The aim of this trial is to evaluate the effects of 6-week administration of probiotics on running performance among non-elite athletes. It is hypothesized that participants receiving probiotics may improve their running performance at an endurance test compared to their placebo-receiving counterparts.

Participants recruited from the university community in the Southeast U.S. will participate in a randomized, double-blind, placebo-controlled interventional study for approximately 9 weeks following obtainment of informed consent. Two weeks prior to randomization participants will begin the pre-baseline period and complete daily and weekly questionnaires (physical activity and muscle soreness, bowel movements and gastrointestinal health, flu and cold symptoms). Visit 2 will occur during the pre-baseline period and participants will complete a VO2 max fitness assessment, which will be used during the endurance testing. Participants will also receive the SenseWear Armdand Mini®, a wearable device that will record their physical activity, sleeping patterns and energy expenditure for one week prior to visits 3 and 4.

Participants will be randomized at visit 3. Prior to this visit, participants will consume a standardized breakfast, collect a stool sample and a saliva sample that will be brought to site. During this visit participants will have a body composition and perform the Submaximal Treadmill Test. During the treadmill test, participants will provide finger prick samples for subsequent analysis of blood metabolites (glucose and lactate) and perceived exhaustion subjectively. Lastly, participants will complete several nutrition and motivation-related questionnaires.

One week prior to the final visit (V4), participants will be asked to wear the SenseWear Armband Mini® again for one week, which they will return at the final visit. Participants will eat another standardized breakfast prior to the final visit, visit 4. They will bring a stool and saliva sample to the site. During visit 4, participants will complete the submaximal treadmill test, while providing finger prick samples for analysis of blood and lactate levels. In addition, body composition will be assessed, as well as nutrition and motivation (subjectively). Visit 4 will be followed by a washout week, during which participants will not intake the study supplement but they will complete daily, weekly, and the final questionnaire.

Inclusion Criteria:

1. Healthy adults between 18-45 years old

2. Regularly participate in running and cross-training, and willing to maintain this level of training throughout the study. Participant must satisfy all three sub-criteria:

   1. 3-5 days per week of running or cross-training AND
   2. 45 minutes - 1.5 hours per activity session AND
   3. Run ≥15 miles per week

3. VO2 max values that in the 60-85th percentile (good-excellent health) range according to ACSM guidelines [1].

Exclusion Criteria:

1. Any physician-diagnosed diseases that would impact exercise performance or participation, including gastrointestinal disease, heart/cardiopulmonary disease, diabetes, thyroid disease, hypogonadism, hepatorenal disease, musculoskeletal disorder, neuromuscular/neurological disease, autoimmune disease, cancer, peptic ulcers or anemia.
2. Professional or elite athletes.
3. Use of any antibiotic drug within 4 weeks of randomization. Volunteer could be eligible to participate after a 2-week washout period.
4. Currently smoking (including vaping)
5. Pregnant, planning to get pregnant, or currently breastfeeding.
6. Lactose intolerance and/or milk, soy or yeast allergy.

After publications of the results, de-identified data will be shared with qualified researchers and scientists upon reasonable request to the sponsor including a detailed proposal of the intended use of the data, as per the Lallemand Health Solutions Inc. Policy on Clinical Trial Transparency and Data Sharing (available upon request).