The term 'alpha' in animal behavior is used to denote the socially dominant or highest status individual in a social group. Therefore, calling a dog 'alpha' implies that their motivation is to have control and/or social status over their handler - frequently called 'dominance'. In this way, 'alpha' is a term inseparable from dominance theory, whether you say you ascribe to it or not. However, domestic dog social groups do not have a single socially dominant/highest status individual - they have no strict social hierarchy whatsoever - and so it's impossible for their behavior to be motivated by the need to control the handler/owner or to display higher social status over them. This makes the entire concept of 'alpha' or 'dominant' dogs inaccurate and sometimes even harmful to finding and applying appropriate training solutions.
Saying a dog that pulls on the leash (for example) is doing it because they are 'alpha' implies that the dog is engaging in the undesirable behavior for the deliberate purpose of controlling the handler and demonstrating the dog's superior social status.
Saying that a dog pulls on the leash because it gets her what she wants is implying that the dog wants to sniff a particular tree and knows that if she just pulls hard enough she'll reach it and get a sniff. No implied intention to manipulate or challenge the handler's social status within the household.
Using inaccurate language like 'alpha' that's closely tied to an outdated idea of canine social behavior that's been thoroughly debunked by modern research can make it harder for people like Isabellethemayor to recognize why the dog is engaging in the undesirable behavior and what needs to be done to fix it. There's loads of nonsense about how to deal with an 'alpha' dog that ranges from silly and useless (like 'eat before the dog') to outright dangerous (like physically pinning a dog down for 'undesirable' behavior) to 'correct' the dog's concept of where she is in the household's social hierarchy... which is a concept she doesn't have to begin with. When we understand "the dog has learned that putting pressure on the leash lets me get to interesting places on a walk", there's a much simpler, more straightforward motivation to work with. Now we know that we need to A: make sure the inappropriate behavior isn't rewarded by what the dog wants and B: an alternate, appropriate behavior does get the dog access to a reward.
I agree this dog needs boundaries, structure, and clear, consistent training. I disagree that it's because she's demonstrating that she believe she's of a higher social status than the handler. I also disagree that physical corrections are necessary to establish boundaries, structure, or clear and consistent training. This is the last I'll say on the matter in this thread.
Isabellethemayor, for the pulling issue (since I'm using it as an example anyway), I'd start at home and do a lot of work on your pup learning how to give into leash pressure. Look up 'silky leash' or 'silky lead' training. It's a very simple method that teaches the dog that pressure on the leash means to give in and release that pressure, instead of their natural instinct to pull against the pressure. This instinctive pull against pressure is called the 'oppositional reflex' and we all do it - imagine if someone was tugging your arm and you didn't want to follow, you'd naturally shift your weight and pull against the tug. It takes a lot of training and practice to change a dog's natural reflex to pressure on the lead from 'pull harder' to 'give in', but starting in a boring space in your home and lots of practice will give you a good foundation. This has been a big help with my environmentally-focused, strong adolescent, who is still working on impulse control, overexcitement, and growing in his adult brain. When he forgets himself or gets overwhelmed by the excitement of the world at large and hits the end of the line, he's very quick to immediately let off the pressure again, instead of trying to freight train ahead with his nails digging in to try to haul me on my butt.
I really don't like having a dog haul on any kind of collar when they're learning leash manners due to the risk of injury to the neck, throat, and other delicate structures there, so I go with a harness that keeps pressure off the throat whenever possible (y-front, h-style). If you choose a back-clip harness, your dog WILL be able to put more strength into her pull, even if it's safer for her neck. An alternative may be choosing a harness that also has an attachment clip at the front, like the Balance Harness by Blue-9, so that if she pulls, she can't get the same amount of strength going forward without the leash turning her around sideways. A back-clip harness that keeps your dog's shoulders free is best for your dog's natural movement and comfort, but a front-clip is better than a 'no-pull' harness that actively tightens when engaged, as those can cause discomfort and soreness by interfering significantly with her natural gait. Either way, a front clip is a management tool to save your back and keep you both safer while teaching your dog appropriate leash manners, not a magic bullet that will fix everything with no training. If you go that route, your goal should be graduating her to a back-clip harness or a collar (whatever your preference) as her leash manners improve.