Principal components analysis to evaluate ventilatory variability: comparison of athletes and sedentary men.

The present work quantifies, through principal components analysis (PCA) the relationships among the variability of breath-by-breath ventilatory parameters [minute-ventilation (VE), tidal volume (Vt), and respiratory rate (FR)] during a maximal progressive exercise test. The results show that the first and second eigenvalues of the covariant matrix contains almost 90% of the variables' variance possible to see through the PCA, which means that the problem can be reduced by a two-dimensional analysis. The results show a close similarity between the global variability in two groups test, athletes and sedentary (control). For the athletes group, the parameter Vt is responsible for the high VE variability values while in the sedentary group the FR is more relevant for VE variability. The result improves the knowledge about respiratory variability during exercise, showing that Vt's and FR's variabilities contribute in different ways to global ventilation variability during a maximal cardiopulmonary exercise test in athletes and sedentary men.

Biomechanical analysis of the muscular power of martial arts athletes.

This study analyzes the performance of knee extension and flexion of Taekwondo and Kickboxing athletes. The power values were extracted through electromyography obtained by an isokinetic dynamometer at 60 degrees per second. These values are resulted from the square of the electromyography signal. The analysis of kick power was made using a modified wavelet algorithm considering values with 95% significance. Both groups presented equivalent power and torque capacity with different training times and experience, on the other hand, the wavelet analysis showed better results in muscular recruitment performance in athletes with more experience, in other words, power is not only performance but also power plus recruitment produces better results. This study uniquely showed that muscular enhancement capacity is not only related to the power capacity of contraction but also to motor coordination.