Profiling the Aerobic Window of Horses in Response to Training by Means of a Modified Lactate Minimum Speed Test: Flatten the Curve

Abstract

There is a great need for objective external training load prescription and performance capacity evaluation in equestrian disciplines. Therefore, reliable standardised exercise tests (SETs) are needed. Classic SETs require maximum intensities with associated risks to deduce training loads from pre-described cut-off values. The lactate minimum speed (LMS) test could be a valuable alternative. Our aim was to compare new performance parameters of a modified LMS-test with those of an incremental SET, to assess the effect of training on LMS-test parameters and curve-shape, and to identify the optimal mathematical approach for LMS-curve parameters. Six untrained standardbred mares (3–4 years) performed a SET and LMS-test at the start and end of the 8-week harness training. The SET-protocol contains 5 increments (4 km/h; 3 min/step). The LMS-test started with a 3-min trot at 36–40 km/h [until blood lactate (BL) > 5 mmol/L] followed by 8 incremental steps (2 km/h; 3 min/step). The maximum lactate steady state estimation (MLSS) entailed >10 km run at the LMS and 110% LMS. The GPS, heartrate (Polar®), and blood lactate (BL) were monitored and plotted. Curve-parameters (R core team, 3.6.0) were (SET) VLa1.5/2/4 and (LMS-test) area under the curve (AUC>/<LMS), LMS and Aerobic Window (AW) via angular vs. threshold method. Statistics for comparison: a paired t-test was applied, except for LMS: paired Wilcoxon test; (p < 0.05). The Pearson correlation (r > 0.80), Bland-Altman method, and ordinary least products (OLP) regression analyses were determined for test-correlation and concordance. Training induced a significant increase in VLa1.5/2/4. The width of the AW increased significantly while the AUC</>LMS and LMS decreased post-training (flattening U-curve). The LMS BL steady-state is reached earlier and maintained longer after training. BLmax was significantly lower for LMS vs. SET. The 40° angular method is the optimal approach. The correlation between LMS and VMLSS was significantly better compared to the SET. The VLa4 is unreliable for equine aerobic capacity assessment. The LMS-test allows more reliable individual performance capacity assessment at lower speed and BL compared to SETs. The LMS-test protocol can be further adapted, especially post-training; however, inducing modest hyperlactatemia prior to the incremental LMS-stages and omitting inclusion of a per-test recovery contributes to its robustness. This LMS-test is a promising tool for the development of tailored training programmes based on the AW, respecting animal welfare.

Longitudinal Training and Workload Assessment in Young Friesian Stallions in Relation to Fitness: Part 1

“…Previous studies have shown that young Friesian horses transfer to anaerobic metabolism, measured by LA > 4 mmol/L, on relatively low intensity work [48,49]. Using a single cut-off point for LA related to HR or velocity, such as HR LA4 or V LA4 , is not the best predictor for the anaerobic threshold [64,65]; horses often cannot maintain LA constant for a longer period of time on that specific velocity or HR. A fixed cut-off value is often an overestimation of the lactate threshold [65][66][67].…”

“…Using a single cut-off point for LA related to HR or velocity, such as HR LA4 or V LA4 , is not the best predictor for the anaerobic threshold [64,65]; horses often cannot maintain LA constant for a longer period of time on that specific velocity or HR. A fixed cut-off value is often an overestimation of the lactate threshold [65][66][67]. Several tests are described to assess the intensity of exercise that leads to a steady state in lactate production, removal and metabolism and the threshold where anaerobic glycolysis participation starts to increase.…”

“…The lactate minimum speed test (LMS) can be performed in a single exercise test and gives an estimation of MLSS in human athletes. It can assess the individual blood lactate steady state without performance until exhaustion [64][65][66][67]. These tests can also monitor training effects over time.…”

High‐level competition exercise and related fatigue are associated with stride and jumping characteristics in eventing horses

“…Blood samples were withdrawn from the left jugular vein and immediately evaluated on‐site by direct measurement of blood lactate concentrations using a portable hand‐held device (Lactate Pro2, Axon Lab AG), previously validated 17 and tested in horses 18 …”

Determination of speed and assessment of conditioning in horses submitted to a lactate minimum test—alternative approaches

“…Despite advancements in technology and research, much animal training, such as horse training, is still conducted based on empirical methods. These methods are often based on widespread protocols that are not tailored to each animal’s capabilities ( Cunha et al, 2009 ; Ferasin and Marcora, 2009 ; Manzo et al, 2009 ; Alves et al, 2012 ; Rodrigues et al, 2017 ; Impellizzeri et al, 2019 ; Restan et al, 2019 ; De Maré et al, 2022 ). Lactate threshold (LT) is a key marker for running performance and lactate-guided conditioning program has become a cornerstone of endurance training ( Dyson, 2002 ; Poole and Erickson, 2008 ; Singer et al, 2008 ; Peyré-Tartaruga and Coertjens, 2018 ; Impellizzeri et al, 2019 ).…”