What began as simply a fitness app is quickly expanding into an all-round health tracking solution. Just a couple of months after RunKeeper launched its Health Graph API, it’s announced today that eleven more partners have come on board, expanding the platform’s possibilities even further.

RunKeeper’s Health Graph API enables users of devices and apps from a range of manufacturers to benefit from health and fitness data which is all in one place, interoperable and trackable over time. These devices and apps can also integrate Runkeeper’s social features.

Today, RunKeeper has announced the following new partners are joining the API’s alpha phase:

Jog Log is an iPhone app that helps you track your running and other fitness activities using GPS.

iSmoothRun lets you use your iPhone as a training aid for running and multisports.

Swim Converter tracks your swimming activities in yards or meters.

WeightConnect lets you connect your WeightBot measurements with your Runkeeper account.

Fitocracy helps you surpass your fitness goals by turning fitness into a game.

Arookoo sends you on challenges that motivate you to move around your city.

Fitness Widget Generator creates a widget you can include on your site to display your activities.

Withings Blood Pressure Monitor takes your blood pressure and updates your RunKeeper profile automatically.

Additionally, Kinetic, a GPS app for running, walking cycling and other activities;  Weight Meter, a web site that can be used to keep track of your daily scale readings; and Superproof, an online fitness game and iPhone mobile app that helps you rally your friends to achieve your health goals together, will all be adopting the API in coming weeks.

With the recent closure of Google Health, it interesting to see a relatively small startup take its own approach to building a social, online health tracking platform.