Seminar 1, growth distance and velocity

Question 1

How is leg length calculated

Answer 1

height-sitting height

Question 2

What are the limitations/points for consideration when calculating distance values for children’s heights

Answer 2

height and sitting height are affected by posture

chair used needs to be standardised

need to standardise the time of day when measurements are taken because of the degree of variability

Question 3

why do children often fluctuate between different percentiles for height distance

Answer 3

all children grow at different speeds and have their growth spurt at different points

reference data for percentiles is calculated from large cohorts and so individual variation is blunted via the averaging process

Question 4

what is the difference between reference and standards data

Answer 4

reference data is relative to the people in that sample (which can include anyone) and doesn’t make a judgement about the desirability or quality of the variable being measured

standards data is more of an aspirational norm, and is based on a sample which are selected because of the characteristics they possess e.g heights

standards are ‘for prescribing as well as describing’
(so can use them to show where and intervention is needed)

Question 5

How do you work out velocity of height increase

Answer 5

find age increment

find the ‘simple velocity’

divide the simple velocity by the age increment

Question 6

why is it necessary to find the age increment

Answer 6

measurements are not taken at exactly 1 year intervals

need to divide by it to give how much they grew over a 1 year period, to standardise the velocity

Question 7

what is the purpose of proportional allotment

Answer 7

to increase the accuracy of the age of PHV

It is likely that it occurs just before or just after this in reality

Question 8

discuss the general findings regarding PHV at a population level

Answer 8

PHV occurs earlier in females

1) Leg length
2) height
3) sitting height