Worth your time?
Is strength training worth the time you spend on it, or not? That is the first practical hurdle in this debate. If you’re running one to three times a week, putting one gym session a week might give you pleasant variety, but one more running session would improve your running more. When running four to six times a week for years, likely with a quality session once or twice a week, you have gone through the initial fitness progressions. If you are running with even more quantity, six to 14 times a week, as elite runners do, you will have reached a physical level and experience where you know exactly how to push yourself as much as you can, both in terms of quantity and quality. Also, your performance might have reached a steady state, due to a highly developed aerobic power and capacity. For these two last categories there should be no doubt that one or two weekly strength sessions of 45 to 70 minutes duration can enhance performance.
Determining factors in distance running
In his article and response, Mr. Karp keeps on emphasizing that " . . . the ability of muscles to perform endurance work depends on the delivery of oxygen to those muscles and their capacity to use the available oxygen." This is true, but the ability of the body to perform endurance work depends more on the usage of your VO2 max and your work economy. Runners with similar measures of VO2 max can have very different PRs in races from 5,000m to the marathon. The truth is that for running fast over long distances, you need to lower the energy consumption of your running; you have to make good use of your VO2 max for a longer time. An efficient use of VO2 max (connected to AT) over a long time, combined with an efficient running economy, are truly what determine performance.
Let’s accept that childhood activity and body dimensions in East Africa create a gap in distance running because of running economy and AT. Instead of bemoaning this, in training let's make use of what we have, and that includes gyms.
When Mr. Karp and Dr. Yessis talk about fatigue in distance running events and note a decrease in stride length, we need to determine why. Limited muscle contractility, meaning a lower rate of activation of the working muscles, is present in 5K and also in the end of long distance events. This kind of fatigue is connected to chemical changes in the muscle environment. In terms of the running style and running economy it seems that one limiting factor is the recruitment of muscle fibers—which is where strength training comes in.
How to use strength training?
If we can benefit from strength training, the big question is: How shall we use the gym? Using many reps with light weights in gyms improves•general muscle endurance. But as Mr. Karp points out, can 20 reps lasting one to two minutes be effective training for aerobic capacity, when we run 60 to 90 minutes for general endurance? Rather, find a hilly loop, and implement more hill running both in tempo runs and long runs to improve specific strength endurance in your legs.
We want to use the gym for three different aims:
•Prevent injuries: By strengthening bones, ligaments and tendons.
•Improve running style: By strengthening the "core" to improve posture and alignment.
•Improve running economy: By improving neural activation, elasticity and muscle power.