Student Work: Pain Following a workout is due to Lactic Acid Build up by Morgan Morrison

Michelle Burns
August 4, 2015

During the course of attending massage school at A New Beginning School of Massage, students are given a number of assignments that requiring research and writing. Some of these assignments result in very insightful and  well thought out information and  decision-making outcomes. I am happy to share some of their assignments for you to enjoy.

To gain respect in the medical community and provide the most effective treatment for 157px-back-pain-clip-art-1388508clients, massage therapy is moving away from an intuition- and tradition-based practice to an evidence-based practice. An evidence-based massage therapy practice has three components;

  • Best research evidence. Therapists review the most current clinical research, examining the accuracy, safety, and efficacy of the therapeutic interventions;
  • Clinical expertise. Therapists use their clinical skills and past experience to develop an individualized treatment plan for each client; and
  • Client values. Therapists recognize and respect the preferences, goals, and expectations that each client brings to the therapeutic relations.1
Type of evidence-based Research

Examples of evidence-based research include:

  • Case reports. A therapist provides detailed documentation of an interaction with one client in a case report. Case reports are not generalizable (i.e., the results are not applicable to a larger population because only one person's reaction to an intervention is studied/documented) and bias (are the study's results directly related to the intervention rather than chance or outside factors?) is inherent. While case reports are a low level of evidence, they offer ideas for future research.2
  • Pilot studies. Researchers use pilot studies to test a hypothesis on a larger group of people -usually less than50). Like a case study, a pilot study does not include a comparison or control group. A pilot study allows the researcher to test and refine the study design before further research. Because an intervention is tested on a greater number of people, a pilot study is more generalizable than a case report. The bias in a pilot study is less than in a case report because the research participants are recruited from outside the therapist's practice. But because only one intervention is provided and the participants agree to receive that intervention, a tendency toward bias exists.3
  • Randomized control trials. Randomized control trials build on the evidence found in case reports and pilot studies. RCTs compare two or more interventions to determine which treatment is most effective for a particular population. Well-designed RCTs limit bias and have generalizable results; therefore, RCT's offer a high level of evidence. RCTs are generalizable because a large number of people participate in the study.4 (The sample size should be large enough to reliably answer the research questions, but not so large that the RCT is too expensive to conduct. Find a statistician to help determine this "magic number")5 Researchers limit bias in RCTs by using a computer program or another blinded selection process to randomly assign participants to one of the interventions being compared. Random assignment limits bias because participants do not choose the treatment they receive or their therapist. In traditional RCTs, the control group receives a placebo intervention (a "sugar pill" rather than the actual medical treatment). In RCTs involving massage therapy or bodywork, the control group becomes a comparison group since designing a placebo treatment is difficult. The RCT will compare massage therapy to another intervention such as aromatherapy.6
  • Meta-analyses. Researchers use meta-analysis to combine findings from similar, independent studies to create a larger pool of evidence. Meta-analysis of massage therapy interventions is lacking because many meta-analyses only consider RCTs and comparatively few RCTs involving massage therapy have been undertaken.7
Quantitative and Qualitative Research

Research in the massage profession includes both qualitative and quantitative research. Qualitative research is focused on how people think and feel and why they make certain choices.8 Quantitative research provides a numerical or statistical explanation of some phenomena.9

A qualitative researcher would ask an open-ended question such as, "How does background music affect your massage experience?" In contrast, a quantitative researcher would ask for a rating, "On a scale of one to five, do you like background music during your massage?" The qualitative researcher would look for themes in the responses while the quantitative research would analyze the numbers.

