INTRODUCTION: The use of hormonal contraceptives (HC) modifies the menstrual cycle, decreases basal levels of estrogen, and increases basal levels of sex-hormone binding globulin (SHBG). Serum concentrations of sex hormones are associated with trainability including muscle mass and strength (Häkkinen et al. 2000) while levels of SHBG affect androgen availability. We hypothesized that use of HC may negatively influence adaptations to combined strength (S) and endurance (E) training, particularly on development of strength and lean mass (LM). The purpose of this study was to examine the possible influence of HC on adaptations to 10 weeks of highintensity combined S and E training in women. METHODS: 19 women participated in the study, 10 using HC (UHC, age: 29±4 years, height 167±5cm, body mass: 59±5kg) and 9 not using HC (NHC, 31±6,168±5, 61±6). The women completed 10 weeks of high intensity combined S and E training consisting of 2 S and 2 E sessions/week. S included maximal and explosive exercises: back squat, leg press, step-ups, and a variety of bilateral and unilateral jumps. E consisted of 4x4minute intervals and 3x3x100m high intensity sprints. Pre and post training intervention, S of the lower extremities was assessed by maximal isometric leg press (MVC) and countermovement jump height (CMJ). A 3km time trial assessed E performance. Body composition was assessed by dual-energy X-ray absorptiometry (DXA) including LM and fat mass (FM). RESULTS: MVC and CMJ increased in both UHC and NHC (MVC by 15±15%, p<0.05 and 6±6%, p<0.05 and CMJ by 6±6%, p<0.05 and 11±5%, p<0.01 in UHC and NHC, respectively). No significant differences in MVC or CMJ improvements were observed between groups. 3km time trial performance improved, however, significantly only in NHC (-2±4% p>0.05 and -2±2%, p<0.05 for UHC and NHC, respectively). No significant between group differences were observed in 3km. LM increased in both groups (1±1%, p =0.06 and 2±1%, p<0.01, for UHC and NHC, respectively) while FM decreased in both groups (-4±13%, p>0.05 and -6±7%, p<0.05). No statistically significant differences were observed in body composition changes between groups. DISCUSSION: Preliminary analyses indicated that UHC and NHC groups adapted similarly to 10 weeks of high-intensity combined S and E training as measured by MVC, CMJ, 3km time trial, and body composition. These findings are in line with Nichols et al. (2008) who found no advantages/disadvantages of using HC during 12-weeks of strength training. CONCLUSION: The present results showed no statistically significant differences between adaptations to training in women who use HC and do not use HC over a 10 week period of combined intensive S and E training. Further analysis of performance measures, body composition, and blood markers are needed to determine whether or not HC might induce other physiologically significant effects on adaptations to training that would be of interest for both coaches and athletes. --- The hosting University of Jyväskylä is planning to publish conference proceedings "Science and Nordic Skiing III". In case you are interested in this publication please contact the editors (Anni Hakkarainen anni.s.j.hakkarainen@jyu.fi) to become registered for the book.
© Copyright 2015 3rd International Congress on Science and Nordic Skiing - ICSNS 2015. 5-8 June 2015, Vuokatti, Finland. Veröffentlicht von University of Jyväskylä; University of Salzburg. Alle Rechte vorbehalten.