Article #29 of 50: I have made it a goal of mine to share at least 50 research articles with you to review in 2012. These articles will be shared with no opinion of mine, just purely the information provided in the research and where to go to read more about the topic. This weekly challenge will feature many different aspects of the field: strength, conditioning, nutrition, psychology, etc. If you would like to submit research articles to be included in this segment, please email me a PDF version of the peer reviewed journal article.
Muscle Nerve 45: 527–535, 2012
Introduction: Our aim in this study was to examine whether the muscle fiber type proportions in different muscles from the same individual are interrelated.
Methods: Samples were excised from five skeletal muscles in each of 12 human autopsy cases, and the fiber type proportions were determined by immunohistochemistry. We further examined the intermuscular relationship in fiber type proportion by reanalyzing three previously published data sets involving other muscles.
Results: Subjects demonstrated a predominantly high or low proportion of type 1 fibers in all examined muscles, and the overall difference between individuals was statistically significant (P < 0.001). Accordingly, the type 1 fiber proportions in most muscles were positively correlated (median r 1⁄4 0.42, range 0.03–0.80). Similar results were also obtained from the three reanalyzed data sets. Conclusions: We suggest the existence of an across-muscle phenotype with respect to fiber type proportions; some individuals display generally faster muscles and some individuals slower muscles when compared with others.