ABSTRACT
OBJECTIVE: The aim of the study is to verify the performance trajectory related to age, classification (KL: kayak level; M: male; F: female), and sex of elite kayak Para canoe athletes. DESIGN: This is a retrospective cohort study. RESULTS: Race results and athletes' data were retrieved from publicly available online databases for 17 competitions and 102 finals between 2015 and 2022. Race time reduced over the years except for KL3-M class. There was a reduction in the relative difference between KL2-M and KL3-M over the years ( r = -0.83, 95% confidence interval = -0.34 to -0.97, P ≤ 0.05). In addition, no significant differences were found in race times relative differences between KL2-F and KL3-F over the years. Although the correlation between age and performance was only found to be statistically significant in the KL3-F class, the ages of all classes (35.2, 32.6, 29.5, 34.6, 37.6, and 30.6 yrs for males and females KL1, KL2, and KL3, respectively) were higher than those in Olympic canoeing (27.8 yrs). CONCLUSIONS: Race times have improved overall since 2015, but not for the KL3-M class. Nevertheless, because of the stochastic ages of the finalist athletes, it was not possible to determine the age at which peak performance is achieved in all classes. Kayak Para canoe classes should be monitored in the coming years to determine whether interventions are necessary to improve differentiation.
ABSTRACT
Mechanomyography (MMG) is a non-invasive technique that records muscle contraction using sensors positioned on the skin's surface. Therefore, it can have its signal attenuated due to the adipose tissue, directly influencing the results. This study evaluates the influence of different mass added to a sensor's assembly and the adipose tissue on MMG signals of elbow flexor muscles. Test protocol consisted of skinfold thickness measurement of 22 volunteers, followed by applying 2-3 s electrical stimulation for muscle contraction during the acquisition of MMG signals. MMG signals were processed in the time domain, using the average of the absolute amplitude, and expressed in gravity values (G), termed here as MMG(G). Tests occurred four times with different sensor masses. MMG data were processed and analyzed statistically using Friedman and Kruskal-Wallis tests to determine the differences between the MMG signals measured with different sensor masses. The Mann-Whitney analysis indicated differences in the MMG signals between groups with different skinfold thickness. MMG(G) signals suffered attenuation with increasing sensor mass (0.4416 G to 0.94 g; 0.3902 G to 2.64 g; 0.3762 G to 5.44 g; 0.3762 G to 7.14 g) and adipose tissue.
