Influence of an acute exposure to a moderate real altitude on motoneuron pool excitability and jumping performance

Štirn, Igor (author), García Ramos, Amador (author), Feriche, Belén (author), Strojnik, Vojko (author), Tomažin, Katja (author)

The aim of the study was to test whether ascending to a moderate real altitude affects motoneuron pool excitability at rest, as expressed by a change in the H-reflex amplitude, and also to elucidate whether a possible alteration in the motoneuron pool excitability could be reflected in the execution of lower-body concentric explosive (squat jump; SJ) and fast eccentric-concentric (drop jump; DJ) muscle actions. Fifteen participants performed four experimental sessions that consisted of the combination of two real altitude conditions [low altitude (low altitude, 690 m), high altitude (higher altitude, 2,320 m)] and two testing procedures (H-reflex and vertical jumps). Participants were tested on each testing day at 8, 11, 14 and 17 h. The only significant difference (p < 0.05) detected for the H-reflex was the higher H-reflex response (25.6%) obtained 15 min after arrival at altitude compared to baseline measurement. In terms of motor behavior, DJ height was the only variable that showed a significant interaction between altitude conditions (LA and HA) and time of measurement (8, 11, 14 and 17 h) as DJ height increased more during successive measurements at HA compared to LA. The only significant difference between the LA and HA conditions was observed for DJ height at 17 h which was higher for the HA condition (p = 0.04, ES = 0.41). Although an increased H-reflex response was detected after a brief (15–20 min) exposure to real altitude, the effect on motoneuron pool excitability could not be confirmed since no significant changes in the H-reflex were detected when comparing LA and HA. On the other hand, the positive effect of altitude on DJ performance was accentuated after 6 h of exposure.

• Language: English
• Keywords: sport, drop jump, H-reflex, hypoxia, squat jump, altitude
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FŠ - Faculty of Sport
• Publication status: Published
• Publication version: Version of Record
• Year: 2022
• Number of pages: 8 str.
• Numbering: Vol. 13, art. 861927
• PID: 20.500.12556/RUL-145333
• UDC: 796.01
• ISSN on article: 1664-042X
• DOI: 10.3389/fphys.2022.861927
• COBISS.SI-ID: 106146563
• Publication date in RUL: 18.04.2023

Record is a part of a journal

• Title: Frontiers in physiology
• Shortened title: Front. physiol.
• Publisher: Frontiers Research Foundation
• ISSN: 1664-042X
• COBISS.SI-ID: 1218939

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.

Secondary language

• Language: Slovenian
• Keywords: šport, skok s padcem, H-refleks, hipoksija, skok iz počepa, višina

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P5-0142
• Name: Bio-psiho-socialni konteksti kineziologije