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PHTA 2473 Therapeutic Exercise II AHS 2213 Athletic Training Practicum III. Chapter 6 Endurance. Aerobic Fitness. Ability to do work Expressed as… Aerobic capacity –or- CV endurance –or- CV fitness –or- Cardio respiratory fitness
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PHTA 2473 Therapeutic Exercise IIAHS 2213Athletic Training Practicum III Chapter 6 Endurance
Aerobic Fitness • Ability to do work • Expressed as… • Aerobic capacity –or- • CV endurance –or- • CV fitness –or- • Cardio respiratory fitness • Long duration, low-intensity exercise enhance aerobic fitness
Endurance Activities • Activities that affect CV system • Activities that affect muscular system • Examples?
VO2 Max (maximal oxygen uptake) • Maximum volume of oxygen consumed during exercise • Measure of efficiency of the aerobic system
Aerobic Activity • Uses metabolic pathways that use oxygen to provide energy for muscle contraction • Aerobic metabolism takes place in the Mitochondria • Oxidative capacity • Forms ATP (adenosine triphosphate) • “oxidative phosphorylation” • 19x more ATP produced this way than by anaerobic adenosine triphosphate-phosphocreatine (ATP-PC) system.
Long term aerobic training can improve aerobic fitness approx. 10%-20% • See Box 6-1 p. 100 Shankman
Adaptive Physiologic Changes With Aerobic Exercise • Notable changes in oxygen transport system • Increased size and # of mitochondria • Increased myoglobin content • Improved mobilization/use of fat and carbs. • Selective hypertrophy of Type I slow-twitch fibers • Decreased resting HR and submax HR • Increased blood volume and hemoglobin • Reduced BP • Improved oxygen extraction rates from blood
Measuring and Prescribing Aerobic Exercise • Age-adjusted maximum heart rate (AAMHR) • ACSM minimal training intensity for improved VO2 max 60% MHR • 220-age=MHR • (220-age)(60% to 90%)=THR • Karvonen formula • 50%-85% VO2 max • Maximum heart rate reserve (MHR reserve) • Difference between MHR and RHR • MHR-RHR=MHR reserve • How to figure: • MHR = 220-age • Take RHR • Choose intensity level between 50%-85% of VO2 max • (MHR reserve)(intensity level) • RHR + Intensity level= Maximum training heart rate • Or
Subjective estimate of exercise Patient reported Relative exertion scale Patients perception of exercise Example: 1st person: Walking up hill-13 2nd person: Running up hill-13 Borg Scale of Relative Perceived Exertion
Borg Scale • Borg Scale • 6 • 7 very, very light • 8 • 9 very light • 10 • 11 • 12 • 13 somewhat hard • 14 • 15 hard • 16 • 17 very hard • 18 • 19 very, very hard Endurance Training Zone Strength Training Zone http://www.medicinenet.com/
Frequency, Intensity, Duration • ACSM recommendations: • Frequency • 3-5 days/week • Intensity • 60-90% age adjusted MHR –or- • 50-85% MHR reserve • Duration • 20-60 minutes continuous aerobic activity
Mode of Activity • ACSM recommendations • Activity that uses: • Large muscle groups • Can be maintained continuously • Rhythmic • Aerobic • Examples • Walking • Biking • Jogging • Stair climbing • Rowing • Swimming
Mode of Activity • Initiation/Intensification of aerobic conditioning program • Higher CV risk • Increased rate of orthopedic injury • Decreased compliance with program
Methods of Aerobic Training(2 types) • Continuous Aerobic Activities • No rest interval • Little variation in HR • Examples • Jogging • Walking • Running • Cycling • Stair climbing • What to use in clinic? • Which would burn more calories and use more oxygen: Treadmill or Stationary Bike? • Why?
Methods of Aerobic Training(2 types)-cont. • Discontinuous Aerobic Activities • AKA Interval training • Can involve same activities as continuous • Rest intervals interspersed with bouts of exercise • Advantages • Large amounts of high-intensity work in short amount of time • Tends to develop strength and power vs. endurance • Ratio of work to rest • 1:1 or 1:1.5 • Rest can be passive or active • Which would stress aerobic pathways? • Which would minimize capacity to develop strength and power?
Orthopedic Considerations for Aerobic Conditioning • Can be challenging • Choose appropriate activity for each condition: • Post surgical R/C • HNP • Grade III ankle sprain • ORIF hip fracture • Post op ACL repair
Muscle Fatigue(2 hypotheses) • Attempt to clarify peripheral neuromuscular fatigue as a result of prolonged or strenuous muscle activity • 1st • Decreasing amounts of energy supplies • ATP • Glycogen • Phosphocreatine • 2nd • Noxious metabolites accumulate • Hydrogen ions • Ammonia • Probably combination of both
Circuit Training • Combination of resistance (strength) and aerobic exercise • Goals • Improve local muscular endurance • Improve cardio respiratory fitness • Improve muscular strength • Can customize for desired outcomes • 12-15 exercise stations • Various levels of resistance • 40-50% of predetermined 1 RM • 2 types • Fixed loaded • Load or resistance remains constant • Improvement occurs when circuit is completed in less time • Target • Time required to complete remains the same • Complete as many reps as possible in prescribed time • 2 ways to perform • 15-20 second bouts-no rest • 30 second bouts-15 second rest in between
Combining Endurance and Strength • Goal • Improve strength • Strength training combined with moderate, long duration endurance program • Goal • Improve endurance • Strength and high intensity interval training • SAID principle