Exam 1 Flashcards
(201 cards)
What are the 5 physiologic adaptations of the equine athlete
- Large maximal aerobic capacity
- Large intramuscular glycogen stores
- High volume of intramuscular mitochondria
- Splenic contraction
- Gait efficiency
What is the benefit of having max aerobic capacity in the athletic horse
It increases cardiac output, stroke volume and hemoglobin concentration which enhances the oxygenation of blood in the lung and supports a high metabolic rate
Why would you want an increased hemoglobin concentration
Because it increases the oxygen carrying capacity of blood
What fuels music contraction at high intensity (anaerobic) exercise
Glycogen
When does fatty acid oxidation became limited and carbohydrate stores recruited
At 40 - 60% VO2 max
What does vo2 max mean
The max oxygen the body uses during exercise
What is utilized when carbohydrate stores are used for oxygenation (which is why athletic horses have an advantage)
Glycogen
Oxidative capacity of the muscle is directly proportional to
The number of mitochondria per unit of muscle
What provides energy for muscle contraction und is critical for aerobic contraction
Mitochondria
Compare the amount of mitochondria in equine muscles to cow muscles
Equine muscle have 2x the amount of mitochondria than cattle due to work differences
What’s more efficient - aerobic metabolism or anaerobic metabolism
Aerobic metabolism
When does splenic contraction occur in horses
Before and during exercise
What is the benefit of splenic contraction
Increases circulating red cell mass (hemoglobin) without increasing plasma volume and increases oxygen carrying capacity of blood (by 50%)
What is critical for equine athletes muscle perfusion and performance during exercise
Splenic contraction because of the increased red cells and increased o2 carrying capacity
What gives the horse the ability to have a catapult like gait and decreases the size of the muscle
Stored elastic energy in muscles and muscle tendon units
Gait efficiency in horses allow for more work with less
Less muscle mass due to stored elastic energy
What is it called when thoroughbreds race long distances over brush like obstacles
Steeplechase
What type of injuries are often seen in steeple chase racing
High speed casualties and repetitive injuries from multiple compression cycles - seen often in thoroughbreds
Where are the injuries likely to be when galloping in races like steeplechases
Fetlock and carpus injuries common - max hyper per extension of carpus and fetlock particularly the right front because the right front bears all the weight
What horse breed does more of the trotting and pacing and why
Standardbreds - more heavily muscled, longer bodies, not as tall
Compare racing injuries between thoroughbreds and Standardbreds
Injuries usually less severe in Standardbreds compared to thoroughbreds because Standardbreds use a 2 beat gait, meaning less rotational forces that reduce the risk of overload injuries like the right front overweight bearing of the gallop done by thoroughbreds
What is the benefit of the 2 beat gaits done by standardbred trotters and pacers
More equal distribution of load which reduces the risk of overload injury, catastophic injuries, and long bone pathologies
What is a breakdown injury
Traumatic disruption of the suspensory apparatus
Slab or chip fractures happen usually at the -
Carpus