Is there an adult male body type that won’t increase muscle strength from working out?
There is no body type that won’t allow growth with proper diet and exercise. If you’ve been trying for over a year and can’t see any results you’re probably doing something wrong, or you are producing results and you just can’t tell. Since there are a number of things you could be doing wrong you should read our question on how to gain muscle mass.
It is also possible you’re working out too much. You need to burn fat to be successful while working out, if you’re working out too often you may be burning muscle to get the energy you require while working out.
Supplements may help too, but be very careful with supplements.