The acute effects of concurrent endurance and resistance training on circulating microRNAs in trained rugby players
Authors: Babault Nicolas , Mathieu Bertrand , Gavinet Alexandre , Cometti Carole , Paizis Christos , Piscione Julien 
Published: May 2023

MicroRNA (miR) are small noncoding RNA involved in the post-transcriptional regulation of gene expression and may serve as biomarkers of muscle fatigue and muscle adaptations. The present study aimed to explore the acute responses of cycling vs. running endurance exercises within a concurrent endurance/resistance training on some specific miR. We hypothesized miR would acutely reveal greater muscle damage during the running endurance exercise as compared to cycling that would affect muscle protein synthesis biomarkers.Twenty-five trained rugby players participated in three randomized experimental sessions: 1) cycling endurance training session followed by a resistance session (CYCLE), 2) running endurance training session followed by a resistance session (RUN), and 3) a single resistance training session (CONTROL). Cycling and running endurance sessions were conducted in the morning and consisted in three sets of six 6-s maximal (cycling or running) sprints with 24 seconds passive recovery. Four hours later, volunteers conducted the resistance training (afternoon) composed of several upper- and lower-body strength exercises with heavy loads and low repetitions. During CONTROL, volunteers only performed the resistance training during the afternoon. Blood samples were collected before (PRE), immediately after (POST) and 3h after (POST3) the resistance training sessions. Extracellular vesicular miR were subsequently extracted and quantified using a real time quantitative PCR.The statistical analyses revealed that hsa-miR-203a-3p, hsa-miR-205-5p and hsa-miR-184 were not affected by our experimental procedures (p>0.05). hsa-miR-9-5p and hsa-miR-1290 were significantly higher during CONTROL as compared to CYCLE (p=.033 and p=.039, respectively). hsa-miR-206 was significantly higher POST during RUN as compared to CYCLE and CONTROL (p=.018 and p=.014, respectively). hsa-miR-19-3p was significantly higher during RUN as compared to CONTROL (p=.38).Taken as a whole, our results revealed some differences in circulating miR as a result of a running endurance exercise as compared to no endurance or cycling endurance exercise. Confirming our a priori hypothesis, the higher values of circulating miR suggested greater muscle damage (i.e., hsa-miR-206) after running that could affect the muscle protein synthesis pathway expected by a subsequent resistance training session. Indeed, the higher hsa-miR-19-3p after RUN could have an inhibitory effect on Akt/mTOR. It is therefore suggested that conducting cycling endurance exercises within a concurrent training program could lower the likely interferences between endurance and resistance training in trained individuals. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.