Chapter 7 Flashcards
Discuss the overall phases of growth, development, and maturation in children.
What is chronological age?
Growth, development, and maturation describe the changes in the body that occur throughout
life.
Growth
• Increase in body size or particular body part
Development
• The natural progression from prenatal life to adulthood
Maturation
• The process of becoming mature and fully-functional
Chronological Age
• The age in months or years
• Not very accurate to define stages of development because children do not grow at
a constant rate
• Substantial differences in development occur between children of the same age
➢ 14-year-old children may differ in height up to 9 inches and weight up to 40
pounds
➢ Children of the same age may differ in physical skills and builds
➢ Differences correspond to variations in timing tempo and magnitude of
growth during puberty - the period of time in which secondary sex
characteristics develop and a child transitions to young adulthood
What is biological age? What role does training age play in development?
What risks does resistance training pose during development? (
Biological Age
• Measured in terms of skeletal age, physique maturity, or sexual maturation
• In women - menarche - the onset of menstruation - is the marker for sexual
maturation
• In boys, sexual maturity is indicated by:
➢ Appearance of pubic and facial hair
➢ Deepening of the voice
• Assessment of maturation can be used to evaluate growth and development
patterns in children.
➢ Helps fairly match children for fitness testing and athletic competition
➢ No evidence that physical training delays or accelerates growth in adequately
nourished children
➢ Osteogenic stimuli essential for skeletal remodeling and growth
• Biological age best determined by skeletal age
➢ Skeletal X-rays compared against standard reference radiographs
• Visual assessment of biological age offers an alternative assessment method
➢ Not practical due to invasive nature (assessment of genitals, breasts, etc)
• Somatic age another option
➢ Longitudinal growth curve analysis
➢ Prediction of age from peak height velocity - age of maximal growth during a
puberty growth spurt
➢ Best assessed every three months for longitudinal assessments
Training age affects growth seen in a given child
• Length of time a child has consistently followed a formalized and supervised
resistance training program
• The magnitude of gain will be affected by the amount of adaptation that has already
occurred
• Peak height velocity typically occurs between age 12 and 14 and may increase risk
of injury - care must be taken to avoid overuse injuries and ensure proper lifting
technique:
➢ Reinforce proper movement patterns
➢ Target flexibility restrictions and correct muscle imbalances
➢ Decrease volume and/or intensity
Discuss the process of muscle and bone growth in youth populations. What
injuries are adolescents particularly susceptible to?
Muscle Growth
• Muscle mass increases steadily throughout developing years
• At birth - ~ 25% of body weight is muscle
• By adulthood ~40% body weight is muscle
• In male puberty - hormonal increases (testosterone, GH, IGF) results in large
increase in muscle mass and shoulder-width
• In female puberty - increased estrogen leads to increased body fat, breast
development, and hip-width
• Muscle mass increase in boys greater than in girls
➢ Both increases are caused by hypertrophy of individual fibers
➢ Peak muscle mass occurs between 16 and 20 in girls unless affected by
training
➢ Peak muscle mass occurs between 18 and 25 in boys unless affected by
training
Bone Growth
• Majority of bone formation occurs in the:
➢ Diaphysis - central shaft of a long bone
➢ Growth cartilage - located in:
▪ Epiphyseal growth plate
▪ Joint surface
▪ Apophyseal insertions of muscle-tendon units
➢ Most bones are fused by early 20s
➢ Cartilage vulnerable to injury from trauma and overuse
▪ Injuries may disrupt blood and nutrient supply
• Results in permanent growth disturbances
▪ Trauma can occur from falls or repetitive stress
➢ Peak incidence of epiphyseal growth damage occurs at peak height velocity
▪ Pre-adolescents may be less susceptible to this type of injury before
they hit peak height velocity
• Injury risk can be lowered by:
➢ The appropriate technique, progression, training loads, and qualified
instruction by strength and conditioning professionals
What developmental changes occur in muscular strength? (
Increases in strength correspond to increased muscle mass throughout adolescence.
• In boys - peak strength gains typically appear 1.2 years after peak height velocity and
0.8 years after peak weight velocity
• Suggest muscle mass increase precedes the ability to express strength with the new
muscle
• Similar for girls but more variation in the strength-weight relationship
• Hormonal responses account for the acceleration of strength in boys during puberty
and plateau in strength in girls
• Myelination of motor neurons required for skilled performance
➢ Full myelination does not occur until sexual maturation
➢ Results in different responses and skill gains between children and adults
Physical functions for a factor of biological age rather than chronological age.
• Early maturing children tend to be mesomorphic - muscular and have broader
shoulders, or endomorphic - rounded and broader hips
• Late maturers tend to be ectomorphic - slender and tall
• Different proportions affect the execution of resistance exercise
➢ Short arms and large chest cavity have an advantage in upper body pressing
➢ Long legs and long torso disadvantage for squatting
➢ Requires individualized resistance training programs for each child
▪ Coaches should use child-sized weights
▪ Coaches should explain to children the difference in programs
▪ Special encouragement for late maturers
What are the general guidelines for youth resistance training programming?
