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Exercise that induces substantial muscle glycogen depletion impairs subsequent anaerobic capacity
Author(s) -
LACOMBE VÉRONIQUE,
HINCHCLIFF K. W.,
GEOR R. J.,
LAUDERDALE M. A.
Publication year - 1999
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.1111/j.2042-3306.1999.tb05237.x
Subject(s) - glycogen , anaerobic exercise , sprint , zoology , treadmill , vo2 max , medicine , blood lactate , endocrinology , chemistry , heart rate , physical therapy , biology , blood pressure
Summary The purpose of this study was to develop a model of muscle glycogen depletion and to study the effect of this model on aerobic and anaerobic capacity of horses. The maximal rate of oxygen consumption (V̇ o 2max ), maximal accumulated oxygen deficit (MAOD), muscle glycogen concentration and blood lactate concentration of 6 fit Standardbred horses were measured on 3 occasions 7 days apart ( Trials 1, 2 and 3 ). Between Trials 2 and 3 , strenuous exercise intended to deplete muscle glycogen was performed by exercising horses on the treadmill on 3 consecutive days. Strenuous exercise resulted in reduction of muscle glycogen concentration by at least 55% (from mean ± s.e. 155.1 ± 5.6 mmol/kg, wet weight, before Trial 2 to 55.4 ± 5.5 mmol/kg before Trial 3; P<.05). V̇ o 2max was similar in Trials 2 and 3 (140.4 ± 5.4 ml O 2 /kg bwt and 141.8 ml ± 6.2 ml O 2 /kg, respectively). Run time to fatigue during a single high‐speed exercise test (253.9 ± 33.3 s and 153.8 ± 16.4 s., P<.05), accumulated oxygen deficit (95 ± 13.2 ml O 2 /kg and 35 ± 13.9 ml O 2 /kg, P<.05) and blood lactate concentration at the end of the sprint (17 ± 1.2 mmol/l and 10.5 ± 1.1 mmol/l, P<.05) were less during Trial 3 than Trial 2. These data suggested that repeated strenuous exercise that causes muscle glycogen depletion results in impairment of anaerobic, but not aerobic, metabolism.