I think its kind of dependent on the type of racing you do. I do mostly sprint distance duathlon so I do a considerable amount of speedwork on both the run and bike. Usually 10x400 or 4x1000meter repeats and a tempo run each once per week on the run and then 4x6:00 hard once per week on the bike with a hard tempo session cycling as well. Volume wise Im at about 12 to 14 hours per week. My long run is rarely over an hour and I rarely cycle more than 90 minutes at a time but I do run and cycle 7 days a week.