Driven Key - Maya
1. Add Attribute
Select Main Ctrl / Attribute box / Attributes tab / add. (Name: Forward or whatever u like)
2. Create Locator
Animation / Create Tab/ Locator.
3. Parent Locator to IK Handle
Outliner / MMC IK to Locator
4. Select All Locator - Set Driven Key (Act like a Null in AF)
Channel Box / Edit / Set Driven Key
5. Load Driver - Main Ctrl (Set Key Frames)
6. Graph Editor (Offset Keyframes & Loop Infinity)