exercise physiology driving force behind all types of work conversion of stored energy to mechanical...
TRANSCRIPT
Exercise Physiology
•Driving force behind all types of work•Conversion of stored energy to mechanical energy
What Influences Athletic Ability?
• Genetics• Training
• Training methodology
• Environment• Nutrition• Track/Arena
Surfaces• Shoes• Jockey• Etc.
ATHLETICABILITY
Heart sizeSkeletal muscle
properties
Anaerobic capacity
Gas exchange
Hemoglobinconcentration
Biomechanics
ENERGY
• Sources– Carbohydrates– Fats
• Effect on performance– ↓ energy = ↓ performance– Must meet energy requirement– Monitor body condition
• ↓ body condition = negative energy balance
Energy Metabolism
• Aerobic– With oxygen– Carbohydrate & fat
– CO2, H2O & ATP
• Anaerobic– Without oxygen– Carbohydrate
(glycolysis)– Lactate & ATP
Muscle GlycogenBlood Glucose
Anaerobic Glycolysis
OxidativeMetabolism
Pyruvate Lactate
ATP
Free-Fatty Acids
CreatinePhosphate
Myokinaseand CPKReactions
CO2and Water
Lipolysis
Oxygen
Synthesis of ATP from aerobic and anaerobic metabolism.
Types of Muscle Fiber
• Type I• – Slow contracting• – ↓ glycolytic activity• – Fatigue resistant• – Aerobic metabolism• – Long term/low stress• work• – Endurance
• Type II• – Fast contracting• – Fatigue quickly• – ↑ Glycolytic activity• – Quick energy bursts• – Speed for longer• distances• – Primarily anaerobic
Energy For Muscle Contraction
• Walking– Slow contractions– Primarily type I
fibers– Fat primary energy
source (very efficient)
Energy For Muscle Contraction
• Trot and Canter– Increased contractions
• Increased contractions require more ATP
• Type II fibers• Fat cannot be
metabolized anaerobically
Anaerobic Glycolysis
• Fastest way to produce ATP
• Less efficient than aerobic glycolysis– Less ATP– Lactic acid produced– Decrease muscle pH– Fatigue/tying up
Horses that can generate a higher proportion of energy aerobically will
outperform horses with lower aerobic capacity
Estimated Types Of Energy Used
Event Preformed Energy
Anaerobic Aerobic
Racing QH 80% 18% 2%
Racing 1000 m 25% 70% 5%
Racing 1600 m 10% 80% 10%
Racing 2400 m 5% 70% 25%
Racing 3200 m 5% 55% 40%
Polo 5% 50% 45%
Estimated Types Of Energy Used
Event Preformed Energy
Anaerobic Aerobic
Barrel Racing 99% 4% 1%
Cutting 88% 10% 2%
Show Jumping 15% 65% 20%
3 Day (Cross Country)
10% 40% 50%
Endurance Rides 1% 5% 94%
Pleasure/Equitation
1% 2% 97%
Cardiovascular System
• Heart rate (HR)– Resting 30-45– Exercising – 240 bpm max
• Stroke Volume (SV)– Volume of blood pumped per
beat– 800 – 900 mls
• HR X SV = Cardiac Output– Can pump > 250 li/min– Equivalent to 55 gal drum
Affect of Exercise On The Cardiovascular
System
• ↑ metabolic activity in limbs = ↑ blood flow• Three ways to increase blood flow
– Increase cardiac output• HR and CO proportional to running speed• Cannot ↑ HR beyond max
– Increase O2 carried in blood• Splenic dumping can double O2 carrying capacity
– Redistribute blood flow• ↑ to locomotive muscle• ↓ to kidneys and small intestines
Respiratory System
• Respiratory Rate – Resting - 8-20 breaths per min
• Exercise– ↑ O2 consumption– ↑ CO2 emission
• To increase air exchange– ↑ Respiratory rate
• RR linked to stride freq.• ↑ Tidal Volume (TV)
– Air inhaled or exhaled in a breath
Locomotor-Respiratory
Coupling (LRC)
• Galloping Horse– 150 Breaths– 12-15 liters of air
• Trotting Horse– 70-85 Breaths– 20-25 liters of air
Respiratory Problems• Laryngeal hemiplegia
– Partial paralysis of larynx– Inadequate gas exchange– Surgical treatment
• Chronic Obstructive Pulmonary Disease– Decreases respiratory rate– Hyperallerginc response to dust,
mold, irritants– House outdoors
• Exercise Induced Pulmonary Hemorrhage– Bleeding in lungs– Speeds above 14 m/s– Variable effects– Furosemide (Lasix)
Thermoregulation
• Importance– Evaporative Cooling
(Sweating)– Most important route
of heat dissipation– Requires ample
blood flow to carry heat from core to surface
• Thoroughbred (race)– 2.5 gal
• Endurance horse (50-100 miles)– 6-12 gal
• Three day event (dressage/cross country)– 5-6 gal
Thermoregulation
• ↑ Exercise intensity > ↑ heat load > ↑ need for heat dissipation
• Prevent dehydration to prevent thermal injury– Provision of adequate water– Normal diet– Salt & mineral supplement
Thermoregulation
• Dehydration– Electrolyte & pH disturbances– Fatigue– Gait incoordination (ataxia)– ↑ risk of orthopedic injury– Muscle damage– Death
• Supplement electrolytes– Beginning training program– Adjusting to high temperature
Types of Training
• Endurance– Enhances aerobic
system
• High intensity/Quick burst– Increases muscle mass
– Strength training
Influence of Training
• ↑ heart size
• ↓ HR at given speed
• Quicker recovery to given heart rate
• ↑ Capillaries– ↑ O2 delivered to muscles
• Increase aerobic capacity
Influence of Training
• ↑ Muscle Cell Mitochondria– ↑ O2 utilization per unit of muscle
• Muscle has quickest adaptation to training of all body tissues
Signs of Fatigue
• Respiration rate > heart rate– Inversion– Hyperventilating– Shallow breathing– Shock
• Muscle soreness (lactic acid buildup)• Ataxia• Deydration