Means That You Can Run the Same Test Again and Get the Same Answer.

Personal trainers should only ever use tests that are valid and reliable. In this page we explain what these guiding principles mean and how to utilize them.

When it comes to fitness testing information technology is imperative that fitness professionals know and understand the dual concepts of validity and reliability.  A reliable measure out is measuring something consistently, while a valid measure out is measuring what it is supposed to measure out.

What is validity?

A valid fitness test is a test that measures exactly what information technology is supposed to mensurate.  For a examination to be valid information technology must 'hit the bull's-heart.'

For instance, if I wanted to measure aerobic running operation then a measure of someone's fifty metre swim time would have poor validity, whereas a measure of the fourth dimension it took for them to run v kilometres would be much more valid.

Test measures tin can be straight or indirect. Directly measures are considered the "gold standard" when testing a certain component of fitness.  This means the examination can measure the component directly, without using any assumptions or estimates.

For aerobic fettle the gold standard examination is considered to be a straight measurement of a client'south maximal oxygen consumption (VO2 max). This test is performed in a lab where the bodily   amount of oxygen and carbon dioxide breathed in and out during maximal exercise can be measured as it is breathed into a bag or tank. Every bit this test straight measures the maximal corporeality of oxygen used this is considered a very valid examination to mensurate aerobic capacity.

An indirect measure is a test that measures factors other than the direct measure (oxygen) and and then, based on certain assumptions gives an estimate of the specific component of fitness.

An example of an indirect measure is the Astrand-Ryhming step test.  Here VO2 max is predicted (estimated) by an equation that takes into business relationship factors such as middle rate later the test, weight and client age.

For some tests the equation doesn't account for all factors.  If your client is unlike than the sample population the indirect test was devised from the results might exist less accurate (invalid).  For example if the examination doesn't account for historic period and was originally carried out on 20 yr old men, and y'all are using the exam on a 55 year one-time adult female the results won't be as valid.

When reading about fitness tests you might see terms such as validity coefficient. When indirect tests (such as the Astrand–Ryhming test) are created the testers measure people on both the direct (VO2 max) and indirect (Astrand-Rhyming) tests to see how shut the results are betwixt the two testing methods. The more than similar the results, the higher the validity coefficient of the indirect test. The score cannot be higher than 1.0 and a test is considered to take a loftier validity score above 0.eight.

Standard mistake of estimates (See) are too a factor in fettle testing. When measuring a component of fitness using both a direct and indirect method (involving assumptions in an equation) in that location would exist a standard estimating mistake of measurement using the indirect method.  For case if VO2max measured directly is 43ml/min/kg the standard mistake (SEE) using a certain indirect method might be +/- 7ml/min/kg from the direct measurement, giving a outcome anywhere from 36-50ml/min/kg. As yous can run into the result could exist a long way from the bodily number. A test with high validity should have a depression Run into.

Fitness tests with depression validity should e'er be avoided every bit they volition not give you relevant data to ready training targets with and won't measure change in the fitness component you lot are trying to affect.

For instance, if I did the swim test every six weeks to measure running improvement, I may non meet much change and I wouldn't be able to work out which grooming arroyo I was using every six weeks was working the best, or hardly working at all.  The examination only isn't valid enough to help inform the training approach or measure truthful improvement.

Our objective then should exist to utilise highly valid tests with low Come across – that is make certain that the tests we use measure, equally closely every bit possible, what we want to go along an eye on.

What is reliability?

A reliable fettle test is a test that you can rely on to measure out something consistently.

For example, y'all may measure your body weight on your bath scales every twenty-four hour period for a year and although they may or may not be very valid (they might non be authentic at the start), they are consistent and show modify in your weight very reliably.

Fitness tests with depression reliability should be avoided as they volition not evidence what progress or lack of progress is actually occurring.  You will also end upwards setting grooming targets that are either likewise low or also high depending on the error in the last test.

For case, if I did a running examination on a treadmill and its speed when yous put it at 15kph was actually closer to 16kph because the belt was warn and the drums that drive the chugalug effectually were new, then my test would evidence that I wasn't that fit.  If I so re-tested half-dozen weeks subsequently a different treadmill that had a new chugalug and old drums and for some reason when it was supposed to be at 15kph was actually at 14kph, the exam would prove that I was much fitter.

Put simply, the reliability of the test in this case could have me registering myself for the 1500m race at the Olympics when in reality I should be doing fun runs with the local running club.  The test is producing unreliable results and my prescription of training as well will get problematic.

