Quake by Amity Cross

Caleb Carmichael’s star studded boxing career came to a screeching halt the day he ended up flat on his back in hospital.
If he fights again, he risks becoming permanently paralysed from the waist down. Professional Boxing is his whole life and he’s lost without it, but he doesn’t have a choice. Reluctantly, he cuts his losses and takes a job running the infamous Melbourne boxing studio, Beat.
But when a frightened woman turns up at the studio looking for a way to take her life back, Caleb realises there might be something out there for him after all.

Juliette Spicer was twenty-three when her twin sister was murdered.
Five years later, haunted by the public scrutiny, she changes her name and moves cities, only to find herself walking the streets the same night another crime is committed. The same crime that took her sister.
Realizing she can’t escape her past, Juliette takes action and finds herself walking into a boxing studio, vowing never to be frightened again.
But what she finds there might save her in more ways than she was expecting.