What it boils down to is that every activity you perform whether it is strength training, steady state aerobics, intervals, or any combination of the three is a form of conditioning. You are conditioning your body to perform a certain way or have a certain "function". All activities fall on the same continuum and a lot more carryover exists between the activities than previously thought. It is up to the participant to figure out what "function" they want to have and what the best way to achieve that would be. For those of us who are looking to improve our fitness and "general preparedness" for life it really does not matter what form of exercise we choose. I do think there should be a balance between higher intensity work and lower intensity work, as well as "strength dominant activities", and more aerobic endurance components. Personal enjoyment also has a lot to do with.
Let’s face it I could say that running the best activity for conditioning the legs and heart, and give valid reasons for this, but if you don’t like to run than you will find valid reasons why running is bad and not needed. Personally I enjoy steady state slow to moderate jogs so I see value and do them often. I also enjoy performing jump rope intervals, and circuit style bodyweight workouts. I have in the past performed more traditional high intensity workouts although I have "cycled" off them as of late. There are too many forms of productive workouts to limit oneself into thinking that there are certain activities to develop condition and other to develop strength. All activities fall on the same continuum some lean more to one side than the other.If you are looking to perform daily activity than I would suggest you not think in terms of strength and condition but in terms of movement. Train each day if you think that is best and do something you enjoy. If you want to go all out on weight training than go for it. The next day if going for a long walk is what you feel like, do that. Your body will let you know when it is time to kick it up and when to back it off. – Doug Scott, Strength & Conditioning Coach, The Pingry School