title: Five-Kilometers Time Trial: Preliminary Validation of a Short Test for Cycling Performance Evaluation.
abstract: BACKGROUND
  The five-kilometer time trial (TT5km) has been used to assess aerobic endurance performance without further investigation of its validity.
  
  
  OBJECTIVE
  This study aimed to perform a preliminary validation of the TT5km to rank well-trained cyclists based on aerobic endurance fitness and assess changes of the aerobic endurance performance.
  
  
  METHODS
  After the incremental test, 20 cyclists (age = 31.3 ± 7.9 years; body mass index = 22.7 ± 1.5 kg/m(2); maximal aerobic power = 360.5 ± 49.5 W) performed the TT5km twice, collecting performance (time to complete, absolute and relative power output, average speed) and physiological responses (heart rate and electromyography activity). The validation criteria were pacing strategy, absolute and relative reliability, validity, and sensitivity. Sensitivity index was obtained from the ratio between the smallest worthwhile change and typical error.
  
  
  RESULTS
  The TT5km showed high absolute (coefficient of variation < 3%) and relative (intraclass coefficient correlation > 0.95) reliability of performance variables, whereas it presented low reliability of physiological responses. The TT5km performance variables were highly correlated with the aerobic endurance indices obtained from incremental test (r > 0.70). These variables showed adequate sensitivity index (> 1).
  
  
  CONCLUSIONS
  TT5km is a valid test to rank the aerobic endurance fitness of well-trained cyclists and to differentiate changes on aerobic endurance performance. Coaches can detect performance changes through either absolute (± 17.7 W) or relative power output (± 0.3 W.kg(-1)), the time to complete the test (± 13.4 s) and the average speed (± 1.0 km.h(-1)). Furthermore, TT5km performance can also be used to rank the athletes according to their aerobic endurance fitness.
authors.affiliation: Department of Neurosciences and Imaging, Gabriele d'Annunzio University of Chieti-Pescara, Chieti, Italy ; Department of Physical Education, State University of Londrina, Londrina, Brazil.
authors.forename: Jose Luiz
authors.initials: JL
authors.lastname: Dantas
authors.affiliation: Center for Biological and Health Sciences, University of Positivo, Curitiba, Brazil ; Department of Physical Education, Federal University of Parana, Curitiba, Brazil.
authors.forename: Gleber
authors.initials: G
authors.lastname: Pereira
authors.affiliation: Department of Physical Education, State University of Londrina, Londrina, Brazil.
authors.forename: Fabio Yuzo
authors.initials: FY
authors.lastname: Nakamura
keywords: Athletes; Evaluation Studies; Power