scholarly journals Osteochondrosis decreases the longevity and racing performance of Standardbred trotters and pacers

2021 ◽  
Vol 53 (S55) ◽  
pp. 16-16
Keyword(s):  
Racing Performance

scholarly journals Maximal Isometric or Eccentric Hamstring Strength—Which Test Modality Might Be More Suitable for Assessments in Youth Alpine Ski Racers?

2021 ◽  
Vol 18 (4) ◽  
pp. 2138
Author(s):  
Roland Luchner ◽  
Lisa Steidl-Müller ◽  
Martin Niedermeier ◽  
Christian Raschner
Keyword(s):  
Mixed Model ◽  
Intraclass Correlation ◽  
Test Procedure ◽  
Knee Injuries ◽  
Racing Performance ◽  
Age Appropriate ◽  
Mean Differences ◽  
Fitness Programs ◽  
Test Retest Reliability ◽  
Ski Racers

Background: Physical fitness is an important component in the development of youth alpine ski racers. To write systematically planned and age-appropriate fitness programs athletes need to be physically tested at regular intervals at an early age. Although well-developed hamstring muscle strength is important for alpine ski racing performance and the prevention of serious knee injuries, it has not been well investigated, especially in youth athletes. Accordingly, the first aim of the present study was to assess the test-retest reliability of the maximum bilateral eccentric (MBEHS) and unilateral isometric (MUIHS) hamstring tests. The second aim of the present study was to assess whether the results of these two methods correlate and if it is possible to commit to one of the two methods to provide an economic test procedure. Methods: The first study included 26 (14 females/12 males) youth alpine ski racers aged between 12 and 13 years. All athletes performed two MBEHS and two MUIHS tests, 7 days apart. The intraclass correlation coefficient (ICC 3,1) and their 95% confidence intervals based on a consistency two-way mixed model were used to estimate the reliability of the two different test modalities. The second study included 61 (27 females/34 males) youth alpine ski racers aged between 10 and 13 years. All athletes performed one MBEHS and one MUIHS test. Bland-Altman plots and the 95% limits of agreement as well as correlations by Pearson (r) between the different test modalities were assessed. Results: In study 1 “poor” to “moderate” (MBEHS right leg 0.79 (0.58–0.90); left leg 0.83 (0.66–0.92); MUIHS right leg 0.78 (0.56–0.89); left leg 0.66 (0.37–0.83)) ICC values and 95% confident intervals were obtained. Standard error of measurement (SEM) between trails was between 18.3 and 25.1 N. Smallest detectable difference (SDD) was between 50.8 and 69.5 N. In study 2 mean differences between MBEHS and MUIHS was around 20 N with higher values for MBEHS. Significant moderate-to-strong correlations were found between the test modalities (r = 0.74–0.84, p <0.001). Conclusions: The MBEHS test has higher ICC values, lower CV values, higher SEM values and lower SDD values than the MUIHS test. All this suggests that the MBEHS test is more suitable than the MUIHS test to determine the maximum hamstring force in young alpine ski racers.

36 The DMRT3 “Gait keeper” mutation affects harness racing performance and riding traits in Finnhorses

2015 ◽  
Vol 35 (5) ◽  
pp. 399 ◽  
Author(s):  
K. Jäderkvist ◽  
L. Johansson ◽  
A. Mykkänen ◽  
M. Mäenpää ◽  
L.S. Andersson ◽  
...  
Keyword(s):  
Racing Performance ◽  
Harness Racing

scholarly journals 378 Making-Do When Big Data Isn’t Big Enough: Limitations and pathways of possible development in the prediction of Thoroughbred racing performance as a breeding outcome

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 140-143
Author(s):  
Roger E Lyons
Keyword(s):  
Genetic Resources ◽  
Statistical Data ◽  
Statistical Significance ◽  
Market Demand ◽  
Real World Data ◽  
Positive Effects ◽  
Racing Performance ◽  
Expected Performance ◽  
The Subject ◽  
Thoroughbred Racing

