Amir Khan can’t hide the stinging pain he feels as he tries out the ab stick for the first time. Khan, who is training for his May 19 rematch with Lamont Peterson, tried the bizarre workout on one of the final days of his camp in Baguio City, Philippines.

The ab stick, which is supposed to prepare a boxer’s muscles for the effects of being hit in a fight, has been a staple of Manny Pacquiao’s regimen for years.