Observant people familiar with dog body language know that a dog is more relaxed and less stressed if the dog is able to choose an “indirect” path — a curve if you will — when approaching people, other dogs, or objects/locations that are unfamiliar or have a history of causing the dog anxiety. Watching well-socialized dogs meet each other while off-leash illustrates this beautifully.
Have a look at the videos from this study where dogs’ heart rates were measured during direct approaches (head-on) and indirect approaches (curves). You will witness the correlation between the heart rate and the dog’s body language and tightness of the leash. In my Wellness & Enrichment dog class, I instruct students to monitor the amount of leash pressure the dog is causing on the walk and use that as a guide to assess the dog’s level of arousal in order to keep the dogs under threshold.
When walking a dog on a leash, remember to avoid head-on direct approaches when passing people, other dogs, skateboards, the yard with the dog barking at the fence, etc. Your dog might be trying to pull away to make that curve, but an uninformed dog handler may give a “correction” or lure/coax the dog to continue the direct approach, causing increased stress levels. This is how dogs become sensitized to these situations, and how many dogs begin to show over-reactive behaviours when encountering these things on a leash.