Youth Training Guidelines
• Each child should understand the risks and benefits of resistance training
• Competent and caring professionals should be in charge of program design
• Exercise environment should be safe and free of hazards
• Dynamic warm-ups should be included before training
• Static stretching should be performed after training when appropriate
• Child tolerance to exercise stress must be carefully monitored
• Begin with light loads to allow appropriate adjustments
➢ Gradually increase resistance (i.e. 5%-10%) as technique and strength
improve
• One to three sets of 6 to 15 repetitions on a variety of movements can be performed
➢ Advanced multi joint exercises such as the snatch and clean and jerk may be
incorporated into the program -
▪ requires appropriate loads and technical proficiency
• Two to three non consecutive training sessions per week
➢ Youth with more training age may train more frequently
• Adult spotters should be available to assist the child in the event of a failed
repetition
• Resistance should be periodized throughout the year
➢ Ensures sequential and varied stimulus
➢ Provides for adequate rest and recovery between cycles
What are the primary sex differences between men and women in terms of
strength and conditioning?
Sex-related differences between men and women in terms of physique, body composition, and
response to exercise can help optimize resistance training for female athletes.
Body Size and Composition
• Before puberty - essentially no differences between men and women
• Compared to men, on average adult women have:
➢ More body fat
▪ Excessive low body fat in women associated with health
consequences
➢ Less muscle
➢ Lower bone mineral density
➢ Lighter total body weight
➢ Broader hips relative to waist and shoulder measurement
▪ Broad shoulders in men can support more muscle mass and have
more mechanical advantage
Strength and Power Output
• In absolute numbers, women typically have ⅔ the strength of men
➢ Lower body strength in women closer to male values than upper body
strength
• Sex-related differences in body composition account for much of this discrepancy
• Relative to bodyweight:
➢ Lower body strength similar to men
➢ Upper body strength still less than men
• Relative to fat-free mass:
➢ Differences in strength tend to disappear
➢ Eccentric strength may be more similar to men than concentric strength
relative to fat-free mass
• Overall comparisons suggest that specific muscle quality is not sex-specific
• Power output differences tend to mirror strength differences relative to body weight
• Differences in power output may also be a function of sex-related differences in rate
of force development and recruitment strategy for muscle activation
What considerations are there for youth resistance training? What responses to
resistance training occur in children?
Considerations
• Children are not miniature adults
• Children should begin training at a level commensurate with:
➢ Maturity level
➢ Physical abilities
➢ Individual goals
• Better to underestimate rather than overestimate a child’s abilities
• Do not impose adult training programs and philosophies on children
Responses to Resistance Training in Children
• Children as young as 5 have benefited from resistance training
➢ Must be programmed properly
➢ Maximum strength gains rate reported between 10%-90%
➢ Typically 30-40% improvement in strength
➢ Rate of change attenuated - requires continued progressive training
• Detraining occurs in children who stop resistance training - strength gains return to
typical biological age levels
• Hypertrophy contributes to strength gains in adolescents and adults - less so for
preadolescents
➢ Preadolescent boys testosterone level 20-60 ng/100mL
➢ Testosterone in boys increases to 600ng/mL during adolescence
➢ Testosterone in females unchanged during adolescence
• Neural factors significant in preadolescent gains
➢ Increased recruitment, synchronization, motor unit activation, and firing
frequency
What are the potential benefits and risks of resistance training for children?
What steps can strength and conditioning professionals take to minimize these
risks?
Benefits of Resistance Training for Children
• Increasing strength, power, and endurance
• Decreases body fat, improves insulin sensitivity, and enhances cardiac function in
obese children
• Enhances bone mineral density in children
• May decrease risk of osteoporosis later in life among women
• Preseason resistance training increases resistance to injury
• Overall increase in athletic performance
Potential Risks of Resistance Training for Children
• Appropriate resistance training for children relatively safe compared to typical
sports and recreational activities
• Injuries typically the result of accidents caused by lack of supervision
• Low risk of epiphyseal plate fracture - although possible
➢ Generally associated with heavy overhead lifts without supervision
Reducing Injury Risk in Children
• Evaluate children by sports medicine physician prior to starting a resistance training
program
• Discuss the risks and importance of preparatory conditioning with parents
• Encourage children to participate in long-term training programs with adequate
recovery time between seasons
• Training programs should be multidimensional and include the following
components:
➢ Elements of resistance training
➢ Fundamental movement skills
➢ Speed and agility development
➢ Dynamic stabilization
• Implement well-planned recovery between sessions and competitions
• Ensure youth follow healthy lifestyle habits (sleep, hydration, nutrition etc.)
• Coaches should participate in continuing professional development programs
• Delay sports specialization until adolescence - expose children to a variety of sports
How do women respond to resistance training? What is the female athlete
triad?
