5 Fitness Myths That Still Persist Today

How Many Do You Still Believe?

Fitness and exercise science has exploded over the past decade. Ultimately a young field, sports science has been able to answer many questions about training and its effects on our bodies. It's also shown us to be wrong about many beliefs we had.

However, many of these beliefs still persist and have entered the territory of becoming "fitness myths".  Some are simply interesting, while some can actually influence your training.

1. Is Muscle Growth Caused By Micro-Trauma?

The Claim: "You need to tear down your muscle so it grows back bigger."

Reality: Muscle hypertrophy occurs through 3 mechanisms (Schoenfeld, 2010).: 

1. Mechanical tension,
2. Metabolic stress,
3. Muscle damage

While muscle damage is one of these, modern research has demonstrated that the primary mechanism is likely mechanical tension, with metabolic damage coming in second.

Muscle damage seems to play a role, but it's not even necessary for muscle growth to occur. At the same time, muscle damage can occur without growth, as in downhill running.

Science-Backed Support: In 2012, Dr. Brad Schoenfeld conducted one of the first extensive reviews examining the role of muscle damage in hypertrophy. At this stage, there was still a large question mark behind the relationship.

Schoenfeld concluded that muscle damage seems to play a role in hypertrophy, but it is not necessary.

"Although research suggests that eccentric exercise has greater hypertrophic effects compared with other types of actions, a cause-and-effect relationship directly linking these gains to EIMD (muscle damage) is yet to be established."

During a recent extensive review, Behringer et al. (2025) examined all research on the various drivers of muscle hypertrophy. While muscle damage may play a role in muscle growth, they concluded it is not necessary.

"In conclusion, while muscle damage may contribute to hypertrophy, it is not a necessary condition for muscle growth. Other mechanisms, such as mechanical tension and metabolic stress, play more central roles in promoting hypertrophy."

When mechanical tension (resistance training) is performed at higher intensities, muscle damage is likely to occur as a byproduct; this explains the correlation.

2. Does Lactic Acid Cause Muscle Burn? 

The Claim: "The burning you feel in your muscle is caused by lactic acid, so you need to let it clear."

Reality: When performing high-intensity exercise, your body relies on the anaerobic glycolysis system to produce ATP through the production of lactate, not lactic acid.

When the exercise is too intense and lasts too long, it can elicit a burning sensation in working muscles. This is caused by a buildup of H+ ions, a byproduct from the production of ATP. It's this buildup of H+ that decreases blood pH and causes the burning sensation (Brooks, 2009).

Science-Backed Support: To understand the confusion, you need to understand several processes and compounds.

• Glycolysis- A Metabolic process that produces ATP during higher intensity work when oxygen is not present 
• Lactate- The end byproduct of glycolysis, which is then used to produce more ATP
• Lactic Acid- A positively charged form of Lactate with a H+ ion attached
• H+ ions- A metabolic byproduct of glycolysis

Originally, it was believed that the process went like this;

• Pyruvate → Lactic Acid → Lactate + H+ ion.

However, this was more or less an educated guess. New research now suggests that lactic acid doesn't even exist!

"...there is no such entity as lactic acid in any living cell or physiological system. Indeed, it is impossible, based on the fundamental laws of physics……..and physiology, for lactic acid to be produced or present in living systems where cellular and tissue pH is regulated to be between 6.0 and 7.45." (Robergs et. al, 2018)

So, while the burn is likely caused by the buildup of H+ ions, it's unclear at what point the H+ ions are produced. Even more interesting, lactate is a good thing and is believed to buffer high pH levels, the exact opposite of what causes burning.

"If muscle did not produce lactate, acidosis and muscle fatigue would occur more quickly, and exercise performance would be severely impaired." (Robergs et. al, 2004)  

3. Does DOMS Mean a Good Workout?

The Claim: "You know you got a good workout when you wake up sore."

