title: Factors affecting the estimation of physical working capacity at the fatigue threshold.
abstract: The purpose of this study was to investigate potential improvements in the methodology associated with the Physical Working Capacity at the Fatigue Threshold (PWCFT) test including: (1) the use of a continuous test protocol; (2) the use of a treadmill; (3) the use of a bipolar EMG lead system for noisy electronic environments; and (4) the potential for residual fatigue from tests repeated 24 hours apart. The results of the continuous test protocol (mean +/- S.D. = 210 +/- 73 watts) correlated well (r = 0.856) with the original discontinuous technique (222 +/- 83 watts) and there was no significant (p greater than 0.05) difference between the mean values (t = 1.146). Treadmill testing required a bipolar lead system to counteract the electrical noise generated by the treadmill motor. The heart rate values which corresponded to PWCFT on the treadmill (mean +/- s.d. = 164 +/- b.p.m.) and bicycle ergometer (153 +/- 18 b.p.m.) were highly correlated (r = 0.833) and there was no significant (p greater than 0.05) difference between the mean values (t = 2.22). The use of a bipolar lead EMG system on the bicycle ergometer resulted in significantly (p less than 0.05) smaller voltage for any given power output, and the PWCFT exhibited a low to moderate correlation (r = 0.60) with PWCFT derived from a unipolar arrangement. The test-retest results of discontinuous PWCFT measurements performed 24 hours apart on the bicycle ergometer were correlated at r = 0.812 with no significant (p greater than 0.05) difference (t = 0.52) between the mean values (test = 198 +/- 60; retest = 191 +/- 63 watts).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Human Performance Laboratory, University of Nebraska-Lincoln 68588-0138.
authors.forename: H A
authors.initials: HA
authors.lastname: deVries
authors.forename: T J
authors.initials: TJ
authors.lastname: Housh
authors.forename: G O
authors.initials: GO
authors.lastname: Johnson
authors.forename: S A
authors.initials: SA
authors.lastname: Evans
authors.forename: G D
authors.initials: GD
authors.lastname: Tharp
authors.forename: D J
authors.initials: DJ
authors.lastname: Housh
authors.forename: R A
authors.initials: RA
authors.lastname: Hughes
mesh_terms: D000328:Adult; D000368:Aged; D005080:Exercise Test; D005189:False Positive Reactions; D005221:Fatigue / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D005082:Physical Exertion / Q000502:physiology*; D012016:Reference Values; D014938:Work Capacity Evaluation