Physiology Of Growth, Development, And Maturation In Children And Youth

Front 1

Define differences between growth, maturation, and development.

Back 1

Growth - refers to change in size or body or body parts

Development - functional changes (differentiation of cells)

Maturation - taking on the adult form.

Front 2

Define infancy

Back 2

first year of life

Front 3

define childhood

Back 3

age 1 until puberty

early childhood - preschool

middle childhood - elementary school

Front 4

adolescence

Back 4

puberty to completion of growth and development

most girls: age 8-19
most boys: age 10-22

Front 5

what are the most useful variables when examining rates of change?

Back 5

change in height (cm/yr)

and

change in weight (kg/yr)

Front 6

what ages are peak rates of growth/height in boys and girls

Back 6

height - 12(F) and 14(M)

weight - 12.5(F) and 14.5 (M)

Front 7

When do bones begin to develop, and from what do they develop from?

Back 7

bones begin to develop from cartilage in the early fetal development

most bones develop from hyaline cartilage

Front 8

what is ossification?

Back 8

the process of cartilage transforming into bone

Front 9

when does ossification primarily occur? when does it generally end?

Back 9

usually occurs during fetal development, and during the ages of 14-22 years old.

ossification generally stops in the mid-20s

Front 10

name 5 function of bone

Back 10

1. points of attachment for muscle
2. structure and support
3. protect delicate tissues
4. reservoir for Ca and Phosphorus
5. some are involved in RBC formation

Front 11

How do we build strong bones?

Back 11

strong bones require a blood supply rich in calcium and other essential nutrients.

exercise can improve bone structure by increasing width, strength of bones, and also increase bone density.

Front 12

factors influencing growth and development (5)

Back 12

1. height/weight
2. bone growth
3. muscle growth
4. fat storage
5. nervous system

Front 13

during what period does the body's muscle mass increase?

Back 13

from birth through adolescence,it steadily increases

Front 14

why does muscle development rate peak at puberty?

Back 14

at puberty, there is a tenfold increase in testosterone levels

Front 15

without additional resistance training, when does muscle development peak in boys and girls

Back 15

boys - 18-25

girls - 16-20

Front 16

What is mainly responsible for muscle growth?

Back 16

Muscle growth results primarily from hypertrophy of existing muscle fibers, rather than hyperplasia

Front 17

What does muscle fiber hypertrophy result from?

Back 17

Fiber hypertrophy results from increases in myofilaments and myofibrils.

Front 18

does bone growth have an effect on muscle growth? How?

Back 18

Yes - muscle length will increase with bone length, due to an increase in number of sarcomeres and length of existing sarcomeres.

Front 19

when does fat begin to form and how long does it last?

Back 19

begins at fetal development, and continues to increase exponentially

Front 20

how do %body fats differ at birth vs. maturity?

Back 20

@ birth - 10-12% TBW is fat

@ maturity - 15 (M)-25(F)% TBW is fat

Front 21

Why is fat storage (%BF) higher in women than in men?

Back 21

When females hit puberty, their estrogen levels rise, which causes an increase in body fat deposition.

Front 22

what are some results of a developing nervous system?

Back 22

increases in balance, coordination, agility

Front 23

what is the driving force for a fast-conducting nervous system?

Back 23

Myelination of nerve fibers!

Myleinated cells can conduct quicker impulses and speed the transmission of electrical impulses

Front 24

when does peak strength occur in males and females?

Back 24

males - 20 to 30 yrs

females - 20 yrs

Front 25

How does strength increase? (without resistance training)

Back 25

Strength increase is a dynamic process. Hormonal increases help with muscle mass increases, and nervous cell myelination helps to transmit signals faster to perform more complex movements

Front 26

How do increases in leg strength differ between boys and girls?

Back 26

For boys, leg strength noticeably increases around age 12, while cross-sectional data shows us that girls increase leg strength at a more linear rate.

Front 27

Why do children have lower BP (rest and submax exercise), and why does it steadily increase into adulthood?

