Strength training has been shown to reduce the risk of injury in runners as well as increasing performance and helping you to recover faster. But why is this and where should you start?
The fundamental principal of all training is “progressive overload”. In order to trigger an adaptation in any tissue, we need to overload it, forcing it to do more work than it is accustomed to. This causes microscopic damage in the tissues. We then need to allow it to recover and rebuild with an increased capacity for this load.
For this to be a constructive, continuous process, two elements are key:
1. The level of overload. Clearly if we overload muscle, or connective tissue too much, all we do is injure ourselves. If a strength session leaves us with DOMS (Delayed Onset Muscle Soreness) and you are unable to walk (let alone run) for 3 days, the level of overload is too high. You might not get any stronger from it and crucially, it takes us away from our main activity of running.
Too little overload and we aren’t challenging the capacity of the tissues so they won’t be triggered to make any adaptation.
As a general rule of thumb, if you have the level of a strength session right, the next day you should be able to feel that you did the session, but it shouldn’t affect your day. Perhaps you are slightly sore or tired, but after a good warm-up this eases and you can still run without any issues.
2. Progression. After a few sessions at any level, your body will adapt to be able to handle that level. So in order to maintain the principal of overload, the workout needs to increase. If you always stick to an identical strength routine you will quickly plateau and get limited benefit from continuing with it.
This principal applies to our running activities, just as much as specific strength work, so you will get some strength gains from running, so long as you are creating overload.
For example uphill reps will generate higher levels of force than easy running, so are a safe and effective way of increasing running power, so long as they are introduced at the correct intensity and progression.
Particularly for trail and mountain runners, the challenge of overload comes with running technical terrain and downhill. In these dynamic movements we risk overloading relatively small, stabilising muscles in an unpredictable, uncontrolled way. So achieving a careful progressive overload is very difficult, more often leading to high levels of soreness and increased injury risk. 
The other consideration are the impact forces through the whole system when running downhill. To overload the larger muscle groups like the quads will also need high impact through the foot/ankle joints. A small overload for one part of the system might be an unsafe overload for another.
Building up your running volume slowly, over lots of years and avoiding sharp spikes in volume or intensity will give you a good chance of building a robust capacity for your running. But why not help this process along with some considered, complementary strength work?
To be able to plan a session with the right amount of overload, it is essential to understand what your capacity currently is. A simple set of screening exercises will give you a benchmark to work from and show up your weaknesses. Think about the elements of strength and chose some movements that are appropriate for your training experience.
Stability - This is the main element that relates to our injury risk. This is the strength and mobility of the muscles, ligaments and tendons that support quality movement through a good range of motion. Can you balance on one leg? Can you touch your toes? Do you have good upper back rotation? Can you perform exercises like the arabesque or clock face with good form and balance? The exercises in our ankle strength circuit are a good place to start.
Power - How much force can you generate? Only once you have the stability to produce good quality movement, can you start to look at power. Either through single muscle groups like we do with a calf raise, or through multiple joints in a squat, lunge or deadlift. For a lot of runners without a strength training history, bodyweight exercise can initially provide sufficient overload, but over time this progression will include the addition of weight to increase resistance.
Endurance - In this context, this is different to running endurance. I’m not interested in doing 1000 bodyweight squats. I am interested in strength endurance. Challenging a muscle group to do a continued high capacity of work. For example with squat jumps or box steps for periods of up to a minute.
There are thousands of different movements and exercises out there, some are very simple needing no equipment, others require mastery of complex skills and become sports in their own right. What is appropriate for you will depend on your current level. Be realistic about your current position and choose a few exercises specific to your needs.
The good news is if you choose the right exercises, you won’t need to do much to achieve overload. 15-30 minutes of quality, once or twice a week can be all that you need.
Remember that adaptation doesn’t happen during overload, it happens during recovery. If you are adding an additional element into your weekly training load, be careful to include enough quality recovery time. As with all of our running training, mobility work with a foam roller can speed up this recovery process.
To find out more about strength training for runners check out our Trail Running Skills weekend and our Strength and mobility for runners workshop.
Also in our Better running series:
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