Yip thats all i do it keeps a good baseline of fittness ,
I always try to get them doing at least 5/6 mile's a day , Which is easy and only takes 35/40 mins, Plus i think it keep them sharp and jumping a treat over every gate fence you come too,
But likes been said take it easy at first,
Edited to say more or less all the running i do beside the bike is free running, They just run beside me or up infront....