Statistics in Fitness - Why it Matters?

READ THE FOLLOWING SITUATION

Teenager who was getting straight A’s at school became interested in weightlifting. He started reading books about strength training, nutrition, supplements, bodybuilding . The semester that he got involved with weightlifting his grades became worse. Although most of his grades were A’s but he also got one B. Parents are worrying that their son might be spending too much time lifting weights and because of that he spends less time studying,

QUESTION FOR YOU 

Would you agree with parents? Because, yes, parents might be right. But there is a possibility that his grades have NOTHING to do with weightlifting. You know WHY? Because of regression toward the mean.

REGRESSION TOWARD THE MEAN

Regression toward the mean is statistical phenomenon stating that very high and very low measurements tend to be closer to the average, if you measure them the second time. IN OTHER WORDS, very high measurements tend to become smaller and very small measurements tend to become higher.

But it is STATISTICS, so why should someone who is related to fitness, bodybuilding, strength training care about it? That is the question I want to target in this article.

If we come back to the example written above, we will see that this student’s grades were very high. He was at his PEAK. So, NATURALLY his grades are likely to become smaller the second time his performance is measured. Let’s say, you gave the student 4 tests to do. He gets 100% on each of them. The next day you give him very similar 4 tests. But this time the same student gets 92%, 89%, 100% and 95%. Just by measuring his performance the SECOND TIME it becomes worse, although the results are not radically different. That is the work of regression toward he mean. The same would probably happen, if you chose A student, who gets very low scores. If you measured his performance the second time, he would probably get higher scores. It is natural phenomen, we can frequently encounter it.

ITS IMPORTANCE IN WEIGHTLIFTING

Below are some examples:

1. You performed an exercise with a very POOR form. Your trainer starts YELLING at you because of that. After the yelling you do the exercise again and this time your form is BETTER. Your trainer (and maybe you too) might think that yelling is a good tool to improve your form, even though it might be simply regression toward mean. The same could happen, if your trainer started PRAISING you after you perform exercise in almost perfect form and after that your form would become worse.

In this example you can also switch the word “your trainer” with “you”, because maybe you are training alone and you might link criticism in your head with better performance and being happy about yourself with worse performance.

2. You have just finished strength training program which helped you to break your PERSONAL RECORDS. Immediately after that you switched to another training routine and you found that doing it you ARE NOT ABLE to lift as much weight as you were doing the previous program. You might think that the program you have just started following is WORTHLESS. But it could also be that it is just regression toward the mean. You achieved your best results on some lifts, so the next time you are doing them there is a posibility that your peroformance will NOT be as good.

3. You are a trainer. You are training a student who is very strong and has JUST WON national level sprinting competition. You started training him AFTER he won the competition, but during this time his results seems to BECOME WORSE. Others might be thinking that you are a bad trainer and do not know wat you are doing. But it could also be a work of regression toward the mean. The OPPOSITE could happen, if you started training a student who has just failed physical education exam. Just by measuring his performance again, you could probably see BETTER results. And it might be unrelated to your work, unrelated to your methods, the MAIN factor of improvement might be simply regression toward mean.

IMPORTANT

This phenomenon is NOT a LAW. You could say ”I know a guy who reached his peak and after that became even stronger”. Of course, things like that HAPPEN, you could probably find many MORE examples like that from your life. BUT what this phenomenon states is that there is TENDENCY (it does not happen 100% of the time) for very high results to become smaller and for very small results to become higher.

WHAT I WANTED TO SAY

What I was NOT trying to say - “When you work with people who are at a very high or at a very low level, your work doesn’t matter”.

What I was trying to say - “Be cautious when interpreting what caused the results to become smaller or higher”.