Lactate pro 2 lt 1730

Participants performed a time-to-exhaustion (TTE) test on a treadmill at T1D3 and T2D3 using a high-intensity intermittent exercise (HIIE) protocol (Figure 2). Utilizing the same setup as VO₂ peak testing (see above), participants wore a facemask connected to a metabolic cart system to analyze oxygen uptake along with a heart rate monitor and custom-made overhead safety harness throughout the duration of the test. The TTE test consisted of 1.5-minute work bouts at the speed associated with their VO₂ peak (sVO2 peak) at 10% grade, calculated using American College of Sports Medicine (ACSM) metabolic equations [45 ], followed by active recovery for 1.5 minute at 3.2 km/h at 8% grade until voluntary exhaustion. Before starting the protocol, resting HR and VO₂ were obtained followed by a three-minute warm-up at 3.2 km/h at 8% grade. The average oxygen uptake for each 90 second work bout was determined and divided by the estimated oxygen uptake requirement, according to the ACSM metabolic equations [45 ], resulting in a calculated percent predicted oxygen uptake for each 90 sec work bout [46 (link)]. Participants were instructed to complete as many work intervals as possible and the total number of intervals completed was recorded for each participant. Participants were not informed of how many intervals they had completed if they failed to maintain a personal count in order to avoid introducing bias. Consistent verbal encouragement was provided by the research team throughout the TTE. If a participant stopped in the middle of a work interval, the fraction of the interval completed was included in the total number of intervals. Blood lactate was measured from the fingertips at rest, immediately after exercise, and three, five, seven, and ten minutes after exercise using a handheld device (Lactate Pro 2 LT-1730, Arkray Inc., Japan). The peak blood lactate measurement post-exercise was recorded so that baseline and peak blood lactate measurements were obtained, and delta lactate levels (Δ lactate) calculated by subtracting baseline lactate from peak post-exercise lactate at each time point.
Figure 2.

Overview of time-to-exhaustion test protocol. sVO2 = speed associated with the participant’s VO2 peak; created with BioRender.com.

Olbrecht (19 ) recommends that ċLa_max should be obtained and measured during a maximal sprint exercise of 10–15 s. In swimming, Mavroudi et al. (21 (link)) reported that ċLa_max values obtained in a 25 m all-out swim were significantly higher than those obtained in 35 m and 50 m all-out swims, shorter duration is appropriate for investigating ċLa_max. Instead of a 25 m all-out swim, we adopted a 20 m sprint swim of front crawl starting from a floating position at the 5 m mark. As it is reported that ċLa_max is a limb and movement specific parameter (15 (link), 18 (link)), this procedure eliminates the movement of the block start or wall push and the underwater phase and make it possible to execute the sprint exercise with front crawl swimming movement only. Our preliminary investigation confirmed that the duration of this swim sprint can last approximately 11 s, which falls within the range recommended by Olbrecht (19 ). ċLa_max was determined using Equation 1 (13 (link), 19 , 25 (link)): $\dot{\mathrm{c}}\mathrm{L}{\mathrm{a}}_{\max }=(\mathrm{L}{\mathrm{a}}_{\max }\text{–}\mathrm{L}{\mathrm{a}}_{\mathrm{pre}})/(t_{\mathrm{sprint}}\text{–}{t}_{\mathrm{alac}})$ where La_max is the highest Bla after the 20 m sprint, La_pre is the Bla measured during the passive rest before the sprint, t_sprint is the time to complete the 20 m sprint, and t_alac is the estimated time when energy is delivered by the alactic system.
Bla was measured using a portable analyzer (Lactate Pro2, LT-1730, Arkray, Kyoto, Japan). Considering the reliability and accuracy of the measurement device (26 (link)), each Bla was examined using two analyzers, and then the average value was used for analysis. Immediately after completing the 20 m sprint swim, participants were seated on the pool deck. An examiner started a stopwatch at the moment swimmer completed the 20 m sprint. Blood was sampled from the fingertips at precise one-minute intervals. The sampling and measurement process continued until the mean Bla value was lower than the previous measurement, indicating that the peak had been reached and passed. The timing of the blood sampling was consistent for all participants, ensuring standardized data collection across the study. The highest value was taken as La_max, and the time to reach La_max after the sprint (tLa_max) was also examined. Two digital cameras (GC-IJ20B; Sports Sensing, Fukuoka, Japan) were set at 5 m and 25 m points to capture the timing of the passage of an LED marker attached to the participant's head through 5 m and 25 m marks of the pool. Their passing times and t_sprint were analyzed using 2-D motion analysis software (Frame Dias V, Q'sfix, Tokyo, Japan). Camera synchronization was achieved through an LED system (LED synchronizer, Q'sfix). t_alac is the period at the beginning of exercise for which no lactate production is assumed. In cycling exercise, t_alac can be determined as the time when power output decreased by 3.5% from peak power output directly measured during the maximal sprint (27 (link), 28 (link)). However, as it is difficult to measure the power output during swimming exercise, a fixed standard value of 3 s was used for t_alac in this study according to previous research (13 (link), 29 (link)). Eleven participants were retested with the same procedure within 4 days to confirm the reliability of the measurement data.

