A Staffordshire should look like a Staffordshire. This sounds obvious but the question is, what does a Staffordshire Bull Terrier look like? There is a written breed standard that I suggest you read. It can be found at the AKC site at the following link (Staffordshire Standard). The problem with written standards is that they are open to interpetation by breeders and judges. If you take the requirement that the breed be heavily muscled to the extreme without taking into account that they be agile too, you can wind up with a dog that looks like Arnold Schwarzenegger but can't scratch it's ear.
Fortunately with Staffy's we don't have to guess what they should look like, we have pictures. When the breed was first allowed to be shown in conformation classes in England in 1935 photography was readily available and there are many fine photos of those early champions to guide todays breeders in how to interpet the standard. If our champions of today do not closely resemble the pictures of these first champions it is a sure sign the breed is getting off course. It is my opinion the breed is beginning to show signs of a course change.
Here at Rockstaff Kennels it is my goal to breed Staffordshire Bull Terriers that closely resemble those early champions. For examples I look to pictures of CH. Lady Eve the first female champion in 1939 and CH. Gentleman Jim the first male champion in 1939. My Staffys should bear a strong resemblance to these early champions.
These early champions were working dogs. After a show a dog might be taken to a fight that night. I abhor dog fighting but I use the example to make the point that these early champions had to be agile, have remarkable stamina, courage and drive. These were not the plodding, muscle bound dogs you often see today. Jim the Dandy, on whom the breed standard was patterned, was 17.5 inches tall, 1.5 inches taller than todays standard allows, yet he only weighed about 36 pounds. This was a lean, agile, terrier type Staffy.
Here at Rockstaff Kennels I try to maintain a dog with stamina and agility while trying to breed out dog aggression. I work my dogs on a spring pole, play ball with them hard nearly every day, run them behind our 4-wheeler and play tug of war with them. All these things allow me to evaluate the agility and stamina of my dogs. If a dog I'm considering keeping to breed can't keep up the pace they are not a candidate for breeding. They must also conform to the structural pattern of those early champions.