A systematic review published by colleagues of mine, at the University of Limerick, demonstrated quite nicely, that strength training enhanced time-trial performance and economy in endurance athletes. In science, we like systematic reviews because they help us pool information from a number of studies to answer a specific question. In this case, does strength-training enhance performance and reduce economy of effort? The answer in this case was yes and it is generally accepted that systematic reviews are the highest level of evidence available.
The Devil is in the Detail
The novice practitioner, coach or athlete can be forgiven for reaching toward the highest level of evidence as a guide to ensure their practice is evidenced based. However, as we’ve discussed previously, there is a greyness around how individuals respond to a training stimulus and it is always better to think in concepts rather than yes-no answers. When you conduct interventions with humans this becomes glaringly obvious. The picture this week, should help to explain.
What Questions Would I Ask?
Running economy and performance have improved. I would want to know was this because the participants encountered less injuries over a given period of time? This would mean they ran more often in the long term and this could be the reason for improvement. Was the variability in the training stimulus related to the improvement? In other words with more variety and less monotony was there increased focus around key run days? Could an increase in strength have improved resilience toward the training load? Would this have helped? Linked to last week’s blog, could it have helped the athlete develop a more robust sense of their capabilities?
What I am getting at here is; what is it about strength training that may have enhanced the major determinant of running improvement – run training! After addressing the major players, then yes, I would also be interested to know how specific muscle-tendon adaptations may have an added role toward improving performance. To conduct a high quality study to answer this question, is very difficult. You would need to try to control injury records, account for increased variability in training, changes in perception of self and the training stimulus and of course changes in muscle performance. Most controlled trials are pretty good at accounting for the volume of running, the amount of strength training and the measurement of changes in muscle performance, but are less well equipped to take account of the bigger picture as we’ve discussed above.
Cause and Effect
There is a tendency to assume that as muscle performance has improved along with economy and performance that one has caused the other. I suspect it is not that simple. While the strength training may be directly related to the improvement, the overall improvement is due to a combination of factors mentioned previously. Our research group is currently performing a systematic review to determine are changes in running economy actually associated with changes in performance. I will keep you posted (even this will have significant limitations).
Strength Training or No Strength Training?
Strength training. The concept based logic we have developed on this blog tells us the following things about strength training will be useful.
- Variability
- Strength
- Enhanced consistency
- Improved perception of our athletic capabilities
How do we answer the question?
The next time you’re asked is strength training good for runners, instead of saying: ‘yes, the strength training makes your running economy better’; you might say, ‘it would seem that after a period of strength training, economy and performance improve; but this response will be highly variable among individuals. Some athletes will gain far more than others (others may not improve at all) and the responses we see are likely a combination of varied training, consistent training and changing perceptions of self and the training load; in addition to some specific muscle-tendon changes’.
It’s as simple and as complicated as that.
Peter Francis 