A wannabe actor needs money, so he continues to do the only other thing he really knows how to do: carpentry. He gets a job installing cabinets at someone's home. That someone will soon start shooting his first major film.

The movie: American Graffiti. The client: George Lucas. The carpenter: Harrison Ford.The telling of those three tidbits allows me to move the story immediately from the middle to the moral: Success and timing are sometimes inseparable.This statement rings true not only for opportunities in life but also in matters of health and fitness. And while this timing can often be guided by scientific study, it often needs to be fine tuned through experience.If I share some of the fine tuning I've done throughout the years, it may expedite the process for you.Even if you only occasionally read articles pertaining to health and fitness, you've surely read more than a few about how most Americans are sleep deprived and how sufficient sleep often seen as eight hours a night for adults burns more calories, aids the immune system, allows for quicker recovery after workouts, and improves mood. Years ago, these articles made such sense to me that I reworked my after-supper schedule to make sure I slept at least eight hours and sometimes more.You can imagine my confusion then when some mornings I woke rested and refreshed but other mornings I rose groggy and listless. After some additional reading on sleep cycles and monitoring of my own, I soon discovered the timing of my rise was as important as total sleep time.I tend to sleep in 90-minute cycles. If my alarm goes off at the end of a cycle, I feel rested and refreshed. If my alarm goes off in the midst of a cycle when I'm in a deep sleep, I awake groggy and listless.In short, I function better sleeping seven and a half hours (or five 90-minute cycles) than eight and a quarter (five and a half). If I ever feel so sleep starved that I want to sleep "extra," I need nine hours (six 90-minute cycles) for it to matter.But I rarely have time for nine hours of sleep during the school year even on weekends. On both days, I rise at five to write this column and ride at nine, usually for four hours.That's why a well-timed nap 20 to 35 minutes in length and with my legs elevated at 90 degrees in the middle of Saturday afternoon really helps. Both the brief sleep and the position of my legs accelerate recovery so that I can usually ride as long and as hard on Sunday as Saturday.If I miss my nap, I know it. During the first 45 minutes or so of the Sunday ride, I suffer. My hips and glutes ache. Sometimes my hamstrings and quadriceps, too.And sometimes for most of the ride.Yet more nap time is not better. If I nap more than 35 minutes, I tend not to sleep well that night, thereby negating the benefit of the nap a clear case of more not being better.More variation in exercise is not always better, either. Timing, once again, plays a crucial role.Even if you only occasionally read articles pertaining to health and fitness, you've surely read more than a few about how cross training reduces the incidence of injury from overuse syndrome, keeps exercisers mentally fresh, and promotes greater all-around fitness. While all this is true, you need to know exactly what you want to get out of your workouts before you decide how much cross training you do.That's because the more time you spend working on a specific sport-related task, the more proficient you become.Don't expect, for instance, to improve upon your best 10k time by running twice a week, cycling once a week, and lifting once a week if you set your previous best by devoting all four weekly workouts to running. It could occur by chance, but don't expect it.If you are content with simply participating in the race while keeping a chronic case of shin splits at bay, then reducing your running days by half makes sense.One final note to cross training: it may throw off your body's routine, resulting in something cyclists call "blocked" legs.You would think that taking two or three days away from a repetitive leg exercise like running or riding a bicycle would translate into greater performance during the first workout after the break. Quite often, however, that's not the case.Because you've disrupted the routine that the body has grown accustomed to by the break, it's now unsure how to react. Your legs feel foreign to you or "blocked."While some hard efforts relatively early in the first ride or run can "unblock" them, you generally don't feel yourself until the following workout.