Is it normal to have a really strong teacher?

So it is the end of the semester in my school and we were all messing around in our last period class. The teacher decided we should play some kind of game and we had a vote. For some reason a lot of people wanted to have an arm-wrestling competition. Since this is a science class, most of the people were pretty small (no offense) Besides for me and maybe 2 or 3 others. Luckily we had just enough people to do an actual tournament bracket and I managed to get all the way to the final and win. My teacher decided to challenge me for the championship and since she's like a 40 year old woman I knew I'd win and I accepted. She's pretty big though(not fat, just tall and and a pretty average weight for a 6'0 tall woman.) But when we started right away I was on the losing and and she absolutely dominated the game and won in like 4 seconds. Everybody was shocked including me and I got super embarrassed. Pretty weird right? It's not like she's a gym teacher or anything