You can connect your Strava account with one or more external accounts including Instagram, Facebook and Twitter. This will allow you to easily share your activities on Facebook and Twitter, Share your Instagram photos to Strava, and also to login to Strava.com using your Facebook or Twitter account.
Link Your Account:
Login to www.strava.com, then go to your Settings on the drop-down menu under your name in the top right, (next to "Upload Activity").
To the right of your Settings page, you'll see a box labeled "Social Connections."
When you click "Connect with Instagram/Facebook/Twitter" you will be asked to authorize Strava to use the specific social account. Click to allow access and you're done!
Posting Pictures from Instagram:
When you upload your activity, we look for photos uploaded to Instagram in the activity's time window and they'll appear in the Activity Feed, as well as on Activity and Profile pages. For more details and frequently asked questions around Instagram integration, go here.
Sharing a Ride:
You can share your own activities either from the feed or from the individual activity page.
From the Feed page, simply click the "Share" button and then pick the way you want to share from the popup menu (Facebook, Twitter, etc…). Note that you can also send the ride to a friend -- or to your rivals -- by email or by embedding it on your blog from the Share menu.
From the Activity page you have quick access to Facebook and Twitter sharing by clicking the icons below the basic information for the activity. By clicking the "More" button you'll be able to email your activity to share it.