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Muscle pain induced by hypertonic saline in the knee extensors decreases single-limb isometric time to task failure

Smith, Samuel, Micklewright, Dominic, Winter, Samantha L., Mauger, Alexis R. (2020) Muscle pain induced by hypertonic saline in the knee extensors decreases single-limb isometric time to task failure. European journal of applied physiology, . ISSN 1439-6327. E-ISSN 1439-6327. (doi:10.1007/s00421-020-04425-2) (KAR id:81745)

Abstract

Purpose: Increased nociceptive activity and the experience of exercise-induced pain (EIP) may contribute to fatigue during endurance exercise. To investigate this, a pain model that produces pain similar to EIP and decouples its’ relationship to exercise intensity is required. This study 1) compared the quality of pain caused by a hypertonic saline injection into the vastus lateralis in resting and exercise conditions, and 2) investigated whether this pain contributes to changes in time to task failure. Methods: On separate days, eighteen participants completed a time to task failure at 20% maximal voluntary torque (MVT), a resting hypertonic saline intramuscular injection, and in a further three visits a time to task failure at 10% MVT following injection of isotonic saline, hypertonic saline or a control (no injection). Results: In a subset of eligible participants (n = 12), the hypertonic saline combined with 10% MVT produced a qualitative experience of pain (assessed by the McGill Pain Questionnaire) that felt similar to EIP. 10% MVT with hypertonic saline significantly elevated pain intensity in the first 20% of the time to task failure and caused a significantly (P < 0.05) shorter time to task failure (448 ± 240 s) compared with the isotonic saline (605 ± 285 s) and control (514 ± 197 s) conditions. Conclusion: These findings demonstrate that hypertonic saline increases the intensity of pain during exercise, which results in a faster occurrence of exercise-induced fatigue. These results provide important evidence supporting pain as a limiting factor in endurance performance.

Item Type: Article
DOI/Identification number: 10.1007/s00421-020-04425-2
Subjects: Q Science > QP Physiology (Living systems)
Divisions: Divisions > Division of Natural Sciences > Sport and Exercise Sciences
Depositing User: Lex Mauger
Date Deposited: 17 Jun 2020 11:13 UTC
Last Modified: 04 Jul 2023 10:47 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/81745 (The current URI for this page, for reference purposes)

University of Kent Author Information

Smith, Samuel.

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CReDIT Contributor Roles:

Winter, Samantha L..

Creator's ORCID: https://orcid.org/0000-0001-7450-1105
CReDIT Contributor Roles:

Mauger, Alexis R..

Creator's ORCID: https://orcid.org/0000-0001-6685-5800
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