module 2

Question 1

what kind of symmetry do humans have?

Answer 1

Humans have bilateral symmetry which allows organisms to move purposefully and efficiently

Question 2

what is the principle of bipedalism and how does it relate to the human evolution?

Answer 2

Humans were favoured by natural selection, and walking on two feet enabled them to get further. They also became taller after becoming bipedal. (lengthed back muscles at the base of the spine).
to help centre the force of gravity on two feet = the human thigh bone developed an inward slope down the knee requiring gluteal abductors to adapt to stress.

Question 3

6 adaptions that favour endurance activities.

Answer 3

arched feet, heel bone and springy tendons.
large hip, knee and ankle joints.
strong hip and knee muscles.
multiple sensitive balance organs
tall narrow body.
hairless, sweating and other thermoregulatory mechanisms.

Question 4

BMI

Answer 4

body mass index

Question 5

what does BMI correlate to?

Answer 5

disease prevalence and mortality rates.

Question 6

what is anthropometry?

Answer 6

standardised techniques to quantify or predict body size, proportion and shape.

Question 7

body density

Answer 7

body mass (BM) per unit body volume

Question 8

specific gravity

Answer 8

BM in air, divided by loss of weight in water (BM / [BM – BWwater])

Question 9

Fat mass

Answer 9

all extractable lipids from adipose and other body tissues

Question 10

lean BM

Answer 10

FFM + essential fat
3% men, 12% women

Question 11

3 purposes of measuring and describing body compostition.

Answer 11

Assess growth and development of children and adolescents

Estimate body composition and health risk in : general population and athletic populations

Assess effects of interventions (exercise training, rehabilitation, lifestyle related)

Question 12

only direct measurment of body composition. bias and what it shows.

Answer 12

cadaver i.e dead bodies. some bias in ethincity and age of cadaver.
actual ratios of internal to subcutaneous FM.

Question 13

imaging of tissues (Dual energy x-ray)

Answer 13

indirect way of measuring. most common is Dual-energy X-ray absorption (DXA). works by fat, bone and protein tissues scatter and transmit energy beams differently more so at low than high energy. issues - specialised and expensive. positives - high accuracy, can measure FFM and bone density.

Question 14

Labelled water dilution. how, issues and positives.

Answer 14

Indirect.
It finds out FFM. because 73% of FFM is water. BM - FFM = FM
issues - time-consuming, must be dehydrated and TBW not always 73% FFM.
positives - accuarte =typical error around 2%.

Question 15

densitometry Underwater weighing). how.

Answer 15

Indirect.
Underwater weighing.
FFM is denser than FM.
knowing body density, and the estimated densities of FM and FMM we can calculate the proportion of those in the body.
body density = mass/volume

Question 16

densitometry (air displacement)

Answer 16

body density = mass/volume
replaces underwater with weighing.
uses pressure change between adjacent chambers, at a constant temperature, to calculate body volume in one chamber.
less validation for children
issues - does not give any info on locations of body fat or muscle.

Question 17

what are the main sources of error with densitometry.

Answer 17

Variable densities of body tissue
Lung residual volume or failure to exhale to that volume
Trapped air in clothing, hair and GI tract.
accuracy will be increased if you incorporate measurements or corrections for the factors above.

Question 18

Bioimpedance analysis.

Answer 18

need standardised conditions. dehydration = decreased electrolytes.
too warm = sweat, decreased impedance.
menstrual cycle = fluid volumes.
positives - quick and convenient.
medium accuracy = 4-5% poor for obese.

Question 19

Skinfolds.

Answer 19

valuable measure of adiposity.
technique is important e.g callipers, location and compression duration.
sensitivity to clients. not used when BMI is higher than 30.

Question 20

what is fat mass and why is it important?

Answer 20

valuable fuel and energy source. 2X cho and protein.
mass to be carried, reduces acceleration, increases energy cost.
insulator.
not just a passive tissue, visceral adipose tissue secrets numerous chemicals.

Question 21

what happens if you are insufficient in fat?

Answer 21

Osteoporosis. amenorrhea - no period > 90 days, long term reproductive issues.

Question 22

what are issues with excess fat?

Answer 22

initial fat gains =hypertrophy (larger cells have more fat in them).
then, hyperplasia (more cells).\FM regulated at higher set point.
which makes it harder to prevent regain of any aft loss, especially in children.

Question 23

what are the chemicals that come from muscle

Answer 23

myokines. ANTI inflammatory

Question 24

what are chemicals that come from adipose tissue ?

Answer 24

adipocytes. PRO inflammatory

Question 25

what organs do the muscle and adipose tissues chemicals interact with.

Answer 25

liver, brain, bone, immune system and gut.

Question 26

muscle factors (i.e myokines)

Answer 26

some have anti-inflammatory and anti-tumour actions. help mobilise fat from adipocytes. help turn adipose into an energy-using tissue. growth factors for nerves and new blood vessels.

Question 27

adipose tissue factors

Answer 27

this is a functionally integrative tissue e.g. contains immune cells. some adipokines have metabolic roles e.g. to regulate themselves. but may appear to drive low grade inflammation. these factors are more important with ageing.

Question 28

the evolution of human musculoskeletal system.

Answer 28

mass concentrated in our core.
good distance runners
powerful throwers
heel was an important development
legs proportionally longer and arms shorter than our ancestors.

Question 29

the turning effect

Answer 29

T=Fr.
Torque (or moment), T, is the turning effect.
Product of magnitude of force r, and distance from the axis (moment arm).

Question 30

class 1 lever.

Answer 30

Axis in the middle of the resistance and the effort.
- Usually a balancing lever. Example – see-saw.
- In the body – atlanto – occipital joint. (In neck)

Question 31

class 2 lever

Answer 31

Resistance and effort applied on the same side of the axis.
- Effort further from the axis than resistance.
- Example – wheelbarrow, nutcracker.
- In the body – metatarsophalangeal joint
- Muscle has the mechanical advantage.

Question 32

class 3 lever

Answer 32

Resistance and effort on one side of the axis.
- Resistance further from axis than effort.
- Example – diving board.
- In the body -most long bones.

Question 33

why can our calf raise so much weight?

Answer 33

Class 2 lever therefore mechanical advantage for muscle. Gastrocnemius and soleus can achieve high force values. Muscle configuration has evolved. High force capacity is evolved and enhanced across the lifespan by weight bearing exercise.

Question 34

what is the effect of using chains?

Answer 34

resistance increases with the bar height, balancing with the increase in joint torque as the bar height increases. end of the lift should feel as difficult as the start.

Question 35

what joints have mechanical disadvantages?

Answer 35

Nearly all joints involve long bones. As they require greater muscle force than resistive force to move to maintain equilibrium.

Increase in torque means decrease in ROM.

Question 36

why is the tendon attachment close to the joint

Answer 36

increases ROM. allowing ends of limbs to reach high speeds. all muscles are limited to how much they cans shorten.

Question 37

what was BMI chnaged to and from.

Answer 37

27.8 to 25