ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04724.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04725.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04726.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryThe skeleton consists of a series of elements with a variety of functions. In locations such as the skull, where shape or protection are of prime importance, the bone's architecture is achieved during growth under predominant genetic control. In locations such as the limbs, where the ability to withstand repetitive loading is important, only the general form of the bone will be achieved as a result of growth alone, the remaining characteristics resulting from an adaptive response to functional load bearing. In the horse, this functional loadbearing will be provided by the animal's natural activity pattern in box or paddock supplemented by the specific activities of the training regimen. It is the adaptive response to the total activity pattern that influences bone modelling and remodelling and so determines the bone's architecture. The objective of the training regimen is to ensure that this response achieves an appropriate match between bone architecture and the loads it is required to withstand during both training and athletic performance. We propose that for the match between architecture and load‐bearing to be established, and maintained, subsequently, bone cells must be able to ‘assess’ directly or indirectly the functional strains produced within the bone tissue. Because these strains are used as feedback they are both the objective of functionally adaptive modelling and remodelling, and the stimulus for its control. The mechanisms whereby bone cells control skeletal modelling and remodelling to produce a functionally competent skeleton are unknown although some of the factors and sequence of events involved are presented here. The extent to which variation in training regimen affects bone architecture has not been studied systematically in any sp

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04727.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryEight horses with previous racing experience were used in a comparative study of training methods for Thoroughbred racehorses. They were randomly assigned to two groups of four horses each. One group was trained using an interval training method (IT) and the other using conventional training (CT) methods. Peak heart rates, heart rate recovery curves, peak plasma lactate levels, plasma lactate clearance rates and run times were used to evaluate differences in the training methods. Peak heart rates, heart rate recovery curves, and run times were not significantly different between the groups. However, higher lactate production and increased plasma lactate clearance by the IT group demonstrated an increased anaerobic capacity.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04728.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryThis paper describes the methodology necessary to perform a clinical exercise test and the expected variability in an individual horse's exercise test measurements based on comparing the results of two repetitions of the test with six horses. The exercise test measurements were obtained with an open flow respiratory gas analysis system, fast time response lactate analyser and an on‐board heart rate monitor during an incremental inclined treadmill exercise test. With the exception of peak venous lactate concentration (LACpeak), the results indicate that the mean variability in peak oxygen consumption (V̇O2peak) peak carbon dioxide production (V̇CO2peak), peak respiratory exchange ratio (Rpeak), peak heart rate (HRpeak), peak packed cell volume (PCVpeak), peak total plasma protein (TPPpeak) and the maximum number of steps completed during the exercise test (STEPmax) was less than 5 per cent. Variation in the regression analysis of V̇O2, V̇CO2and HR versus velocity was also less than 5 per cent. Slightly higher variation was recorded for LAC and R. Mean variation in the regression analysis of PCV and TPP versus velocity was more than 16 per cent. Mean variation for all of the post exercise test measurements was less than 10 per cent at 1, 5 and 15 mins post exercise. Therefore, the results obtained during a single exercise test are a reliable assessment of a horse's metabolic capab

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04729.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryClinical exercise stress testing is an important diagnostic tool for evaluating exercise intolerance and degree of fitness in human athletes. The purpose of this paper was to describe the methodology necessary to perform a clinical exercise test and report the results of performance evaluations on 10 Thoroughbred racehorses using this test. The test utilised an open flow gas analysis system for ease of use with untrained horses and a fast time response lactate analyser for rapid data analysis. Exercise test measurements used to evaluate fitness included peak oxygen consumption (mean V̇O2peak = 161.9 ± 12.9 ml/kg/min), peak heart rate (mean HRpeak = 232 ± 10 b/m), peak venous blood lactate concentration (mean LAC peak = 15.2 ± 5.8 mmol/l), peak packed cell volume (mean PCVpeak = 0.64 ± 0.3 l/l) and the maximum number of steps completed (mean STEPmax = 8.7 ± 0.5 steps). The relationship between these exercise test measurements with velocity and time post exercise was also evaluated. Change in serum creatine kinase levels resulting from exercise test were minimal (mean ΔSCK = 72 ±

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04730.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryA greater knowledge of the biomechanics is necessary in equine orthopaedics, therapeutics, farriery and for the selection of athletic horses. The purpose of this study was to determine the normal distribution of the vertical component of the hoof force using a measuring boot. The measurements were carried out using 20 sound horses walking and trotting on a straight hard track. A force measuring horseshoe, attached to the foot with a boot, provided continuous recording of vertical forces at four locations on the hoof. For each measuring location, a computer program produced curves and calculated gait and force parameters. The position of the resultant force moved cranially during the stance phase. The vertical component was not distributed uniformly over the whole hoof surface. Thus the mechanical loading was greater in the caudal area than in the cranial area, especially after the foot impact on the ground. It was concluded that the heels and the quarters seemed to take a prominent part in dampening concussion and supporting bodyweight. More investigations are necessary to establish the relationships between the two functions and the frequent pathology of the caudal region of the foot.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04731.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryTo determine whether maximum oxygen uptake (VO2max) in the horse is influenced by type of exercise test, five different protocols were evaluated in eight untrained Thoroughbreds exercised on a treadmill. With all protocols, horses were given a 5 min warm‐up on a 10 per cent treadmill slope. Three protocols were at a 10 per cent slope and included: 1) increasing the running speed by 1 to 2 m/sec every 60 sees from 4 m/sec to a maximum of 12 m/sec; 2) running at 12 m/sec until fatigue; and 3) running for 3 to 4 mins at speeds ranging from 6 to 12 m/sec with rest pauses between exercise bouts. The fourth protocol employed a 24 per cent slope where animals exercised for 5 mins at 2 m/sec followed by 3 mins at 5 m/sec, and 2 mins at 6 m/sec. The fifth test involved running at 11 m/sec while the slope of the surface was increased every 2 mins until the horses could not maintain the pace. A plateau in V̇O2occurred in all protocols except when exercise was performed on a 24 per cent slope. Slow speed exercise at a steep grade (24 per cent) produced the highest V̇O2(P<0.05) even though there was no plateau in the V̇O2. A steady state for V̇O2and V̇CO2existed 90 secs after the onset of exercise with all protocols which involved 2 mins or more at each speed. The V̇O2and V̇CO2values at all speeds of the rapid incremental exercise test were not different to those found at steady state in the third exercise

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04732.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY

摘要:

SummaryPeak expiratory sound intensity (dB SPL), obtained by means of a radiostethoscope, and peak expiratory flow rate, obtained using a mask incorporating a thermistor flow sensor, were measured in six Thoroughbreds over a range of stride rates from 100 to 140 strides per min. The results show linear relationships between peak dB SPL and stride rate, peak expiratory flow rate and stride rate and also between peak expiratory flow rate and peak dB SPL. Peak expiratory dB SPL can therefore indicate peak expiratory flow rate.

ISSN:0425-1644    

DOI:10.1111/j.2042-3306.1990.tb04733.x

出版商:Blackwell Publishing Ltd    

年代:1990

数据来源: WILEY