In this study, the effect of citrus extract on exercise performance will be investigated. The study consists of three groups: one group will receive a high dose citrus extract, one group will receive a low dose citrus extract and the last group will receive a placebo. After four and eight weeks the effects on performance are measured through a Wingate cycling test. It is expected that exercise performance will increase in the citrus extract groups, compared to the placebo group.

Inclusion Criteria:

• healthy idividuals
• Participants are amateur or (semi-) professional athletes in resistance or interval sports (engage in >4 hours of intense physical activity per week).

Exclusion Criteria:

• Use of creatine supplements and/or anabolic steroids.
• Allergy to test product/placebo
• Allergy to citrus fruits
• BMI lower than 18 or higher than 30
• Recent muscle injury in less than one month before the start of the study.
• Cardiovascular complications
• Use of medication that may interfere with the study results
• Administration of investigational drugs or participation in any scientific intervention study which may interfere with this study (to be decided by the principle investigator), in the 180 days prior to the study.
• Abuse of products; alcohol (> 20 alcoholic units per week) and drugs.