I have a showline bitch that i have trained only obediece but i have done all training with strict koehler methods, which include force training. I used force retriving method of ear pinching. and strong corrections for everything else. There were times when she seemed like she didn't get it but a week later she was retrieving that dumbell like  a labrador. It takes time and some common sense on the trainers part. Every dog is different and in my experience with people who hold back on force training it was that the correction was not tough enough to get a good result. you can't hold back. Do the force or correction with enough toughness and calmness and you won't have to do it again. Get your point across the first time or your just abusing the dog. you shouldn't have to ear pinch or correct the dog every week if you are then it's not a strong enough correction and you are just being abusive at that point. And in all trainng even force training lay the groundwork down. Make sure the dog knows what you want before you use the correction. You can't correct the dog for what it doesn't know.