Agnieszka Maciejewska-Skrendo, Paweł Cięszczyk, Jakub Chycki, Marek Sawczuk and Wojciech Smółka
Athletic performance is a multifactorial phenotype influenced by environmental factors as well as multiple genetic variants. Different genetic elements have a great influence over components of athletic performance such as endurance, strength, power, flexibility, neuromuscular coordination, psychological traits and other features important in sport. The current literature review revealed that to date more than 69 genetic markers have been associated with power athlete status. For the purpose of the present review we have assigned all genetic markers described with reference to power athletes status to seven main groups: 1) markers associated with skeletal muscle structure and function, 2) markers involved in the inflammatory and repair reactions in skeletal muscle during and after exercise, 3) markers involved in blood pressure control, 4) markers involved in modulation of oxygen uptake, 5) markers that are regulators of energy metabolism and cellular homeostasis, 6) markers encoding factors that control gene expression by rearrangement of chromatin fibers and mRNA stability, and 7) markers modulating cellular signaling pathways. All data presented in the current review provide evidence to support the notion that human physical performance may be influenced by genetic profiles, especially in power sports. The current studies still represent only the first steps towards a better understanding of the genetic factors that influence power-related traits, so further analyses are necessary before implementation of research findings into practice.
Adam Zajâc, Miłosz Czuba, Stanisław Poprzecki, Zbigniew Waśkiewicz, Jarosław Cholewa, Jan Pilch and Jakub Chycki
Effects of Growth Hormone Therapy and Physical Exercise on Anaerobic and Aerobic Power, Body Composition, Lipoprotein Profile in Middle Aged Men
Recently growth hormone therapy has been used as an age delaying drug in middle aged men and women as well as in the elderly. Positive effects have been shown in regards to body mass and body composition changes, fat metabolism, bone mineral density and muscle strength. Exercise is a potent physiological stimulus for growth hormone secretion and both aerobic and resistance exercise results in significant, acute serum increases in GH concentration. It is unclear however whether a combination of exercise and hGH therapy further increases physical performance in adults and increases changes in body composition and biochemical variables related to health. For this purpose a group of 15 middle aged men (45,7±5,8 years, 93,2±16,3kg and 183,3±4cm), slightly overweight were randomly divided into an experimental and control groups. Both groups exercised for 3 month, performing 2 aerobic sessions per week and 2 resistance workouts, increasing training loads every two weeks. The experimental group received additionally hGH subcutaneous injections beginning with 0,2 IU daily for the first month and then increasing it to 0,4 and 0,6 IU in successive month. VO2max was evaluated during a progressive ergocycle test to volitional exhaustion, while anaerobic power and capacity were measured during the 30s Wingate test. Additionally body mass and body composition were evaluated as well as the lipoprotein profile and the concentration of chosen anabolic hormones. The results indicate a significant rise in resting concentrations of GH and IGF-1 after the replacement therapy but no additional benefits in regards to aerobic fitness and fat metabolism in comparison to exercise only. A more profound effect was observed in case of anaerobic performance, thus it was concluded that even small doses of hGH stimulated additional protein synthesis following resistance exercise what allowed for significant increases in FFM, anaerobic power (W/kg) and capacity (J/kg) as evaluated obtained during the Wingate test. It was concluded that for a more significant effect of hGH therapy in regards to physical performance greater doses of this hormone have to be used, along with an intensive exercise program.
Jakub Chycki, Miłośz Czuba, Artur Gołaś, Adam Zając, Olga Fidos-Czuba, Adrian Młynarz and Wojciech Smółka
The aim of the present study was to evaluate the effects of a 6 week resistance training protocol under hypoxic conditions (FiO2 = 12.9%, 4000 m) on muscle hypertrophy. The project included 12 resistance trained male subjects, randomly divided into two experimental groups. Group 1 (n = 6; age 21 ± 2.4 years; body height [BH] 178.8 ± 7.3 cm; body mass [BM] 80.6 ± 12.3 kg) and group 2 (n = 6; age 22 ± 1.5 years; BH 177.8 ± 3.7cm; BM 81.1 ± 7.5 kg). Each group performed resistance exercises alternately under normoxic and hypoxic conditions (4000 m) for 6 weeks. All subjects followed a training protocol that comprised two training sessions per week at an exercise intensity of 70% of 1RM; each training session consisted of eight sets of 10 repetitions of the bench press and barbell squat, with 3 min rest periods. The results indicated that strength training in normobaric hypoxia caused a significant increase in BM (p < 0.01) and fat free mass (FFM) (p < 0.05) in both groups. Additionally, a significant increase (p < 0.05) was observed in IGF-1 concentrations at rest after 6 weeks of hypoxic resistance training in both groups. The results of this study allow to conclude that resistance training (6 weeks) under normobaric hypoxic conditions induces greater muscle hypertrophy compared to training in normoxic conditions.