SLT (Strengthen - Lengthen - Tone) | 2,406 followers on LinkedIn. If cardio, strength training, and Pilates had a baby…it would be SLT. At SLT, our mission is to give our clients the full body reSuLTs they have always wanted. Set in a semi-private environment, SLT is done on a machine called a Megaformer which requires constant engagement of the core.