AUTHOR=da Rosa Rodrigo Gomes , Oliveira Henrique Bianchi , Gomeñuka Natalia Andrea , Masiero Marcos Paulo Bienert , da Silva Edson Soares , Zanardi Ana Paula Janner , de Carvalho Alberito Rodrigo , Schons Pedro , Peyré-Tartaruga Leonardo Alexandre 

TITLE=Landing-Takeoff Asymmetries Applied to Running Mechanics: A New Perspective for Performance

JOURNAL=Frontiers in Physiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2019.00415

DOI=10.3389/fphys.2019.00415

ISSN=1664-042X

ABSTRACT=<sec><title>Background:</title><p>Elastic bouncing is a physio-mechanical model that can elucidate running behavior in different situations, including landing and takeoff patterns and the characteristics of the muscle-tendon units during stretch and recoil in running. An increase in running speed improves the body’s elastic mechanisms. Although some measures of elastic bouncing are usually carried out, a general description of the elastic mechanism has not been explored in running performance. This study aimed to compare elastic bouncing parameters between the higher- and lower-performing athletes in a 3000 m test.</p></sec><sec><title>Methods:</title><p>Thirty-eight endurance runners (men) were divided into two groups based on 3000 m performance: the high-performance group (P<sub>high</sub>; <italic>n</italic> = 19; age: 29 ± 5 years; mass: 72.9 ± 10 kg; stature: 177 ± 8 cm; 3000<sub>time</sub>: 656 ± 32 s) and the low-performance group (P<sub>low</sub>; <italic>n</italic> = 19; age: 32 ± 6 years; mass: 73.9 ± 7 kg; stature: 175 ± 5 cm; 3000<sub>time</sub>: 751 ± 29 s). They performed three tests on different days: (i) 3000 m on a track; (ii) incremental running test; and (iii) a running biomechanical test on a treadmill at 13 different speeds from 8 to 20 km h<sup>−1</sup>. Performance was evaluated using the race time of the 3000 m test. The biomechanics variables included effective contact time (<italic>t</italic><sub>ce</sub>), aerial time (<italic>t</italic><sub>ae</sub>), positive work time (<italic>t</italic><sub>push</sub>), negative work time (<italic>t</italic><sub>break</sub>), step frequency (<italic>f</italic><sub>step</sub>), and elastic system frequency (<italic>f</italic><sub>sist</sub>), vertical displacement (<italic>S</italic><sub>v</sub>) in <italic>t</italic><sub>ce</sub> and <italic>t</italic><sub>ae</sub> (<italic>S</italic><sub>ce</sub> and <italic>S</italic><sub>ae</sub>), vertical force, and vertical stiffness were evaluated in a biomechanical submaximal test on treadmill.</p></sec><sec><title>Results:</title><p>The <italic>t</italic><sub>ae</sub>, <italic>f</italic><sub>sist</sub>, vertical force and stiffness were higher (<italic>p</italic> &lt; 0.05) and <italic>t</italic><sub>ce</sub> and <italic>f</italic><sub>step</sub> were lower (<italic>p</italic> &lt; 0.05) in P<sub>high</sub>, with no differences between groups in <italic>t</italic><sub>push</sub> and <italic>t</italic><sub>break</sub>.</p></sec><sec><title>Conclusion:</title><p>The elastic bouncing was optimized in runners of the best performance level, demonstrating a better use of elastic components.</p></sec>