When most people think of hyper-active dogs, they usually envision small dogs such as the Chihuahua or Pomeranian as opposed to larger dogs such as the boxer. This can lead to pet owners being surprised when they purchase a boxer and the dog turns out to be very energetic and hyper-active, and may result in the dog not receiving the amount of exercise that he needs in order to stay healthy and happy. Many potential pet owners overlook warning signs of a hyper-active boxer and dismiss it as simply the playfulness of a puppy, only to find out too late that the particular dog that they picked is much more work than they had bargained for.
While most boxers are playful, the majority of them also have a calm and independent side to their personality which can enable them to become used to their owner's schedule and allows for quiet time in between the walks and play sessions. A hyper-active boxer, however, will be much more likely to cause mischief while their owners are trying to work or have a quiet moment since the dog will get bored and look for some way to divert its excess energy. Hyper-active boxers can gnaw on or otherwise damage furniture, and may also be much more prone to having accidents in the house (especially leaving pet stains on carpeted areas when excited.)
Boxers are strong-willed dogs, and obedience training can go a long way toward keeping their strong-willed nature from developing into restlessness and hyper-activity. A truly hyper-active boxer will be more difficult to train, but with sufficient work you should be able to get your dog's behavior under firm control. If you purchase a boxer puppy and begin to suspect that he may be hyper-active, then you should begin training at a young age before those hyper-active tendencies have a chance to develop into potentially larger problems such as destructiveness or aggression when the puppy is full grown.
If possible, take some time to examine and observe boxer puppies before choosing one to take home with you. It's generally easy to determine whether the puppy that you're considering is hyper-active by watching how it behaves around its litter-mates and how it acts when alone. Find out as much as you can about the parents of the litter as well, talking to the breeder if you can in order to discover whether either of the parents had any signs of being hyper-active when younger or if they still display hyper-active behavior now. While there's nothing wrong with adopting a hyper-active boxer, given the dog's eventual size and strength it's important that you are able to curb any destructive or aggressive tendencies while it's still young or else you may have to face the consequences later.