Instructions
Launch Wii Fit and select your Mii from the Wii Fit Plaza. Click "Start."
Select the graph icon in the lower-left corner of the calendar screen.
Select the "Fit Credits" icon from the top of the graph and press "A" on the Wiimote. Select "Activity Log" and press "A" again.
Click "Yes" to confirm that you want to add outside exercise. Select the level of activity performed -- "Light," "Normal" or "Hard" -- and press "A."
Place the hand cursor over the arrow buttons and click "A" to enter the amount of time spent exercising. Click "OK" to save the activity to your activity log.
Select "Yes" if you want to add more outside exercise time to your activity log. Select "No" to return to the Activity Log screen.