Opinions differ when it comes to dog training.
Some trainers advocate punishment-based training such as jerking the leash, shouting or slapping the dog when the dog is not behaving.
To get the dog to sit, they can use methods such as pulling the leash upwards and then releasing the pressure when the dog sat down.
Other trainers advocate reward-based training such as giving candy, petting and giving praise when the dog sat down.
If the dog misbehaves, they turn their backs on the dog.
Study at dog training schools
To date, there has been no observational research on how exercise affects dogs.
Previous studies have been based on questionnaire responses from dog owners.
But now researchers at the Universidade do Porto in Portugal have found out how the dogs feel during and after training.
- This is the first study I know of where they really went experimentally and evaluated the dogs' behavior objectively, says Per Jensen, professor of ethology at Linköping University.
The study was conducted at seven different dog training schools in Portugal.
Some schools used only punishment training, one group used only reward training and a third group used a mix of the two different training methods.
The study consisted of a total of 92 dog owner pairs and is published in the journal Plos One.
During the training, the researchers observed the dogs' body language, such as tense bodies, whining and yawning.
They also measured the dogs 'cortisol levels before and after training and performed a psychological test to measure the dogs' well-being.
Punishment-based training worse for the dog
It turned out that the dogs that received punishment training had higher levels of the stress hormone cortisol and a more stressed body language.
In the group that received reward training, the researchers could only see a few tense bodies and they did not show a stressed body language to the same extent as the other groups.
Even outside the training sessions, the dogs that received reward training felt better.
The psychological test showed that those dogs were more optimistic.
- The results clearly show that punishment-based dog training leads to increased stress and impairs the dogs' well-being in the long term, says Per Jensen.