This may be the result of a setting you may have overlooked:
Did you release your workouts?
Check the published date and time of your workout, you'll find that within the workout editor.
Did you explicitly hide your workouts?
At a quick glance of your workout list, you can immediately see if you have a workout explicitly hidden from the leaderboard regardless of its published date.
Did you release your leaderboard?
You can quickly glance at your dashboard to view or update the release date of your leaderboard.
Did you publish your scores?
If you have turned on 'Delayed' scoring, check to make sure you've published your scores.
Within the scoring page, check the workout in question to make sure the scores have been published.