I see a lot of posts along the lines of 'resistance is king' and 'ditch the boring cardio'.
Everyone is entitled to their own opinion, but Personal Trainers should know better....
Firstly the way the articles are written implies that you should never do cardio. The premise is that only resistance training will give you the body you want.
Secondly let me briefly talk about the 6 S's. Shape, size, strength, speed, stamina and suppleness (if you can come up with a better 's' for 'flexibility' then please let me know) :)
Your goals are usually aimed specifically at one, but are likely to incorporate one or two of the others. You can't be good at all of them however. To be truly strong, doesn't leave you with the well defined body-building shape. To be built for speed you are unlikely to have true stamina. (Try telling a 100m sprinter to run 6 miles!) You get the idea...
Finally then, the most important point. YOUR goals.
Depending on what your goals are would dictate which are the best methods of training. If you want to get strong or have a well defined muscular shape then resistance training is vital. If you are looking to improve your speed or change your shape (lose weight) then resistance training is very beneficial. If however you are looking to do the Great North Run, or a marathon then cardio training becomes much more important.
So do you have to do resistance training because that is all that will work? NO!
Should you never do cardio? NO!
Should your training be specific to your goals? YES!