Roles of metabolites in muscle fatigue OBJECTIVES Methodology:Methodology: Experimental approachExperimental approach TemperatureTemperature Are the changes in metabolites responsible for the decrease in force during fatigue at the level of the sarcomereAre the changes in metabolites responsible for the decrease in force during fatigue at the level of the sarcomere

INTRODUCTION

ATP PRODUCTION – METABOLIC PATHWAYS ATP HYDROLYSIS CREATINE PHOSPHATE PURINE CYCLE ADENYLATE KINASE ATP + H 2 O  ADP + Pi + H + + WORK PCr + ADP  ATP + Cr 2 ADP  ATP + AMP AMP + H 2 O + H +  IMP + NH 4 + IMP + ASPARTATE + GTP  ADENYLSUCCINATE + GDP +Pi ADENYLSUCCINATE  AMP + FUMARATE

ATP PRODUCTION – METABOLIC PATHWAYS GLYCOGENOLYSIS AND GLYCOLYSIS KREB’S CYCLE & OXYDATIVE PHOSPHORYLATION GLUCOSE + 2 ADP + 2 Pi  2 ATP + 2 PYRUVATE GLUCOSE + 6 O ADP + 36 Pi  36 ATP + 6 CO 2 NO O 2 2 LACTATE O 2  -OXIDATION FATTY ACID  ACYL-CoA  KREB’S CYCLE & OXYDATIVE PHOSPHORYLATION GLUCOSYL + 3 ADP + 3 Pi  3 ATP + 3 PYRUVATE

FATIGUE: FAST & GLYCOLYTIC TWITCH MUSCLE

FATIGUE: SLOW & OXIDATIVE TWITCH MUSCLE

ATP EFFECT ON MAXIMUM SHORTENING VELOCITY

ATP EFFECT ON MAXIMUM FORCE

DISCUSSION

CONTROL EARLY FATIGUE FATIGUE Mg MgATP ADP total AMP total P i total PCr Creatine pH ALL CONCENTRATION IN mM

Δ DURING FATIGUE F MAX Ca 50 H+H+H+H+↑↑↓↓↓↓ PiPiPiPi↑↑↓↓↓↓ ATP↓↑↓ ADP↑↑↑ AMP↑↑↑ IMP↑↑↑ PCr↓↓↑↑ Creatine↑↑↓↑ Lactate↑↑→→

0% CO 2 WATER 15% CO 2 30% CO 2