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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effects of a high calcium pre-event meal on biomarkers of calcium homeostasis in female cyclists
Scientific title
The effects of a calcium-rich pre-exercise meal on Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP) in competitive female cyclists.
Secondary ID [1] 284823 0
Nil Known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Osteopenia (prevention) 292208 0
Oestoporosis (prevention) 292209 0
Condition category
Condition code
Musculoskeletal 292543 292543 0 0
Diet and Nutrition 292609 292609 0 0
Other diet and nutrition disorders

Study type
Description of intervention(s) / exposure
Cyclists completed two 90 min cycling trials (80 min at 60% maximal aerobic power followed by a 10 min maximal time trial) separated by 1 day. Exercise trials were preceded 2 h by either a calcium-rich (mean +/- SD; 1352 +/- 53 mg calcium) dairy based meal or a control meal (46 +/- 7 mg calcium). The calcium-rich meal consisted of rolled-oats cooked with calcium-fortified (Tricalcium phosphate, Nano-calcium) milk, yoghurt and additional milk.
Intervention code [1] 289616 0
Comparator / control treatment
The control meal provided oats cooked with water and served with tinned fruit and nuts. The calcium content was 46 +/- 7 mg.
Control group

Primary outcome [1] 292411 0
The primary outcome of this study was the effects of a calcium pre-exercise meal on the exercise induced changes in bone turnover (formation and resoprtion). This was measured as the average serum concentration of Cross Linked C-Telopeptide of Type I Collagen (CTX-I), Cross Linked C-Telopeptide of Type II Collagen (CTX-II), Parathyroid Hormone (PTH), and bone formation (Procollagen I N-Terminal Propeptide (PINP) measured using Enzyme-Linked immunoSorbent Assay (ELISA)
Timepoint [1] 292411 0
pre-trial (time = 0 min); pre-exercise (t = 115 min); and immediately post-exercise (t = 210 min), 40 min post-exercise (t = 250 min), 100 min post-exercise (t = 310 min) and 190 min post-exercise (t = 400 min)
Secondary outcome [1] 308888 0
Gut comfort measured using a custom design Likert scale questionnaire.
Timepoint [1] 308888 0
pre-trial (time = 0 min); pre-exercise (t = 115 min); and immediately post-exercise (t = 210 min)
Secondary outcome [2] 308889 0
Cycling time trial performance measured as the average work completed in the final 10 min of the cycling trial. Average work is measured using a Wattbike ergometer (Nottingham, UK) which estimates power using a load cell placed near the chain of the ergometer.
Timepoint [2] 308889 0
post-exercise (t = 210 min)

Key inclusion criteria
Aged 17 to 32 y; greater than or equal to 18 mo cycling racing experience; able to commit to a 10 d camp based at the Australian Institute in Canberra.
Minimum age
17 Years
Maximum age
32 Years
Can healthy volunteers participate?
Key exclusion criteria
Exclusion criteria were vitamin D deficiency (25-OH Vitamin D < 30 ng/mL), thyroid dysfunction (n=1), liver or kidney dysfunction, regular use of medications or supplements known to affect bone or calcium metabolism or thyroid function (e.g., thiazide diuretics, bisphosphonates, oral steroids).

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Following approval from the Australian Institute of Sport Ethics Committee, emails advertising the study were circulated to all State Sport Institutes and Cycling Coaches, athletes previously involved in such studies and training camps and National Road Series team managers and athletes.

The Australian National Road Series had 107 female cyclists registered at the time of this study and an average (+/- SD) race attendance of 47 +/- 16. Of this population, 33 cyclists expressed interest in participating and 25 met the inclusion criteria (17 to 32 y; greater than or equal to 18 mo racing experience; no medical condition affecting calcium homeostasis, able to commit to 10 d camp). The additional participants included an international professional, an ultra-endurance mountain biker and 5 well-trained National club-level cyclists.

