There are plenty of plugins that will allow you to create a light stroke effect in After Effects, as well as more than one technique. Here, Uwe Schweer-Lambers (Equiloud) shows one method for creating a light stroke effects in After Effects using only After Effects bundled tools.

Creating a looping Light Strokes Effect with built-in Plugins in After Effects- It´s 2D only

Equiloud notes that this technique is strictly a 2D endeavor, using the Vegas Plugin, a Glow effect, and Turbulent Displace within After Effects creatively to build an effective and nice looking light stroke effect.