I am not sure exactly what you mean by your wrists feeling weak without being able to perform an examination or ask you a few more questions. For that reason, I think it is worthwhile for you to talk to your primary care doctor
about the issue, as they will be able to do just that.
It is common for people to develop injuries in their wrists. Most of the time, these are due to repetitive strain or over use injuries, such as might be contracted by typing at a computer keyboard all day long. Some symptoms of these strain or repetitive use injuries might include pain or a sensation of weakness in the wrist, especially when flexing the wrist or performing other similar types of actions. In cases where there is nerve involvement, there may also be numbness
or tinging in the hand or in the fingers.
Your doctor will be able to examine your hands and wrists and help determine whether something like this might be going on. If so, there are a number of treatments that are typically used. Some of these include anti inflammatory medications, wrist braces
or splints, and rest from certain types of repetitive actions.
Talk to your doctor!