Study Notes for KNES 355: Human Growth and Development
Course Information
Course Title: KNES 355: Human Growth and Development
Instructor: Leigh Gabel, PhD, Assistant Professor, Faculty of Kinesiology
Course Readings
Recommended Readings:
Human Growth and Development – 3rd Edition by Noel Cameron and Lawrence M. Schell
Available online through the library
Growth, Maturation, and Physical Activity – 2nd Edition by Robert Malina, Claude Bouchard, Oded Bar-Or
On reserve in the library
Reference:
Human Anatomy and Physiology text from KNES 259/260
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Course Objectives/Overview
Objective #1:
Differentiate between the following concepts:
Somatic growth
Maturation
Development
Discuss the rationale for studying Growth, Maturation, and Development
Reference: Cameron Text Chapter 1
Terminology:
Somatic: “affecting the body”
Importance of Studying Growth, Maturation, and Development
Reasons for Study:
Understand biological variation in humans at individual and population levels
How does a child’s growth vary over time?
Within-subject variation
Between-subject variation
Between population variation
Objectives:
Examine the impact of various environments to optimize growth
Physical environment
Nutritional environment
Training environment
Social environment
Human Biological Variability
Definition:
Human biological variability refers to the range of measurable characteristics (physical context) at different levels:
Individual
Group
Population
Influences on Variability:
Genetics
Prenatal environment
Nutritional status
Education
Cultural, social, familial environment
Abuse/neglect
Terminology and Definitions
Somatic:
“of the body”
Somatic Growth:
Growth of the body
Refers to body cells (usually diploid)
Involves tissues, organs, and systems
Includes gross morphological features such as height, weight, and BMI
Variability Factors
Individual Variability
Factors explain somatic changes:
Differences may vary by age and sex
Group Variability
Factors explaining somatic differences between individuals
Practical Applications of Understanding Human Variability
Assessing “normalcy” of Growth, Maturation, & Development status through comparison to reference charts
Evaluating normalcy of rates of change/progress
Predicting future outcomes (tracking growth)
Interpreting the effect of physical activity or exercise on biological outcomes
Lifetime Developmental Stages
Pre-natal Stages:
1st, 2nd, 3rd trimester
Childhood Stages:
Early childhood (1-5 years)
Middle childhood (6-8 for females; 6-10 for males)
Late childhood (9-10 for females; 11-12 for males)
Adolescence (11-19 for females; 13-22 for males)
Young Adult Stage:
19-40 years old
Middle Adult Stage:
40-60 years old
Older Adult Stage:
60 years and older
Key Concepts of KNES 355
Growth:
Increase in the size of the body and its parts
Maturation:
Progress towards a biologically mature state; timing and tempo vary
Development:
Learning appropriate behaviors expected by society, encompassing cognitive, emotional, social, and motor aspects
Overview of Growth
Definition:
A process reflecting quantitative change in size, including length, width, mass, volume, and density; occurs over time or between individuals
Growth Status:
Size attained at any point compared to age or maturity norms
Indicators of Health and Nutrition
Growth is one of the best indicators reflecting genetics and environmental influences.
Common Measures of Size:
Height
Weight
Underlying Processes of Growth
Hyperplasia:
Increase in cell number
Hypertrophy:
Increase in cell size; changes in length, width, mass, volume, and density
Accretion:
Increase in interstitial material
Growth in Skeletal Muscle Tissue
Contributors to Size Changes:
Increase in muscle cell thickness & length doesn't equal increased cell number; shape changes can occur
Concepts of Size
Definition of Size:
Differences in physical magnitude, which are multi-dimensional at various levels (cell/tissue/body)
Measurement of Size:
Quantitatively in absolute units but often expressed relatively (larger or smaller)
Examples of Changes in Size
Head and Legs Comparison:
Head: ~0.8 kg at birth vs. ~6 kg at 18 years
Legs: ~15% of body mass at birth vs. ~30% at 18 years
Considerations of Growth and Maturation
In childhood, growth is predominant, while maturation tempers and affects growth rates; in adulthood, changes in size are primarily due to residual growth potential
Examples of Size Influences in Sports
Relative Age Effect:
Disparities in age within age-grouped sports leading to an advantage for older children born earlier in the year
Consequences of Growth-Related Changes
Alterations in shape may positively, neutrally, or detrimentally impact functions such as biomechanics, thermoregulation, physiology, and reproduction
Maturation Overview
Definition:
Tempo and timing of physical change processes lead towards a mature state; Maturation is a process whereas maturity is a status
Most biochemical systems mature by early adulthood (around age 18)
Characteristics of Maturation
Involves specific changes in tissues, organs, and systems such as secondary sex characteristics and skeletal structures, typically measured by quantitative or qualitative changes
Growth vs. Maturation Recap
Growth:
Refers to increase in size; measurable through height and weight, may occur without maturation changes
Maturation:
Refers to reaching adulthood; indicated by changes in development and increases in some somatic features
Development Overview
Definition:
A broad term encompassing behavioral and biological contexts including learning expected behaviors (cognitive, emotional, social, moral, motor)
Growth vs. Development Comparison
Growth:
Size; structural; easily measurable
Development:
Complexity; functional; more challenging to measure
Change Occurrences in Childhood
Change is consistent but occurs at variable times and rates across various dimensions with predictable effects
Differences in Human vs. Animal Growth
Human growth differs from other species as humans experience a prolonged childhood and a unique adolescent growth spurt
Scammon’s Curves of Systemic Growth
Represents growth patterns and rates across various systems from birth to age 20 with differential tissue growth display
Growth in height is reflected by general growth curves
Features of Human Growth
Unique aspects include the longest growth period among primates, with significant phases such as delayed somatic growth, prolonged infant dependency, and resurgent growth at adolescence
Advantages of Human Growth Traits
Extended growth allows time for critical brain development and acquisition of essential survival and social skills
Human Growth Summary
Every child possesses unique genetic potentials for the characteristic human growth pattern, with considerable variability in the timing and tempo of growth stages across individuals
Growth is primarily focused on size and shape, maturation on timing and rate, and development on quality and complexity, all influenced by genetics and environmental factors.
