Reliability and Validity

PhotobucketMorne and Larisa, Ted and Mindy move the prowler in another cold morning. A quick word. The two most important aspects of any measurement are the validity (are you measuring what you are claiming to measure) and reliability (are the measurements consistent). You can have reliability without validity but you cannot achieve a valid measurement without it being reliable. For example, if you take air filled bumper plates that claim 20 kilos, test your 1RM Snatch, then come back a week later and re-test, that would be reliable. You were consistent with the testing protocol, air filled plates both times. It is obviously not valid, as air filled plates do not equal 20 kilos, i.e. you are not measuring what you are claiming to measure.

A test that is not reliable cannot be valid. For example if the prowler changes the surface when you use it, then that surface will be different every time you do the movement. This is inconsistent, unreliable and therefore invalid as a testing platform.

In our case this change of surface has made it a little easier over time to push the prowler, as we have been in a sense filing the ruff pavement down to a slick almost ice-like surface (you can see how the sun glistens off the pavement where the prowler has been used). We have no doubt everyone has gotten stronger with the prowler, I’m sure a lot of you can feel that. And I'm sure you can all feel that the prowler is in no way a waste of time. It is just important to have an accurate or valid perspective when assessing training progress, as to (for one reason) avoid discouragement.

The point of this post is to talk about the importance of consistency when training as to avoid being discouraged. A good example of this is shorting range of motion. For example, say you tested your dead hang pull up max last week. You counted three reps but the second may have been a little short on the chin over bar and the third had a little kip. You come back 7 weeks later, re-test and get three perfect strict pull ups. You went from 3 to 3. That doesn't sound so great but it doesn't matter because the test was not consistent, it was not reliable and therefore not valid and should be thought of as such.

The decrease in friction on the surface of the pavement which is allowing the prowler to move a little easier is perfectly fine. Just add more weight. But if it ever rains, that will add more friction to the surface areas of the pavement and prowler. So do not be discouraged when you load the thing up and it's way harder. It should not be looked at as the same “test”, as a main variable has been altered and you are in a sense doing a different movement. Any comparison to a previous prowler push would be invalid due to the inconsistencies.


Press 5-5-5

3 Rounds (3-4 min rest between rounds) 250m Row Sprint 1 Prowler Trip (~50 meters)

Programming: Tara

Specialty Kettlebell Class with our very own Dominic Griego!  Take advantage of this amazing opportunity.  January 28th, 12-2p.m.  Part of the unlimited membership and regular drop in price.