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There is a tremendous amount of anecdotal evidence surrounding the efficacy
of creatine monohydrate. In fact, it would be virtually impossible to find a
patron of an exercise facility who doesn't know someone who is using creatine.
Formal research on creatine only started in the 1990's. Unfortunately, there is some conflicting evidence among various research
studies. In their article, Stevenson and Dudley explain that performing research
on creatine users is difficult because they use different training protocols,
they must be convinced for the duration of the study that switching protocols
won't harm their training, and, "At best, this reduces the subject pool; at
worst one studies poorly motivated trainees."
Research Studies
Increases in strength: One double-blinded placebo
controlled study was conducted over 9 weeks on 25 NCAA Division I redshirt
football players using 20 g/d loading doses x 5 days followed by 5 g/d for the
duration of the study (Bemben et al.). This study indicates that there
were significant increases in body weight (3.5%) and lean body mass (3.8%) in
the creatine-supplemented group, while the control group had no significant
gains. However, this gain in lean body mass was accounted for by a concomittant
increase in total body water (average of 3.2 L). This study does demonstrate a
greater increase in strength in creatine-supplemented athletes, measured by
bench press and squat 1-rep max, which is statistically significant. The authors
suggest that these gains may be due to quicker resynthesis of ATP after
short-term exercise, allowing higher-quality bouts of exercise.
Another study of 19 handball players indicates that
short-term creatine supplementation (20 g/d x 5 d) improved lower body maximal
strength and total repetitions performed until fatigue during bench press and
half-squat exercises (Izquierdo et al.). However, it had no effects on
performance of endurance running exercises.
Assistance in short-duration, explosive activities: Burke et al. report in their double-blinded placebo controlled study
designed to measure specific indices of strength gain in 41 men receiving 7.7
g/d x 21 days that creatine-supplemented subjects performed more total work
until fatigue, had significantly greater improvements in peak force and power,
and maintained elevated mean peak power for a longer period of time. They
conclude that creatine supplementation assists in short-duration, high-intensity
activities.
Enhanced sprint performance: Mujika et al.
and Jones et al. report in separate double-blinded placebo controlled
studies that 5 g/d for 6 days and 10 weeks, respectively, enhanced athletes'
performance in 15-second sprints and limited decay in jumping ability.
Use in improving quality of life in elderly: Another
double-blinded placebo controlled study postulated that one week of creatine
supplementation could increase strength and improve the quality of life in
normally active older men, aged 59-72 (Gotshalk et al.). Strength was
tested with 1-rep maximum bench and leg presses, knee extension and flexion, and
sprints. Their data suggests that creatine increased all indices of muscle
performance, and may be a useful strategy to attenuate loss of strength and
performance of functional living tasks in older adults.
Efficacy in women: Brenner et al. report in
their double-blinded placebo controlled study of f16 female lacrosse players
using 20 g/d x 7 days loading and 2 g/d x 4 weeks that there was significant
upper body strength gain and decreased body fat.
Efficacy in highly trained athletes: O'Conner et al.
studied the effects of six weeks of creatine monohydrate supplementation
(3grams/day) on aerobic and anaerobic performance of highly trained rugby
players. They found that there was no statistical significance in their
performance before and after the six week study.
Effect on body composition and performance measures:
Lehmkuhl et al. studied the effects of eight weeks of creatine
monohydrate supplementation on collegiate track athletes. They found that
creatine significantly increase body mass, lean body mass, and initial
rate of power production during multiple cycle ergometer bouts.
Creatine's effect on body weight and percent body fat: Kutz et al. stuided the effects of four weeks of creatine supplementation on
total body water, body water content, percent body fat and daily caloric intake
in 17 active males. They found a significant increase in total body water and
body water content. There was no significant change in percent body fat or daily
caloric intake. This study supported previous research which suggests weight
gain associated with creatine supplementation may be in part due to water
retention. |
