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Metabolic and performance-related consequences of exercising at and slightly above MLSS

Iannetta, Danilo, Inglis, Calaine Erin, Fullerton, Chris, Passfield, Louis, Murias, Juan M. (2018) Metabolic and performance-related consequences of exercising at and slightly above MLSS. Scandinavian Journal of Medicine & Science in Sports, . ISSN 0905-7188. (doi:10.1111/sms.13280)

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Abstract

Exercising at the maximal lactate steady state (MLSS) results in increased but stable metabolic responses. We tested the hypothesis that even a slight increase above MLSS (10 W), by altering the metabolic steady?state, would reduce exercise performance capacity. Eleven trained men in our study performed: one ramp?incremental tests; two to four 30?min constant?load cycling exercise trials to determine the PO at MLSS (MLSSp), and ten watts above MLSS (MLSSp+10), which were immediately followed by a time?to?exhaustion test; and a time?to?exhaustion test with no?prior exercise. Pulmonary O2 uptake (V?O2) and blood lactate concentration ([La?]b) as well as local muscle O2 extraction ([HHb]) and muscle activity (EMG) of the vastus lateralis (VL) and rectus femoris (RF) muscles were measured during the testing sessions. When exercising at MLSSp+10, although V?O2 was stable, there was an increase in ventilatory responses and EMG activity, along with a non?stable [La?]b response (P<0.05). The [HHb] of VL muscle achieved its apex at MLSSp with no additional increase above this intensity, whereas the [HHb] of RF progressively increased during MLSSp+10 and achieved its apex during the time?to?exhaustion trials. Time?to?exhaustion performance was decreased after exercising at MLSSp (37.3±16.4%) compared to the no?prior exercise condition, and further decreased after exercising at MLSSp+10 (64.6±6.3%) (P<0.05). In summary, exercising for 30 min slightly above MLSS led to significant alterations of metabolic responses which disproportionately compromised subsequent exercise performance. Furthermore, the [HHb] signal of VL seemed to achieve a “ceiling” at the intensity of exercise associated with MLSS.

Item Type: Article
DOI/Identification number: 10.1111/sms.13280
Uncontrolled keywords: Maximal lactate steady state, exercise tolerance, O2 extraction, fatigue
Subjects: G Geography. Anthropology. Recreation
G Geography. Anthropology. Recreation > GN Anthropology
G Geography. Anthropology. Recreation > GV Recreation Leisure
G Geography. Anthropology. Recreation > GV Recreation Leisure > Sports sciences
Divisions: Faculties > Sciences > School of Sport and Exercise Sciences
Depositing User: Louis Passfield
Date Deposited: 29 Aug 2018 09:26 UTC
Last Modified: 17 Aug 2019 23:00 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/68848 (The current URI for this page, for reference purposes)
Iannetta, Danilo: https://orcid.org/0000-0001-6914-174X
Fullerton, Chris: https://orcid.org/0000-0003-2933-1578
Passfield, Louis: https://orcid.org/0000-0001-6223-162X
Murias, Juan M.: https://orcid.org/0000-0002-6460-6453
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