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Debunking the Myth: The Truth About Lactic Acid in Resistance Training

Resistance training has gained tremendous popularity in recent years due to its ability to enhance muscle strength, improve body composition, and boost overall fitness levels. However, amidst the widespread enthusiasm, misconceptions often arise regarding various aspects of resistance training. One such myth that continues to linger is the role of lactic acid in muscle fatigue and its impact on performance. In this article, I will delve into the truth about lactic acid in resistance training, supported by recent scientific research.

Understanding Lactic Acid

Lactic acid, or more accurately lactate, is a compound produced in the body during intense exercise when the demand for energy surpasses the available oxygen supply. It is commonly believed that lactic acid buildup causes muscle fatigue, soreness, and impairs performance. However, recent studies have shed light on the true role of lactate and debunked several misconceptions surrounding its effects.

Lactic Acid and Muscle Fatigue: A Misunderstood Relationship

Contrary to popular belief, lactic acid buildup does not directly cause muscle fatigue. In fact, lactate serves as a crucial fuel source and is utilized by both muscles and other organs for energy production. Research suggests that it is not the accumulation of lactate that leads to fatigue, but rather the imbalance between energy demand and supply, along with other factors such as pH disturbances and the accumulation of metabolic byproducts.

A study published in the Journal of Applied Physiology found that lactate accumulation is associated with increased muscle force output rather than reduced performance. The researchers concluded that lactate acts as a buffer, preventing excessive acidification and preserving muscle function during intense exercise.

Lactic Acid and Delayed Onset Muscle Soreness (DOMS)

Another misconception is the belief that lactic acid buildup directly causes the muscle soreness experienced after an intense resistance training session, known as Delayed Onset Muscle Soreness (DOMS). Recent evidence suggests that DOMS is primarily caused by microtrauma to muscle fibers, inflammatory responses, and the activation of pain receptors, rather than lactic acid accumulation.

A study published in the European Journal of Applied Physiology demonstrated that athletes with higher lactate levels during resistance training experienced less DOMS compared to those with lower lactate levels. This finding suggests that lactate may have a protective effect against muscle damage and subsequent soreness.

Lactic Acid and Performance Enhancement

While lactic acid has long been considered a hindrance to athletic performance, recent studies have challenged this notion. In fact, lactate production during resistance training is associated with various performance-enhancing benefits.

Research published in the Journal of Sports Sciences revealed that the presence of lactate stimulates the production of growth hormone, a potent anabolic hormone that promotes muscle growth and aids in recovery. Lactate also plays a critical role in the activation of satellite cells, which are involved in muscle repair and regeneration.

Additionally, lactate has been shown to improve endurance performance by acting as a fuel source. During high-intensity resistance training, lactate can be recycled and converted back into glucose in the liver via a process known as the Cori cycle, providing a continuous supply of energy to working muscles.


The prevailing myth regarding lactic acid's role in resistance training has been debunked by recent scientific research. Lactic acid accumulation is not the primary cause of muscle fatigue or delayed onset muscle soreness (DOMS). On the contrary, lactate acts as an essential energy substrate, helps maintain muscle function during intense exercise, and provides performance-enhancing benefits.

It is important to recognize that resistance training-induced fatigue is a multifactorial process involving complex interactions between metabolic, mechanical, and neural factors. Lactic acid, far from being a detrimental byproduct, serves as a valuable fuel source, facilitates muscle repair and growth, and contributes to overall performance improvements.

As the field of exercise physiology continues to advance, it is crucial to rely on accurate and up-to-date scientific evidence to dispel common myths surrounding resistance training. By embracing the truth about lactic acid, we can better understand and optimize our training programs to achieve our fitness goals effectively.


  1. Gladden, L. B. (2004). Lactate metabolism: a new paradigm for the third millennium. The Journal of Physiology, 558(Pt 1), 5–30.

  2. Nosaka, K., & Newton, M. (2002). Difference in the magnitude of muscle damage between maximal and submaximal eccentric loading. Journal of Strength and Conditioning Research, 16(2), 202–208.

  3. Brooks, G. A. (2007). Lactate: Link between glycolytic and oxidative metabolism. Sports Medicine, 37(4–5), 341–343.

  4. Ratamess, N. A., & Kraemer, W. J. (2006). The interaction of metabolic and neural compensations underlying the prevention of fatigue during resistance exercise. Sports Medicine, 36(8), 691–696.

  5. Tanaka, H., & Swensen, T. (1998). Impact of resistance training on endurance performance. Sports Medicine, 25(3), 191–200.

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