This is heavily disputed, and honestly, it varies on a person-by-person basis. Some people are visual learners (so it's effective for them to use videos and pictures to help them study), some prefer being hands-on, etc...
Generally though, I'd say the most effective method that works for most people is through visceralisation. This is the process of associating concepts, words. phrases etc. with your different senses (sound, touch, images...). You can read up more on it by searching up "visceralisation for studying".
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Measuring the flexibility of your joints is important because it determines if you have postural imbalances, 10 foot instability, or limitation for your motion range.
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you can start like some kind of marathon in your community, and maybe get a couple of sponsors on board too.
