Muscle substrate utilization and lactate production.
Biopsies (biceps) were examined in 8 bodybuilders across a typical arm-curl training session (80% 1-RM). [PCr] and [glycogen] decreased 62 and 12% after 1 set (n = 4), and 50 and 24% after 3 sets (n = 4). [Lactate] was 91 and 118 mmol &times kg-1, respectively, after 1 and 3 sets. Fatigue was probably partially caused by decreased [PCr] and increased [H+] (first set) and by decreased [H+] in subsequent sets.
MacDougall
J D
JD
Department of Kinesiology, McMaster University, Hamilton, ON L8S 4K1 Canada.
Ray
S
S
Sale
D G
DG
McCartney
N
N
Lee
P
P
Garner
S
S
D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000328:Adult; D000704:Analysis of Variance; D001132:Arm / Q000502:physiology; D001707:Biopsy, Needle; D006003:Glycogen / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D006859:Hydrogen / Q000378:metabolism; D019344:Lactic Acid / Q000096:biosynthesis* / Q000097:blood; D008297:Male; D009119:Muscle Contraction / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000737:chemistry / Q000378:metabolism*; D010725:Phosphocreatine / Q000032:analysis / Q000378:metabolism*; D014891:Weight Lifting / Q000502:physiology*
D010725:Phosphocreatine; D019344:Lactic Acid; D006859:Hydrogen; D000255:Adenosine Triphosphate; D006003:Glycogen