A Statistical Analysis of Muscle Fiber Area

Abstract: In the present study the cross sectional areas of individual muscle fibers were investigated with focus on statistical methodology. This thesis includes data from two studies; Resistance Study and Method Study. The Resistance Study analyzes the effect of exercise by comparing muscle fiber area before and after eight weeks of resistance training. Muscle biopsies from the vastus lateralis muscle were obtained from young male participants. The purpose of the Method Study was to examine the variation between right and left leg. Contrary to previous studies, this thesis focuses on individual data rather than on group-based data, and therefore takes a different approach than the previously published articles. This is proven to be successful since information is lost when analyzing group-wise, as the increase in small muscle fibers did not show when analyzing as a group. The results of the Resistance Study is similar to the results of the Method Study. Means and standard deviations have a wide spread both between subjects and between biopsies taken from the same subject. Inference on the 10th and 90th percentiles shows a positive pattern in the Resistance Study, in the sense that both the smallest and the largest muscle fibers have grown as a result of the resistance training. If muscle fiber area is used as a proxy for training effect, the conclusion is that many people seem to have responded well to the training.