The hardest part of strength training for most endurance athletes is getting started. There are many good reasons for this, both for health and performance. But there is one important fold that is not getting much attention: when should you stop?
The practice of tapering – a short-term reduction in training before an important competition – is common practice. A comprehensive review of the tapering studies in 2007 found that the best approach is a two-week period during which you gradually reduce exercise volume by 40 to 60 percent without changing the frequency or intensity of your exercise. More recently, researchers have suggested that “mental rejuvenation,” which avoids stressful or mentally tiring activities before a big race, might be useful. But how and when do you rejuvenate your strength training?
A new study in Sports magazine provides some data from a team led by Nicolas Berryman of the Université du Québec á Montréal. It is a belated continuation of an earlier study examining the effects of strength training on running economy. This is a measure of how much energy it takes you to maintain a particular pace. This study, like many similar ones, found that adding certain types of weight training actually made runners more efficient. The new study re-analyzes data on a subset of the original subjects who received additional tests four weeks after they stopped doing strength training.
It’s worth summarizing some of the details from the original study, which included just one training session per week for eight weeks. One group performed “dynamic strength training” with concentric half-squats, using a squat rack that exploded upward as quickly as possible. The other group did plyometrics and drop jumps by stepping out of a box and immediately jumping as high as possible. The box height was 20, 40, or 60 centimeters based on the height that gave the highest jump for each subject. In both groups, they started the first week with three sets of eight repetitions each with a three-minute break between sets, and eventually reached a maximum of six sets.
In the original study, the plyometric group improved their running economy by an average of seven percent, the dynamic strength training group by four percent, and a control group that did not saw no change in their running economy. This is in line with other studies that found an improvement in running economy of two to eight percent through various forms of strength training. In context, keep in mind that Nike’s Vaporfly 4% shoes turned the running world upside down as they offer an average four percent improvement in running economy. Weight training is legitimate, at least among the recreational athletes in this study.
So what happens four weeks after the test subjects stop their strength training? Only eight subjects completed this follow-up (four from the plyometric group, four from the dynamic group) so they are all pooled for this analysis. These subjects retained their newly improved running economy and reduced their 3,000 meter racing time even further.
Here is a graph of some of the key results. The triangles show changes from the initial value after eight weeks of strength training. The circles show changes from baseline after the additional four weeks without strength training.
The running economy (shown here as “energy costs of the company”) remained essentially unchanged due to the four-week rejuvenation. Aerobic capacity (shown here as “VO2peak” which is basically the same as VO2 max) actually seemed to decrease somewhat during rejuvenation, which is surprising and possibly just a coincidence. In contrast, performance at 3,000 meters is 2.4 percent better after strength training and 4.4 percent better after strength training – exactly the kind of extra bump you would hope for in a cone.
(We’ll ignore “aerobic endurance” in the graph above. It’s defined as the ratio of the maximum treadmill speed in the VO2 max test to the 3,000 meter racing speed. I’m not sure what this means, but not during anyway change of taper.)
The authors make every effort to highlight any reservations here, particularly the small sample size of eight subjects. We also don’t really know how things changed during the four week rejuvenation. Perhaps the best performance of all was actually a week or two after finishing strength training. However, the results suggest that the running economy boost you get from weight training – which is widely viewed as the main performance benefit for endurance athletes – lasts for at least four weeks without additional weight training. If nothing else, this suggests that you can be careful about breaking your strength routine early on.
The question that is still open is whether the additional increase in the 3,000-meter performance after rejuvenation (despite the constant running economy and poorer VO2 max) is just a statistical characteristic or whether it is something real. There just isn’t enough data here to draw any conclusions, but there is some evidence in previous studies that there might be an “overshoot” effect that recharges your fast-twitch muscle fibers a week or two after you finish your strength training. This is the fodder for future research – but even without an overshoot, these results support the idea that you can and probably should cut down on strength training at least a week before a big race.
If you’d like to learn more about Sweat Science, visit me on Twitter and Facebook, subscribe to the email newsletter, and read my book Endure: Mind, Body, and the Strangely Elastic Limits of Human Achievement.
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