Mnemonic Device for Lever Classes

Posted by on Sep 1, 2013 in Exercise Science, Review Topics, Study Strategy | 4 comments

This helpful mnemonic device comes from reader Jackson.  His biomechanics lab TA shared this one with him, and he in turn shared it with me via email.

Remember levers and their different lever classes?  Check out this post for a refresher.

Now, which is which?  1st class lever has the fulcrum, load, and effort applied to which ends?  To be honest, I’ve already forgotten.  I remembered when I wrote the original post on it, and probably remembered for a while afterwards…but use it or lose it.


Which lever class is which?

Which lever class is which?

Can you identify them?


If you had trouble with this, then you should read this piece from Jackson:

I just graduated from the University of Tennessee-Knoxville in kinesiology, and my next step is taking the CSCS exam which is in just a few hours for me. I started studying for the exam in May while working part-time as a personal trainer.

Your blog has helped me prepare quite a bit, so I thought I would share one of my tips.

My biomechanics lab TA showed me the mnemonic “FLE 123” for remembering lever classes. F = fulcrum, L = load, and E = effort. The fulcrum is in the middle for 1st class levers. The load or resistance is in the middle for 2nd class levers. And, the effort force is in the middle for 3rd class levers.

Hopefully, that helps you.

Pure gold!

This is a brilliant mnemonic device for remembering lever classes

This is a brilliant mnemonic device for remembering lever classes

The genius of this mnemonic lies in the symmetry.  Identifying the component in the middle of the lever is the only information necessary to identify the lever, as the other two components can be flipped and the lever still retains it’s class.  Effort-Fulcrum-Load is the same as Load-Fulcrum-Effort, they are both first class levers.

Prove it to yourself.  Pull out a piece of paper, and write down FLE 123.  Now draw the three classes of levers and fill in the middle item using the FLE123 mnemonic.  Fill in the rest.  You can do this on exam day on your scratch paper and will always have all three levers handy.

Thanks Jackson!


  1. Great stuff! I honestly just got done review this less than 10-minutes ago, and then I find this post! Great job, FLE is will remember come Wednesday. Also stated in the symposium CD set, 3rd class is the most common lever class

    • Good to know! When in doubt, default to 3rd class.

  2. I came across the same method with a different mnemonic while browsing youtube. ARF. if the axis is in the middle it’s 1st. Resistance in the middle it’s 2nd. Force in the middle it’s a 3rd class lever.

    • Same concept, I guess use whatever is easier to remember. ARF ARF


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