Further glycogen decrease during early recovery after eccentric exercise despite a high carbohydrate intake.
BACKGROUND
Delayed onset muscle soreness (DOMS) is a well-known phenomenon of athletes. It has been reported from muscle biopsies that the rate of muscle glycogen resynthesis is reduced after eccentric compared to concentric exercise.


OBJECTIVE
Try to compensate by a carbohydrate (CHO)-rich diet the decelerated glycogen resynthesis after eccentric exercise, measured by magnetic resonance spectroscopy.


METHODS
Glycogen, phosphocreatine, ATP, and Pi were measured in the human calf muscle. Twenty athletes divided into two groups (DOMS and CONTROL), reduced glycogen in M. gastrocnemius during two different running protocols. Additionally, 12 DOMS subjects performed an eccentric exercise while the CONTROL group rested. Subsequently, subjects consumed a CHO-rich diet (> 10 g/kg body mass/24 h).


RESULTS
In both groups, glycogen has been reduced by about 50%. The first 2 h after exercise, glycogen dropped further (-15.6 +/- 15.7 mmol/ kg ww) in the DOMS but rose by +18.4 +/- 20.8 mmol/kg ww in the CONTROL group (P < 0.001). CONTROL subjects reached resting glycogen within 24 h (137 +/- 47 mmol/kg ww), while DOMS subjects needed more than one day (91 +/- 23 mmol/kg ww; P < 0.001). Pi and Pi/PCr, indicators of muscle injury, rose significantly in the DOMS but not in the CONTROL group.


CONCLUSIONS
The diet rich in CHO's was not able to refill glycogen stores after eccentric exercise. Glycogen decreased even further during the beginning of recovery. This loss, which to our knowledge has not been measured before is probably the consequence of muscle cell damage and their reparation.
Zehnder
Monica
M
Exercise Physiology, Institute for Human Movement Sciences, Swiss Federal Institute of Technology and Institute of Physiology, University of Zurich, Zurich, Switzerland. zehnderm@access.unizh.ch
Muelli
Mirjam
M
Buchli
Reto
R
Kuehne
Guido
G
Boutellier
Urs
U
D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006003:Glycogen / Q000096:biosynthesis*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000293:injuries* / Q000378:metabolism*; D012420:Running / Q000293:injuries / Q000502:physiology
D004040:Dietary Carbohydrates; D006003:Glycogen