Lecture 3

Question 1

what is a definition of ergometry

Answer 1

the measurement of mechanical energy production

Question 2

what is force

Answer 2

resistance to overcome

Question 3

what is work

Answer 3

volume of exercise

Question 4

what is power

Answer 4

intensity of exercise

Question 5

what is an ergometer

Answer 5

a device from which work and power can be determined

Question 6

three things you would assess with an ergometer

Answer 6

fitness = strength, power, endurance

clinical or research = bodies response to stress

ergonomics = energy cost of activities

Question 7

three ways you know if you are assessing something appropriately

Answer 7

validity (relevance) and accuracy (get the right number) and reliability (reproducible)

Question 8

what is strength

Answer 8

force = mass x acceleration

the maximum force that can be produced by a muscle group in a single movement which depends on …..

Question 9

what does strength depend on

Answer 9

• muscle size
• fibre orientation
• fibre type proportions
• neural activation
• metabolic factors

Question 10

what is work and the equation for it

Answer 10

the energy imparted into an object when it is moved to a position of higher potential energy

work = force x displacement

Question 11

in exercise acceleration often relates to …

Answer 11

• gravity
• body mass
• equipment

Question 12

what is power and the equation for it

Answer 12

the rate of doing work

power = work / time

Question 13

what does power depend on

Answer 13

• the ability to supply energy fast
• on strength
• on resistance not being too high (so velocity not too low)

Question 14

what is power often expressed relative to

Answer 14

• body mass or lean body mass (watts/kg)
• upper limit attainable (% peak power output)

Question 15

what is endurance

Answer 15

the ability to maintain force or repeated contractions

Question 16

what does endurance depend on

Answer 16

• energy
• strength
• motivation
• injury
• thermoregulation
• efficiency

more….

Question 17

equation of efficiency and what does it range from, also what is needed to calculate it

Answer 17

efficiency = work rate / metabolic rate x 100

it ranges from 0-25%

can only calculate when can measure power output

Question 18

what is the resistance used in air-braked ergometers

Answer 18

resistance is usually of wind vanes to movement through air

Question 19

what happens to resistance and work rate when cadence increases using air braked ergometers

Answer 19

resistance and so workrate increases exponentially with cadence (rpm)

Question 20

what are the pros and cons to air braked ergometers

Answer 20

pros = relatively cheap

cons =
- difficult to calibrate
- need to know barometric pressure

Question 21

how do friction (mechanically) braked ergometers work

Answer 21

apply a known mechanical resistance against a flywheel

Question 22

what happens to work rate as cadence increases on friction braked ergometers

Answer 22

as cadence increases, so does work rate = linear relation

Question 23

what are the pros and cons to friction braked ergometers

Answer 23

pros
- easy to use, calibrate and calculate
- relatively cheap, portable and robust

cons
- limited precision of work rate control, reduces reliability

Question 24

what happens to resistance compared to cadence in electromagnetically braked ergometers

Answer 24

resistance varies inversely with cadence

Question 25

what are the pros and cons of electromagnetically braked ergometers

Answer 25

pros
- wide power range
- fine control of power
- allows setting of constant power output, or varies patterns
- decrease measurement error by increased reliability within and between species

cons
- can be expensive

Question 26

what are the pros and cons of treadmill ergometry

Answer 26

pros
- can be highly specific e.g runners
- encourages central rather than peripheral fatigue

cons
- cost and size
- variable in running efficiency, therefore less certainty in energy expenditure if its not measured