Can you see it requires more in a static holding, this is building muscle power and you have to do things, and muscle can build it if, it c if you asked that those legs to do that every day they would get better at it, because what the body would then do would be build in more muscle fibre to cope with the job, so can you see it, what you ask the body to do, you've got to ask it the right amount, not too much or else you damage and you've got to ask it regularly and gradually increase it if you want to improve the muscle power.