Lactate pro 2 analyzer

In this exercise test athletes had to perform the direct kick (i.e., Apchagui) as fast as possible applied on a taekwondo racket with the dominant and non-dominant leg for 10 s and 1 min. The total number of kicks executed with the dominant and non-dominant leg during the 10 s and 1 min trial was documented for final analysis. Moreover, [La] was measured before and after the 1 min repeated technique tests using the Lactate Pro² Analyzer (Arkray, Tokyo, Japan) and Δ values were used for the final analysis. ICC for test–retest trial from the present study were 0.86 and 0.87 for dominant and non-dominant legs for the 10 s exercise and 0.87 and 0.80 for the dominant and non-dominant leg during the 1 min exercise, respectively.

The 5 m shuttle run test consisted of running as far as possible within 30 s by going back and forth between the start line and lines in the distance of 5 m, 10 m, 15 m, and 20 m. The 5 m shuttle run test is performed 6 times for 30 s with 35 s rest between each trial. During the 35 s recovery period, the athletes returned to the starting position for each of the six repetitions [18 ]. The covered distance was calculated for every repetition in the nearest one meter. The total distance and the best distance recorded during the test were used for final analysis. Additionally, the fatigue index (i.e., (maximum of distance–minimum of distance)/maximum of distance) [18 ] was calculated. Blood samples were collected at 10 min before and immediately after the 5 m shuttle run exercise from the fingertip and [La] was measured using the Lactate Pro 2 Analyzer (Arkray, Tokyo, Japan) and only delta change (Δ) values were used for the analysis. ICC for test–retest trial from the present study of the total covered distance was 0.752.

Before training, fasting blood test, 12-lead ECG at rest and blood pressure measurement were performed. Peripheral lactate was also analyzed before and immediately after the test using a Lactate Pro 2 Analyzer (Arkray Inc., Japan).

Physiological respiratory variables were collected and recorded using a portable Oxycon Mobile gas analyzer (Jaeger, Heidelberg, Germany), taking a sample every 5 s. The gas analyzer was automatically calibrated following the recommended protocols and the manufacturer’s instructions [22 (link)]. Peak blood lactate concentration ((La ⁻)_peak) was measured with a Lactate Pro 2 analyzer (Arkray Inc., Kyoto, Japan), obtaining capillary blood samples from the ear lobe. Heart rate (HR) and running velocity were also recorded using a Forerunner^® 405 watch (Garmin, Olathe, KS, USA). Athletes’ stride length and frequency were measured using individual video analysis with a camera (Sony HDR-CX405, Sony Corporation, Tokyo, Japan) placed in the stadium control tower, with a sampling rate of 50 Hz. The kinematic variables were subsequently analyzed using Kinovea software (version 0.8.7), following previous recommendations [23 (link)]. Running velocity (Vr), stride frequency (SF), and stride length (SL) were calculated every 50 m. This was accomplished by placing 16 marks around the entire track: eight marks at each 50 m partial point, and eight different colored marks at different points to control the parallax effect that could occur when using a single camera.

The determination of the power associated with a blood lactate concentration of 4 mMol·L⁻¹ (P4) was performed on a TACX ergo trainer (Neo Smart 2T, Wassenaar, The Netherlands) in a progressive, continuous test with four or five levels. This test was preceded by a 10 min warm-up period at a power output of 100 W.
The starting power for the test was determined based on somatic characteristics, years of practice, and some performance data, and started at either 130 W or 150 W. Each stage lasted for 6 min, with increments of 30 W from one stage to the next. Capillary blood lactate concentration was measured immediately after each 6 min stage, without pauses. The Lactate Pro 2 analyzer (Arkray Inc., Kyoto, Japan) was used for this purpose.
The test to determine P4 was terminated when the blood lactate concentration exceeded 4 mMol·L⁻¹ at any of the stages performed. Heart rate was measured continuously throughout the test. The average of the last 15 s of each stage was recorded and used as the reference value for that stage.