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Effect of Whey Protein on Soccer Performance

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified March 2010 by VU University of Amsterdam.
Recruitment status was:  Recruiting
ClinicalTrials.gov Identifier:
First Posted: April 26, 2010
Last Update Posted: April 26, 2010
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by:
VU University of Amsterdam

Rationale: During exercise protein breakdown in muscles is larger than protein synthesis. This negative muscle protein balance leads to increased muscle damage and thereby to a reduced muscle tissue recovery. To achieve a positive muscle protein balance and reduce muscle damage, many athletes use proteins. In professional soccer players, considerable stress is placed on the musculoskeletal system. Recovery time is often too short for these players to restore homeostasis, which results in catabolic processes. This increases playing errors and will lead to lapses in concentration. Therefore, it is of great importance for a professional soccer team to be in optimal condition and a fast recovery after exercise is desirable to accomplish maximum performance. Supplementation with whey proteins is thought to support this.

Objective: To assess whether post-exercise supplementation with whey protein will lead to a better muscle recovery than supplementation with carbohydrates in Dutch soccer players between the age of 15 and 18 years old.

Study design: A double blind randomised controlled cross-over trial.

Study population: Healthy soccer players of the A and B selection of AJAX between the age of 15 and 18 years old.

Intervention: Supplement, containing either whey proteins or an isocaloric carbohydrate placebo. Each supplement will be administered for 2 weeks separated by a 7 day washout period. Treatment order will be randomly assigned.

Main study parameters: The main study parameter will be the Yo-Yo intermittent recovery test level 2 score and the vertical jump test. The scores will evaluate the soccer players' ability to repeatedly perform intense exercise and his potential to recover from this exercise.

Condition Intervention
Muscle Damage Dietary Supplement: Whey protein

Study Type: Interventional
Study Design: Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary Purpose: Prevention
Official Title: The Effect of Post-exercise Supplementation With Whey Protein Versus Carbohydrate on Soccer Performance.

Further study details as provided by VU University of Amsterdam:

Primary Outcome Measures:
  • Muscle recovery [ Time Frame: 2 weeks ]
    Recovery will be measured with the test scores on the Yo-Yo Intermittent Recovery Test level 2 and the Countermovement Jumping Test.

Estimated Enrollment: 50
Study Start Date: March 2010
Estimated Study Completion Date: July 2010
Estimated Primary Completion Date: June 2010 (Final data collection date for primary outcome measure)
Intervention Details:
    Dietary Supplement: Whey protein
    20g, oral, dissolved in yoghurt-drink, after every training and match for 2 weeks

Information from the National Library of Medicine

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Ages Eligible for Study:   15 Years to 19 Years   (Child, Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • performing soccer >1 year
  • part of A & B selection of AJAX

Exclusion Criteria:

  • presence of lactose intolerance
  • presence of illness
  • presence of injury
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01110122

Contact: Ingeborg A Brouwer, PhD +31-20-5987702 ingeborg.brouwer@falw.vu.nl

Ajax Recruiting
Amsterdam, Netherlands
Contact: Niels Wijne, MD       .n.wijne@ajax.nl   
Principal Investigator: Niels Wijne, MD         
Sponsors and Collaborators
VU University of Amsterdam
Principal Investigator: Ingeborg A Brouwer, PhD VU University of Amsterdam
  More Information

Responsible Party: Ingeborg A Brouwer, VU University of Amsterdam
ClinicalTrials.gov Identifier: NCT01110122     History of Changes
Other Study ID Numbers: AJA-PROT-IAB-001
First Submitted: April 22, 2010
First Posted: April 26, 2010
Last Update Posted: April 26, 2010
Last Verified: March 2010

Keywords provided by VU University of Amsterdam:
Muscle recovery
Intermittent exercise
Whey protein