You ve changed intensity or varied the length of your long runs. You ve even tried stretching. Still no improvement. No, that can t be it. Frequency is the number of days per week you exercise.
Frequency equals consistency.
Duration is the length of time you exercise. For runners, this can be measured in minutes or miles. Progression means starting slowly and building gradually trying not to add more than 10 percent to your weekly exercise program, in either time or distance. Intensity means the level at which you exercise. The one factor that is common to all aerobic activities is heart rate.