How runners can avoid "hitting the wall"

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Source: Flickr, Yenra

Most distance runners have had the experience of “hitting the wall.”  Practically speaking, it’s often a point about 20 miles into a marathon when a person feels their muscles cramping and shutting down. Scientifically speaking, “the wall” occurs when the volume of carbon dioxide production exceeds the volume of oxygen consumption, and the removal of carbon dioxide (through exhalation) can no longer maintain blood acidity within reasonable limits.

Conventional wisdom has been that the buildup of lactic acid is the main culprit for causing leg cramps and extreme muscle soreness. Recent studies, however, have begun to disprove this theory and are helping researchers develop more accurate explanations for muscle soreness and how to prevent and treat it with proper training, nutrition and recovery.

Following the right training plan

Following a proper training plan decreases the chances of experiencing extreme muscle fatigue. The scientific reason for this is that when such a plan is followed, the body learns to efficiently use lactic acid as fuel (a by-product of muscle cells using carbohydrates anaerobically for energy). Vice versa, people without proper training physically cannot use lactic acid as efficiently.

Muscle soreness is not attributed to the presence of lactic acid itself, but to the breakdown of lactic acid into lactate (good) and hydrogen ions (bad). The best distance runners will have trained to utilize lactic acid as fuel, thereafter quickly ridding the body of it and reducing muscle soreness.

A good training plan will include running beyond your lactate threshold (LT), which, according to Runner’s World, is a “pace that requires a hard but manageable effort and forces your body to begin producing considerably more lactate.” Running experts say that practicing “comfortably hard” tempo runs is the ideal method for running beyond your LT.

Proper nutrition is important

There is a multitude of resources on what and how much to eat before, during and after running to achieve optimal race performance and recovery.

A new study, published in the American Chemical Society’s Journal of Agricultural and Food Chemistry, showed that drinking watermelon juice can play a role in reducing muscle soreness. Researchers attributed their findings to watermelon’s naturally-occurring amino acid called L-citrulline. This amino acid works to speed up the body’s ability to remove lactic acid.  Because lactic acid is produced at a larger volume during high-intensity exercise than during low-intensity exercise, researchers concluded that watermelon can be helpful for individuals performing high-intensity exercise. Other studies have had similar findings that watermelon may help aid muscle relaxation.

Evidence shows that consuming carbohydrates is vital in muscle recovery, due to the body’s need to replenish glycogen stores after endurance exercise. Both male and female athletes should consume carbohydrates as soon as possible after exercise to maximize the glycogen store repletion, researchers said in one study published in Sports Medicine.

Researchers say that combining carbohydrates with protein works to both reduce muscle soreness and rebuild muscles post-exercise. Multiple studies have shown that chocolate milk is a beneficial recovery drink with an ideal ratio of carbohydrates to protein (about 3:1). Other carbohydrate-rich foods recommended to reduce muscle soreness are yogurt, fresh fruit and bagels, which should be consumed 15 to 30 minutes after a long run.

Iron-rich foods, such as animal protein, raisins, tofu and bananas have also been shown to improve endurance and help runners avoid muscle fatigue.

What happens after exercise

Muscles burn modest amounts of lactic acid during very low-intensity activities, and this doesn’t do the body any harm. During high-intensity exercises, however, muscles burn more carbohydrates and produce more lactic acid. It is during high-intensity, long-distance running when the body reaches this lactate threshold.

But what happens to the lactic acid when you are done running?

The body naturally removes lactic acid from its muscles by using it as fuel and by regular blood flow. Blood acidity) returns to normal, and muscle cells resume using carbohydrates as their primary source of fuel.

By speeding up the rate at which your body removes lactic acid from your muscles, runners are able to  reduce muscle soreness associated with initial lactic acid buildup. Recovery foods help expedite this removal process and reduce soreness.

Delayed onset muscle soreness

Runners with muscle soreness more than three days following a distance run are likely experiencing delayed onset muscle soreness (DOMS). Studies have shown that DOMS is not the result of lactic acid buildup.), as previously thought, but rather the result of actual muscle cell damage and small tears in the muscle.

Foods that help expedite lactic acid removal, therefore, will not assist in ongoing muscle soreness.  Treatment for runners experiencing DOMS includes rest, ice, compression, elevation, sometime known as RICE, plus certain anti-inflammatory drugs.


  • Lactic acid itself does not cause muscle soreness. When the acid is broken down into lactate and hydrogen ions, it is the hydrogen that contributes to soreness.
  • Sticking to a proper training plan with tempo runs can help runners learn to efficiently use lactate for fuel and minimize post-run soreness.
  • The body naturally rids muscles of lactic acid, but certain foods, such as watermelon, can help expedite this process.
  • Following a long run, carbohydrates, protein and iron should be consumed to restore glycogen stores, aid in muscle recovery and reduce soreness.
  • Initial post-run soreness and DOMS are caused by different factors and are have different recommended treatments. Runners experiencing DOMS should use the RICE method and might need to consult a specialist in some cases.


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