy intake - energy expenditure of physical activity)
Time Frame: Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)
The investigators aim to capture the spectrum and variability of energy availability in endurance athletes under normal training conditions, describing in detail training regimen, total energy expenditure and nutrition habits during three distinct phases of training that are habitually followed by endurance athletes.
Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in athletic performance
Time Frame: Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)
The investigators will measure the effect of energy availability on exercise performance during baseline, after 4 weeks of intensified training, and after a 2-week recovery, by measuring the relationship of energy availability to maximal oxygen consumption (VO2max) and 3200 meter time trial performance. The investigators will test the hypothesis that performance will be affected by changes in energy availability in a dose-dependent fashion.
Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)
Change in ovarian function
Time Frame: Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)
The investigators will measure salivary estradiol and progesterone concentrations daily throughout the study, in order to test the hypothesis that ovarian function may be suppressed by intensified training and decreased energy availability.
Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)
Change in bone turnover markers
Time Frame: Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)
The investigators will measure plasma bone turnover markers during baseline and at the end of the intensified training period, in order to test the hypothesis that bone turnover may be compromised by intensified training and decreased energy availability.
Baseline (week 4), after 4 weeks of intensified training (week 8) and after a two-week recovery period (week 10)

Collaborators and Investigators

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

Sponsor

USDA, Western Human Nutrition Research Center

Collaborators

University of California, Davis

Investigators

  • Principal Investigator: Gretchen A Casazza, PhD, University of California, Davis

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Helpful Links

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

January 1, 2014

Primary Completion (Actual)

December 1, 2015

Study Completion (Actual)

December 1, 2015

Study Registration Dates

First Submitted

August 21, 2014

First Submitted That Met QC Criteria

August 22, 2014

First Posted (Estimate)

August 25, 2014

Study Record Updates

Last Update Posted (Estimate)

January 28, 2016

Last Update Submitted That Met QC Criteria

January 26, 2016

Last Verified

September 1, 2015

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • FL94

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

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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