Reality: While we understand the premise, DOMS does not indicate you had a good workout. All DOMS means is your muscle experienced some trauma and has not recovered; this could be due to poor sleep or poor nutrition.

The reality is, researchers aren't even quite sure what causes DOMS. Regardless, consider these facts;

• Different people are more susceptible to DOMS in different areas of their bodies. 
• Different people experienced DOMS at different levels from similar workouts
• Different body parts tend to experience DOMS to varying degrees, e.g., the dreaded leg day.
• DOMS tends to decrease as you become more experienced

In other words, there's no direct correlation that you could use to determine the effectiveness of a workout with the level of DOMS.

Science-Backed Support: As we discussed above, there is no evidence of a relationship between muscle damage and hypertrophy. As DOMS is associated with muscle damage, it follows that it too has no direct relation with muscle hypertrophy either (Nosaka et al., 2003; Schoenfeld, 2012)

However, research has also shown there's a poor connection between DOMS and muscle damage as well.

"It appears that DOMS is a poor indicator of exercise-induced muscle damage, and the magnitude of DOMS does not necessarily reflect the magnitude of muscle damage."  (Nosaka et al, 2003)

4. Does Fasted Exercise Burn More Fat? 

The Claim: "When your body is depleted of carbs (glycogen), your body will burn more fat."

Reality: This one is nuanced but essentially comes down to conflating "burning fat" with "losing fat".

Fat is your body's primary source of fuel. This means you are always burning fat, even during very high-intensity activity or while sleeping.

When you fast, you deplete your body's glycogen stores. Therefore, exercising in a fasted state forces your body to burn fat "more effectively". Emphasis on "more effectively".

But this does not mean you're losing fat. Again, your body is always using fat.

Science-Backed Support: In 2014, Schoenfeld et al. conducted an experiment comparing weight loss during cardio performed fasted vs. fed.

Both groups were in a caloric deficit, with all other factors held constant. After the program, both groups lost weight, but there was no significant difference between the two.

"In conclusion, our findings indicate that body composition changes associated with aerobic exercise in conjunction with a hypocaloric diet are similar regardless of whether or not an individual is fasted before training." (Schoenfeld et. al, 2014)

5. EMG Means More Growth

The Claim: "The study shows greater EMG, so it's a better exercise."

Reality: This one is a bit more technical. However, it's essential to address it as it's a common source of confusion.

EMG stands for Electromyography and is a measurement of electrical activity produced by muscle fibers when activated by the neuromuscular system. However, many factors change EMG readings, such as; 

• Specific part of the movement or joint angle
• Fatigue 
• Total load

At the same time, other factors affect hypertrophy as well, and EMG does not automatically indicate better muscle growth.

We can prove it: Flex your biceps as hard as you can. EMG readings would have fired, but you're never going to build significant muscle mass with just flexing.

Using EMG allows researchers to read muscle activation sequences, compare movements, and predict the effectiveness of an exercise. In fact, we have written articles on the best exercises for body parts according to EMG!

Science-Backed Support: In 2017, Vygotsky et al. conducted a review of EMG and its use in research to predict long-term hypertrophy gains. They concluded that, due to a range of misconceptions and unaccounted-for variables, EMG was not a predictor of muscle hypertrophy.

" Given the limited evidence validating the amplitude of surface electromyograms as a predictor of longitudinal hypertrophic adaptations, coupled with its weak mechanistic foundation, we suggest that acute comparative studies that wish to assess stimulus potency be met with scrutiny."

Later, in 2022, Vigotsky et al. again addressed this issue with examples: low-load and high-load training may yield different EMG readings, yet both result in similar hypertrophy when taken to proximal failure.

"…provide more data that unequal EMG amplitudes are obtained during fatiguing contractions with low-load and high-load conditions and the novel finding that both conditions elicit similar RPE."

