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Hormone Response in Swimmers

 Below is an interview on hormone response in swimmers, specifically  Serum IGF-I, IGFBP-3 and ALS concentrations and physical performance in young swimmers during a training season.  We have the  latest article by H. Tourinho Filho ” Serum IGF-I, IGFBP-3 and ALS concentrations and physical performance in young swimmers during a training season.” Review his latest studies and complete research work sites can be found here.

1. Explain the GH/IGF-I axis Concentration and Performance in young swimmers?

The GH–IGF-I axis is composed of hormones, growth factors, binding proteins (BPs) and receptors that regulate many essential life processes, including growth and development, metabolic and reparative processes and aging. Therefore, the understanding of the axis must consider each individual component and the interaction between them under both physiologic and pathological conditions; and it has been shown that exercise programs are related to the anabolic function of this axis. Basal GH and IGF-I concentrations are positively correlated to muscle mass and physical fitness in children, adolescents, and adults. Puberty, in particular, is profoundly marked by the activation of the GH /IGF-I axis and its interactions with the gonadal steroids are directly related to the peak of growth.

2. How did you decide to study IGF-I, IGFBP-3 and ALS for your study?

GH and IGF-I and their binding proteins (IGFBP3 and ALS) play an important role in this growth phase and probably in the performance. In this sense, we decided to investigate the acute and chronic effects of training in adolescent athletes and its relation to the concentrations of these growth mediators.

3. Why is monitoring these proteins important for sports training and young swimmers?

Our study is the first to demonstrate a significant reduction in IGF-I concentrations during the intensive phase and a significant increase during the tapering phase. The effectiveness of physical training depends essentially on the intensity, volume, duration and frequency of training, and on the individual ability to tolerate training. An imbalance between the training load and the individual’s tolerance leads to under or overtraining. Therefore, many efforts have been made to find objective parameters to quantify the balance between training load and the athlete’s tolerance, with limited success. The endocrine system, by modulation of anabolic and catabolic processes, plays a major role in the physiological adaptation to exercise training. Changes in the anabolic/catabolic balance by different training sessions at different phases of the season may aid coaches and athletes in planning training to improve performance. In this study, serum IGF-I concentrations proved sensitive to both the acute and chronic effects of exercise, while IGFBP-3 concentrations were only sensitive to the chronic effects. Thus, it can be suggested that these components of the GH/IGF-I axis may be used as important markers of the training condition of adolescent swimmers during their preparation throughout a season.

4. What is the hormone response in swimmers? How do these hormones (IGF-I) and proteins (IGFBP-3) change during different training loads?

In our paper “Serum IGF-I, IGFBP-3 and ALS concentrations and physical performance in young swimmers during a training season” you can view a catabolic and an anabolic phase of IGF-I during the season; a behavior that has been hypothesized by several authors as the “two phase theory”. The catabolic phase observed in the present study occurred during the most intensive period of training, and was marked by a reduction in serum IGF-I concentrations (intensive phase). This phase preceded the anabolic phase, which took place at tapering and was characterized by an increase in IGF-I concentrations. The clear identification of these two phases (catabolic and anabolic) is due to the controlled distribution of the training loads and intensity used throughout the season.

5. What influences these hormones and proteins?

Others factors can also influence the GH/IGF-I axis beyond exercise, such as the reduction of pre competition weight, high carbohydrate and lipids diet.

6. What was researched and what were the results?

The aim of our study was to analyse if changes in serum IGF-I, IGFBP-3 and ALS concentration in adolescent swimmers could be a marker of training adequacy. In this way, we studied the athletes at different stages of a training season and compared IGF-I, IGFBP-3 and ALS concentration with physical performance parameters and body composition. The results revealed that  serum IGF-I concentrations proved sensitive to both the acute and chronic effects of exercise, while IGFBP-3 concentrations were only sensitive to the chronic effects. Increases in serum IGF-I and IGFBP-3 concentrations coincided with increases in Peak and Average Force at the tapering phase. Tapering is often used when trying to achieve the best athletic performances in the training season, in preparation for the main competitions of the year. Thus, it can be suggested that these components of the GH/IGF-I axis may be used as important markers of the training condition of adolescent swimmers during their preparation throughout a season.

7. How could someone get proteins tested?

Blood samples were collected before the start of the training session, following 30 min of rest, and 60 minutes after the end of the session. Samples were kept at 0-4ºC until centrifugation and the serum stored at -80ºC until analysis. Serum concentrations of IGF-I, IGFBP-3 and ALS were determined by specific immunoassays using commercial kits.

8. Who should have these proteins tested and why?

In our studies with soccer, Jiu-Jitsu and swimming we found that both IGF-I and its IGFBP-3 binding protein can be used as training state biomarkers in both adult athletes and adolescent athletes. The evaluation of possible changes in IGF-I concentrations and their binding proteins may be of interest for:

  1. Directly interfere with the performance of athletes;
  2. In their process of growth and development.

9. What can be done in this field of research?

Further studies that follow the training program of young athletes and its effects on the body are necessary; including analysis of cytokines, insulin, glycaemia and other IGF-I binding proteins that may explain the reduction in growth mediators at certain training phases and explore the potential repercussions of this suppression on the growth and development of adolescent athletes.

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