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Post-Polio Health (ISSN 1066-5331)

Vol. 18, No. 1, Winter 2002

Pilot Study on the Effects of Creatine
on Muscle Strength

Sophia Chun, MD, Rancho Los Amigos National Rehabilitation Center, Downey, California

SUMMARY: The purpose of the study was to analyze the effect of creatine on measured quadriceps strength and endurance, walking velocity and subjective fatigue, and recovery time in symptomatic post-polio syndrome subjects.

METHOD: Twelve polio survivors were randomly assigned to either the creatine (C) or the placebo (P) group. Seven subjects in the creatine group received 10 grams for 5 days, followed by 5 grams per day of pure creatine. There were 5 subjects in the placebo group. One subject in the creatine group dropped out of the study, with a net of 6 subjects.

The following outcome measures were obtained for each of the subjects at baseline, at 1 week and at 4 weeks: maximum knee extensor (quadriceps) strength, quadriceps recovery time, 6-minute walk distance, fatigue survey results and weight.

RESULTS:

At week one: There was a measurable decrease in knee extensor strength in both the creatine and the placebo group.

At week four: In the creatine group, there was an average increase of 12.25 ft/lb (5-18) absolute knee extension torque in those (N=4) who had 3+ manual muscle grade (about 25% normal muscle strength). Torque to weight ratio was calculated. All subjects that experienced increase in measured muscle strength had an average of 33.2 (28-37.6) torque to weight ratio (Q/T ratio).

Creatine group subjects with manual muscle test of 4+ and 5 (grade 4 is about 40% normal muscle strength) (N=2) did not show any improvement in maximum knee extensor strength. Both subjects showed decrease in measured knee extension torque at 4 weeks. However, it is noteworthy that both subjects reported subjective improvement in their post-polio syndrome symptoms while on creatine.

In the placebo group, two of the five subjects showed no change in knee extensor strength at four weeks. One subject gained absolute torque of 17 that was negated by another subject that lost an absolute torque value of 17. Unlike the creatine group, there was no correlation of Q/T ratio and strength gained or lost in the placebo group.

There were no significant side effects from a four-week continuous administration of creatine. Two of the six subjects experienced minor GI symptoms.

Fatigue scores did not correlate with gain or loss of knee extensor strength except in the creatine group; the subject with the largest percent gain in knee extensor strength had the greatest increase in fatigue. Recovery time was not affected by creatine.

CONCLUSION: Creatine supplement seems to measurably improve the strength of manual muscle grade less than 3+ in post-polio muscles with very minor side effects, which was measurable at 4 weeks. This improvement in strength may contribute to the subjective feeling of improvement in post-polio syndrome symptoms. However, it is also noted that subjective improvement may lead to increase in physical activity thus resulting in increase in fatigue.

It was also noted that at one week all the subjects had decline in strength, which may be due to the delayed recovery resulting from the baseline testing exertion of the same limb.

FUTURE STUDIES: Further studies that may be pursued for creatine and post-polio syndrome pending research funding include:

Larger study with more subjects with muscle grades of 3 to 3+ (i.e., muscles that are at least able to resist gravity to those muscles that are able to resist two-finger resistance)

Long-term study looking at the progression of post-polio syndrome with and without creatine.

COMMENT: Creatine does appear to provide an "edge" or slight advantage to muscles that under maximum or super maximum demand, such as in the case of weak (e.g., 25% of normal) post-polio affected muscles that are put under maximum demand for activities such as walking. This may be the reason that creatine has shown effectiveness in athletes who are also putting their "normal" muscles under maximum demand for training purposes.