There are many dogmatic opinions available from veterinarians, pet owners, breeders and others concerning a common question owners of new puppies have, How much exercise is ok for puppies? This is an especially pertinent question for owners of large breed puppies, since these breeds have a higher incidence than others of developmental orthopedic disorders such as hip dysplasia, elbow dysplasia, and cartilage abnormalities known as osteochondrosis dissecans (OCD). As is all too often the case, however, these opinions generally lack solid scientific evidence to support them. Very little is known about the precise risks and benefits of different types and intensities of exercise in growing animals.
One case control observational study  surveyed dog owners and found playing with other dogs to be a risk factor for OCD. Another, similar study  found chasing balls and sticks was a risk factor for development of hip dysplasia and elbow abnormalities. However, these studies cannot answer the overall question, which is how much and what kinds of exercise pose how great a risk and provide how great a benefit. One study  found exercise to be part of the treatment of carpal laxity, another joint abnormality seen in large breed puppies, and there is no question that exercise has many benefits, including reducing the risk of obesity and simply being part of a normal, enjoyable life for a puppy.
There are many more studies on the effects of exercise in children than in puppies, and though it is always risky to extrapolate from one species to another, some useful information can be gained by using one organism as a model for another, as long as conclusions drawn in this way are cautious and tentative pending better data. In general, while some intense and repetitive exercise can pose a risk of damage to growth plates in children, exercise is overall seen as beneficial in improving bone density and reducing the risk of obesity and related health problems.
The research evidence, then, really does not provide anything like a definitive answer to questions about the effects of exercise in growing puppies. Common sense suggests that forcing a dog to exercise heavily when it does not wish to is not a good idea. Likewise, puppies sometimes have more enthusiasm than sense and can exercise to the point of heat exhaustion, blistered footpads, and other damage that may be less obvious. Therefore, a general principle of avoiding forced or voluntary extreme exercise is reasonable, but specific and absolute statements about what kind of exercise is allowed, what surfaces puppies should or should not exercise on, and so forth is merely opinion not supported by objective data. Such opinions may very well be informed by personal experience, and they may be reliable, but any opinion not founded on objective data must always be taken with a grain of salt and accepted provisionally until such data is available.
1. Slater MR, Scarlett JM, Donoghue S, Kaderly RE, Bonnett BN, Cockshutt J, et al. Diet and exercise as potential risk factors for osteochondritis dissecans in dogs. Am J Vet Res. 1992 Nov;53(11):2119-24.
2. Sallander MH, Hedhammar A, Trogen ME. Diet, exercise, and weight as risk factors in hip dysplasia and elbow arthrosis in Labrador Retrievers. J Nutr. 2006 Jul;136(7 Suppl):2050S-2052S.
3. Cetinkaya MA, Yardimci C, Sa?lam M. Carpal laxity syndrome in forty-three puppies.Vet Comp Orthop Traumatol. 2007;20(2):126-30.