Our objective should be to use highly reliable tests – that is make sure that the tests we use are repeatable and will accurately show change in what we are measuring when information technology occurs.

And every bit well as but using highly reliable tests we must ever brand certain the tests nosotros utilize are highly valid – that is they measure but and exactly what nosotros want to measure out.  At that place is admittedly no do good to using tests that are neither valid nor reliable.

Improving examination reliability

Reliability is affected by several factors, some which are manageable and some which can't be changed.  To improve reliability we need to focus on the elimination of equally much error from the tests as we possibly tin can.

Random mistake

Random error is an error that occurs sometimes.  An instance would be using trunk weight scales that weren't calibrated once, and so were calibrated the adjacent.  The error is manageable but we haven't addressed it by being consistent.

Another example would be testing a client's flexibility once when they were cold, and another time when they had warmed up.

To minimize random mistake equally a fitness professional you must:

1. Learn the exam protocols very well and stick to them – this ways each time you lot exam you do exactly the same matter, in the same mode.
2. Make sure the surroundings and your client are in the aforementioned condition – this means recording data about the circumstances yous test in each time and apply preparation information with your client to ensure they are in the same state.  Imagine a customer being tested afterwards a days work and four coffees and a traffic jam, versus a Sunday morn after a nice relaxing slumber in…
3. Perfect the utilise and scale of your measurement tools – this means practise what y'all practise in a test until y'all tin't get information technology incorrect and know how to make certain the equipment you will apply is 'calibrated' each time.  How often are yous the aforementioned weight on ii different sets of scales on the same mean solar day?  How well tin can you use a tape measure on a customer's waist?  How practiced are yous at accurately finding and marking skinfold sites when you lot are going to complete skinfold testing?  How well practiced are you at recording centre rates whilst increasing treadmill speed, whilst keeping an centre on the time?

Standard error

A standard error occurs every fourth dimension.  That means, the error is built in to our test, and information technology volition be consequent.

An example would be having a watch that only times down to the 2nd and trying to fourth dimension 40 metre sprints.  The person may end at 5s or 6s only considering nosotros tin't mensurate the '5.3s sprint'.  The tool we are using ways there is quite a lot of standard error in the exam.

To minimize standard error as a fettle professional you lot must:

1. Cull tests with the lowest standard mistake – for example if y'all are going to do a skinfold test, and then just total the sites rather than use an equation to calculate body fat percentage as the equation introduces further standard error as it 'predicts' torso fat percentage.
2. Reduce measurement fault by increasing the sensitivity of the tool being used – an example would be using a tape measure out that had millimetre divisions on it rather than simply centimetres as this volition allow more than accurate measurement.  Similarly – finish watches that go to the thousandth of a second are meliorate for measuring short dart times.

Improving the different 'measures' of reliability

Reliability can be measured to give you an understanding of how good your examination or testing is.  There are several different measures of reliability as follows

Intra -reliability – This tells you how accurate you are at completing the test repeatedly on the same day.  I.east. if you did a thigh girth test on the same customer in the morn and the afternoon and got exactly the same issue your testing would show high intra-reliability.

Inter-reliability – This tells y'all how authentic you lot and someone else are when testing the same person on the same day.  I.e. If you and a fellow trainer took the same clients thigh girth measurements on the same 24-hour interval and recorded exactly the same results then your combined testing would show high inter-reliability.

Test -retest reliability – This tells you how reliable the test is between two test times.  I.eastward. if the change in test results between two examination times can solely exist attributed to a change in the variable being measured (i.eastward. thigh girth) then the test will have high test-retest reliability.  If the difference between test results could exist due to factors other than the variable being measured (i.e. not sticking to the exact aforementioned test protocol) and so the examination will have a low test-retest reliability.

Once yous have completed a test there are three outcomes possible:

1. The results are as close as possible to accurate
2. The results are a 'false-negative'.  This means the results are beneath what they should exist – for example the fettle component measured has improved by five percent when actually an accurate test, washed well, would show a ten percent improvement.
3. The results are a 'false-positive'.  This means the results are to a higher place what they should exist – for example the fitness component measured has improved by fifteen per centum when actually an accurate test, done well, would prove a ten percent improvement.

To understand how reliability and validity piece of work together allow's wait at a scenario.

Sue is working toward running a ten kilometre run later on in the year.  Sue has come in for her second fitness test subsequently six weeks of training.  It's a bicycle exam at the gym in the evening and the protocol is that she cycles for three minutes, then the load is increased, and then she cycles for three minutes, the load is increased over again, then she cycles for a final three minutes.  Eye rates are taken throughout the test.

