ES - Knowledge of Anatomical, Physiological, and Biomechanical differences of athletes Flashcards
(38 cards)
Sex Differences - Body Size and Composition
Stature
BF, Muscle, BMD
Anthropometric measurements
Adult men have greater over stature than adult women.
On average, adult women tend to have more body fat, less muscle, lower bone mineral density, and tend to be a lighter weight than men.
Although some women have lower BF% than men, extremely low BF% in women may be associated w/ adverse health consequences.
Anthropometric measurements: men tend to have broader shoulders relative to hips to support more muscle tissue and provide a mechanical advantage for muscles acting at the shoulder.
Women have broader hips relative to their waist and shoulders.
Sex Differences - Absolute strength
women generally have ~2/3 strength of men. The absolute lower body strength of women is generally closer to male values as compared to the absolute values for upper body strength.
Women are generally weaker than men b/c of their lower quantity of muscle.
B/c the average man and woman differ considerably in body size, it’s useful to compare sex differences in strength relative to… (3)
body weight
fat-free mass
muscle cross-sectional area
Relative to body weight, lower body strength of women is…
If comparisons are made relative to….
Relative to body weight, lower body strength of women is similar to men, while upper body strength of women is still somewhat less.
If comparisons are made relative to fat-free mass, differences in strength between men and women tend to disappear.
Eccentric v Concentric Strength in men v women
data suggests eccentric strength msg be more similar between men and women than concentric strength when compared relative to fat-free mass.
Strength differences relative to muscle cross-sectional area for men v women
when strength is expressed relative two muscle cross-sectional area, no significant difference exists between sexes, which indicates that muscle quality (peak force per cross-sectional area) is not sex specific.
Sex differences and muscle fibers
Even though muscle fibers in men and women are also similar in fiber type distribution sand histochemical characteristics, men tend to have a larger muscle fiber cross-sectional area.
Sex difference and power output
similar to muscle strength.
Women’s power output relative to total body weight was ~63% of men’s during snatch and clean pulling movements.
Vertical and standing broad jumps are lower than men (smaller gap when compared relative to fat-free mass).
Sex related differences in rate of force development and the recruitment strategy of muscle activation partly explain these findings.
Basic differences in physiological adaptations that occur between prepubescents as compared to adults
a
How does bone mineral density change w/ age?
BMD decreases and bone porosity (full of tiny holes) increases, causing bones to become fragile over time.
Osteopenia: BMD of -1 to -2.5 standard deviation of young adult mean/
Osteoporosis: BMD of
Osteopenia and Osteoporosis
Osteopenia: BMD of -1 to -2.5 standard deviation of young adult mean/
Osteoporosis: BMD of
How does force production change w/ age?
Reductions in the size and number and the gradual denervation of muscle fibers lead to a decrease in power generation and force production.
Decrease in force production affects ability for older adults to perform activities like climbing stairs and walking.
Power decreases at a faster rate than muscle strength w/ aging.
Decrease in muscle cross-sectional area, decreased muscle density, reductions in tendon compliance, and increased intramuscular fat after age 30.
How does aerobic endurance change w/ age?
Maximal aerobic power decreases w/ age b/c of reduced muscle mass and strength, and increased fat mass in both trained and untrained.
Aerobic power in men v women
On average, when men and women are matched by age, aerobic power values of women range from 73%-85% of the values of men. These differences may be caused by physiological differences such as: women’s higher BF% and lower blood hemoglobin and men’s larger heart size and blood volume.
Initial adaptations that account for strength gains as a result of resistance training?
What adaptations occur later?
Table 5.2
Unchanged or decreased adaptations to resistance training
Decreased:
Capillary density (no change possible)
Mitochondrial Density
BF%
No change:
Myofibrillar Density
Lactate dehydrogenase
Aerobic power (may increase slightly)
What adaptations of resistance training occur later?
As an individual continues resistance training, the CNS may adapt by allowing the recruitment of more motor units in a nonconsecutive order; i.e. by recruiting larger motor units first to promote greater production of power or speed in a movement.
Level of tissue activation also results from chronic resistance training for hypertrophy. As muscle size increases it doesn’t require as much neural activation to lift a given load. Suggesting the importance of progressive overloading.
Physiological adaptations of aerobic exercise - (Performance) Muscle strength Muscle endurance Aerobic power Max rate of force production Vert Jump Anaerobic power Sprint speed
MS - no change ME - increases for low power output AP - increases Max ROFP - no change or decreases VJ - ability unchanged AP - no change SS - no change
Physiological adaptations of aerobic exercise - (Muscle Fibers) Fiber size Capillary density Mitochondrial density Myofibrillar packing density and volume Cytoplasmic density Myosin heavy chain protein
FS - no change or increase slightly CD - increases MD - increases Myofib. PD and V - no change to either Cyto Den. - no change MHCP - no change or decreases in amount
Physiological adaptations of aerobic exercise - (Enzyme activity) Creatine phosphokinase Myokinase Phosphofructokinase Lactate dehydrogenase Sodium-potassium ATPase
Cr PhoKi. - increases Myokinase - increases PFK - variable LDH - variable NaK ATPase - may slightly increase
Physiological adaptations of aerobic exercise - (Metabolic energy stores) Stored ATP Stored Creatine phosphate Stored glycogen Stored triglycerides
ATP - increases
CP - increases
Glycogen - increases
Triglycerides - increase
Physiological adaptations of aerobic exercise - (Connective Tissue) Ligament strength Tendon strength Collagen content Bone density
Ligament strength - increases
Tendon strength - increases
Collagen content - variable
Bone density - no change or increases
Physiological adaptations of aerobic exercise - (Body comp.)
%BF
Fat-free mass
%BF - decreases
FFM - increases
Performance improvements following anaerobic exercise - (Muscular strength)
During periods of 4 weeks to 2 years, mean strength can increase approx. 40% in untrained 20% in moderately trained 16% in trained 10% in advanced 2% in elite
Positive shift in muscle fiber types for higher-order MU’s. Type Iix transitions to II and reflects greater fatigue resistance at similar absolute force outputs.
