If you use a harness, take a minute and genuinely watch this video. Do you see the difference in natural gait on this dog as the various harnesses affect shoulder movement? I’m not “against” harnesses, but you should understand/be aware that many commercial harnesses can and will affect their joints/movement/muscle mass etc.

Now consider how using a harness can affect growth and development on a young dog. Front lead harnesses are ever growing more popular bc of the pressure (correction?) they apply over the chest/shoulder. That same pressure is going to directly affect joint health, gait, and subsequent muscle tone.

I have used harnesses for appropriate tethering for organized exercise (biking with my dogs) but great care was spent selecting an appropriate harness that evenly distributed pressure across the chest and didn’t restrict movement and was used with a loose lead. Additionally, such activities were limited to mature, adult dogs.

See the effects of various harnesses here: https://www.facebook.com/419753771785101/posts/605720159855127/?vh=e&d=n

For example, here is Myst on a biking excursion: