ASICS Men's GEL-DS Sky Speed Running Shoe 100% Synthetic and mesh Rubber sole Impact Guidance System (I.G.S.) (RUNNING) ASICS Design Philosophy. Employs linked componentry that enhances the foot's natural gait from heel strike to toe-off. Asymmetrical Lacing Design An anatomically correct lacing environment that reduces potential for irritation and provides improved comfort and fit. Guidance Line