R.L. Stine 
Rotten School #4: Lose, Team, Lose! [EPUB ebook] 

Jennifer Ecch is so tough…She’s at Rotten School on an Arm Wrestling scholarship!Bernie Bridges calls her Nightmare Girl. But she’ll do anything to get him to be her boyfriend.That’s why she joined the all-boys football team. With Jennifer playing, they can’t lose. But wait. If they win, they have to play the National Champion team — the Bone Breakers!Someone’s got to stop the attack of the Ecch — or else Bernie and his teammates will be in the hospital by halftime!