It’s Detrimental To Long-Term Development
While there is no doubt training for the marathon helps you improve your aerobic development, increases your mileage tolerance, and can be great for building endurance, training for multiple marathons in a row isn’t the best option for your long-term development. In fact, racing marathon after marathon often leads to stagnant results and a lack of progression.
As covered earlier, training correctly for the marathon requires an intense focus on the on the specific demands of the marathon race. Very rarely in marathon training should you be doing VO2 max, high anaerobic threshold runs, or pure speed workouts (notice I said rarely, not never). These are training adaptations that are important for success at shorter distances, but don’t translate well to good marathon racing.
Unfortunately, if you neglect certain energy systems or physiological elements for a long period of time, you start to lose overall fitness. To continually improve, the body needs a change of stimulus — a new type of demand for the muscles and body.
Desiree Davilla of the Hansons-Brooks Distance Project is a perfect example of how marathoners need to take a break from a marathon training cycle to consistently improve. After a great performance at the 2009 world championships, Desi took a break from the roads and focused on hitting the track to improve her speed. The result was a jaw-dropping performance at the 2011 Boston Marathon.
If you’ve done more than three marathons in a row without dedicating a specific training block to 5K or 10K training, running another marathon might not be the best choice if you want to record a new PR.
With the extreme popularity and accessibility of marathons these days, it can be hard to forgo the temptation to race one every season. However, if you’re a new runner or a veteran looking to break through to the next level, perhaps you should look closely at your training and goals to determine if running another marathon is the right choice for you.