Why do weak muscles shake?
There are quite a few reasons why weak muscles might shake. These muscles could just be spending the last of their energy.
muscles shake as they get tired,or are needing fluids etc the shaking is natures way of telling you to back off thats not entirely true. muscles can shake from the second you start an exercise. it's actually just your body telling you that they're not used to this movement. if you continue training those muscles over time the shaking will stop. expect to be sore the next day though :)