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Getting fit and fast requires the stress of training. That stress, or overload, is supplied by running faster or running longer, or both. In the simplest of terms, stress produces adaptation. A steady progression of training is usually enough to improve performance. Until it’s not.
The more trained the runner, the greater the stress required to eke out even small gains. To walk the tightrope between under and overtraining, training has to be a mixture of push and pull. Some days or weeks can be pushed, others pulled back for recovery.
When the usual steady slope of a training program isn’t getting results, or an athlete is ready for an added challenge, some coaches turn to a short-term high-volume overload period. The training block, usually three days to three weeks in duration, can increase volume and/or intensity by 20 to 30 percent. Ideally, the tradeoff for that hard, long training and subsequent fatigue — when followed by a recovery or taper period — is supercompensation, a bounce back of fitness that boosts performance over and above what’s expected after normal training. At least that’s the theory.
Overload training, inducing a state of heavy fatigue with weeks of die-hard training and minimal recovery, can result in something called functional overreaching, a state defined as a short-term decrease in performance with or without related symptoms of overtraining.
Of course, going out and running oneself into the ground doesn’t have to be a fancy scientific name. “Overload training isn’t anything new,” said Jim Vance, a triathlon coach and author of Run with Power. “Athletes go flog themselves all the time.”
Much of the traditional overload training was conducted under the belief that overload training needs to achieve that overreached state to be useful. The verdict on that is both yes and no.
Proven to Work: With a Catch
Research on short-term overload training shows that it works. One study on triathletes found that athletes who completed a three-week period of overload training (30 percent greater than normal training load) had a 68 percent chance for a larger improvement in VO2max than the group that just trained normally. In short, overload training was highly effective, for some.
Here’s the catch: The study further separated the runners into two groups, one that was merely acutely fatigued after the hard training and another that exhibited signs of overreaching (large decrease in performance, increase in fatigue). The significant (5 percent) performance improvement was only seen in the non-overreached athletes of the overload training group, those that didn’t exhibit the heavy fatigue. The only thing the overreached triathletes got in return for their three weeks of hard training was a much higher likelihood of an upper respiratory tract infection.
Another review study, published this February in the journal Sports Medicine, had similar conclusions: Yes, the usefulness of overload training does seem to depend on the level of fatigue and performance after the overload block. But no, overloading to the level of overreaching actually dampened the potential gains of the training block. Too little fatigue wasn’t the problem but too much was.
The article’s author, Phillip Bellinger, a researcher at Griffith University in Australia, concluded that, “in the studies that do report a performance super-compensation effect following functional overreaching, the magnitude of performance enhancement is no greater than that of athletes who completed the same relative increase in training load without experiencing a performance decrement.”
In other words, there doesn’t seem to be much evidence to suggest that inducing a state of soul-sapping, bone crushing fatigue is necessary to get a performance improvement. So, runners needn’t search for the level of overload training that produces profound physiological and psychological fatigue.
For runners looking for a way to bust through a plateau, high volume overload training can push performance to the next level. But, like a high reward, volatile stock, playing the market with ultra-intense or extra-long workout periods can deplete reserves.
Walking the Line
Walking the line between functional and non-functional overreaching can take a little training finesse. Get it right and supercompensation is the reward. Tip the scales too far and it could take weeks or months to restore performance. That worst case comes with some mixture of reduced performance, disturbed sleep, reduced immunity, hormonal flux and other negative consequences.
Given that overload training works but overreached does not, how does a runner avoid too much of a good thing?
Here’s how a sample of how overload training might work for you:
Duration: 3 days
Plan: Add 20–30 percent to volume (mileage) of a 3 day block of training. Maintain the same intensity of training (don’t run faster and longer). This doesn’t have to be 3 consecutive days; since recovery days aren’t typically used as part of the overload schedule, keep them the same and add to the load days, spreading the increased volume over 4–5 days. Keep the usual recovery days and add to the volume load days. Many already follow a similar plan when scheduling longer runs on Friday, Saturday and Sunday.
Duration: 7 days
Plan: Add 20–30 percent to volume (mileage) of a 7 day block of training. Maintain intensity and add the volume to non-recovery days. Don’t jump immediately to the heavier volume. For the first day or two of the overload block add 10–15 percent to the day’s mileage. For the remaining days of the overload block add the increased volume to the load days (not the recovery or interval training/track days).
Duration: 10–14 days
Plan: Add 20–30 percent to volume (mileage) of a 10–14 day block of training. Maintain intensity. Don’t jump immediately to the heavier volume. For the first 3 days of the overload block add 10–15 percent to each day’s mileage. Similarly, for the remaining days of the overload block add the increased volume to the load days (not the recovery or interval training/track days).
Note: while Vance explains that overload can be applied with extra intensity or extra volume — but not both simultaneously — we’ve stuck with volume in these examples for simplicity.
To avoid overreaching and injury, Vance believes that overload training can be successful when these rules are followed:
- Do follow the “two-day rule.” Take two days easy after an overload block and then test your recovery with a harder workout. “After a heavy block of training, if a runner has two light days of recovery, the third day should be a home run,” Vance says.
- Do take recovery days. Another staple of Vance’s overload training period is a mix of recovery and adaptation days intermixed into the high-volume days. “Every day doesn’t have to be hard, there still needs to be time to adapt and recover.”
- Do try it if you have specific long-race goals. Overload training is suited for any athlete who has specific goals. Also, it’s best for athletes in longer duration events — half or full marathon. Athletes competing in shorter events don’t need as much high-volume training to improve performance.
- Don’t increase volume (mileage) and intensity (speed) at the same time.
- Don’t get too fatigued. Monitor fatigue (use the two day rule above) and avoid the point where recovery requires weeks not days.
- Don’t attempt overload training if coming off of an injury.
Mind the Details
Bellinger says that a number of other factors, including nutrition, recovery and stressors outside of training, are also important for avoiding the negative aspects of overreaching. Increasing carbohydrate intake can help solve some of the training induced fatigue while upping protein can prevent the increased likelihood of upper respiratory tract infection.
Though sleep is also impaired in athletes undertaking overload training, experts like Bellinger aren’t sure whether athletes who sleep poorly become overreached or whether overreaching/training causes impairments in sleep. Stressors outside of training also contribute to how an athlete may adapt to an overload training period.
Bellinger doesn’t believe that there is a specific percentage of training load increase that will work for every athlete. “I don’t think there is a golden rule with a given XX% of training load increase,” he says, “But I think standard monitoring tools, talking to athletes and weekly submaximal exercise tests to determine how an athlete is coping to the given training plan are effective ways to see how athletes are responding to training.”
As a simple means of monitoring for signs of overreaching, Bellinger recommends using a couple of aspects of heart rate.
One of the more straightforward metrics to monitor is heart rate during exercise. Overreached athletes can have a lower heart rate response to exercise, accompanied by an increase in fatigue. So, if you are feeling tired and your usual runs aren’t consistently resulting in the same heart rates (lower than normal), you might be close to overreaching.
He does note that similar heart rate responses are also seen in athletes who gain fitness — so context, the presence of greater than normal fatigue or lack of energy, is key.
In the case of overload training, trusting the process may not be enough. Monitoring the result is also critical in making sure the long, hard miles pay off in meaningful gains in fitness.