I'm gonna have to go with below the waist .... Oh yeah ;)
Would you rather have super strength, but only below the waist; or super speed, but only from the waist up?
Neither. I just want all over long-lasting very gooooooooood health.
You've described Strephon (from Iolanthe) who was a fairy down to the waist but from the waist down was a blithering idiot.
Strength below the waist...I'm liking the way that sounds ;)
I'm already a super speed! So i'd choose super strength!