At the onset of parturition, a 10-mL blood sample was collected from ewes when visible contractions were seen, or the amniotic sac was expelled, then again 4 h after the second lamb was born. Ewe blood samples were immediately measured for blood gas, chemistry, and metabolites using a blood gas analyzer (EPOC, Alere, Waltham, MA, USA). Blood samples were then processed and stored as described in the ewe prepartum measures section. Immediately after a lamb was born, a 1-mL blood sample was collected via jugular venepuncture using a 2-mL syringe and 21G 1″ needle to measure blood lactate (Lactate pro 2 LT-1730, Arkray Global Business, Inc. Japan). When a lamb was born, the time of birth, assistance at parturition (yes/no), and meconium score (1, no staining; 2, mild staining; 3, moderate staining; and 4, severe staining) were recorded (Castro-Nájera et al., 2006 (link)).

Sweat extraction was carried out by following a previously proposed method with minor modification^{19 (link),20 (link),25 (link)}. The ball of subject’s forefinger was cleaned with running 1 vol% ethanol-water for 15 sec. 30 μl of Dulbecco’s phosphate buffered saline (DPBS, 2.7 mM KCl, 137.0 mM NaCl, 1.5 mM KH₂PO₄, 8.1 mM Na₂HPO₄, pH 7.4) was put into a 0.6 mL of microcentrifuge tube (ASONE, 6.0 mm in diameter). The microcentrifuge tube was put on the washed skin surface as DPBS was contacted with skin surface for an arbitrary amount of time. After that, the components in the collected DPBS was quantified using commercially available L-lactate sensor (Lactate pro2 LT-1730, Arkray) or Na⁺ ion meter (Horiba, LAQUAtwin Na-11).

One hundred and fifty-three HR recordings from 17 participants during the three game formats (9 matches per participant; 3 for each game format) were analyzed. Exercise intensity was assessed using HR monitors (Firstbeat Technologies Ltd., version 4.5.0.2, Jyväskylä, Finland). Selected HR zones were ≤60, 61–70, 71–80, 81–90, 91–100% HR_max. In this study, the individual HR_max was determined as the highest value reached either during the VO_2max test, YYIE1 or matches, according to a multiple testing approach [43 (link)]. Capillary blood samples (30 μl) were drawn from the right earlobe to determinate BL concentrations (306 records from 17 players), at baseline (resting conditions) and at the end of the first and third period of the matches. For this analysis, a portable electroenzymatic lactate device analyzer (Lactate Pro 2 LT-1730, Arkray, Amsterdam, The Netherlands) was used. RPE is a practical, reliable and valid tool to estimate internal load and adding differential RPE (i.e., respiratory and muscular), may increase the sensitivity of internal load measurements [44 (link)]. Therefore, differential RPE [45 (link)] and fun levels (using a visual analogic scale; 0–10 AU) [46 (link)] were registered at the end of all game formats. Participants were familiarized with the use of the considered psychometric scales in training sessions performed before this study.