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

1. Assessing “normalcy” of Growth, Maturation, & Development status through comparison to reference charts

2. Evaluating normalcy of rates of change/progress

3. Predicting future outcomes (tracking growth)

4. 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

1. Hyperplasia:

   • Increase in cell number

2. Hypertrophy:

   • Increase in cell size; changes in length, width, mass, volume, and density

3. 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.

• PREP FOR NEXT CLASS

Course Objectives and Terminology

• Objective #1$: Concept Differentiation</strong></p><ul><li><p><strong>Somatic Growth:</strong> 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.</p></li><li><p><strong>Maturation:</strong> The progress towards a biologically mature state. It focuses on the timing and tempo of change rather than size alone.</p></li><li><p><strong>Development:</strong> A broad, functional term encompassing the acquisition of cognitive, emotional, social, and motor behaviors expected by society.</p></li></ul></li><li><p><strong>Rationale for Study:</strong> Studying these concepts allows us to understand human biological variation and assess the impacts of environment and genetics on life-cycle outcomes.</p></li><li><p><strong>Terminology:</strong></p><ul><li><p>Somatic: "affecting the body" or "of the body."</p></li></ul></li></ul><h5 id="4fc9ab48-79ef-4e69-8c8b-aef19b7bfbba" data-toc-id="4fc9ab48-79ef-4e69-8c8b-aef19b7bfbba" collapsed="true" seolevelmigrated="true">Importance of Studying Growth, Maturation, and Development</h5><ul><li><p><strong>Reasons for Study:</strong></p><ul><li><p>Understand biological variation at individual and population levels.</p></li><li><p><strong>Variation Over Time:</strong> A child's growth varies through:</p><ul><li><p><strong>Within-subject variation:</strong> Changes in an individual's own rate over time.</p></li><li><p><strong>Between-subject variation:</strong> Differences between individuals of the same age/sex.</p></li><li><p><strong>Between population variation:</strong> Differences across different geographical or ethnic groups.</p></li></ul></li><li><p><strong>Environmental Optimization:</strong> Examine how the following impact growth:</p><ul><li><p>Physical environment (climate, altitude)</p></li><li><p>Nutritional environment (caloric/nutrient intake)</p></li><li><p>Training environment (physical activity levels)</p></li><li><p>Social environment (socioeconomic status, family structure)</p></li></ul></li></ul></li></ul><h5 id="df80aed1-d946-4dea-a88a-8c9fa3bbbccf" data-toc-id="df80aed1-d946-4dea-a88a-8c9fa3bbbccf" collapsed="false" seolevelmigrated="true">Human Biological Variability</h5><ul><li><p><strong>Factors Influencing variability:</strong></p><ul><li><p>Genetics and prenatal environment</p></li><li><p>Nutritional status and education</p></li><li><p>Cultural, social, and familial factors</p></li><li><p>Experiences of abuse or neglect</p></li></ul></li></ul><h5 id="73cbde0a-56e9-4851-8c84-9c6855608dcc" data-toc-id="73cbde0a-56e9-4851-8c84-9c6855608dcc" collapsed="false" seolevelmigrated="true">Practical Applications</h5><ol><li><p>Assessing "normalcy" using reference charts.</p></li><li><p>Evaluating rates of change and progress.</p></li><li><p>Predicting future outcomes (tracking growth).</p></li><li><p>Interpreting the effects of exercise on biology.</p></li></ol><h5 id="6aeb3a55-c771-4c38-bada-c95294c00577" data-toc-id="6aeb3a55-c771-4c38-bada-c95294c00577" collapsed="false" seolevelmigrated="true">Lifetime Developmental Stages</h5><ul><li><p><strong>Pre-natal:</strong>$1^{st}, 2^{nd}, 3^{rd}$trimesters</p></li><li><p><strong>Childhood:</strong></p><ul><li><p>Early:$1-5$years</p></li><li><p>Middle:$6-8$(F),$6-10$(M)</p></li><li><p>Late:$9-10$(F),$11-12$(M)</p></li><li><p>Adolescence:$11-19$(F),$13-22$(M)</p></li></ul></li><li><p><strong>Adulthood:</strong></p><ul><li><p>Young Adult:$19-40$years</p></li><li><p>Middle Adult:$40-60$years</p></li><li><p>Older Adult:$60+$years</p></li></ul></li></ul><h5 id="72d6213e-5ef0-4080-a261-daede01ba545" data-toc-id="72d6213e-5ef0-4080-a261-daede01ba545" collapsed="false" seolevelmigrated="true">Underlying Biological Processes</h5><ol><li><p><strong>Hyperplasia:</strong> Increase in cell number.</p></li><li><p><strong>Hypertrophy:</strong> Increase in cell size (length, width, volume).</p></li><li><p><strong>Accretion:</strong> Increase in interstitial material.</p></li></ol><h5 id="3f32e00a-b9a8-4b61-9e53-f4953528e1c8" data-toc-id="3f32e00a-b9a8-4b61-9e53-f4953528e1c8" collapsed="false" seolevelmigrated="true">Notable Growth Comparisons</h5><ul><li><p><strong>Mass Changes by Age$18$:</strong></p><ul><li><p>Head:$\approx 0.8$kg at birth vs.$\approx 6$kg at adulthood.</p></li><li><p>Legs:$\approx 15\%$of body mass at birth vs.$\approx 30\%$at adulthood.</p></li></ul></li><li><p><strong>Scammon’s Curves:</strong> 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:

1. 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?

2. 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?

3. 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?

4. 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?

5. 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?

6. 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?