proper BJJ has nothing to do with actual strength. While strength can help you it can also tire you the fuck out if that's all you rely on. Most high level people who train BJJ rely souly on technique. There's a time and place to be explosive and a proper way to use it. My favorite example of this is the current world champ who competes at the heaviest level (he's straight muscle though) Marcus "Buchecha" Almeida. He can overpower a lot of people but his technique is so damn deadly and he moves like he's 150 pounds. I always try to go for the person who has 50+ pounds on me because I know it will force me to use technique. And it feels so damn good knowing you can probably fuck up 80% of the population (so long you're not only trained in sports jiu jitsu but the self defense aspect of it too) regardless of how much weight or strength they have over you. This is why BJJ is such a beautiful sport.