This was a counterbalanced crossover design meaning that subjects served as their own control. The order with which they received the experimental and control treatments was randomised.
Subjects were randomised into one of two groups that were balanced for menstrual phase (luteal or follicular which was confirmed with measures of oestrogen and progesterone on trial day one; ovulation was avoided), menstrual regularity (amenorrhea, oligomenorrhea or regular) and use of contraceptives (oral contraceptive pills, contraceptive devices, implants or injections).
Allocation concealment was not carried out. The same person who determined eligibility also determined group allocation.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Group 1 received the control treatment meal first and group 2 received the treatment (calcium-rich) meal first. Subjects were sorted based on menstrual regularity (irregular or regular) and use of contraceptives. Subjects were then randomised into groups 1 and 2 using a computerised sequence generation ( so that each group had an equal number of subjects who had a regular menstrual cycle and of those an equal number who were in their follicular or luteal phase; irregular menstrual cycle; or were using a contraceptive device.
This was deemed more appropriate than using a random number generator prior to accounting for menstrual status, as menstrual status is known to effect calcium homeostasis and so balancing the groups was prioritised.
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?

Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
The study was sized to detect a 20 pg/mL attenuation in the pre-post exercise difference in serum PTH due to the administration of calcium using a paired t test, assuming a SD of the difference of 30 pg/mL, with 95% power at the 0.05 level.

Recruitment status
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)

Funding & Sponsors
Funding source category [1] 289435 0
Commercial sector/Industry
Name [1] 289435 0
Dairy Australia
Address [1] 289435 0
Level 5, IBM Centre, 60 City Road, Southbank, VIC, 3006
Country [1] 289435 0
Primary sponsor type
Australian Institute of Sport - Nutrition, Physiology
Leverrier Street, Bruce ACT 2617
Secondary sponsor category [1] 288125 0
Name [1] 288125 0
Address [1] 288125 0
Country [1] 288125 0
Other collaborator category [1] 278006 0
Name [1] 278006 0
Monash University
School of Public Health & Preventive Medicine
Department of Epidemiology & Preventive Medicine
Address [1] 278006 0
Level 6, The Alfred Centre
99 Commercial Road
Melbourne VIC 3004
Country [1] 278006 0
Other collaborator category [2] 278007 0
Name [2] 278007 0
University of Queensland
School of Human Movement Studies
Address [2] 278007 0
The University of Queensland, Brisbane, QLD 4072
Country [2] 278007 0

Ethics approval
Ethics application status
Ethics committee name [1] 291193 0
Australian Institute of Sport Ethics Committee
Ethics committee address [1] 291193 0
Australian Institute of Sport, Leverrier Street Bruce, ACT 2617
Ethics committee country [1] 291193 0
Date submitted for ethics approval [1] 291193 0
Approval date [1] 291193 0
Ethics approval number [1] 291193 0

Brief summary
Background: An issue of high importance to the AIS is the prevention/treatment of low bone density in athletes: low bone mineral density (BMD) is common in both male and female cyclists. This may be because of a lack of weight-bearing activity, menstrual disturbances, and low energy availability due to weight loss practices or the high energy expenditure. An additional risk factor of interest is the acute effect of sweat calcium loss. These sweat calcium losses during prolonged exercise may cause a significant decline in blood calcium concentrations during training. The body protects blood calcium levels by stimulating the bones to release calcium into the blood to restore levels, and increasing bone re-absorption.

Purpose: to determine whether a high calcium pre-event meal can reduce levels of hormones that are
responsible for increasing bone resorption.

Hypothesis: based on previous findings involving calcium-fortified water, it is hypothesised that a calcium-rich dairy based meal will reduce the exercise induced rise in biomarkers of bone resorption observed during cycling.
Trial website
Trial related presentations / publications
Public notes
Attachments [2] 92 92 0 0

Principal investigator
Name 49290 0
Mr Eric Haakonssen
Address 49290 0
Australian Institute of Sport
Leverrier Street, Bruce ACT 2617
Country 49290 0
Phone 49290 0
Fax 49290 0
Email 49290 0
Contact person for public queries
Name 49291 0
Mr Eric Haakonssen
Address 49291 0
Australian Institute of Sport
Leverrier Street, Bruce ACT 2617
Country 49291 0
Phone 49291 0
Fax 49291 0
Email 49291 0
Contact person for scientific queries
Name 49292 0
Mr Eric Haakonssen
Address 49292 0
Australian Institute of Sport
Leverrier Street, Bruce ACT 2617
Country 49292 0
Phone 49292 0
Fax 49292 0
Email 49292 0

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary