Running and playing fetch is great for developing puppies to get out energy, just keep it in moderation! For example, daily jogs may not be ideal as your puppy is growing. Running large amounts puts a lot of stress on a dog’s developing joints. High energy, low impact activities such as swimming in the pool or a local pond/lake are great alternatives!
Just like kids, puppies go through different growth stages & growth spurts, and they vary greatly. Males tend to develop slower than females, and larger breeds take much longer to develop than smaller breeds. Smaller dogs’ tend to finish developing around 6 months, however their bones can take until 8 months to finish fusing. Larger breeds can take up to 24 months! It’s very important for the longevity of the dog that they’re fed and exercised an appropriate amount as a puppy. Too much exercise can hurt just as bad as too little! When in doubt, ask your vet! They see your dog one on one and have all the info you’ll need on diet advice and exercise regimens.
A steady, healthy regimen and diet helps tremendously in the end. Malnutrition, overfeeding, too much exercise, and too little exercise can all cause problems when the dog gets older. A healthy dog = a happy dog!