Transcript Development Issues in Exercise Science

Development Issues in Exercise
Science
Introduction
Developmental Issues in
Exercise Science
Physical Responses on Exercise
Conditioning in Adolescence
Developmental Continuum
Prenatal
– Embryo
– Fetus
Neonate
Infancy
– Early
– Later
2-8 weeks
8weeks-birth
birth-4 weeks
birth-12 months
12-24 months
Childhood
– Toddlerhood
24-36 months
– Early Childhood (Preschool)
3-5 yrs
– Late Childhood
6-10 yrs
Adolescence
– Pre-pubescence
Females
Males
10-12 yrs
11-13 yrs
– Post-pubescence
Females
Males
12-18 yrs
14-20 yrs
Adulthood
– Young adulthood
– Middle adulthood
– Older adulthood
Young old
Middle old
Frail old
18-40 yrs
40-60 yrs
60-70 yrs
70-80 yrs
80+ yrs
Motor Development
Described as “Progressive change in Motor
behavior throughout the life cycle”
1. Physical Changes
2. Biomechanical Changes
Developmental Changes in Youth
Fitness
Female 9-11, Male 11-13 children’s bodies
begin to changes due to hormonal change with
puberty
These change influence by health-related
physical fitness
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Muscular strength/endurance
Aerobic endurance
Joint flexibility
Body composition
Field based research
– Know about the motor performance of youth is
derived
– Conducted in school, play grounds…
– Realistic motor performance situations
– More relaxed atmosphere than a formal Lab
Muscular Strength and Endurance
Key components of Health-related physical
fitness.
Measurement: bent knee sits-ups, hand grip…
Pre-pubertal growth spurt, girls and boys
follow a same pattern until male growth spurt.
Obvious gender differences are muscle mass
increases of male
Aerobic Endurance
Can use treadmill test to measure maximal;
oxygen capacity in children
Lab tests v.s. Field tests
Female improve their running time until 14 yrs
of age
Male show improvement across age groups
until age 16
Can be due to increase muscle mass in male
and limit physical activity as acquisition of a
driver license in female
Performance-Related Fitness
Components
Exercise Scientist’s Interests
Biomechanist: an increase length
accompanying growing bodies
Physiologist:an increase in body fat on the
performance of a prepubescent girl
Joint Flexibility
Sit and reach is the test most use in determine
flexibility
Generally increases until about age of 16
A reduction in joint flexibility may occur until
the muscles and tendons growth
Body Composition
From age of 10 to 15 yrs, females experience
an increase in body fat
Male undergo an increase in muscle mass and
consistent body fat percentage
May throughout adolescence and subject to
lifestyle behaviors as physical activity levels
and nutritional patterns
Can help researchers establishing weight
reduction strategies and so on.
Youth Sports
American children in 1999 are 13 pound
heavier than same age group were in 1983
10 yrs old required longer time to run a mile in
1989 than those measure in 1980
Modern children may be fatter, less fit, more
susceptible to chronic disease
School system tried to solve budgetary
problem by decreasing physical education
classes of eliminating them entirely
After school youth sport program like
community soccer and Little League baseball
Those program can serve to develop skills for
enjoyable fitness activities
Considerations of Athletic Training
Training principles and injury susceptibility
and prevention
Speed
While pre-puberty, boy’s and girl’s are similar
in their average running velocity and pattern of
speed improvement
While pubertal change begin, male continue to
improve in speed and female begin to plateau
Muscular strength is a major component of
running speeds in male
Girl tends to plateau in speed at about age 11
and may due to puberty-related gain in body
fat
Speed also largely related to genetically
determined muscle fibers type of young
athletes, but improved with training
Muscular Power
The result of a forceful muscular contraction
performed rapidly
Most adolescents participate require muscular
power to successful skill performance
Performance patterns are similar to the patterns
observed in other fitness characteristics
Increases in muscle mass in male and body fat
in female are major contributors to the
performance patterns following the onset of
puberty
Muscle power is highly individual’s
genetically determined muscle fiber
characteristics
Scientist may help determine an athlete’s
potential in a power-oriented skills
Measurement of
muscular power have a
skill component that
may reduce their
validity
Reaction Time
Time interval from the onset of a signal to the
initiation of the appropriate movement
response
Ability to process movement-oriented
information rapidly
Can improve their reaction time throughout
adolescence and then begin to plateau
Factors Influence Reaction Time
The familiarity of the
skill to be performed
The opportunity to
practice the required
skill
The number of
movement choices from
which the performer
must select
Intensive Training and Health
Considerations for the Young Athletes
High-intensity Training Considerations
Children are not miniature adults
Young athletes differ from adult athletes
– Cognitively: conceptualize and strategize in sport
situations
– Psychologically: motivated differ from parents and
coach
– Physically:
– Physiologically: immature bodies response to
intense training
Degree o f Skeletal Maturity
Bone growth take place at the epiphyseal
growth plate
Excessive weight bearing or shearing forces
can result in fractures of the plate
A reduction in blood flow to the growing bone
and subsequent premature cessation of bone
growth
Growth plate remain a concern for
prepubescent and adolescent population until
the ages of 18 to 20 yrs.