Back 27

1.BP is directly related to body size. Children have smaller body sizes so their blood pressure is usually smaller.
2. Children have a lower total peripheral resistance

Front 28

Why do children have a lower stroke volume at rest and during submax exercise?

Back 28

1. children have smaller hearts
2. children have lower total blood volume

Front 29

Why are kid's submax exercise HR higher than adults? (at same absolute O2 requirement)

Back 29

They need to compensate for the lower SV.

Front 30

Why is the AV-O2 difference higher in kids?

Back 30

Again, they need to compensate for the lower SV and decreased peripheral resistance

Front 31

When does VO2 max peak in males and females? How does it decrease?

Back 31

Males - age 17-21

Females - age 12-15 (may decrease at age 15, due to reduction in P.A.)

VO2 max will tend to decrease linearly

Front 32

Why is absolute VO2 max lower in kids?

Back 32

Lower body weights and less blood volume.

(relative to body weight, there is little difference in aerobic capacity b/w kids and adults)

Front 33

Why are boys absolute lung values and peak lung values higher than girls?

Back 33

Boys are generally larger in size than girls

Front 34

For the most part, how do children compare to adults in anaerobic capabilities?

Back 34

Generally, children's ability is much lower than adults, in regards to performing anaerobic activity

Front 35

How does a lower RER affect a child, in regards to their anaerobic capacity

Back 35

low RER values mean that there is less production of carbon dioxide, which in turn indicates less buffering of lactic acid

Front 36

what is PFK

Back 36

Phosphofructokinase

a rate-limiting enzyme of anaerobic glycolysis

Front 37

what is another enzyme, besides PFK than may also be lower in children?

Back 37

Lactate dehydrogenase

Front 38

when will a child's anaerobic capacity be lower than an adults? When will this capacity not be compromised?

Back 38

Activities lasting 15 sec. to 2 min will be compromised (Anaerobic-glycolytic process)

It will not be compromised during bursts of exercise less than 10-15 seconds, because a child's ATP-PCr system is similar to an adults

Front 39

Why do children have a lower running economy than adults?

Back 39

Shorter legs
weaker muscles
lower stride frequency

All these factors increase with age to help improve running economy

Front 40

Can children and adolescents experience an exercise training effect?

Back 40

Yes! Most improvements will be related to growth and development, but improvements can be made due to training. Children will adapt well to same training routine used by adults (with special considerations, of course) - need to age appropriate!

Front 41

How does training affect children's body composition? (includes both aerobic exercise and resistance training)

Back 41

decrease in body weight and fat mass
increase in fat free mass
decrease risk of obesity
increased bone density

Front 42

How does training affect aerobic capacity?

Back 42

Very small increase in aerobic capacity in prepubescent children (5-15%) but has a more substantial effect once the child reaches puberty (increases of 15-25 percent)

this may be related to SV and heart size

Front 43

How do strength increases differ in prepubescent children vs. adolescents?

Back 43

In prepubescents, strength gains come primarily from improved motor skill coordination and increased motor unit activation.

In adolescents, strength increases due to neural adaptations and muscle fiber hypertrophy

Front 44

Can anaerobic training programs improve a child's anaerobic capacity?

How?

Back 44

Yes!
-increased resting levels of PCr, ATP, and glycogen
-increased PFK activity
-increased max. blood lactate levels

Front 45

Describe the training effects on motor ability.

Back 45

Generally increases for the first 18 years of life, but for girls, tends to plateau around puberty.

Front 46

Why do girls' motor abilities plateau around puberty. give 3 reasons

Back 46

1. Increase in estrogen levels at puberty lead to increase in fat deposition, and performance tends to decrease as fat increases

2. girls have less muscle mass

3. social aspect - around puberty, girls become more sedentary, because they are more interested in socializing and less interested in P.A. -- motor abilities plateau

Front 47

How do children respond to thermal stress?

Back 47

-evaporative heat loss is lower, b/c sweat glands produce less sweat
-acclimatization to heat is slower in boys than in older men
-conductive heat loss is greater, increasing the risk of hypothermia
-exercising in extreme temps should be MINIMIZED