Chapter 3

Chapter 3

Basic Concepts of Anthropometry

Objective (from syllabus)

To understand the relationship between human body size, shape and composition, and movement capability

Anthropometry Definition:

Dimensions and composition of the body E.g. bone thickness & proportions, body fat %, lean body

mass See also kinanthropometry, which is the same thing

but as applied to movement Tools for measurement

All kinds of rulers, calipers and so on (and for lean body mass, some regression models to estimate body fat % based on a variety of assumptions)

Stadiometers, anthropometers, bicondylar calipers, skinfold calipers etc...

Height, body segment length, bone diameter, skinfold + fat width

Anthropometry Body size

It’s a field for the obsessive in terms of measuring protocols

Determination of body shape A variety of proportions are measured

BMI (mass/ht2) [(Sitting ht)/)(standing ht)] x 100

Certain proportions and shapes have been found to be associated with health or performance in certain activities, hence the interest

Exceptions are always interesting though (e.g. Usain Bolt)

Consider also cause and effect

dimensionality

Limb length relative to torsoBulk

(fatness?)

Anthropometry Tissues composing the body

Anthropometry is interested in estimating tissue proportion in the living

Most popular example is lean body mass & fat – gives the 2-component anthropometric model

The book cites errors even with underwater weighing, which is normally the gold standard for estimation of body fat %

Should bear in mind that with all estimation techniques, they work best for typical people

DEXA (dual x-ray absorpiometry): 3-component model – lean tissue divided into calcified tissue and other non-fat tissue

More accurate, but a lot more expensive than a set of calipers General idea here...as opposed to losing weight, you should

increase lean body mass (yes, increase...or at least not lose it).

So, abnormally fat, thin, or muscular

people don’t get such accurate estimates

Implies increased training to build muscle mass...which in

turn leads to fat loss

MRI, CAT scans even better but

even more expensive

Anthropometry

Somatotyping The practice of classifying body types according to

3 dimensions (following the most popular Heath-Carter method)

Endomorphy (fatness) Mesomorphy (muscularity & bone size) Ectomorphy (thinness)

Replete with measurement errors, but still tends to be quite reliably associated with performance stereotypes

Skinfolds relative to height

Bone girth relative to arm, leg girth, with fatness taken out

Weight relative to height

Anthropometry Human variation

Emerges from a variety of causes Age and activity are covered in the next chapters

In the musculoskeletal system Nothing very interesting here (and open to

misinterpretation) In physical dimensions

As before, these are open to misinterpretation and stereotyping (androgyny, ethnic differences [not racial])

Features that are more determined by genetics might (??) be more reasonably analyzed (e.g. jaw line in males generally larger)

“typical” make up of males and females is an example of this – see Caster Semenya controversy

Chapter 4

Musculoskeletal changes across the life span

Objective from syllabus

To summarize how concepts related to the musculoskeletal system and anthropometry are affected by growth and maturation

Auxology and gerontology defined

Auxology – the science of growth Is physical age proceeding apace with

chronological age? Gerontology – the science of aging

What does aging do to your body & mind? Tools for measurement

Similar to anthropometry (after all, it’s still measurement)

Changes across the lifespan Physical growth, maturation, and aging

Embryological development Ovum + spermatozoan zygote (fertilized cell) Zygote repeatedly divides and multiplies Mesodermic development follows

Growth of organs, tissues, musculoskeletal system Marked by hyperplastic growth (increase in # cells)

The postnatal years Keep on growing, keep on maturing (a term implying

genetically determined growth) Exercise and aging – see ch. 12

As opposed to hypertrophic – growth in size of cells

Ability of exercise to offset effects of aging is quite strong

Changes across the lifespan Age-related changes in the skeletal and articular systems

Two main phases Foetal (hyperplasia) Pubertal (hypertrophy)

Stages in development of bone Bone grows initially from cartilage Cells calcify and then remodeling proceeds via formation

and erosion of cells to give the final shape Growth of length and width of bone

Epiphyseal (growth) plate in which cartilage calcifies causes bone to lengthen

Continues until cartilage ceases to calcify Change in thickness/diameter not limited by age (see ch. 5)

“Endochondral ossification”

Process: in # of cartilage cells, then in size, then surrounds are calcified...then ossified/remodeled (osteoblasts /osteoclasts)

“Appositional growth”

Changes across the lifespan Age-related changes in the skeletal and articular

systems Skeletal composition changes across the life span

Childhood: more collagen, thus more flexible bone (Young) Adulthood: more salt, thus more strength Old Adulthood: yet more salt, so more brittle, but also

total mass of bone decreases Increased porosity, decreased density, increased

hardness, more brittle...not good news...

2/3 of bone is cartilaginous

2/3 is mineral (calcified)

Only 10% of bone is cartilaginous

Old bone only 40% - 55% of the density of young bone

at its peak

Changes across the lifespan Age-related changes in the skeletal and articular systems

Osteoporosis In post-menopausal women, linked to estrogen depletion, so that

bone absorption increases relative to it’s growth To offset this, as bone mass peaks at 16 to 20, health experts

recommend maximizing bone mass by that time Osteoporosis in males is accelerating (lifestyle changes)

Bone failure in relation to bone development, age or activity Type of fractures change with age and type of bone Forearm fractures in childhood Hip and wrist fractures in elderly women

Effect of various factors on range of motion Decrease with age (how many can still suck their [own] toes)? Decrease with arthritis

Growth plates

Lack of force absorption

Rheumatoid arthritis: inflammation of synovial membrane. Osteoarthritis: wasting of articular cartilage

Changes across the lifespan Age-related changes in the

muscular system Umm...the more

interesting stuff is in chapter 5 (hopefully)

