title: An ultra-cycling race leads to no decrease in skeletal muscle mass.
abstract: Ultra-endurance races lead to an enormous energy deficit, and a decrease in body mass in the form of fat mass as well as skeletal muscle mass can be found. The decrease in skeletal muscle mass has been demonstrated in ultra-runners. We investigated therefore, in an ultra-cycling race, whether ultra-cyclists also suffered a decrease in body mass and whether we could find changes in skeletal muscle mass and/or fat mass. The anthropometric method was used to determine body mass, skeletal muscle mass and fat mass in 28 male Caucasian, non-professional, ultra-cyclists before and after a 600 km ultra-cycling race. In order to quantify hydration status, we measured total body water, haematocrit, plasma sodium and urinary specific gravity. In addition, plasma urea was determined as a marker of protein catabolism. Body mass as well as fat mass decreased highly significantly (p<0.01) whereas skeletal muscle mass did not change (p>0.05). The post race minus pre race difference (Delta) in body mass was associated with Delta fat mass (p<0.05). Urea increased highly significantly (p<0.01); however Delta urea was not associated with Delta skeletal muscle mass. We concluded that ultra-cycling in contrast to ultra-running leads to no reduction in skeletal muscle mass.
authors.affiliation: Gesundheitszentrum, St. Gallen, Switzerland. beat.knechtle@hispeed.ch
authors.forename: B
authors.initials: B
authors.lastname: Knechtle
authors.forename: A
authors.initials: A
authors.lastname: Wirth
authors.forename: P
authors.initials: P
authors.lastname: Knechtle
authors.forename: T
authors.initials: T
authors.lastname: Rosemann
mesh_terms: D000328:Adult; D000886:Anthropometry / Q000379:methods; D001642:Bicycling / Q000502:physiology*; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D001834:Body Water / Q000378:metabolism; D006400:Hematocrit; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*; D010807:Physical Endurance / Q000502:physiology*; D012885:Skinfold Thickness; D012964:Sodium / Q000097:blood; D014508:Urea / Q000097:blood
chemical_list: D014508:Urea; D012964:Sodium