title: Body composition and power performance improved after weight reduction in male athletes without hampering hormonal balance.
abstract: The aim of this study was to investigate the effects of a 4-week weight reduction period with high protein and reduced carbohydrate intake on body composition, explosive power, speed, serum hormones, and acid-base balance in male track and field jumpers and sprinters. Eight participants were assigned to a high weight reduction group (HWR; energy restriction 750 kcal·d) and 7 to a low weight reduction group (LWR; energy restriction 300 kcal·d). Energy and carbohydrate intake decreased significantly (p ≤ 0.05) only in HWR by 740 ± 330 kcal·d and 130 ± 29 g·d, respectively. Furthermore, total body mass and fat mass decreased (p ≤ 0.05) only in HWR by 2.2 ± 1.0 kg and 1.7 ± 1.6 kg, respectively. Fat-free mass (FFM), serum testosterone, cortisol, and sex hormone-binding globulin did not change significantly. Ca ion and pH decreased (p ≤ 0.05) only in HWR (3.1 ± 2.8% and 0.8 ± 0.8%, respectively), whereas (Equation is included in full-text article.)declined (p ≤ 0.05) in both groups by 19.3 ± 6.2% in HWR and by 13.1 ± 8.5% in LWR. The countermovement jump and 20-m sprint time improved consistently (p ≤ 0.05) only in HWR, by 2.6 ± 2.5 cm and 0.04 ± 0.04 seconds, respectively. Finally, athletes with a fat percentage of 10% or more at the baseline were able to preserve FFM. In conclusion, altered acid-base balance but improved weight-bearing power performance was observed without negative consequences on serum hormones and FFM after a 4-week weight reduction of 0.5 kg·wk achieved by reduced carbohydrate but maintained high protein intake.
authors.affiliation: 1Department of Biology of Physical Activity, University of Jyväskylä, Jyväskylä, Finland; 2Dextra Sports and Injury Clinic, Helsinki, Finland; and 3Department of Track and Field, University School of Physical Education in Wrocław (AWF), Wrocław, Poland.
authors.forename: Heikki T
authors.initials: HT
authors.lastname: Huovinen
authors.forename: Juha J
authors.initials: JJ
authors.lastname: Hulmi
authors.forename: Juha
authors.initials: J
authors.lastname: Isolehto
authors.forename: Heikki
authors.initials: H
authors.lastname: Kyröläinen
authors.forename: Risto
authors.initials: R
authors.lastname: Puurtinen
authors.forename: Tuomo
authors.initials: T
authors.lastname: Karila
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Mackala
authors.forename: Antti A
authors.initials: AA
authors.lastname: Mero
mesh_terms: D000136:Acid-Base Equilibrium; D000328:Adult; D015415:Biomarkers / Q000097:blood; D001823:Body Composition / Q000502:physiology*; D050528:Diet, Carbohydrate-Restricted; D004038:Diet, Reducing; D004044:Dietary Proteins; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism*; D013739:Testosterone / Q000097:blood*; D014142:Track and Field / Q000502:physiology*; D015431:Weight Loss / Q000502:physiology*
chemical_list: D015415:Biomarkers; D004044:Dietary Proteins; D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D006854:Hydrocortisone