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Trial registered on ANZCTR


Registration number
ACTRN12614000845639
Ethics application status
Approved
Date submitted
26/07/2014
Date registered
7/08/2014
Date last updated
7/08/2014
Type of registration
Retrospectively registered

Titles & IDs
Public title
Blackcurrant supplementation on sporting performance in adolescent hockey players
Scientific title
Effect of blackcurrant supplement consumption on physical performance, mental acuity and health in adolescent hockey players over an 8-week training period; possible involvement of mitochondrial adaptation?
Secondary ID [1] 285061 0
None
Universal Trial Number (UTN)
U1111-1154-1776
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Exercise performance 292585 0
Health and fatigue 292615 0
Cognitive performance 292616 0
Condition category
Condition code
Diet and Nutrition 292889 292889 0 0
Other diet and nutrition disorders
Mental Health 292933 292933 0 0
Studies of normal psychology, cognitive function and behaviour

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
In this nutritional intervention study, we aimed to examine how timed blackcurrant supplementation prior to each training session or game influenced the health, physical and cognitive performance parameters of adolescent field hockey players over an 8-week training period. The blackcurrant (freeze-dried powder) supplement used in this study was enriched with anthocyanins (30%) and was from a commercial supplier (Just-the-Berries, Nelson, New Zealand). The participants were given the blackcurrant extract (equivalent 150 mg anthocyanins) as a small opaque gelatine capsule and asked to consume the supplement 1 hr prior to each training session (4 per week) or hockey game (1-2 per week) over the 8-week period. Compliance was monitored by (i) providing particpants with only enough capsules (placebo or blackcurrant) for a week to ensure that the treatments are being taken (ii) notify the trial co-ordinator by text each time they took their treamtent, and (iii) trial coordinator reminded the particpants. In this study, the trial coordinator for this trial was also a hockey coach and so monitored the participants closely. Participants were asked to maintain their normal eating habits but to omit dietary supplements high in antioxidants over the 8-week period. In addition, trial participants were assessed (a) prior to and after an 8-week training periods and (b) weekly (on the same day each week) for their (i) fitness, (ii) cognitive “smart game” skills, and (iii) health.
Intervention code [1] 289898 0
Lifestyle
Intervention code [2] 289927 0
Treatment: Other
Intervention code [3] 289928 0
Behaviour
Comparator / control treatment
Control treatment comprised of a opaque gelatin capsule containing the equivalent fruit sugar (fructose and glucose) present in the blackcurrant extract given to the particpants.
Control group
Placebo

Outcomes
Primary outcome [1] 292764 0
Physical performance parameters
Timepoint [1] 292764 0
Fitness assessment by measuring VO2max was performed prior to the start of the trial and then again at the end of the 8-week training period. VO2 max was assessed on a cycle ergometer. The method used required the subject to cycle at incrementally increasing wattage until volitional fatigue. At the commencement of the VO2 max test, participants were instructed to cycle at a work rate of 50 W for 2 min followed by incrementally increasing target workload (i.e. 1 W every 2 sec) until volitional fatigue. In addition we performed a series of performance measures weekly. These included (a) Yoyo "bleep" performance test, (b) hand grip strength using a hand grip dyanometer and (c) leg muscle strength using a timed squad against a wall.
Primary outcome [2] 292804 0
Cognitive performance
Timepoint [2] 292804 0
This was measured before the start of the 8-week study and then every week on the same day for 8-weeks. Cognitive performance was assessed using a mixture of tests looking at psychomotor skills (Perdue pegboard and finger maze) and a series of 8 short computerized "brain games" on iPads, commerically known as "joggle".
Secondary outcome [1] 309621 0
Innate immunity biomarkers
Timepoint [1] 309621 0
Innate immune biomarkers were measured before the start of the study and then every week over the 8-week period of the study. Plasma IL-6, IL-10, C-reactive protein and TNFa and salivary B-defensins, cortisol and IgA were measured using commercially available ELISA kits.
Secondary outcome [2] 309775 0
Perceived energy, fatigue and motivation
Timepoint [2] 309775 0
At each weekly training session, changes in perceived energy, fatigue and motivation were assessed at the start and then again at the end. This was assessed using visual analogue scales (VAS) forms.
Secondary outcome [3] 309777 0
Oxidative stress and antioxidant status
Timepoint [3] 309777 0
Changes in oxidative stress parameters were measured at the beginning and end of the each weekly training session. We specifically measured plasma oxidative stress parameters, (a) radical oxygen species using fluorescence assay using hydrolysed DCF, (b) superoxide and (c) nitric oxide using commercially available assay kits (Abcam). In addition, we assessed changes in superoxide dismutase, catalase and GPx activity in PBS washed (x2) erythrocytes using “in house” colorimetric bioassays and plasma total antioxidant capacity measured using hydrolysed fluorescent probe DCF and H2O2 as the pro-oxidant stimulus.

Eligibility
Key inclusion criteria
Inclusion criteria for participation in this study include written informed consent. Participants had to be member of the Hamilton Boy’s High School hockey squad and aged between 16-19 yrs. All participants were in good general health, free of injury.
Minimum age
16 Years
Maximum age
19 Years
Sex
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Exclusion criteria included the inability to provide written informed consent to take part in the study. Unable or unwilling to comply with study procedures, including only consuming the treatment at the appropriate time. Individuals were also be excluded if they were known to have experienced hypersensitivity to blackcurrants or berryfruits or their health situation changes that they became unable to train, e.g. injury, heart and/or breathing problems. Individuals were also not able to take part if they have any of the following health conditions; blood borne diseases (e.g. hepatitis), clinically diagnosed high/low blood pressure, recent bacterial or viral illness or vaccinations, chronic illness that affects their immune system (e.g. lupus) or are taking medication that affects the properties of blood, e.g. clotting.


Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
(a) Participants were only recruited from Hamilton Boy’s High School hockey squad. Recruitment was done in consultation with parents/guardian and hockey coaches.
Subjects interested, together with coaches and parents or guardians, were given a presentation about what they could expect in the study and were allowed to ask questions and given an information sheet and health questionnaire. If interested they made an appointment with the trial co-ordinator (Robyn Wells) to discuss the study in detail. They were given two weeks to decide whether they wish to take part in the study. Once informed consent and the health questionnaired had been assessed against the study' inclusion and exclusion criteria by an independent occupational health service, they were recruited.
(b) This is a two-arm parallel study. Participants were allocated into one of two groups; blackcurrant extract or placebo. Study investigators and participants were blinded from the dietary intervention given to participants. THis allocation process was undertaken by a fellow scientist who is not involved in this study. Participant treatment allocation is held concealed until completion of the trial and analysis of the data is finished (on-going). Furthermore, participants were given their dietary treatments as an opaque gelatin capsule, which masked the colour of the blackcurrant extract or placebo.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Allocation of participants into the two treatment groups were performed using a spreadsheet random function.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s

The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis
Power analysis. The fitness level, VO2 max measurement on cycle ergometer, from a previous trial was used to calculation of the minimum sample size likely to show an effect in this study. Using this parameter, a sample size of 10 has a desired statistical power level of 0.8 with a probability level of 0.05. This is calculated on an anticipated effect size (Cohens’s d) of 1.159 based on paired SD for a difference in VO2 max L/min.
Data will be analyzed using Statistical Analysis Software (SAS) 9.1 for Windows (version 5.1.2600). Using a repeated measures analysis of variance (ANOVA), comparison between conditions over time for each measure (independent variable) will also be determined, providing levels of significance for trial effect, treatment effect, and interaction effect between treatment and trial. In some situation, i.e. cognitive testing, the raw data may be appropriately transformed to allow for participant variation, prior to statistical analysis. Data will be expressed as mean + / - standard error of the mean. In addition, post-hoc tests may be performed to identify significant differences at each time point. Values will be presented as means + / - standard deviation (or standard error) at a 95% significance level (p = 0.05). Pearson’s Product Moment Correlation Coefficient’s may also be assessed using SPSS 15.0 for Windows to investigate if there are any relationships between certain variables by giving an R-value between 0.0 and 1.00 (or -0.0 and -1.00).

Recruitment
Recruitment status
Completed
Date of first participant enrolment
Anticipated
Actual
17/04/2014
Date of last participant enrolment
Anticipated
Actual
28/04/2014
Date of last data collection
Anticipated
Actual
Sample size
Target
10
Accrual to date
Final
Recruitment outside Australia
Country [1] 6254 0
New Zealand
State/province [1] 6254 0
Hamilton, Waikato

Funding & Sponsors
Funding source category [1] 289666 0
Government body
Name [1] 289666 0
New Zealand Institute for Plant & Food Research
Country [1] 289666 0
New Zealand
Primary sponsor type
Government body
Name
New Zealand Institute for Plant & Food Research
Address
Private Bag 92169,
Auckland 1142
Country
New Zealand
Secondary sponsor category [1] 288357 0
None
Name [1] 288357 0
Address [1] 288357 0
Country [1] 288357 0
Other collaborator category [1] 278064 0
Individual
Name [1] 278064 0
Assoc. Prof. John Podd
Address [1] 278064 0
School of Psychology
Massey University
Private Bag 11-222
Palmerston North 4442
Country [1] 278064 0
New Zealand

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 291403 0
Health and Disability Ethics Committee (HDEC)
Ethics committee address [1] 291403 0
Minstry of Health
No. 1 The Terrace
PO Box 5013
Wellington 6145
Ethics committee country [1] 291403 0
New Zealand
Date submitted for ethics approval [1] 291403 0
Approval date [1] 291403 0
16/04/2014
Ethics approval number [1] 291403 0
14/CEN/45

Summary
Brief summary
Eating fruit as part of your diet keeps you healthy. Recent studies show certain fruits contain compounds that boost the body’s natural defences. Hockey training is very demanding for young athletes. Finding a fruit that may help them keep healthy, recover quickly after injury, and play better during the hockey season would be helpful. The pricipal question being asked by this study is does the regular consumption of a blackcurrant supplement prior to each hockey practice and game facilitate sporting performance (physical and mental) and maintain the health of young hockey players over an 8-week period.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 50238 0
Dr Suzanne Hurst
Address 50238 0
New Zealand Institute for Plant & Food Research Ltd., Private Bag 11600, Palmerston North 4442
Country 50238 0
New Zealand
Phone 50238 0
+64 (6) 355 6231
Fax 50238 0
+64 (6) 351 7050
Email 50238 0
[email protected]
Contact person for public queries
Name 50239 0
Robyn Wells
Address 50239 0
New Zealand Institute for Plant & Food Research, Ruakura campu, Private Box 3123, Hamilton 3240
Country 50239 0
New Zealand
Phone 50239 0
+64 (7) 959 4490
Fax 50239 0
Email 50239 0
[email protected]
Contact person for scientific queries
Name 50240 0
Suzanne Hurst
Address 50240 0
New Zealand Institute for Plant & Food. Ltd., Private Bag 11600, Palmerston North 4442
Country 50240 0
New Zealand
Phone 50240 0
+ 64 (6) 355 6231
Fax 50240 0
+64 (6) 355 6231
Email 50240 0
[email protected]

No information has been provided regarding IPD availability


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

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