Department of Physical Education, State University of Maringa, Maringá, Brazil.
J Sports Sci. 2012;30(12):1267-74. doi: 10.1080/02640414.2012.702424. Epub 2012 Jul 10.
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.
本研究考察了回归模型和递增测试的初始强度对最大偏差法估计的乳酸阈与耐力表现之间关系的影响。16 名非竞技性、娱乐性的女性跑步者进行了不连续递增跑步机测试。初始速度设定为 7km·h⁻¹，每 3 分钟增加 1km·h⁻¹，每个阶段之间休息 30 秒，用于采集耳垂毛细血管血样。乳酸-速度数据通过指数加常数和三阶多项式方程拟合。对于两种回归方程，使用所有坐标（不包括第一个和前两个初始点）来确定乳酸阈。10km 公路赛的平均速度是性能指标（3.04±0.22m·s⁻¹）。与多项式衍生的等效值相比，指数衍生的乳酸阈与性能的相关性更高（0.98≤r≤0.99），估计标准误差（SEE）更小（0.04≤SEE≤0.05m·s⁻¹）（0.83≤r≤0.89；0.10≤SEE≤0.13m·s⁻¹）。指数乳酸阈大于多项式等效值（P<0.05）。结果表明，指数乳酸阈是一个有效的性能指标，与递增测试的初始强度无关，优于多项式等效值。