Epiphyseal Growth Plate Damage
Overuse injuries due to the repeated
application of many small stresses that by
themselves create no apparent injury as stress
fractures and tendinitis
May have originated before an athlete reached
puberty but cumulative effect may reveal until
adolescence
Thermoregulation in the Young Athlete
Children loss heat rapidly, due to small body
surface area to mass ratio
Children tend to perspire less than adults
When training in warm or hot temp.
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Training lighter than normal
Session should shorter than normal
Frequent rest in the shade
Drink fluids before thirst levels
Training time and intensity should be increased
gradually until athlete become acclimated
When training in cool or cold temp.
– Out of water when not training or competing
– When water below 22℃, stay in the water a
maximum of 15 min
Exercise scientist need to educate about
developmental differences in thermoregulation
and take step to prevent the athlete’s health
Nutritional Concerns
Growing bodies of young athletes require a
healthy diet
Excessive caloric restrictions can result in loss
of bone mineral density
Young athletes have either intrinsic or extrinsic
pressure to obtain a leaner body build may
attempt rapid weight loss by unhealthy
behaviors
Yo-Yo dieting as gain weight after meet and
loss before meet
Resistance Training with the
Prepubescent Athlete
Two concerns
1. Potential damage of epiphyseal plate as a
result of excessive weight bearing on
growing bones
2. Prepubescent resistance training is its
efficacy
Safety Guidelines for Prepubescent
Strength Training Program
Neural Efficacy
Levels of testosterone are need for muscle
hypertrophy to occur and then strength
increase
Short-term weight training in prepubescents
reveal a strength gains occur without changes
in muscle size without hypertrophy may
concern neural efficiency
Adult Development and Aging
Aging is the accumulation of changes in a
person over time
– Juvenile [via infancy, childhood, preadolescence,
adolescence (teenager)]: 0-19
– Early adulthood: 20-39
– Adulthood (20 to 40 yrs)
– Middle adulthood (40-60 yrs)
– Old adulthood (60+ yrs)
The Demographics of Aging
Many factor
contributing to this
trend toward a greater
proportion of older
adults
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Health care
Proper diet
Physical activity
Smoking
The Physiology of Aging
Aging in humans refers to a multidimensional
process of physical, psychological, and social
change
Understanding the effects aging has on specific
physiologic systems assists the professional
working upon principles of
– Task specificity
– Interindividual / intraindividual variability
Nervous and muscular systems are of
particular importance when motor performance
of older adults is examined
Muscle in Aging
With increasing age
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Slow-twitch fiber increase
Fast-twitch fiber decrease
May represent a model of disuse
Total muscle size and muscle strength decrease
Can be test by measuring tape and MRI
– The relationship between muscle size and muscle
strength is not perfect in older adults
The Central Nervous System
Some evidence that the number of brain cells
decreases with advancing age
The numbers of connections or synapses
between brain neurons decrease with age
Motor behavior in older adult may be altered
because of deteriorated neural pathways
Aging brain also susceptible to the reception of
an inadequate amount of oxygen, hypoxia
– The nerve cells’ function and longevity are
affected
Reaction time and Aging
The ability of react quickly to certain
situations may diminished
RT demonstrate a tendency to ward slowing
with age.
