now, of course in programming for elite athletes it gets much more complicated than thsi. you may also have a 6 month "overload" period, during which you have a series of 5 week periods each consisting of 3 weeks of hard work and 2 weeks of lower stress training. then you may have another 3 or 4 month period of "recovery" consisting of 1 week of "loading" or hard work, then 1 or 2 weeks of reduced training.
all this may be superimposed upon 3 years of slightly harder overall work, in other words slightly higher volume overall... then 1 year of slightly lower volume.
this fits into the fact that the olympics are every 4 years and athletes want to hit their highest performance at the olympics. the greeks do 3 loading weeks followed by 1 unloading week (approx 12 workouts a week during loading, and 9 workouts a week during unloading, also all weights are lowered by about 10kilos during the unloading week)... these are "loading" months, then every 4th month is an "unloading" month consisting of only 1 loading week and 3 unloading weeks. close to a big competition like the olympics... they switch to alternating weeks, 1 loading week followed by 1 unloading week.