My Bullmastiff is TOO hyper!?

I adopted a 3 year old bullmastiff about 7 months ago and she has been really difficult. She's extremely hyper, jumps around, knocks everything around her over including me half the time and I get bruises all over my feet where she accidentally steps on me, and when I tell her to go into her kennel she's so hyper that she sprints into it causing it to slide across the floor and slam into the wall. When I researched the breed I read that they were alot more laidback and easygoing than this, and I thought along with adopting an adult she would be pretty calm. I take her on daily 30-40 minute walks to get her energy out but it doesn't seem to do anything for her hyperness, and even the walks are a struggle because I've been trying to train her to heel with no luck at all. She's incredibly stubborn! I'm so frustrated that it's hard to enjoy her companionship. I need advice please! Is it possible to train her to calm down and if so, HOW??