This is a good drill to build defensive intensity, agility and quickness endurance. The aim of the drill is to simulate full intensity defensive slides for the duration of the shot clock.
Focus on correct technique: step with your lead foot pointing in the direction of your slide and pushing for power with your support foot in a push-step-slide motion, moving as quickly as you can without compromising technique. Be sure not to bounce and strive to stay upright throughout the 24 second set.
To build up your defensive endurance, work on a 24 seconds on/24 seconds off (rest) rotation, working up gradually until you can complete 8 complete sets in a session.