Abstract A performance genetics model adapted to real-world data of Thoroughbred racing and breeding will be presented. The continuity of ancestry and performance is documented in the annals of pedigree, not as functional counterparts, but as corresponding signs of market value. Pedigree invites chronic misprision of highly diverse genetic resources competing for scarce opportunity in the racing economy, resulting in samples that are often small and of dubious composition. Data is specialized for competing “pedigree analysis” that packages the system of signification to meet market demand for meaning. Given statistical deficits, this data is a necessary inferential asset of the model. The model’s premise is that predictability is optimized if racing performance is defined as the function of an indivisible relation between parents. Statistical data consists of 6-generation ancestries of mares that produced offspring by a subject stallion. Comparison of proportions is used to identify effects resulting from his relation to individual ancestors of the subject mare. Expected performance by the sire’s offspring is defined as the proportion of mares that produced a superior runner by him. Each ancestor of a subject mare also has descendants among the mares that produced offspring by the stallion. For each of those groups, the proportion of mares that produced a superior runner is compared with the stallion’s expected performance using a t-test of statistical significance at the .10 level. Probable effect is further tested by case study involving such variables as racing class, generational distance, sex-linkage, inbreeding, and an ancestor’s pattern of effect across the stallion population. Stallions with the highest prevalence of positive effects are preferred for the subject mare. This model, under the trade name LyonScore®, has been used since 2012 by Werk Thoroughbred Constultants, Inc. as a component of its client services. Table 1: The data, listed in tabular format below, is graphically displayed for actual use on an ancestry tree whose nodes are numbered by relation to a subject mare (“Position”). Each statistical data item in the table is derived from the stud record of a stallion named Distorted Humor and corresponds with an ancestor of a mare named Positively Royal. Each ancestor of this mare is also an ancestor of a group of mares that produced offspring of Distorted Humor and were at least three years of age as of 2019. A proportion of each of those groups of mares produced at least one superior runner. Proportions that differ significantly from Distorted Humor’s expected proportion are so indicated. Only ancestors involving a group of at least 18 mares are considered to have inferential value on statistical grounds. Table 2: The sire Danzig is an ancestor of Positively Royal, along with 75 mares that produced foals by Distorted Humor, only five of which produced a superior runner by him, significantly fewer than expected. However, since Distorted Humor’s dam is by Danzig, the question of generational distance is relevant as a variable to the effect of inbreeding. The table below shows Danzig’s proportional distribution by genetic relation to those 75 mares as indicated by “Position.” Of the 64 mares in descent of Danzig within three generations, three mares produced a superior runner. It’s notable, though, that 2 of 6 mares with the same relation to Danzig as Positively Royal produced superior runners. Since Danzig is the only ancestor with a negative effect, further consideration is warranted. Table 3: In a population that tends to slough off unprofitable genetic resources, overspecialization is the main risk of close inbreeding. Some generational variations of an ancestor’s contribution can turn inbreeding to less specialized effect, but this depends on generational distance. Distorted Humor’s earliest opportunity with mares in descent of Danzig involved offspring closely inbred to Danzig, but later in his career he encountered mares for which variation was more likely. As the table shows, two of six mares descending from Danzig in position 25 (4th generation) produced Distorted Humor’s best runners inbred to Danzig, so it is of some interest that Positively Royal, the subject mare, is also a postion-25 descendant of Danzig. However, that those two mares happen to be full sisters whose breeding has little else in common with that of Positively Royal leaves the question of Distorted Humor’s fitness for this mare less certain than would be preferred.

Relationship between exercise-induced systemic inflammatory like reaction and racing performance in endurance horses

2012 ◽  
Vol 8 (3-4) ◽  
pp. 213-218 ◽  
Author(s):  
D. Serteyn ◽  
I. Caudron ◽  
J.-P. Lejeune ◽  
D. Votion ◽  
J. Ceusters ◽  
...  
Keyword(s):  
Plasma Concentrations ◽  
Significant Negative Correlation ◽  
Strenuous Exercise ◽  
Related Factors ◽  
Mean Values ◽  
Racing Performance ◽  
Intrinsic Capacity ◽  
Exercise Induced ◽  
Race Performance ◽  
Voluntary Basis

Endurance race induces a rise of serum creatine kinase (CK) activity and a systemic inflammatory like response characterised by an increase of neutrophil counts, plasma and muscle myeloperoxidase (MPO) and elastase (ELT) concentrations in horses. Horses performing the same standardised exercise test do not respond with the same magnitude of inflammatory reaction. The aim of the present study was to measure the total neutrophil count, the ratio neutrophil:lymphocyte, the MPO and ELT plasma concentrations and concomitant increases of serum CK activities in competing endurance horse and to relate these results to their race performance. Twenty one horses participating in a 120 km 4 star endurance race recruited on a voluntary basis finished the race with a mean speed ranging from 13.1 to 19.8 km/h. Blood was taken the day before the race and two hours after the race. Mean values of neutrophil counts, ratio neutrophil:lymphocyte, plasma MPO and ELT concentrations and serum CK activities after the race were significantly higher than the pre-race values. There was no correlation between neutrophil counts, MPO, ELT or CK and the mean speed of the horses during the race except for the ratio neutrophil:lymphocyte where a significant negative correlation was observed. These results showed that systemic responses induced by strenuous exercise such as an endurance race is not clearly related to performance but also to horse-related factors, such as intrinsic capacity or training.

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