title: Influence of regression model and incremental test protocol on the relationship between lactate threshold using the maximal-deviation method and performance in female runners.
abstract: This study examined the influence of the regression model and initial intensity of an incremental test on the relationship between the lactate threshold estimated by the maximal-deviation method and the endurance performance. Sixteen non-competitive, recreational female runners performed a discontinuous incremental treadmill test. The initial speed was set at 7 km · h⁻¹, and increased every 3 min by 1 km · h⁻¹ with a 30-s rest between the stages used for earlobe capillary blood sample collection. Lactate-speed data were fitted by an exponential-plus-constant and a third-order polynomial equation. The lactate threshold was determined for both regression equations, using all the coordinates, excluding the first and excluding the first and second initial points. Mean speed of a 10-km road race was the performance index (3.04 ± 0.22 m · s⁻¹). The exponentially-derived lactate threshold had a higher correlation (0.98 ≤ r ≤ 0.99) and smaller standard error of estimate (SEE) (0.04 ≤ SEE ≤ 0.05 m · s⁻¹) with performance than the polynomially-derived equivalent (0.83 ≤ r ≤ 0.89; 0.10 ≤ SEE ≤ 0.13 m · s⁻¹). The exponential lactate threshold was greater than the polynomial equivalent (P < 0.05). The results suggest that the exponential lactate threshold is a valid performance index that is independent of the initial intensity of the incremental test and better than the polynomial equivalent.
authors: Department of Physical Education, State University of Maringa, Maringá, Brazil. famachado_uem@hotmail.com
authors: Fabiana Andrade
authors: FA
authors: Machado
authors: Fábio Yuzo
authors: FY
authors: Nakamura
authors: Solange Marta Franzói De
authors: SM
authors: Moraes
mesh_terms: D000328:Adult; D015308:Anaerobic Threshold; D005080:Exercise Test; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008433:Mathematics; D008875:Middle Aged; D008954:Models, Biological; D010807:Physical Endurance / Q000502:physiology*; D012044:Regression Analysis; D012420:Running / Q000502:physiology*
chemical_list: D019344:Lactic Acid