Thursday, 28 July 2016

Balance, Or Not

The second half of our unit with the Seniors, is biomechanics; getting our heads around the biomechanical principles and then applying them to movements. Today's focus was balance and stability. Balance and stability have three key concepts students need to understand and be able to interrelate; base of support (BOS), centre of gravity (COG) and line of gravity (LOG). 

Put simply, our BOS are the points of contact with the ground, and the area in between. The wider this base of support, the greater balance and stability we have. COG is the centre of the mass of the object, this may be on or outside an object depending on the makeup and placement. The LOG is straight through the COG to the ground. If this hypothetical line falls out of the BOS, this is when something becomes unstable and loses balance. Thus, a widened BOS, ensures a lower COG and the LOG is less likely to fall out of the BOS.

This afternoon 12PE replicated some poses with 2, 3, 4 or 5 people, then were asked to identify where the BOS, COG and LOG were and explain why. If they could not replicate a pose, they needed to identify why they weren't balanced/stable and how to increase their balance and stability. We attempted to create a class pyramid, but unfortunately collapsed as I was trying to capture the moment and the bell had gone! So hopefully we can attempt this in the future, as this clearly demonstrates the balance and stability principle. I'm looking forward to experimenting with more of the principles!

If you are interested to learn more about balance and stability, check out this clip. The YouTube channel RBHS PE with Mr Dalton whom created this video, has created various clips that are useful to describe other components of HPE, if you are an educator like me!

Yellow - COG
Blue - LOG
Red - BOS


  1. This is such a cool way to teach something that could otherwise be quite tricky! By actually creating the structures with their bodies they were able to understand and locate the BOG, COG and LOG. It looks like it would have been fun as well. This has got me thinking of how I could possibly do something similar with my learners, as learning through doing is so much better!

    1. Initially they were hesitant but once they got engaged they were smiling and laughing the whole time! We started with the theory so they had some understanding of the principle, then moved into the practical to revise what we had just learnt. I agree - moving away from books and screens and utilising our bodies and movement is a great way to change things up and reinforce learning :)


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