Source Endurance Puts Our PR Lotion To The Test

Coming on the heels of the clinical trial at San Diego State University by Dr. Mark Kern that showed notable improvements in both performance and recovery from the Topical Edge Performance & Recovery group, Source Endurance performed an independent study of their own. The double-blind, randomized and controlled test of PR Lotion was done at the Source Endurance Training Center of the Rockies using eight cyclists with each test subject performing two sessions of high-intensity intervals to exhaustion, one using Topical Edge PR Lotion and one with Control lotion. The PR Lotion group showed a greater than 20% performance improvement versus the Control lotion, completing an additional 3.4 intervals. Read the full study below.

Background: Athletes continuously search for safe, effective and compliant ergogenic aids that will improve their performance and give them an edge on their competitors. Oral sodium bicarbonate (baking soda) use is a time-tested and effective method of providing that edge, but oral use causes a myriad of intolerable side-effects such as indigestion, gastric pain, vomiting, and diarrhea which limits use. Topical Edge PR Lotion (TE-PR) delivers sodium bicarbonate transdermally. If proven effective, it will provide athletes the ability to use sodium bicarbonate, without the limiting side effects that come with oral use.

Objective: The objective of this field-testing exercise was to evaluate the impact of Topical Edge PR Lotion use on high-intensity interval cycling performance utilizing a randomized, controlled and blinded testing protocol.

Testing Design: Eight volunteer competitive cyclists who were current clients of the Source Endurance Training Center of the Rockies (SETCR) tested Control lotion versus Topical Edge PR Lotion in a controlled, randomized, blinded, cross-over design.

Testing Methodology: Cyclists were informed of the testing procedures and signed waivers prior to participation. All cyclists had an athlete profile already built that included a reliable measure of functional threshold power (FTP). A 20-minute time trial was performed prior to the test sessions to set power for test sessions. All testing was completed on personal bicycles on a Wahoo Kickr smart indoor bike trainer >being driven by PerfPRO Studio software. Two sessions of high-intensity Intervals were completed using Topical Edge PR Lotion (TE-PR) or Control lotion (contained all ingredients except sodium bicarbonate) provided in blinded tubes (labeled A or B) by the manufacturer. To create the double-blind, cyclists and test administrators did not know the identity of each lotion. For the first testing session, the choice of Control or TE-PR was randomized. For the second test, the alternate lotion, Control or TE-PR, was used. Cyclists were instructed to apply 1 tablespoon of assigned lotion per leg 30 minutes prior to beginning a warm up. In order to prevent uncontrolled training schedules from confounding the testing results, the following schedule was adhered to:

Day 1: Cyclists completed 60 minutes of light riding at a recovery pace

Day 2: Cyclists completed a 20 minute time trial (see Table 1)

Day 3: Same as Day 1

Day 4: Cyclists completed high-intensity intervals until exhaustion (see Table 1)

Day 5: Same as Day 1

Day 6: Cyclists completed high-intensity intervals until exhaustion (same as Day 4 but with alternate sample used, see Table 1)

Results were analyzed by using a paired t-test with a significance level set at p<0.05. Results are presented as means ± standard deviations.

Results:There was a significant difference (p=0.009) between Topical Edge PR Lotion and Control lotion in the number of high-intensity cycling intervals completed before exhaustion. Cyclists completed an average of 13.6 ± 3.9 intervals when using Control lotion versus 17.0 ± 4.9 intervals when using the Topical Edge PR Lotion (see Figure 1).

Discussion: Strengths of this testing protocol included the tight control of exercise done before each day of testing and the temporal proximity of test sessions. In the Kern et al. study (in review) of Topical Edge PR Lotion, which was completed during a competitive season, training outside of the test sessions was un-controlled resulting in test sessions falling variably after heavy training days, light training days or competitions. This led to cyclists being tested in different physiological states (e.g. exhausted, partially recovered or fully-recovered) and could have introduced variability into performance metrics. A limitation of this evaluation is the small number of cyclists tested (n=8). However, based on the data from this trial, the probability is 80% that a study of a similar cross-over design would detect a treatment difference at a two-sided 0.05 significance level with only 6 subjects, fewer than this study.

Conclusion: Testing of Topical Edge PR Lotion in this well-controlled and blinded evaluation demonstrated a significant (p=0.009) performance improvement. Well-trained cyclists were able to complete significantly more high-intensity intervals before exhaustion when using Topical Edge PR Lotion compared to Control. The greater than 20% performance improvement observed (3.4 additional intervals completed) is similar to that demonstrated with use of oral sodium bicarbonate, but without the side-effects associated with oral use. Krustrup, et al. (1) and Price, et al. (2) Krustrup et al. (1) demonstrated a 14% improvement in performance (total number of meters ran before failure) of high-intensity intermittent (intervals) exercise (20-meter runs with 20 seconds of active recovery jogging), and Price, et al. (2) demonstrated an 11% performance improvement measured as peak power during intermittent cycling sprints (10 repeated 3-minute blocks of intermittent cycling at 40%, 60% and maximal sprint separated by 16 seconds of recovery). The similarity of results between this test and that by Krustrup, et al. (1) may be attributed to the similarity of testing protocols that are based on exercise to failure/exhaustion rather than measures of work done (power or wattage) during fixed testing as in that utilized by Price, et al. (2)

Additionally, no side-effects were reported. Topical Edge PR Lotion may, for the first time, allow athletes to use sodium bicarbonate for performance improvement without the fear of experiencing the typical side-effects associated with oral use.


1. Krustrup P, Ermidis G, Mohr M. Sodium bicarbonate intake improves high-intensity intermittent exercise performance in trained young men. J Int Soc Sports Nutr. 2015;12:25.

2. Price M, Moss P, Rance S. Effects of sodium bicarbonate ingestion on prolonged intermittent exercise. Med Sci Sports Exerc. 2003;35(8):1303-8.

Acknowledgements: Source Endurance would like to thank Topical Edge for providing blinded Control and Topical Edge PR lotions for testing.

About Source Endurance: Source Endurance is a group of professional coaches dedicated to the activities and lifestyles that make an endurance athlete, and work tirelessly to prepare each client for success. Our coaches leverage formal higher education in exercise physiology, nutrition, and humanities along with a multitude of certifications, practical experience at the elite level, and years of professional coaching experience to ensure that each client meets or exceeds their performance/ fitness goals.

About the Source Endurance Training Center of the Rockies (SETCR): The Source Endurance Training Center of the Rockies is dedicated to bringing the complete indoor cycling training facility to the athletes of Northern Colorado. With educated, well trained coaches, a rounded indoor cycling training class schedule, weights and gym equipment, certified bike fitting, performance testing, plyometric classes, yoga and motor pacing, SETCR has what it takes to take athletes’ training to the next level even in the coldest, darkest months of winter and no matter their goals.

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