No, it is not necessary to use physical punishment in aggressive dog training, and in fact, it can be counterproductive and even dangerous. Using physical punishment to train an aggressive dog can make their behavior worse and damage the relationship between the owner and the dog. Here are some reasons why physical punishment should be avoided in aggressive dog training:

1. Aggression is a Symptom: Aggression is a symptom of an underlying problem such as fear, anxiety, or frustration. Using physical punishment to control the symptom will not address the underlying problem and may make the behavior worse.
2. It can cause More Aggression: Using physical punishment can make an aggressive dog more aggressive. Dogs may become more fearful, anxious, or frustrated, which can lead to more aggressive behavior.
3. It can Damage the Relationship: Physical punishment can damage the relationship between the owner and the dog. Dogs who experience physical punishment may lose trust in their owner, become more fearful, or even become aggressive towards their owner.
4. It can Lead to Injury: Physical punishment can cause physical injury to the dog. Using physical punishment such as hitting, kicking, or choking can cause pain, injury, and even death.
5. It is Ineffective: Physical punishment is an ineffective training technique for aggressive dogs. It does not address the underlying problem and may even worsen the behavior.

Instead of physical punishment, positive reinforcement should be used in aggressive dog training. Positive reinforcement involves rewarding the dog for good behavior and ignoring or redirecting unwanted behavior. This technique helps the dog associate good behavior with positive experiences and motivates them to repeat that behavior in the future. Positive reinforcement is a safer, more effective, and humane way to modify aggressive dog behavior.

In conclusion, physical punishment should be avoided in aggressive dog training. It is ineffective, can cause more aggression, damage the relationship between the owner and the dog, and even lead to injury. Positive reinforcement is a safer, more effective, and humane way to modify aggressive dog behavior. If a dog owner is struggling to train their aggressive dog, they should seek professional help from a certified dog trainer or behaviorist.