Hopker, James G., OGrady, Ciaran, Pageaux, Benjamin (2016) Prolonged constant load cycling exercise is associated with reduced gross efficiency and increased muscle oxygen uptake. Scandinavian journal of medicine & science in sports, 27 (4). pp. 408-417. ISSN 1600-0838. (doi:10.1111/sms.12673) (KAR id:55697)
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Official URL: http://dx.doi.org/10.1111/sms.12673 |
Abstract
This study investigated the effects of prolonged constant load cycling exercise on cycling efficiency and local muscle oxygen uptake responses. Fourteen well-trained cyclists each completed a 2-h steady-state cycling bout at 60% of their maximal minute power output to assess changes in gross cycling efficiency (GE) and muscle oxygen uptake (mVO2) at time points 5, 30, 60, 90, and 120 min. Near-infrared spatially resolved spectroscopy (NIRS) was used to continually monitor tissue oxygenation of the Vastus Lateralis muscle, with arterial occlusions (OCC) applied to assess mVO2 . The half-recovery time of oxygenated hemoglobin (HbO2 ) was also assessed pre and post the 2-h cycling exercise by measuring the hyperemic response following a 5-min OCC. GE significantly declined during the 2-h cycling bout (18.4 ± 1.6 to 17.4 ± 1.4%; P < 0.01). Conversely, mVO2 increased, being significantly higher after 90 and 120 min than at min 5 (+0.04 mlO2 /min/100 g; P = 0.03). The half-recovery time for HbO2 was increased comparing pre and post the 2-h cycling exercise (+7.1 ± 19s), albeit not significantly (d: 0.48; P = 0.27). This study demonstrates that GE decreases during prolonged constant load cycling exercise and provides evidence of an increased mVO2 , suggestive of progressive mitochondrial or contractile inefficiency.
Item Type: | Article |
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DOI/Identification number: | 10.1111/sms.12673 |
Uncontrolled keywords: | Cycling efficiency;lactate threshold;maximal oxygen uptake;endurance performance;muscle efficiency |
Subjects: |
G Geography. Anthropology. Recreation > GV Recreation. Leisure > Sports sciences R Medicine > RC Internal medicine > RC1235 Physiology of sports |
Divisions: | Divisions > Division of Natural Sciences > Sport and Exercise Sciences |
Depositing User: | James Hopker |
Date Deposited: | 25 May 2016 19:44 UTC |
Last Modified: | 09 Dec 2022 00:08 UTC |
Resource URI: | https://kar.kent.ac.uk/id/eprint/55697 (The current URI for this page, for reference purposes) |
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