I aproch this in a Taoist prerspective.

it is always good to be in shape, but the key is to work with your body type and not fight it. if you are a little person, embrace that, be little and be wise about what you do to survive, if you are huge and muscular work with that.

If you are slow and methotical, be that, it can help you survive just as being fast and light.

It is key to not envey those who posses strengths you do not have, but to reoginze what you do have and acentuate your strengths and work with them.