Look after their legs now and they will look after themselves when they are older. Definately no jogging with them.
Very wise words
Agree with others on the jogging front - that's definitely a very bad idea. My 4yr old show type who will run and hunt all day with my Weimaraner even struggles with jogging on lead for any period - it's too 'steady' for him and I used to do it with him occasionally, but have stopped as I can tell it's not really doing him any good. Some cockers find it a bit easier, but in general they are more point and squirt type dogs and like to go flat out in lots of different directions then have a rest, steady on lead jogging doesn't really suit their design very much and will seriously hammer and potentially damage a puppy's soft joints. I cycle with my two (they're 4 and 6 yrs) and have the same the same issue there - my Weim is a good design for keeping a steady pace up for a long time, the cocker really struggles with it and needs to take breaks a lot more frequently.
I would advise leaving any unnatural (to them) 'hard' exercises until your pup is a year and a half at least and then introduce gently
I've always done the odd longer walk than the 5 min rule with pups though - just be sensible about it. A good rucksack is useful for carrying them to give them a rest, I used to wear it on my front so I could hang on to a wriggling pup if necessary! That way you can go a lot further and not feel so restricted
You want your dog to be as fit as possible for as many years as possible and so investing in restricted exercise now will pay off in bucket loads for the rest of their hopefully long and active life