Abstract
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
function.
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
function.
| Translated title of the contribution | Glykogen modulerer EC koblingen hos triatleter ved at påvirke SR Ca20 frisætningsraten |
|---|---|
| Original language | English |
| Publication date | 14. Sept 2010 |
| Publication status | Published - 14. Sept 2010 |
| Event | European Muscle Conference - Padua, Italy Duration: 11. Sept 2010 → 15. Sept 2010 |
Conference
| Conference | European Muscle Conference |
|---|---|
| Country/Territory | Italy |
| City | Padua |
| Period | 11/09/2010 → 15/09/2010 |