CHALLENGING YOURSELF DURING a workout shouldn't be a matter of overcomplicating your routine. You don't need a ton of time or equipment to do it, either—just a plan and a limitless well of effort.

Update: The Benefit Gala has been canceled. The fitness festival and workout for seniors will take place as scheduled.

Khloé Kardashian is on the mend from an injury. On Saturday, June 1, the reality star, 39, shared an inspirational video of herself working out with personal trainer Don Brooks (a.k.a. Don-A-Matrix) ...