Nike is building on its Audio Cheers feature for the Nike+ Run Club app on iOS and Apple Watch by adding support for custom audio cheers. If the preset cheers aren’t giving you enough motivation, this new update might give you the push you need. You can get these customized cheers from your Nike+ Run Club friends by turning on Nike Run Club Cheers in Run Settings > Audio Feedback. Inversely, you can send one to your friend and help motivate them on their run. The update also brings with it general bug fixes and enhancements to the app.
Source: 9to5Mac