Purpose: To assess the effects of creatine monohydrate on isometric force-t
ime curve parameters of sedentary college males aged 18-25 yr. Methods: Thi
s double-blind study randomly assigned subjects to either a treatment (with
creatine (Cr)) group (N=11) or placebo group (P) (N=8). The Cr group recei
ved 20 g-d(-1) of Cr for the first 5 d, in 5-g doses, four times daily (loa
ding period) followed by a 5-g.d(-1) dose for the next 5 d (maintenance pha
se) and then no Cr ingestion for 7 d (washout period). Each 5-g dose was mi
xed with 250 mL of Gatorade(R). The P group received a placebo (cornstarch)
following the exact same dosage regimen and protocol as the Cr group. All
subjects were sedentary and had not used any nutritional supplements for 6
months before the study. Measurements of isometric force production of four
muscle groups (elbow flexors and extensors; knee flexors and extensors) we
re characterized by a number of force-time parameters including strength (M
F), time to maximal force (TMF), rate of force development (MRFD), and inte
rmittent endurance (total impulse (TI) and percent force decrement (PFD)).
Testing was done at pretreatment, after the 10-d loading and maintenance ph
ases, and after the washout phase. Results: Repeated measures ANOVA indicat
ed no significant group effect for any muscle group concerning the maximal
strength parameters and only two significant time effects for the knee flex
ors during MF and MRFD. Similarly, there were no significant group effects
for any muscle group during the endurance trials; however, there was a sign
ificant time effect concerning TI for each muscle group tested. Conclusion:
Our findings indicate that oral supplementation with creatine monohydrate
in untrained males does not positively influence isometric strength but may
enhance intermittent isometric muscular endurance.