Altitude‑induced effects on neuromuscular, metabolic and perceptual responses before, during and after a high‑intensity resistance training session Márquez, Gonzalo Benavente Bardera, Cristina Padial Puche, Paulino Feriche Fernández-Castanys, María Belén Hypoxia Transcranial magnetic stimulation Strength training Corticospinal excitability Intracortical inhibition Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work was supported by the Spanish Ministry of Science, Innovation and Universities under Grant (PGC2018-097388-B-I00-MCI/AEI/FEDER, UE), by the Andalusian FEDER Operational Program (B-CTS-374-UGR20) and FPU pre-doc- toral Grant (FPU18/00686) awarded to one of the authors (CB). The authors have no relevant financial or non-financial interests to disclose. Purpose We tested if an acute ascending to 2320 m above sea level (asl) affects corticospinal excitability (CSE) and intracortical inhibition (SICI) measured with transcranial magnetic stimulation (TMS) at rest, before, during and after a traditional hypertrophy-oriented resistance training (R-T) session. We also explored whether blood lactate concentration (BLa), ratings of perceived exertion (RPE), perceived muscular pain and total training volume differed when the R-T session was performed at hypoxia (H) or normoxia (N). Methods Twelve resistance-trained men performed eight sets of 10 repetitions at 70% of one repetition maximum of a bar biceps curl at N (SpO(2) = 98.0 +/- 0.9%) and H (at 2320 asl, SpO(2) = 94.0 +/- 1.9%) in random order. Before each session, a subjective well-being questionnaire, the resting motor threshold (rMT) and a single pulse recruitment curve were measured. Before, during and after the R-T session, BLa, RPE, muscle pain, CSE and SICI were measured. Results Before the R-T session only the rMT differed between H (- 5.3%) and N (ES = 0.38). RPE, muscle pain and BLa increased through the R-T session and were greater at H than N (12%, 54% and 15%, respectively) despite a similar training volume (1618 +/- 468 kg vs. 1638 +/- 509 kg). CSE was reduced during the R-T session (similar to 27%) but recovered ten minutes after, regardless of the environmental condition. SICI did not change after any R-T session. Conclusions The data suggest that acute exposure to moderate hypoxia slightly increased the excitability of the most excitable structures of the corticospinal tract but did not influence intracortical or corticospinal responses to a single R-T session. 2023-06-16T10:04:54Z 2023-06-16T10:04:54Z 2023-05-20 journal article Márquez, G., Altitude‑induced effects on neuromuscular, metabolic and perceptual responses before, during and after a high‑intensity resistance training session. European Journal of Applied Physiology. [https://doi.org/10.1007/s00421-023-05195-3] https://hdl.handle.net/10481/82545 10.1007/s00421-023-05195-3 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Springer