Female Responses to Exercise
• Responses to exercise relative to pre-training baselines are similar in men and
women
• Absolute strength gains tend to be higher in men
• Relative strength gains in terms of percentage increase tend to be higher in women
➢ May reflect lower baseline neuromuscular levels in women
• Short term hypertrophy gains (up to 16 weeks) similar between men and women
• Genetic disposition and baseline natural testosterone levels may affect individual
hypertrophy responses in women
Female Athlete Triad
• The interrelationship between menstrual function, energy availability, and bone
mineral density in female athletes
➢ Health-risk for females who train for prolonged periods with insufficient
energy intake to meet energy expenditure
➢ Can lead to:
▪ Reduced BMD and heightened risk of osteoporosis
▪ Amenorrhea - the absence of a menstrual cycle for more than 3
months
• Caused by reduced luteinizing hormone secretion from the
pituitary gland
▪ Risks include:
• Bone stress fractures
• Endocrine and gastrointestinal complications
• Sporting performance decrements
• Resistance training helps attenuate age-related BMD decline via stress from
mechanical loading
➢ Preadolescence is an opportune time to participate in weight-bearing
activities to enhance BMD
• Nutritional intake must support training demands to stimulate adaptation and
recovery
➢ Must ensure sufficient calcium, vitamin D, and protein among other nutrients
➢ Risk of eating disorders often associated with subjective scoring measures
based on physical appearance (i.e. gymnastics, dance)
What are the program design considerations for women? How can female
athletes reduce the risk of an ACL injury?
Very little differences between appropriate strength training programs for men and women.
• Programs should enhance the needs of the individual sport
• The main difference is the absolute workload
• Resistance training in young female athletes crucial for ensuring they reach their
genetic potential
• Main female-specific concerns are upper body strength development and injury
prevention
Upper Body Strength Development
• Emphasizing upper body strength and power in women is crucial for strength and
conditioning
➢ Especially for upper body strength-power dependent sports
➢ Worthwhile to add 1-2 extra upper body exercises or sets
➢ Incorporating snatch and clean derivatives particularly effective
Reducing ACL Injuries
• Female players in sports such as basketball and soccer 6 times more likely to suffer
an ACL injury potentially due to:
➢ Joint laxity
➢ Limb alignment
➢ Body movement
➢ Notch dimensions
➢ Ligament size
➢ Skill level
➢ Hormonal levels
➢ Shoe surface interactions
• Programs should include:
➢ Resistance, plyometrics, agility, and balance training
➢ Focus on correct movement mechanics during jumping, landing, twisting,
cutting
• Women must consume adequate calories, protein, and healthy fat consumption as
part of a well-rounded diet
• Wear appropriate clothing and shoes
What age-related changes occur beyond the age of 30?
Changes to Musculoskeletal Health
• Steady decline of bone and muscle loss with age
➢ Increases risks of falls, fractures, and long term disability
➢ Osteopenia - BMD between -1 and -2.5 standard deviations from adult mean
➢ Osteoporosis - BMD below -2.5 standard deviations from adult mean
▪ Both conditions increase the risk of bone fracture
• Sarcopenia - Loss of muscle mass and strength
➢ Muscle cross-section area begins decreasing around age 30
➢ Most pronounced in women
➢ Results from decreased physical activity and gradual denervation of muscle
fibers
➢ Decreases power as well as strength due to gradual denervation and
decrease in size and number of fibers
➢ May rapidly affect the ability to safely perform daily movements
Changes to Neuromotor Function
• Decreases in reaction time, balance, and postural stability
• Preactivation - muscle contraction before ground contact
➢ Helps increase limb stiffness via fast stretch reflexes
• Cocontraction muscle contraction following ground contact
➢ Increases to offset the decrease in balance and coordination
• Use of low-intensity plyometrics, balance and dynamic stabilization and
proprioception develop the ability to react more efficiently with the ground
• Seniors must engage with and adhere to multidimensional programs that
incorporate resistance and balance training
• Balance and flexibility training must accompany resistance training to reduce risk of
falls
How do older adults respond to resistance training?
Age does not enhance or reduce the ability of the musculoskeletal system to respond to
resistance training.
• Resistance training in older adults can improve:
➢ Muscle strength
➢ Muscle power
➢ Muscle mass
➢ Bone mineral density
➢ Functional capabilities
➢ Quality of life
➢ Risk of mortality (decrease)
• High-velocity resistance training effective for improving power in seniors
• Maximal muscle strength training more effective than low-to-moderate intensity
training
What are the program design considerations for older adults?
Program Design Considerations for Older Adults
• Fundamental principles are the same for older adults as younger adults
• Seniors should complete medical history and risk-factor questionnaires
• Physician clearance may be required
➢ I.e. before vigorous activity with cardiac rehab patients and cancer survivors
• Strength tests should be performed using the intended equipment for the training
program
• Ultimately free weight, multi joint resistance training offer the greatest training
stimulus
• Begin with low volume and intensity for untrained seniors
• Avoid Valsalva maneuver
• Perform low-intensity warm-up of 5-10 minutes prior to resistance training
• Progress from 1 set of 8-12 repetitions at 40%-50% 1RM to three sets at 60%-80%
1RM for strength exercises
• Power exercises should be performed at 40%-60% 1RM for 6-10 repetitions with
high velocity
• Perform exercises using only a pain-free range of motion
• Allow 48-72 hours between training sessions
• Begin with a training frequency of twice per week
