Motor Learning and Development, N. DiCicco, Ed D

CR Endurance Book Definition  One’s ability to sustain vigorous activity  Includes:  Short burst of intense exercise  a long period of sub-maximal work  A combination of the above  Anaerobic System: ATP-PC & Lactic Acid major energy systems for short bursts of intense exercise (1 sec- 3minutes)  Aerobic System: Aerobic Glycolysis (primary source for > 10 minute sub-maximal intensity)

Anaerobic Energy System & Development  At any age anaerobic performance is related to:  Bodysize- larger, the more Fat Free Mass/Muscle  The ability to metabolize fuel sources (ATP) in the muscle (training/nutrition improves this)

Anaerobic Energy System & Development  Childhood –  Less absolute energy reserves in muscle due to less muscle, thus children have less anaerobic power than adults  As child grows there is a concomitant in anaerobic power (more muscle is growing) Mean power output (bodymass x distance/time) & peak anaerobic power improves as one grows and develops

Anaerobic Energy System & Development  Other factors such as neuromuscular coordination and skill improve anaerobic power as more efficient movements require less energy. (e.g. poor running technique in a sprint).  In adulthood anaerobic power is stable except for training.  Some studies show lost of An. Power of 50% by age 75. This is not conclusive and most likely relates to the concomitant loss of muscle mass with age.

Anaerobic Energy System & Development  ASSESSMENT of An. Power  Wingate 30s bicycle ergometer testergometer test  Margaria step running test Margaria step running test  40 or 5o yd dash.  To be valid it must be a maximum effort (?)

Aerobic System & Development  System depends on transportation of sufficient O2 to the working muscle for long periods of time.  O2 is delivered through in H.R., respiratory rate, Q (cardiac output) & O2 uptake (how much oxygen is taken in from the air and delivered into the blood and ultimately muscle tissue)

Aerobic System & Development  Fick Equation : Q= S.V. x H.R.  Untrained 71 ml per beat vs trained 100 ml per beat.  Training increases Stroke Volume (S.V.) which increases cardiac output  So 71 (untrained) x 70 beats = 4970 ml or 5L of blood moved vs 100 (trained) x 70 beats or  7 L of blood moved, so a trained athlete’s heart will have the same Q with only 50 beats ( 100 x 50 = 5000 ml or 5L)

Childhood & Aerobic Output  Children’s Q < Adults due to a smaller sized heart and thus smaller S.V.  Children have a higher H.R. at any given level of exercise ( to compensate for lower S.V.)  Women have 10% lower Hb level than men thus a lower capacity to deliver O2)  Hemoglobin (Hb) transports O2 in blood.  Can only deliver the amount of O2 that can be carried by Hb, so excess O2 cannot be transported beyond the amount of Hb.  Children have lower HB concentration thus lower ability to transport O2

Childhood & Aerobic Output  Children have lower tolerance for extended periods of exercise  VO2 max linearly in children from 4 – late adolescence in boys & to in females  VO2 max is a better predictor of adult performance  Running tests in children are more accurate predictors of anaerobic performance (1500m or 1 mile run is the best field test)

Childhood & Aerobic Output  As body grows increased ability to sustain exercise  Increases in lung volume, Heart size, stroke volume, Hb, and lean body mass (Structural Constraints)  Better to relate exercise capacity to body size rather than age.  By late adol. Males have edge over females in O2 consumption and work capacity.  Hard to differentiate training effects vs. growth effects. Pre- pubescent children show same increases in SV, Q, BV, Hb as a result of training as adults.

Aging & Aerobic Output  Decrease in Max HR 188 in 20s, s  Q decreases  BP increases due to rigidity of vessels  HB maintained, SV inconclusive  Resp. functin decreases  Training increases most of the above