Apple is developing a more advanced version of the Nike + iPod sport kit, while the world's governing body for marathon runners is mulling over a wholesale ban on the use of iPods by athletes.

AppleInsider reports the company is developing a service that will help people keep stay fit. The service is based around the iPhone and the iPod touch, and has been revealed in a series of patent filings uncovered at the US Patent and Trademark Office.

The system features hardware-based heart rate and physiological sensors, a rewards tracker, and "a component to facilitate synchronous group activities," the report explains. It also uses iTunes as a portal for distribution of elements of the system. As explained, the system interviews users to assess a personalised training plan for them.

But the move to broaden iPod's appeal to sportspeople may face an unexpected hurdle. The IAAF Road Running Commission, the world's governing body for marathons, will discuss a wholesale ban on use of iPods and other similar devices during races at a meeting in September.

The move follows the imposition of a similar ban in the US, on the grounds of health and safety. Reading between the lines, it appears that organisers of long distance runs were forced to pay more for their general race insurance if use of iPods were allowed.

Jill Geer, spokeswoman for USA Track & Field, told The Observer: "Some runners are irate and we understand and respect the thousands who like to listen to music. But we have a fundamental duty to guarantee the safety of participants."