Massage therapy is "a complex intervention with physiological, psychological, social, and spiritual components."10 Because of its complexity, a mixed-method approach that combines both qualitative and quantitative methods may offer greater insights into the effectiveness of massage than a strictly quantitative approach. For example, the physiological effects of massage are measurable, and therefore, well suited for quantitative research.The psychological, social, and spiritual components are not easily measured and are better suited for qualitative research, which "explores, documents, focuses on people's perceptions, experiences, and views, as well as the meaning that they give them."11 While numbers and statistics are important, a mixed-method approach allows researchers to "provide insights into the outcomes, process and context of massage therapy that cannot be fully achieved through quantification alone."12

Research Validity

Because in massage therapy, the measurable results of an intervention as well as the subjective parts of the therapeutic relationship matter, both quantitative and qualitative research are valid and offer useful information for the profession.13 The hypothesis or research question directs which type of research is most appropriate to answer or investigate a particular question.

Some questions about the effectiveness of massage therapy are better answered with quantitative research. For example, determining whether massage flushes lactic acid from the muscle cells requires quantitative data (What is the blood lactate level before massage? What is the blood lactate level after massage? What is blood lactate level for the control group?) A qualitative approach (How does the person perceive the amount of lactic acid in her blood?) simply cannot provide an accurate answer to whether massage flushes lactic acid from the blood.

On the other hand, some questions about the effectiveness of massage therapy are better answered with qualitative research-for example, why do athletes seek out massage after an event? Or, how does receiving massage effect an athlete's perception of recovery after an event? These questions might be answered with a number, but a number does not give a full aaccounting of why the person things the way she does.

In some quantitative studies, the participants believed that the massage intervention caused a change, but the hard data did not support their perceptions. Qualitative research "provides the opportunity to examine the context of the intervention, since the context may influence the outcome(s) of the intervention.14

Evaluating the Validity of Research Studies

Criteria to consider when reviewing a research study for its validity include:

  • Timeliness. When was the study published? Is the information current or out-of-date?
  • Relevance. Is the information too technical or too simplified?
  • Authority. What are the author's credentials? Is the researcher affiliated with an education institution or prominent organization?
  • Accuracy. How well designed was the study methodology? Does the study design lead to reliable evidence?
  • Purpose. Is there obvious bias or impartiality? For example, was the research funded by an organization that has a stake in the outcome?15

Some massage research studies have been criticized for faulty methodology such as:

  • Using a sample size that is too small to provide meaningful data;
  • Failing to use a control or comparison group;
  • Failing to randomly assign participatns to a group;
  • Inadequate outcome measures (i.e., the tool to measure an outcome lacks validity or reliability); and
  • Lack of standardization in the methodology.16

Reviewing how a study's methology addresses these common research flaws helps evealuate the validity of that pariticular study's results.

Importance of Research to the Massage Profession

Research is important to the massage profession. If massage therapists want to be considered health care practitioners and gain standing in the medical community, then massage therapists must base their practice on the research and scientific evidence upon which other medical professionals rely. Although, a double standard appears to exist regarding evidence-based practice. Some researchers found that 20-50 percent of mainstream Western medical care and almost all surgery have not been evaluated by TCTs.17

Nevertheless, treatment decisions should not be based on personal experience alone. While the handing down of knowledge from practitioner to practitioner is a vital aspect of the massage tradition, personal experiences have an inherent bias (our own assumptions and viewpoints) and are not generalizable to the larger population. Examining the findings of both quantitative and qualitative research allows massage therapists to develop more effective and appropriate treatment plans, which will lead to credibility with clients and in the medical community.18

Furthermore, as practitioners in the complementary and alternative medicine field, we have an ethical duty to "do no harm" to our clients.19 Using research findings to inform treatment decisions helps ensure that clients receive the safest, most effective, and appropriate interventions.

Gaining standing in the medical community is also important for business reasons. For example, accepting and billing insurance may provide an additional revenue stream for a therapist. But, insurance companies must view massage as medically necessary before a therapist can bill for her services.20 Further, doctors and other health care providers are important referral sources (70% of respondents in ABMP's 2015 consumer survey said that they would give a lot of importance to a doctor's recommendation for massage and 59% would give a lot of importance to a physical therapist's recommendaiton21). If these medical providers do not see research evidencing the benefits of massage, they will likely not recommend massage to their patients.