For example, the incline bench press will produce greater EMG in the upper chest than the flat bench press. Since both exercises allow heavier loads, with relatively similar movement patterns (horizontal pushing), the incline will likely lead to better upper-chest development.

EMG is just a part of the puzzle, and even still, it's not fully understood.

References

1. Behringer, M., Heinrich, C., & Franz, A. (2025). Anabolic signals and muscle hypertrophy: Significance for strength training in sports medicine. Sports Orthopaedics and Traumatology, 41(Suppl 1). https://www.sciencedirect.com/science/article/pii/S0949328X2500002X
2. Brooks, G. A. (2009). Cell–cell and intracellular lactate shuttles. Journal of Physiology, 587(23), 5591–5600. https://doi.org/10.1113/jphysiol.2009.178350 
3. Brooks, G. A. (2020). The science and translation of lactate shuttle theory. Cell Metabolism, 31(2), 330–346. https://doi.org/10.1016/j.cmet.2019.12.003 
4. Paoli, A., Marcolin, G., Zonin, F., Neri, M., Sivieri, A., & Pacelli, Q. F. (2011). Exercising fasting or fed to enhance fat loss? Influence of food intake on respiratory ratio and excess postexercise oxygen consumption after a bout of endurance training. International Journal of Sport Nutrition and Exercise Metabolism, 21(1), 48–54. https://doi.org/10.1123/ijsnem.21.1.48 
5. Nosaka, K., Lavender, A., Newton, M., & Sacco, P. (2003). Muscle damage in resistance training: Is muscle damage necessary for strength gain and muscle hypertrophy? International Journal of Sport and Health Science, 1(1), 1–8. https://doi.org/10.5432/ijshs.1.1
6. Robergs, R. A., Ghiasvand, F., & Parker, D. (2004). Biochemistry of exercise-induced metabolic acidosis. American Journal of Physiology–Regulatory, Integrative and Comparative Physiology, 287(3), R502–R516. https://doi.org/10.1152/ajpregu.00114.2004 
7. Robergs, R. A., McNulty, C. R., Minett, G. M., Holland, J., & Trajano, G. (2018). Lactate, not Lactic Acid, is Produced by Cellular Cytosolic Energy Catabolism. Physiology (Bethesda, Md.), 33(1), 10–12. https://doi.org/10.1152/physiol.00033.2017 
8. Schoenfeld, B. J. (2010). The mechanisms of muscle hypertrophy and their application to resistance training. Journal of Strength and Conditioning Research, 24(10), 2857–2872. https://doi.org/10.1519/JSC.0b013e3181e840f3 
9. Schoenfeld, B. J. (2012). Does exercise-induced muscle damage play a role in skeletal muscle hypertrophy? Journal of Strength and Conditioning Research, 26(5), 1441–1453. https://journals.lww.com/nsca-jscr/fulltext/2012/05000/Does_Exercise_Induced_Muscle_Damage_Play_a_Role_in.37.aspx)
10. Schoenfeld, B. J., Aragon, A. A., & Krieger, J. (2014). Effects of fasted vs fed-state aerobic exercise on fat loss. Journal of the International Society of Sports Nutrition, 11(1), 54. https://doi.org/10.1186/s12970-014-0054-7
11. Vigotsky, A. D., Beardsley, C., Contreras, B., Steele, J., Ogborn, D., & Phillips, S. M. (2017). Greater electromyographic responses do not imply greater motor unit recruitment and "hypertrophic potential" cannot be inferred. Journal of Strength and Conditioning Research, 31(1), e1–e4. https://doi.org/10.1519/JSC.0000000000001249 
12. Vigotsky, A. D., Halperin, I., Trajano, G. S., Vasenina, E., Needham, R. A., Paoli, P., & Vieira, T. M. (2022). Longing for a longitudinal proxy: Acutely measured surface EMG amplitude is not a validated predictor of muscle hypertrophy. Sports Medicine, 52(1), 193–199. https://doi.org/10.1007/s40279-021-01619-2