title: Relationship between perceived exertion and blood lactate concentrations during incremental running test in young females.
abstract: BACKGROUND
  To investigate more practical handling of Borg's ratings of perceived exertion (RPE) and category-ratio scale of RPE (CR-10), we evaluated interrelationships between RPE, CR-10, and blood lactate concentrations (bLa) during incremental treadmill running tests for young females with different aerobic fitness levels.
  
  
  METHODS
  Oxygen consumption, heart rate, bLa, RPE, and CR-10 were measured from distance runners (DR; n = 15), race walkers (RW; n = 6), and untrained females (UT; n = 11). These variables corresponding to the lactate threshold (LT) and onset of blood lactate accumulation (OBLA) were compared among these groups.
  
  
  RESULTS
  The UT had significantly lower RPE at LT than DR and RW, although the CR-10 at LT was not significantly different among these groups. The CR-10 at OBLA was significantly lower for the UT than DR. The relationship between bLa and CR-10 was approximated well by two linear regression lines in all groups. The bLa at the intersection only for the RW was significantly lower than that at LT, however, such intersections were observed at CR-10 = 3.1 to 3.2 without significant group differences. The CR-10 scores at LT and intersections were not significantly different in each group.
  
  
  CONCLUSIONS
  These results suggested that an intersection between CR-10 and bLa was observed at the CR-10 score around three points of first half regardless of the aerobic fitness levels in young females, and such CR-10 scores would be associated with LT.
authors.affiliation: Biodynamics Laboratory, Center for Health and Sports Science, Kyushu Sangyo University, 2-3-1 Matsukadai, 813-8503 Higashi-ku, Fukuoka Japan.
authors.forename: Daijiro
authors.initials: D
authors.lastname: Abe
authors.affiliation: Department of Health and Sports Sciences, Graduate School of Medicine, Osaka University, 1-17 Machikaneyama, 560-0043 Toyonaka, Osaka Japan.
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Yoshida
authors.affiliation: Department of Environmental and Applied Physiology, Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1 Tsukide, 862-8502 Higashi-ku, Kumamoto Japan.
authors.forename: Hatsumi
authors.initials: H
authors.lastname: Ueoka
authors.affiliation: Department of Health and Physical Education, Faculty of Education, Shizuoka University, 836 Ohya, 422-8529 Suruga-ku, Shizuoka Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Sugiyama
authors.affiliation: Department of Environmental and Applied Physiology, Faculty of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, 3-1 Tsukide, 862-8502 Higashi-ku, Kumamoto Japan ; Faculty of Health and Sports Science, Doshisha University, 1-3 Miyakodani, 610-0394 Kyotanabe, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Fukuoka
keywords: CR-10; LT; OBLA; Physical fitness; RPE; Training