Skeletal muscle morphology and function in former elite distance runners : a 20 year follow-up

dc.contributor.advisorCostill, David L.en_US
dc.contributor.authorTrappe, Scott W.en_US
dc.description.abstractThe purpose of this investigation was to examine the effects of 20 years of distance running training on the morphological and functional characteristics of skeletal muscle. Sixty men (current age = 49.2 ± 2.4 yr.) were first studied between 1966-1974 when they were all highly trained. Based on their training regimens in the interim between testing, subjects were described as highly trained (HI), fitness trained (FIT) or untrained (UT). Gastrocnemius muscle biopsy samples revealed an increase (p<0.05) in the proportion of type I fibers of the FIT (52.9 ± 5.3 vs. 61.9 ± 5.2%) and UT (56.3 ± 2.9 vs. 65.4 ± 3.8%) groups, while the HI group, who was initially characterized by a high percentage (>70%) of type I muscle fibers, was unchanged. Among the elite distance runners who had continued high volume, high intensity running, succinate dehydrogenase (SDH) activity and type I and type II muscle fiber areas were similar between evaluations. In 1993, the HI group had higher (p<0.05) SDH and citrate synthase (CS) activities compared with the FIT and UT groups, whereas phosphorylase activity did not differ. Capillary density and capillary-to-fiber ratio were also greater (p<0.05) in the HI group compared with the other two groups. Isokinetic plantar flexion strength at 60°/s and 180°/s and cross-sectional area (CT scans) of the lower leg (gastrocnemius and soleus) were similar among groups. These data suggest that aging may have a significant effect upon the distribution of muscle fibers and may be dependent upon fiber composition as a young adult. In addition, sustained endurance training appears to maintain the oxidative characteristics of the skeletal muscle, but does not provide an advantage in absolute calf muscle strength compared with individuals who train considerably less or not at all.en_US
dc.description.degreeThesis (Ph. D.)en_US
dc.description.sponsorshipSchool of Physical Education
dc.format.extentviii, 104 leaves : ill. ; 28 cm.en_US
dc.identifierLD2489.Z68 1994 .T7en_US
dc.sourceVirtual Pressen_US
dc.subject.lcshOlder athletes -- Physiology.en_US
dc.subject.lcshMuscle strength.en_US
dc.subject.lcshRunners (Sports) -- Physiology.en_US
dc.subject.lcshAging -- Physiological aspects.en_US
dc.titleSkeletal muscle morphology and function in former elite distance runners : a 20 year follow-upen_US
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