The numbers are then punched in to an equation and Sue's aerobic fitness is 'predicted' by the results.

The room is hot, every bit it's summertime and she was last tested in spring.  She comments she's had a huge day every bit after work she tried to get the last of her Xmas shopping done and "man is it busy out there".  She also points out that her tiffin was a bit rushed too as she wanted to railroad train and get that last bit of fitness nether her belt.  The last thing she drank was a coffee which she had whilst going around the shops later piece of work.

You complete the test with Sue.  Her first exam was completed by another trainer as you lot were on holiday when she was outset tested and asked the other trainer to complete Sue's test for you.  You know how to do the exam, merely you've had a little trouble with the bicycle at times as it seems to be harder on some days than others.  You also lose eye rate readings occasionally every bit the center rate monitor goes blank.

Y'all have seen Sue in the club a lot, completing her personal training sessions with you and her prescribed 'independent' preparation on the rower and treadmill, and you expect to see a dramatic improvement in her fitness, as she has been making steady progress during these sessions.

The results come back and information technology shows that after six weeks of training iii hours per week doing aerobic exercise Sue's fitness hasn't changed at all!

Alarmed you lot tell Sue that you think there is an error in the test and that you'd like her to repeat the test again next week.  Sue begrudgingly agrees.

Let's take a expect at what could have gone incorrect to make this 'fake negative' occur.

Potential error	Reliability or validity an issue	Ways to fix this for next time
Bicycle examination when her training is rowing and running won't be as sensitive to changes in her fitness	Validity – the test isn't measuring the correct thing	Chose a test that represents what y'all want to measure out – due east.g. running aerobic fettle
The equation used to calculate aerobic fettle introduces error due to predictions made	Standard error affecting validity	Choose a test that is performance based and doesn't employ 'normative' data – nosotros demand to know what Sue's fitness was when she started and how it's progressing, not how she stacks up confronting American college students or akin
A hot room can hands increase heart rate every bit the body pumps blood to the peel to help with cooling at the aforementioned time as it needs to pump claret to the working muscles	Random mistake affecting examination-retest reliability	Take the ambient temperature in the room and if information technology varies by more than a few degrees, absurd the room or plan testing at a improve time.
High levels of stress (rushing and shopping) earlier the test tin cause higher heart rates and claret pressure level	Random mistake affecting test-retest reliability	Give Sue pre-test information which will include what to exercise the twenty-four hour period leading into a test, what to beverage, what to eat, how much residuum to accept, and that testing should always be booked in at the same time of day.
Caffeine prior to exercise can increase heart rates and claret pressure	Random error affecting test-retest reliability	As above
Training at tiffin fourth dimension volition mean Sue is notwithstanding drawn and as a consequence her fitness volition appear worse than it would exist if she was rested	Random error affecting test-retest reliability	As higher up
Information technology appears Sue hasn't eaten since tiffin time and there is no mention of water intake so it'southward possible she has low claret saccharide and is slightly de-hydrated – both increasing heart charge per unit and fatigue	Random mistake affecting test-retest reliability	As above
You prepare Sue up slightly differently than the first instructor who tested her – the wheel seat is lower than the peak used by the other trainer	Random error affecting inter-reliability and test-retest reliability	Practice your protocol and concur with all trainers how to guess what tiptop the seat on the bike should exist at, plus tape that each time you test
The loss of heart rate readings at fundamental times ways you record slightly higher values than you should because Sue'south heart rate continues to increase throughout the test and you tin can only write it down when information technology's there!	Random error affecting intra, inter and test-retest reliability	Replace the heart charge per unit monitor with one that works and bank check with other trainers to encounter if it's affecting them as well.  Also bank check other factors such equally cell phones, and under wire bras which tin can give heart rate monitors problem.
You don't calibrate the bike which is why it's harder on some days than others – the harder it is, the higher the heart rates	Random error affecting intra, inter and examination-retest reliability	Read and practice the calibration protocol for the bike and become everybody to practise it every time.

The above scenario does happen, which is why, if you are going to examination, you want to select proficient valid tests and do them well.  Again, yous must remember the reason for testing is safe, training focus, and motivation.  You lose all of these benefits if the testing is not completed well.

And 1 last time for adept luck…make sure that when you fitness exam your personal training clients you only apply tests that are valid and measure out exactly what y'all want to measure, and you tin trust the results by ensuring the test is as reliable equally possible.

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Source: https://www.ptdirect.com/training-delivery/client-assessment/understanding-validity-and-reliability-in-fitness-testing