In terms of sets and repetitions, you ll need to find what you re capable of. In general, begin with only a few repetitions of each exercise if you re new to them. If you don t have enough muscular endurance to do this many reps in one set, divide you exercises into two to three sets. To see maximum benefits, do these exercises at least three times a week during your off-season. During your racing season, cut down to once or twice a week.
Some runners do strength exercises immediately after their run.
This can cause problems, because if you re overly fatigued from your run your form is likely to suffer on the strengthening exercises. This increases your risk of injury. For this reason, schedule your strength-work days for your easy running days, or if possible, do the strengthening exercises several hours before or after you run. Prior stretching is usually not necessary before doing these exercises because each involves a stretch. To warm up, start off slowly and do the exercise with a shortened range of motion.