Alternating periodization involves alternating acute training variables from one microcycle to the next. The microcycle can vary in length from 3-4 days through to 4-6 weeks.
This type of periodization may involves alternating between phases of higher volume (more sets and reps, less weight) and higher intensity (less sets and reps, heavier weight). For example, you would do a three to four week block of ten reps followed by a three to four week block of three reps.