When we do the same movements with our bodies over and over again, we overuse some muscles. And that overuse can lead to strain and injury. Sometimes those problems can come from doing sports. But exercise professionals say they are now seeing another cause for muscle problems: hand-held technology devices. Staring down at your phone or tablet for long periods of time puts great tension on your neck and spine. Many people who use tech devices also hunch their shoulders forward. Experts say this posture puts strain on the entire upper body. Muscle strain linked to hand-held technology has become such a common condition that it now has a name: tech neck. Kimberly Fielding, an exercise teacher in New York City, explains that constantly looking down at our devices creates an unnatural curve in our spine. This can cause nerve pain and other problems.