Samuel Ornelas, M.D.
Education: Bachelor of Science in kinesiology (May 2008)
Master of Public Health from Kansas State University
Doctor of Medicine specializing in internal medicine from the University of Kansas
McNair Project: Influence of muscle fiber type on O2 uptake kinetics during moderate intensity cycle exercise (2007)
Mentor: Thomas Barstow, Ph.D.
Motor units are recruited sequentially, beginning with type I, transitioning to type II. Changes in work rate from baseline to one in the lower domain of moderate-intensity work rates would express low gain and fast time constants, consistent with type I motor unit recruitment, transitions in the upper domain would express a higher gain and slower time constant, consistent with type II motor unit recruitment. If this interpretation is true, these differences should be exaggerated in subjects with different muscle fiber types. This study will determine if endurance athletes (possessing predominantly type I muscle fibers) will express faster time constants and lower gains than sprinters (possessing predominantly type II muscle fibers) in the upper domain of moderate-intensity work rates. Each subject will perform nine separate testing trials on a cycle ergometer. The first test will be an incremental ramp test to fatigue to establish peak VO2 and estimate the lactate threshold. Each subject will perform 8 more exercise tests.