Wednesday, January 30, 2008

Pullups - it is better if you are short!

Are you good at chins?

Here is a good one - following statistical analysis, this study indicates that short individuals are more likely to achieve maximum chin-up test scores. I am over 6 foot, so that is my excuse for being a bit rubbish at pullups. I can do singles with an extra 20kg, but with no added weight I struggle to get to 6.

Chin-up strength tests: does stature matter?

AIM: Many organizations place high value on employee physical fitness and use standardized physical fitness tests (PFT) to quantify it. The chin-up strength test is an example of such a test. Participants' anecdotal reports raise some concern that the latter is inherently biased against tall individuals. A demonstration that tall individuals are less likely than short individuals to achieve maximum score on a chin-up strength test, and modified scoring tables that equalize this likelihood across the stature range are sought.
METHODS: A statistical summary of 85 chin-up test outcomes is analyzed for likelihood of maximum scores as a function of stature. Scoring tables modified by reducing the number of chin-ups required for maximum score in a ratio inverse to a fixed power of the stature ratios are introduced.
RESULTS: Statistical analysis shows that short individuals are more likely to achieve maximum chin-up test scores (P<0.05). Stature adjusted scoring tables are shown to neutralize this trend.
CONCLUSION: Current scoring standards for chin-up strength tests favor short statures. Bias-free chin-up strength tests can be achieved by using stature-adjusted scoring tables. Similar bias problems may exist for other strength tests.


Scott said...

I'm not sure I agree with this Chris. I'm a little shorter than you (an even 6'), but still, I can't recall ever being unable to perform chin-ups.

Overall height may be a minor factor, but I'd suggest that it's only one of many.

Chris said...

Thanks for the comment Scott.

I've definitely always been rubbish at chins

Billy Oblivion said...

I'll bet you seni-serious levels of cash that if you re-ran the stats correlating *arm length* rather than just overall height that you'll find a bigger correlation.

As someone who regularly has to take PFTs, "norming" depends on what you're trying to measure. For people in fields where performance is more important than "condition" (Firefighters, police, etc.) PFTs SHOULD be based on functional tests rather than some actuarial BS, and should NOT be normed. A 6'8 inch firefighter in his mid 40s has to carry the same loads, run the same stairs and do the same crawling as a 23 year old who's only 5'5.

Chris said...

Good point Billy - thanks for the comment

Marc said...


I'm curious; how does rest factor in after a pull up fest like this?
Two days off? one perhaps?

I attempted this and was sore and not in the mood to lift anything for five days!


Chris said...


I know what you mean. If I did that I am sure I'd be sore for a week.

Crossfit's normal schedule (that si a crossfit video)is 3 days on then one off, but they vary the type of workouts in there - e.g. singles one day, 10K run another, circuits somewhere else...

I think that sort of thing is a bit over the top though - not really needed for fitness or strength.

Anonymous said...

Annie and Kelly on Crossfit are both about 5' tall and can do lots of pullups, and very quickly. But with their short arms and legs, they have to do more "reps" to cover the same distance as a taller person running or on the rower. Also, in powerlifting, the deadlift favors longer arms and the bench press favors shorter arms, so for the highest total it is probably best to be somewhere in between.