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Course Objectives and Terminology
Objective #1: Concept Differentiation
Somatic Growth: Refers to the quantitative increase in the size of the body and its parts (e.g., height, weight, mass). It is a structural change involving hyperplasia, hypertrophy, and accretion.
Maturation: The progress towards a biologically mature state. It focuses on the timing and tempo of change rather than size alone.
Development: A broad, functional term encompassing the acquisition of cognitive, emotional, social, and motor behaviors expected by society.
Rationale for Study: Studying these concepts allows us to understand human biological variation and assess the impacts of environment and genetics on life-cycle outcomes.
Terminology:
Somatic: "affecting the body" or "of the body."
Importance of Studying Growth, Maturation, and Development
Reasons for Study:
Understand biological variation at individual and population levels.
Variation Over Time: A child's growth varies through:
Within-subject variation: Changes in an individual's own rate over time.
Between-subject variation: Differences between individuals of the same age/sex.
Between population variation: Differences across different geographical or ethnic groups.
Environmental Optimization: Examine how the following impact growth:
Physical environment (climate, altitude)
Nutritional environment (caloric/nutrient intake)
Training environment (physical activity levels)
Social environment (socioeconomic status, family structure)
Human Biological Variability
Factors Influencing variability:
Genetics and prenatal environment
Nutritional status and education
Cultural, social, and familial factors
Experiences of abuse or neglect
Practical Applications
Assessing "normalcy" using reference charts.
Evaluating rates of change and progress.
Predicting future outcomes (tracking growth).
Interpreting the effects of exercise on biology.
Lifetime Developmental Stages
Pre-natal: 1^{st}, 2^{nd}, 3^{rd} trimesters
Childhood:
Early: 1-5 years
Middle: 6-8 (F), 6-10 (M)
Late: 9-10 (F), 11-12 (M)
Adolescence: 11-19 (F), 13-22 (M)
Adulthood:
Young Adult: 19-40 years
Middle Adult: 40-60 years
Older Adult: 60+ years
Underlying Biological Processes
Hyperplasia: Increase in cell number.
Hypertrophy: Increase in cell size (length, width, volume).
Accretion: Increase in interstitial material.
Notable Growth Comparisons
Mass Changes by Age 18:
Head: \approx 0.8 kg at birth vs. \approx 6 kg at adulthood.
Legs: \approx 15\% of body mass at birth vs. \approx 30\% at adulthood.
Scammon’s Curves: Used to represent the growth patterns of different body systems from birth to age 20$$.
Human-Specific Growth Features
Humans have a unique growth pattern compared to other primates, characterized by:
Prolonged infant dependency.
Extended childhood for brain development and social learning.
A resurgent adolescent growth spurt.
Lecture Engagement Questions for KNES 355
Based on the course introductory materials and key concepts, here are some questions you can use to guide your note-taking and check your understanding during the lecture:
Definitions & Differences
How would you explain the difference between Growth (quantitative) and Development (qualitative) using a real-world example?
Is it possible for a child to experience somatic growth without progressing in maturation? Or vice-versa?
Biological Variation
What is an example of within-subject variation versus between-subject variation in a classroom of grade school children?
Which environmental factors (physical, nutritional, training, or social) does the instructor emphasize as having the greatest impact on biological outcomes?
Cellular Growth Processes
Can you distinguish between Hyperplasia, Hypertrophy, and Accretion? Which of these specifically involves the increase in cell number?
In skeletal muscle tissue, why does an increase in size not necessarily mean an increase in the number of muscle cells?
Human Growth Patterns
Why is the human "prolonged childhood" evolutionarily advantageous compared to other primates?
How do Scammon’s Curves illustrate that different body systems (e.g., neural, lymphoid, genital) do not grow at the same rate?
Practical Applications
How are growth reference charts used to determine if a child’s development is "normal"?
What is the "Relative Age Effect," and how might it influence talent identification in youth sports?
Developmental Stages
At what approximate age do most biochemical systems reach a mature state?
Note the age differences between males and females in Middle and Late childhood; why do these timelines diverge?