Muscle ischemic preconditioning reduces feedback from group iii and iv muscle afferents.

Angius, Luca and Pageaux, Benjamin and Hopker, James G. and Marcora, Samuele Maria (2013) Muscle ischemic preconditioning reduces feedback from group iii and iv muscle afferents. In: European College of Sports Sciences, 26-29 June 2013, Barcelona. (Unpublished) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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Abstract

INTRODUCTION The primary aim of this study was to test the hypothesis that muscle ischemic preconditioning (MIP) reduces feedback from group III and IV muscle afferents measured indirectly by muscle metaboreflex. The second aim was to investigate whether the hypothesized reduction in afferent feedback (Crisafulli et al, 2011) causes a reduction of rating of perceived exertion (RPE) as predicted by the afferent feedback model of PE (Marcora, 2009) MATERIAL AND METHODS Nine healthy subjects visited the laboratory three times in a single-blind, randomized and counterbalanced experimental design. In a preliminary day they underwent a one leg incremental test up to exhaustion to detect Wmax then an experimental (EXP) and control (SHAM) session in separated days. To test muscle afferent activity, two post-exercise muscle ischemia (PEMI) were executed. PEMI involved: 3 min of baseline, 3 min of exercise at 70% of Wmax, 3 min of thigh occlusion followed by 3 min of recovery. MIP treatment during EXP or SHAM was executed between the two PEMI sessions. MIP involved 3 cycles of occlusion of 5 min at 220 mmHg separated by 5 min of reperfusion. During the SHAM session, occlusion was 20 mmHg. Cardiac output (CO), mean arterial pressure (MAP) and RPE during exercise were monitored during both PEMI sessions. RESULTS CO and MAP responses were significantly reduced after MIP (CO = 6.92 ± 1.81 vs 5.79 ± 1.39 l•min-1 and MAP= 109.25 ± 9.85 vs 103.70 ±10.43 mmHg). RPE was not affected by MIP (15.67 ± 1.87 vs 15.56 ± 2.07). None of the parameters reported any statistical changes in the SHAM condition. DISCUSSION This study shows for the first time that MIP reduces feedback from group III and IV muscle afferents as indicated by a significant reduction in muscle metabo-reflex. Despite this reduced afferent feedback, RPE was unchanged. This finding provides further experimental evidence that feedback from III and IV muscle afferents is not a sensory signal for PE. REFERENCES Crisafulli A. et al J Appl Physiol. 2011 Aug;111(2):530-6. Marcora S. J Appl Physiol. 2009 Jun;106(6):2060-2.

Item Type: Conference or workshop item (Paper)
Subjects: R Medicine > RC Internal medicine > RC1235 Physiology of sports
Divisions: Faculties > Sciences > School of Sport and Exercise Sciences
Depositing User: James Hopker
Date Deposited: 10 Aug 2016 12:14 UTC
Last Modified: 03 Oct 2017 09:26 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/56797 (The current URI for this page, for reference purposes)
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