Neuromuscular and hormonal adaptations during strength and power training. A review.

Increases in muscular strength among initially untrained subjects are relatively easily attained taking place during the earlier weeks of strength training mainly due to neural adaptations with a gradually increasing contribution of hypertrophic factors as the training proceeds. Muscular strength development in strength athletes is much more limited and special attention should be given to high training loading intensity and to individual training programming. The magnitudes and the time courses of the neuromuscular adaptations in strength athletes may therefore differ from those among initially untrained subjects but the actual mechanisms of strength increase may be basically the same. The initial status of the athletes makes the process more complicated to follow and more difficult to substantiate. In strength athletes with a long training background and with a high training volume, the role of endogenous hormone balance may have increasing importance for strength development. During the most stressful training weeks of prolonged strength training the level of biologically active unbound testosterone as well as the balance between the androgenic-anabolic activity and the catabolizing effect of glucocorticoids may be of great importance for the trainability of muscular strength. These observations together with the findings about the specific effects of heavy resistance strength and power training on the neuromuscular performance may also have some implications for the more accurate determination of the trainability status of an individual athlete at a given time in order to optimize the training process.