There are a lot of ways that dogs try to take control of the leash walk and there are a lot of ways that humans are unintentionally giving up their potential for leadership on the leash walk which is leading to the bad behaviour and the poor mindsets elsewhere in the dogs life.
The obvious way that a dog tries to control the walk is through reactivity… barking, lunging, pulling, overexcitement, etc. towards a trigger like other dogs or people. This bad behaviour gets reinforced every time we don’t correct it in a meaningful way. Distracting the dog with food, avoiding triggers, letting dogs interact wildly with triggers, etc. never works to resolve reactivity but actually serves to reinforce it, making reactivity worse over time.
Some of the more subtle ways that a dog tries to control the walk (and the human accidentally enables when it goes uncorrected!) is putting on the brakes and refusing to move forward, deeking and diving for every smell, marking, changing directions or weaving to pull towards something in the environment, etc. There is certainly a time and a place for dogs to explore, sniff, play and investigate appropriately, but the structured leash walk for a formerly reactive/anxious/aggressive dog isn’t that time.
The purpose of the daily structured leash walk is leadership building between human and dog. It is the most quintessential example of a human leading and a dog following that leadership. When we give up control in the small moments that enable a dog to take over in naughty ways, it doesn’t stop there… the dog usually feels entitled to take control in all the other moments in life too. It comes down to setting and maintaining fair and consistent boundaries and rules. The more consistent we are, the better the dog’s mindset and behaviour will be.