Glycogen modulate EC coupling in elite triathletes, by affecting SR Ca2+ release rate

Niels Ørtenblad, Kasper Degn Gejl, Rune Dueholm Bech, Tobias Nygaard, Line Barner Dalgaard, Ulrik Frandsen

Research output: Contribution to conference without publisher/journalConference abstract for conferenceResearchpeer-review


Little is known about the precise mechanism that relates skeletal
muscle glycogen to muscle fatigue. However, based on data from
in vitro studies I has been proposed that glycogen affects sarcoplasmic reticulum (SR) function. The aim of the present study was to examine the effect of glycogen on SR function in elite triathletes (n = 15, VO2max 70 ± 1 ml kg-1 min-1
) before, immediately after, and 4 and 22 h after a fatiguing 4 h cycling at 75%
HRmax. Triathletes were randomised to receive either water or
carbohydrate (CHO) during the first 4 h recovery, and thereafter all
received CHO enriched food. The muscle glycogen was reduced to
33 ± 4% following exercise (708 ± 28 to 239 ± 29 mmol kg-1
dw), while SR Ca2+ release rate was reduced to 84 ± 3% of initial.
During the 4 h recovery with CHO, the SR Ca2+ release rate was
fully normalized and glycogen was noticeably recovered (59 ± 2%
initial). However, in the absence of CHO during the first 4 h
recovery, the muscle glycogen and SR Ca2+ release rate remained
low and reduced (39 ± 4 and 83 ± 3%, respectively), with both
parameters being normalized after the remaining 20 h recovery
with CHO. Interestingly, the SR Ca2+ release rates and muscle
glycogen contents was highly significant correlated (P\0.0001,
r = 0.57). There was no effect on SR Ca2+ uptake. These observations from trained humans, is in agreement with the emerging
concept of glycogen having a regulatory effect on the SR release
Translated title of the contributionGlykogen modulerer EC koblingen hos triatleter ved at påvirke SR Ca20 frisætningsraten
Original languageEnglish
Publication date14. Sept 2010
Publication statusPublished - 14. Sept 2010
EventEuropean Muscle Conference - Padua, Italy
Duration: 11. Sept 201015. Sept 2010


ConferenceEuropean Muscle Conference

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