Chapter 6 - Adaptations to Aerobic Training Programs

cardiac output

• stroke volume x heart rate

• initially increases rapidly then more gradually until it reaches a plateau

heart rate increases _____ with increase in intesntiy during aerobic exercise

linearly

oxygen uptake

• amount of oxygen consumed by the body’s tissues

• increases wiht aerobic exercise

blood pressure

increase in systolic BP (up to 220-260 mmHg), diastolic - stays stable or decreases slightly

local circulation

active muscle blood flow increases (at rest 15-20% of cardiac output is distributed to skeletal muscle, with vigorous exercise may rise to 90% of cardiac output)

minute ventilation

• volume of air breathed per minute

• increases due to both frequency and depth of breathing

bradycardia

• slower heart rate

• some endurance athletes resting heart rate can ragne from 40 - 60 bpm

• most significant change in long term 6-12 months of aerobic enduance training is increase in maximal cardiac output primarily from improved stroke volume

• increased muscle fiber capillary density

• decreases the diffusion distance for oxygen and metabolic substrates

respiratory adaptations

ventilation generally does not limit aerobic exercise and is either unaffected or moderately affected by training

neural adaptations

• athletes produces more efficient locomotion during activity with lower energy expenditure

what is good running form?

• head over foot

• upper body twist

• depends on the person running the event

muscular adaptations

• increase in the aerobic capacity of the trained musculature

• athlete performs a given absolute intensity of exercise with greater ease

• for example: an ahtletes who can run the marathon at a pace equal to 75% of VO2 max (maximal oxygen uptake) = the size of aerobic engine, may, after training be able to maintain a pace that is 80% of VO2 max

  • due to gluycogen sparing (less glycogen use during exercise)

  • increased fat utilization within the muscle

  • prolongs performance at the same intensity

bone/connective tissue adaptation

• the key to success of aerobic exercise in stimulating new bone formation is that the activity must be significantly more intense than the daily activities the person normally engages in

  • This must exceed the minimum threshold intensity as well as at a cyclical strain to exceed the minimum and straing frequency for bone growth

  • Eventually, it may become difficult to overload bone through aerobic exercise

• in order to provude ostoegenic stimulus it must exceed what strain the bone is used to

  • endurance runner likely won’t increase bone density by running at similar paces

  • unlike a couch potato who will likely increase bone density with running if they are used to sitting on the couch

who has higher bone density a trained endurance runner or a trained power lifter?

• power lifter because of the muscular contraction

• endurance runners become predictable

endocrine adpatations

• recent evidence suggests that net protein synthesis in skeletal muscle of endurance-trained athletes does occur and may lead to muscle hypertrophy, but most likely is due to mitochondrial rather tahn contractile proteins

aerobic endurance training results in:

• reduced body fat

• increased maximal oxygen uptake

• increased running economy

• increased respiratory capacity

• lower blood lactate concentrations at submaximal exercise

• increased mitochondrial and capillary densities and improved enzyme activity

improved oxygen delivery

• increased stroke volume

• increased cardiac output

• increased blood volume

• increased VO2 max

improved oxygen utilization

• increased capillary density

• increased mitochondrial density

• increased oxidative enzyme activity

improved endurance metabolism

• increased fat utilization

• increased glycogen storage

• increased intramuscular triglycerides

small or variable changes

• fiber size / slight increase

• bone density / slight increase

• collagen content variable

minimal or no improvement

• maximal rate of force production → no change

• vertical jump ability → unchanged

• anaerobic power → no change

• sprint speed —> no change

little structural change in muscle fibers

• fiber size —> no change or slight increase

• myofibrillar packing density —> no change

• myofibrillar volume —> no change

• cytoplasmic density —> no change

• myosin heavy chain protein —> no change or decreases