Quest 3

Why is there limited research in equine exercise physiology?

• Expensive

• Typically performance enhancing methods are seldomly tested because people by the product without testing, so why would the company pay to have the product tested if it could come out as not true?

• Ex: neutraceuticals → feed additive that behave in a medicine way that are developed for dogs or humans

what are some benefits of understanding exercise science?

• Faster race times → not always good

• Fewer injuries → injuries cause setbacks and can be costly

• Fewer working hours spent training → more effective training methods, time is money

how long does a thoroughbred horse, quarter horse, and endurance horse run and how fast?

TB → 1000m - 3000m; 68 km/h

QH → 229m - 796 m; 87.5 km/h

Endurance → 80 km - 160 km;

Why do we train horses?

• Improve on genetic potential

• habituate

• improve body systems

• locomotive efficiency → long stride

• mental fortitude → treats

• reduce injury/breakdown

• delay fatigue

• skill, strength, velocity, distance

what is respiratory gas analysis?

• Measurement of oxygen consumption/aerobic capacity

  • Respiratory Exchange Ratio (RER)

what is RER?

• Respiratory Exchange Ratio

• CO2 produced/O2 consumed

• relative proportions of metabolic fuels used at exercise intensity

• Measure one horse over time to determine if it is getting fitter

• 0.7 = more aerobic

• 1+ = more anaerobic

what is VO2 max?

• Tells you how well the body takes in O2 and transports it through the body

• Measure of O2 consumption

• Good indicator of fitness

• Not an indicator of speed

Can horses blood dope naturally?

Yes, which is why they have such a high VO2 max

• when sprinting stored RBCs in the spleen are released which increases O2 carrying and therefore more ATP is produced

• The transport of O2 is highly reliable on RBC concentration and hemoglobin content

What is the equation for VO2 max?

Rate of O2 consumption = (cardiac output*[(a-v)Do2])

Q = cardiac output → heart rate*stroke volume

Stroke volume → how much blood can the heart pump in each contraction

what is the average resting heart rate for horses?

30-40 bpm

• horses do not decrease resting heart rate with an increase of fitness because it is already low

• Heart rate is hard to measure do to them always being stressed out, leading to an increase in rate

what is a horses maximal heart rate?

240-250 bpm (10x higher than resting)

what is stroke index?

• lets you make comparisons across individuals

• stroke volume/body weight

what is hematocrit?

the percentage of your blood volume that is made up of red blood cells

how to measure hematocrit values?

• Packed cell volume → “PCV” - estimates the size of RBCs

• Levels are at 32-45% at rest and 60-70% during max exercise

What is arteriovenous oxygen difference?

• Two components of VO2 max

• Max [(a-v)Do2] in horses is only slightly greater than humans

• BIGGEST PLAYER:

  • Heart rate drastically increases from rest to active, meaning the cardiac output (Q) and the O2 carrying capacity of blood increases

what are other factors to determine superior athletic ability in horses?

• Locomotive efficiency

  • longer strides are better

  • Form to function → good conformation

• Percentage of VO2 max sustained during prolonged exercise

  • how long can we stay at VO2 max before we fatigue?

what is respiratory frequency : stride ratio?

• 1:1 synchronization at gallop (1 breath = 1 stride)

  • Front legs move backward → thoracic cavity size decreases → more pressure → more air out → guts slide forward

  • Opposite when front legs are less forward

• temp affects respiration

Is respiration a good fitness indicator?

no because high temp/humidity affects how deeply a horse breathes

• Breathing rate is faster in the summer

what is tidal volume?

• Amount of air going in and out in one breath

  • doubles at gallop/sprinting speed

• In horse → tidal volume is doubled at a gallop

what is minute volume

• Amount of air taken in per minute

• increases linearly with speed → should never plateau

• at fast gallop, pulmonary ventilation 8-10x at rest

• important for training techniques evaluated using V200 (velocity that horse travels at heart rate 200/minute)

  • the fitter the horse is, the faster the speed should be before hitting this

describe lactate in horses?

• peak lactate concentrations

  • another indicator of fitness in individual horses

• High acidity in muscle

• Potent cause of fatigue due to low pH

• Can be used to measure for a singular exercise over course of time

• Have a high ability to handle higher levels of lactate

• 
  

what is the importance of cool down in horses?

• Suggested to cool down horses after exercise so that metabolism shifts back to aerobic

• Some training methods are to not cool down horse

  • adapt to increased lactate and high peak lactate levels

What are other factors determining athletic ability?

• Genetics

  • to be great → select the parents

  • 35% variability due to hereditary factors

  • 65% variability due to environmental

• Good reason to concentrate an environmental and training factors

Describe other factors that impact equine exercise?

• nutrition

• training

• shoes

• housing

• track surfaces

• jockey, rider, driver

what are some different training methods?

1. traditional

2. interval

• makes fast twitch fibers turn to FO

• more endurance but slower

• May not prepare horses for high-intensity

1. 3-phase:

• Foundation (continuous → endurance)

• cardiovascular interval (increased intensity, same volume)

• Anaerobic interval (strengthening) → galloping up hills

  • once here, you cannot go backwards or else they will slow down in speed

describe swimming for horses?

• great for cardiovascular, but no concussion on bone, so ill-prepared for work

• Heart rate decreases but high lactate compared to running on land

• Good for rehab

describe muscle fiber composition in horses

• training horses for endurance can’t really change muscle fiber types

• they are designed to have more type 2 (fast twitch, sprinting)

what are the thoughts of using human training methods in horses?

• just because a method works in humans doesn’t mean it works in horse training

• Ex: Don’t carb load or else you will increase chance of colic