Age-related structural changes in the brain are
inevitable, older adults can moderate the
influence of aging on brain function
– Physical activity
Maintenance or enhancement RT ability in older adult
may stem from an increase in cerebral blood flow and
increase oxygen to brain cell
Balance
Involves many variables (vestibular system,
somatosnesory system…)that interacts to
control an individual’s posture and prevent
falls
Seniors may use different methods to recover
from loss of balance (older adults tend to
activate muscle groups of the lower body of a
different pattern)
Compensatory mechanism to prevent falls
– Environmental considerations
Firm surface underfoot
Improving room lighting
– Muscle fitness
Increasing the muscular strength of the ankle, knee, and
hip
Skeletal System
Following skeletal maturity, age-related changes in
bone characteristics are generally not noticeable until
old adulthood
In older adults, reduction in the water content of
intervertebral discs, spinal misalignment, and loss of
bone mineral density
Loss of water in the discs of the spinal column,
reduces their shock absorption and capacities, and
discs compression may reduces the length of spinal
column
Osteoporosis
Bone mineral production and
absorption are ongoing processes
When absorption becomes more
accelerated than what is accounted for
by the normal aging, it is known as
osteoporosis
Two major concerns become apparent
– Brittle bones may experience
fractures form within
Usual seen in vertebae of the
spinal column
– The potential for bone fractures
following event minimal trauma
Sensory Systems
Visual system
– Many changes adversely affect the quality of
vision (fig.)
– Functional changes
Decrease in visual clarity
Reduction in the constricting and dilating properties of
the eye muscle
Decline I n the ability to adapt to dim light settings
– Improvement
Surgical procedure for cataracts
Increasing room illumination
Wearing corrective eye wear
Auditory System
– Presbycusis, or age-related hearing loss, is the
cumulative effect of aging on hearing. Also known
as presbyacusis, it is defined as a progressive
bilateral symmetrical age-related sensorineural
hearing loss (fig.)
– Can be result from a loss of nerve cells in the inner
ear, a decreased in the flexibility of the bones and
membranes of the middle ear, and the increased
secretion of cerumen (earwax)
– Older adults experience tinnitus, which is a
constant ringing or buzzing noise in the ears
Longitudinal Versus Cross-Sectional Aging
research
– Longitudinal research involves observation of the
dame individuals for an extended duration
– Cross-Sectional research might study a group with
similar
aged
Genetics
Lifetime physical activity
Nutritional history
General socioeconomic
Medical background
Intervention Strategies
Compensatory techniques for offsetting these
age-related declined using principles of task
specificity, interindividual and intraindividual
variabilities
Altering environmental conditions
Use medical advances
Increasing muscular strength
Practice postural stability task
Risk Factors for Falling and Possible
Intervention Strategies
Possible Risk Factors
Of the Older Adult
Possible Intervention Strategies
Decrease in muscular strength
Strength training exercise
Assistance device (cones, walkers, handrails)
Decrease in joint flexibility
Active lifestyles
Stretching exercise
Decrease in visual abilities
Increased room lighting
Reduced glare
Eye glasses
Surgical treatment
Decrease in auditory abilities
Removal of cerumen
Hearing assistance devices
Decrease in proprioception
Firm walking surface
Focused attention on task
Allowance for practice of task
Increased motivation
Medicine
Awareness of drug side effects
Awareness of drug interaction side effects
Adapted from Gallahue & Ozmun, 1995
Elite Motor Performance in Older
Adulthood
Gerontology is the scientific study of
the aging process
Chronologic age v.s. biologic age
Motor performance in adulthood is
highly variable
Some older individuals may be come
to frail and suffer serious health
problems at a early older age
Continue to excel in their
performance throughout adulthood
and appear to be minimally affected
by the aging process