Proteomic Markers of Non-functional Overreaching During the Race Across America (RAAM): A Case Study

Edward K Merritt; David C Nieman; Brian R Toone; Arnoud Groen; Artyom Pugachev

doi:10.3389/fphys.2019.01410

Proteomic Markers of Non-functional Overreaching During the Race Across America (RAAM): A Case Study

Front Physiol. 2019 Nov 15:10:1410. doi: 10.3389/fphys.2019.01410. eCollection 2019.

Authors

Edward K Merritt¹, David C Nieman², Brian R Toone³, Arnoud Groen⁴, Artyom Pugachev⁴

Affiliations

¹ Department of Kinesiology, Southwestern University, Georgetown, TX, United States.
² North Carolina Research Campus, Appalachian State University, Kannapolis, NC, United States.
³ Department of Mathematics and Computer Science, Samford University, Homewood, AL, United States.
⁴ ProteiQ Biosciences GmbH, Berlin, Germany.

Abstract

In a previous study, proteomics procedures identified blood proteins as potential overreaching and overtraining biomarkers, and a targeted proteomics panel of 21 proteins was developed.

Purpose: To measure targeted blood protein changes in an ultraendurance cyclist competing in RAAM.

Methods: The athlete underwent testing 4-week pre-RAAM and 4-day post-RAAM to determine body composition and aerobic capacity. During RAAM training distress score (TDS) and body mass were measured daily. Power output and heart rate (HR) were measured during cycling. Blood sampling for proteomic analysis occurred 4 weeks, 24, and 2 h before the start, twice per day of the race, and after 1 and 4 days recovery.

Results: The athlete completed the 4941 km race in 10.1 days at a speed of 24.5 km/h with 20 total hours of sleep. TDS was very low, 1, pre-RAAM and increased to very high, 47, at the finish. Post-RAAM maximal aerobic capacity and HR were 6.3 and 5.7% lower (61.6 vs. 57.5 mL.kg^-1.min^-1 and 192 bpm vs. 181 bpm). Body composition did not change. The change in blood proteins was calculated using pre-race samples and samples collected on days 8, 9, and recovery day 1. The blood proteins with the largest increase were complement component C7 (359%), complement C4-B (231%), serum amyloid A-4 protein (210%), inter-alpha-trypsin inhibitor heavy chain H4 (191%), and alpha-1-antitrypsin (188%).

Conclusion: The RAAM athlete exhibited non-functional overreaching symptoms including increased training distress and decreased work capacity. Proteomic analysis indicated large increases for immune-related proteins involved with complement activation and the acute phase response, which could be useful biomarkers for non-functional overreaching.

Keywords: RAAM; cycling; overreach; overtraining syndrome; proteomics; ultraendurance.