Adrenaline junkies looking for the newest trend might want to give “grinding” a try. Rollerblade Inc. has introduced its first shoe, the RB Grind Shoe, to tap into the new craze for jumping and sliding along curbs, handrails and other urban obstacles, known as grinding. Designed like a street shoe, it’s what’s inside and on the bottom that sets the RB Grind apart. The sole features a twin bar roller system, two metal bars that float and spin independently of each other. When attacking railings and curbs, the bars spin to provide a smooth grind any time. Available in gray suede with white accents and blue suede with white accents, the shoe comes in sizes 6 to 12; $79.99 at sporting goods stores.