A General Strength Training Routine Still Has It's Place
You don't HAVE to relegate yourself to just performing specific strength training for runners, however. You can also improve your running and your overall fitness by performing a classic full-body resistance training routine twice per week for 3-8 reps. Be sure to choose 2 exercises that are quad-dominant, 2 that are hamstring-dominant, 1-2 for the low back, 1-2 for the chest, 1-2 for the shoulders, and 2-3 for the abdominals. Go here for a classic strength training routine you can perform at home OR at the gym. This is a better option if you are more of a casual runner who is doing it for health rather than for racing purposes. And even if you do race, you can do full body routines during your off season.
Whether you choose the strength training for runners or the classic strength training routine, it is most desirable for you to perform your strength training exercises during a separate session of exercise on a day that you do a less-taxing cardio session. They can also be done before your cardio sessions or on your "off" days from running.
If you perform a strength training workout and a cardio workout back-to-back, it's best to sip a sports drink, coconut water or some diluted fruit juice, or at least have a good-sized meal a couple of hours before training. Stretching exercises are best performed after your running and/or resistance training. Focus your stretching on your calf, shins, hips, glutes, and low back.