Date of Award
Master of Science
Human Performance and Sport Studies
David R. Bassett Jr.
Edward T. Howley
During a progressive multi-stage running test, heart rate (HR) increases linearly with running speed. However, the HR eventually reaches a speed where it begins to level off. Conconi et al. call the velocity at HR deflection (Vd) and they repot a close agreement (r = 0.99) between Vd and the lactate threshold or LTdiscont (using a test of there own design). Other researchers have compared Vd to continuous LT protocols (LTcont), and have found that Vd overestimates LTcont. In an effort to determine if the discrepancy results from the different LT protocols used, this study compared LTcont to LTdiscont protocols. Additionally, this study compared Vd to LT on continuous and discontinuous tests. Seven trained runners completed four tests each: 1.) a V O2 max test, 2.) a Concom HR test conducted on a 400 m outdoor track with speeds increasing ~ 0.5 km/h every 200 m, 3.) an LTdiscont conducted on a 400 m outdoor track with six runs at predetermined speeds (3 above and 3 below) Vd and 4.) an LTcont protocol with 3-min stages on a treadmill. There were significant differences (P < 0004) between LTdiscont (16.84 ± 1.72 km/h) and LTcont (13 56 ± 2.29 km/h) The correlation between Vd and LTcont was r = 0.86, while a correlation of r = 0.94 was found between Vd and LTdiscont. In conclusion, Conconi’s LTdiscont significantly over-estimates LT as determined by a conventional LT protocol (LTcont). Therefore, the validity of the Conconi test must be questioned and Vd should not be used as an estimate of LT.
Langley, Jason Glenn, "A comparison of two lactate threshold protocols. " Master's Thesis, University of Tennessee, 2000.