title: Knee flexor torque and perceived exertion: a gender and reliability analysis.
abstract: OBJECTIVE
  The objectives of the present study were to examine gender differences and between-day variability of isometric hamstring muscle peak torque and perceived exertion.
  
  
  METHODS
  Subjects included 20 healthy, college-aged male (N = 10) and female (N = 10) volunteers. Each subject completed five maximal voluntary isometric hamstring muscle contractions (MVC), in a prone position, with their knee at 30 degrees flexion. Subjects then completed, in random order, isometric contractions at 10, 20, 30, 40, 50, 60, 70, 80, and 90% of their three highest averaged MVC. Perceived exertion was measured with a modified Borg CR-10 scale after each contraction. Ten randomly chosen subjects were asked to return approximately 1 wk after the initial evaluation to repeat the same procedure. Peak hamstring muscle torque was examined in absolute (N.m), relative (N.m.kg-1), and allometric-scaled (N.m.kg-n) units. Perceived exertion across the contraction intensities was modeled to a power function in order to determine the exponent and proportionality constant.
  
  
  RESULTS
  Males generated significantly greater hamstring muscle torque than females in absolute, relative, and allometric-scaled units (P < 0.05). No significant differences in perceived exertion occurred across the submaximal contraction intensities between females and males, nor for the derived exponents and proportionality constants. Perceived exertion ratings were observed to be significantly lower (P < 0.05) across the contraction intensity range on the second day.
  
  
  CONCLUSIONS
  The major findings demonstrated that perceived exertion did not differ between healthy young female and male adults, despite males generating significantly more hamstring muscle torque, and perceived exertion ratings decreased at similar relative contraction intensity levels across testing days.
authors.affiliation: Human Performance and Fatigue Laboratory, Department of Kinesiology, The University of Toledo, Toledo, OH 43606, USA. danny.pincivero@utoledo.edu
authors.forename: Danny M
authors.initials: DM
authors.lastname: Pincivero
authors.forename: Robert M
authors.initials: RM
authors.lastname: Campy
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Coelho
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology*; D008297:Male; D010465:Perception; D005082:Physical Exertion / Q000502:physiology*; D012727:Sex Characteristics; D019415:Torque