Sportlegs is a commercially available dietary/sports supplement. It is manufactured by a local, Colorado-based company: Sport Specifics Inc. Although Sportlegs has been on the market for approximately 20-years, very little empirical research has been completed to determine if Sportlegs improves exercise performance. Sport Specifics Inc. has commissioned Colorado State University to investigate the ergogenic effects of Sportlegs.

1. Study Significance: Based on published survey data, it is estimated that more than 50% of Americans consume dietary supplements, including sport drinks. In light of widespread use, research that evaluates the claims made by the manufacturers of supplements and sport drinks appears to be relevant to a great number of people. Scientific evaluation of Sportlegs will provide potential customers with an opportunity to make an informed decision as to how they wish to spend their money.
2. Sport Specifics Inc., has had considerable commercial success selling their product, Sportlegs. However, they recognize the potential benefit of being able to support claims pertaining to the efficacy of their product with peer-reviewed scientific data. Noteworthy, they also are aware of the potential risks of a scientific evaluation that may demonstrate that their product has no effect on exercise performance, or possibly even a negative/unfavorable effect.
3. Literature Review: To date, only one scientific study of Sportlegs has been published (see attached). The data suggest that Sportlegs may increase blood bicarbonate concentration (an important factor controlling blood pH) and fatigue resistance, as described by time to exhaustion.
4. The primary ingredient in Sportlegs is lactate. Lactate is a modified form of sugar (glucose) and is therefore a potentially important source of fuel for exercise. In this regard, the potential for Sportlegs to improve exercise performance by making more fuel available is intuitively appealing.
5. Historical thinking has misclassified lactic acid as metabolic waste product, and a potential source of fatigue and muscle damage. The modern contemporary opinion is that lactate is a gluconeogenic precursor (i.e. a source of glucose), an excellent source of chemical energy for many organs including the heart and skeletal muscle, and it may even have favorable clinical relevance with respect to a number of chronic diseases (see attached review for more details). The current proposed work may contribute to the field of Exercise Physiology by providing further confirmation of the functional benefits of lactate and correcting previously erroneous interpretations of data.

Inclusion Criteria:

• Aged 18-30 years (inclusive)
• Minimum of 150 minutes/week of moderate intensity endurance exercise during the previous 12-months.

Exclusion Criteria:

• Pregnancy
• Breastfeeding
• Use of Sportlegs within the previous 4-weeks
• Use of magnesium supplements within the previous 4-weeks
• Unwillingness to abstain from the use of other potentially ergogenic dietary supplements throughout the duration of participation in the study
• Inability or unwillingness to perform vigorous cycle ergometer exercise

Investigators and Participants are both blinded to whether the participants will be consuming Sportlegs or Placebo during a given study visit.