Heart rate and blood lactate responses during the cross-country test of 2-star to 5-star eventing competitions

Abstract

The objective of this retrospective study was to evaluate the physiological demands of cross-country competitions at different levels. Heart rates (HR) and post exercise blood lactate concentrations (LAC) measured between 2010 and 2019 in response to 1,463 cross-country competitions (437 at 2-star, 703 at 3-star, 313 at 4-star and 10 at 5-star level) in 294 horses were analysed. The effect of competition level, mean velocity, height profile, total distance, number of jumping efforts, climate, age, sex, percentage of Thoroughbred blood and performance level on HR, LAC, HR recovery and LAC disappearance rates was evaluated by Linear Mixed Effects Models. Mean HR and LAC significantly increased from 2-star to 4-star level (P<0.001). Each 30 m/min increase in mean velocity was associated with a 3 beats/min increase in HR (P<0.001) and a 41% increase in LAC (P<0.001) and each 30 m increase in cumulative elevation with a 2 beats/min increase in HR (P<0.001) and a 32% increase in LAC (P<0.001). Each 20 m increase in mean distance per jumping effort was associated with a 1 beat/min decrease in HR (P<0.01) and a 13% decrease in LAC (P<0.001). Compared to Warmbloods, horses with 75% Thoroughbred blood had 4 beats/min lower HRs (P<0.05) and 34% lower LAC values (P<0.001). Each 5 years increase in age was associated with a 4 beats/min decrease in HR (P<0.001, only in mares) and an 11% decrease in LAC (P<0.01). The HRs during the first 3 minutes of recovery were higher at warmer and more humid conditions (P<0.05). The rate of LAC disappearance was higher in horses with higher percentages of Thoroughbred blood (P<0.05).

Quantitative Gait Analysis Before and After a Cross-country Test in a Population of Elite Eventing Horses

“…However, the serum muscle enzymes levels were measured four hours after the cross-country test and AST peak activities may not have been captured. Blood LA levels measured immediately after the cross-country test were in the range of those reported by Kirsch et al [32] in CCI3* and CCI4* eventing horses and had a small negative effect on AvstrT. Further studies are required to assess the effect of exercise and fatigue on stride duration.…”

“…One study identified an association between blood LA concentrations measured immediately after show jumping competition and muscle soreness detected two days later in 10 horses [30]. In the current study, post exercise levels of CK, AST and LA were investigated as an indicator of muscular and metabolic fatigue [15,31,32,33]. We found only a small and significant increase in CK activity four hours after the cross-country test but no effect on the gait symmetry parameters nor on stride duration measured the day following the cross-country test.…”

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

“…In our analysis regarding blood lactate concentrations in relation to kinematic characteristics between the jumps, we found an association with the mean running speed over the whole cross‐country test. This is in line with the observations in more than 1400 cross‐country starts at different levels between 2010 and 2019, where an increase in mean speed of 30 m/min was associated with an increase of blood lactate 10 min after finishing of approximately 41% 32 . We found only a weak association between lactate concentrations and mean stride frequency and mean stride length; future studies should focus on reducing the variability of the sample and test these associations under more controlled conditions.…”

“…The frequency of fences in a cross‐country course seems to have a high impact on the exercise intensity of eventing horses. In a recent study, it was found that an increase in total distance (without a proportional increase in jumping efforts) resulted in a decrease in heart rate and lactate concentrations, whereas an increase in jumps led to an increase in these two parameters and this phenomenon was explained by the fact that the technical difficulties of the cross‐country fences make the process of jumping slower provoking faster galloping between the fences with reduced muscle recovery 32 …”

Monitoring Performance in Show Jumping Horses: Validity of Non-specific and Discipline-specific Field Exercise Tests for a Practicable Assessment of Aerobic Performance

“…The internal load imposed on equine athletes competing in different equestrian disciplines has been thoroughly investigated in the last decades. The findings from numerous studies have considerably increased the knowledge of the internal load induced by exercise performed during eventing (Marlin et al, 1995;White et al, 1995a,b,c;Serrano et al, 2002;Kirsch et al, 2020) and endurance competitions (Rose et al, 1983;Serteyn et al, 2010;Larsson et al, 2013;Ertelt et al, 2021). However, there are still relatively few studies that evaluate the internal load that is induced by show jumping competitions (Art et al, 1990a,b;Lekeux et al, 1991;Barrey and Valette, 1993;Bazzano et al, 2016).…”