Change in body dimensions across the life span

The “growth spurt” (peak height velocity) see. P. 49

In females early maturers ended up being no different to late maturers in height

In males, late maturers started off being shorter and ended up being significantly taller

Bigger people – more muscle fibers

Loss of muscle thru disuse far greater than thru aging

Changes across the lifespan

Age-related changes in the muscular system Combining size measurements to provide

information about shape

Changes across the lifespan

Age-related changes in the muscular system Secular trend in body dimensions

Changes across the lifespan

Age-related changes in the muscular system Growth rates of body segments

As expected following fig. 4.5, body parts grow at different rates

Limbs grow faster than trunk; legs grow faster than arms Growth rates of body tissues

Brain size close to adult early on Reproductive tissue grows rapidly through puberty

Changes across the lifespan Age-related changes in

the muscular system Sexual dimorphism in

growth Female growth spurt

two years earlier than males’

Females often taller than males between 10-13 years

Fatness progresses differently for males and females

Changes across the lifespan

Age-related changes in the muscular system Somatotype changes during growth, maturation,

and aging 2 pubertal stages in males

First an increase in ectomorphy at around 11-15 yrs Then an increase in mesomorphy between 15-24 yrs

Methods of determining age Dentistry, bone growth, menarche and sexual

maturity are the methods, but there’s nothing of particular interest here. Correct me if I’m wrong

Chapter 5

Musculoskeletal adaptations to training

Objective from syllabus

To summarize how concepts related to the musculoskeletal system and anthropometry adapt to physical activity

Musculoskeletal adaptations to training Effects of physical activity on bone

Generally, the more activity a bone sustains, the more it will adapt to be suited to that activity (gets thicker with prolonged use)

Effects of activity level on bone Elite youth athletes and stress fractures – too much too

soon Loss of bone mass in space Loss of bone mass at rest (bone needs activity to stay

healthily dense) Exercise generally increases bone mass (weight bearing –

swimmers vs. others)

Structural reorganization as well as gain in mass (to resist force most economically)

osteopenia

Lack of P.A. loss of bone (+muscle) mass

Tennis players’ humerus

Musculoskeletal adaptations to training Effects of physical activity on

bone Effects of activity type on

bone Weight bearing activities

best to add bone Swimmers vs. wtlifters Takes about 3-4

remodelling cycles to reach new steady state for bone tissue quality

Bone decreases in quality quicker than it increases, so activity should be sustained for maximum effect

Bone repair and physical activity

See fig. 5.1 – the implication is that bone (& other tissue) needs time to repair from any inactivity

Weightlifters have higher bone density than swimmers

1 remodeling cycle – 3 months

Musculoskeletal adaptations to training Effects of physical activity on joint structure and ranges of

motion Synovial fluid, articular cartilage, and ligaments

Cartilage Short bout of cyclical exercise results in thickening of cartilage Thickens as a result of absorbing synovial fluid Chronic exercise leads to long-term thickening

(except where compressive forces are excessive – e.g. downhill running)

Better force dissipation

Musculoskeletal adaptations to training Effects of physical activity on joint structure and ranges of

motion Synovial fluid, articular cartilage, and ligaments

Synovial fluid Short run can increase synovial fluid from about .2-.5ml in the

knee to three times as much Becomes less viscous (hence more easily soaked up by cartilage) Cartilage soaks it up, so it is probably still the cartilage doing the

protection Ligament

Exercise strengthens and stiffens ligaments (increase in both collagen synthesis & cross linking)

Note v. small volumes

Endurance activity better than sprint?

Musculoskeletal adaptations to training Effects of physical activity on joint structure and

ranges of motion Degenerative joint disease and exercise

Linked with obesity (physical activity?), ageing Does jogging lead to osteoarthritis (degenerative joint

disease)? Clinicians apparently say so, but the evidence is weak

Epidemiological studies imply the relationship exists only for those with previous ligament damage – so that the joint moves abnormally over a protracted period of time

Musculoskeletal adaptations to training Effects of physical activity on muscle-tendon units

Muscle size decreases with disuse Flexibility

A function of the muscle-tendon unit, not the joint capsule or ligament

Joint laxity is a bad thing (stretched ligaments) Highly joint and activity specific Seems to be primarily increased through stretchiness of

connective tissue (some sarcomere adaptation) Not limited by increased muscularity (being muscle-bound is

not inevitable)

Think of male gymnasts

People naturally differ in flexibility

Musculoskeletal adaptations to training Effects of physical activity on muscle-tendon units

Strength training First 6-8 weeks: neurotrophic stage – improved

coordination leads to rapid increases in strength Then...hypertrophic stage – muscle fibers increase in

cross-sectional area Tendon adaptation

Slower to adapt than muscle Adapts via collagen synthesis Injuries most common at muscle-tendon junction

Musculoskeletal adaptations to training Effects of physical activity on body size, shape, and

composition Body composition will alter as a result of exercise, but

ectomorphy might not (and weight might increase) Role of lifestyle factors in determining physique

Many differences between athletes’ physique and those of the “normal” population are simply adaptations to training

Relationship of body sizes and types to sports Well, we can see it can’t we?

Long distance runners are lighter, sprinters more muscular, gymnasts shorter, and so on...

Why?

Think changes in lean body mass

Results of Lab

"Somatoplots"

-6

-4

-2

0

2

4

6

8

10

12

14

-10 -8 -6 -4 -2 0 2 4 6

Our class average somatotype

Definitely need to take these with a pinch of salt. We could all do with training/retraining on skinfold techniques, and even then there were some definite issues with the equations

Ectomorphy

Endomorphy

Mesomorphy

Compare to p.61