For many years endurance athletes have stayed clear of weights and the gym, worried about gaining mass and getting bulky. We have found as athletes and coaches, that strength training is necessary. Not only does it help to get stronger, but it is also a vital component of injury prevention. Being stronger allows your body to withstand more training stress. Your ability to handle loads without breaking down, will improve with consistency and will allow you to go longer and faster season after season.
Especially for running, a strong foundation is key and improves your running economy - So essentially your energy consumption during sub-maximal running will be lower and running will take less effort. Furthermore, if you are stronger you will be able to hold a higher quality of technique for longer, reducing deterioration of running form as you get tired.
When should you do weight training? Your season plan should be periodised, meaning it is broken up into different phases with varying focus. The best time for heavy strength training is in the base phase/off season, a time when you can lift higher loads while keeping a lower intensity in Swim/Bike/Run. For the rest of the season strength training should be specific to where the athlete is at in the season. Through the race season, strength maintenance is the goal.
What exercises should you perform? In the base phase, you should focus on higher load and low reps. If you are in the gym I would suggest these exercises for 6 weeks. If at any time you your technique fails, then stop and start the next set or reduce the weight to an amount that allows you good technique. Suggested exercises:
Heavy Bar bell Squat 6-8 reps, 4 sets
Split Squat on smith machine 6-8 reps, 4 sets
Pull ups (Not chin ups)- Until Failure, 4 sets
Calf Holds/Raises on smith machine, Heavy load - 30 seconds each leg, 4 sets
Dead lift - 6-8 reps, 4 sets
Leg press- 6-8 reps, 4 sets
Take 2 minutes rest in between sets. Make sure post session you get in a recovery drink with a good amount of protein.
Be aware that you might be damn right sore after the first 2 sessions, so DO NOT plan a hard session around these strength sessions.