Oral creatine supplementation augments the repeated bout effect.
OBJECTIVE
We examined the effects of creatine supplementation on the response to repeated bouts of resistance exercise.


METHODS
Young men (24.1 ± 5.2 yr) were divided into Creatine (CM, n = 9) and Placebo (PL, n = 9) groups. On day (D) 1 and D15, subjects performed four sets of bicep curls at 75% 1-RM to concentric failure. On D8-D13, subjects consumed either 20g/d creatine monohydrate or placebo. Muscle soreness and elbow joint range of motion (ROM) were assessed on D1-D5 and D15-D19. Serum creatine kinase activity (CK) was assessed on D1, D3, D5, D15, D17, and D19.


RESULTS
The first exercise bout produced increases in muscle soreness and CK, and decreases in ROM in both groups (p < .001). The second bout produced lesser rises in serum CK, muscle soreness, and a lesser decrease in ROM (bout effect, p < .01 for all), with greater attenuation of these damage markers in CM than PL. CK levels on D17 were lower (+110% over D15 for CM vs. +343% for PL), muscle soreness from D15-19 was lower (-75% for CM vs. -56% for PL compared with first bout), and elbow ROM was decreased in PL, but not CM on D16 (p < .05 for all).


CONCLUSIONS
Creatine supplementation provides an additive effect on blunting the rise of muscle damage markers following a repeated bout of resistance exercise. The mechanism by which creatine augments the repeated bout effect is unknown but is likely due to a combination of creatine's multifaceted functions.
Laboratory of Physiology and Biokinetic, Universidade Iguacu, Itaperuna, Brazil.
F T
FT
Veggi K
Marco
M
Machado
Alexander J
AJ
Koch
Sandro C
SC
Santana
Sedison S
SS
Oliveira
Michael J
MJ
Stec
D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D003401:Creatine / Q000008:administration & dosage* / Q000097:blood*; D003402:Creatine Kinase / Q000097:blood; D019587:Dietary Supplements; D004551:Elbow Joint / Q000187:drug effects / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology; D015596:Nutrition Assessment; D016059:Range of Motion, Articular / Q000187:drug effects; D055070:Resistance Training; D064133:Sports Nutritional Physiological Phenomena; D055815:Young Adult
D003402:Creatine Kinase; D003401:Creatine