Assumption to Investigate

Pain following a workout is due to lactic acid build-up.

Research Article Reviewed

Cheung, Karoline, Patria A. Hume, and Linda Maxwell. "Delayed Onset Muscle Soreness: Treatment Strategies and Performance Factors." International SportMed Journal, 2003. Available at

Summary of Research Findings

Muscle soreness following physical activity is classified as "acute" or "delayed onset." Acute muscle soreness (or muscle fatigue) occurs during the final stages of an intense activity; this type of pain is attributed to the restrition of vessels supplying blood to the active muscle and th accumulation of metabolic waste products.22 Lactic acid is not a waste product; the muscles produce it from glucose and burn it to obtain energy. Further, almost all lactic acid produced during exercise is removed within one hour after exercise by the circulatory system.23

On the other hand, delayed onset muscle soreness (DOMS) peaks 24-72 hours after intense exercise has been completed and then subsides within one week. DOMS symptoms range from muscle tenderness to severe pain. It is one of the most common and recurrent forms of sports injury. DOMS can only be treated after it occurs; no interventions are currently known to prevent DOMS. One of the reasons for the lack of prevention interventions is because the cause of DOMS is not known.24

Post-exercise soreness depends on the intensity and duration of the activity as well as the type of activity performed. Activities requiring eccentric contractions, in which the muscle fibers lengthen, cause more post-exercise soreness than activities requiring concentric or isometric contractions. Examples of activities requiring eccentric contractions include downhill running, squatting, throwing a ball, and lowering a barbell.25

Six theories have been posited to explain the cause of DOMS: lactic acid; muscle spasm; connective tissue damage; muscle damage; inflammation; and enzyme efflux theories.

  • Lactic acid theory suggests that eccentric muscle activity continues to produce lactic acid after intense exercise stops and that an accumulation of lactic acid accounts for the pain. However, DOMS is not experienced with concentric muscle activity even though it produces more lactic acid than eccentric muscle activity. In addition, DOMS peak blood lactate levels do not correspond with peak DOMS. If lactic acid caused pain following a workout, it would likely remain in the system longer to coincide with peak muscle soreness.
  • Muscle spasm theory asserts that increased levels of resting muscle activity after eccentric exercise causes DOMS. The evidence is inconclusive: some studies showed increased resting muscle activity in sore muscles and other studies did not.
  • Connective tissue damage theory states that the connective tissue of fast twitch muscles is more susceptible to strain and is damaged after intense eccentric activity. The presence of certain amino acids in urine indicates the breakdown of connective tissue. One study found that maximum levels of these amino acids and peak DOMS both occur at 48 hours post-exercise.
  • Muscle damage theory states that eccentric activity requires a muscle's weakest fibers to contract, leading to microscopic lesions and pain. Research has shown that one indicator of muscle damage (creatine kinase levels) increases following eccentric exercise; however, its peak levles do no match peak muscle soreness times.
  • Inflammation theory asserts that eccentric activity causes swelling and the mvoement of fluid across the cell memberance and into the muscle's extracellular spaces, which leads to pain. Studies show that peak swelling coincides with peak muscle soreness, but the timing of inflammatory cell infiltration does not match up.
  • Enzyme efflux theory speculates that calcium accumulates in injured muscles after damage to the sarcolemma and these high calcium concentrations lead to the stimulation of pain nerve endings.26

The research findings do not support the statement that pain following a workout is due to lactic acid build-up. According to Cheung et al., the lactic acid theory has received the most criticism of the proposed theories and has "largely been rejected."27 Most researchers say that one theory cannot explain DOMS. A combination of muscle damage; connective tissue damage; enzyme efflux; and inflammation theories seems to offer the best explanation but warrants further research.28

While the cause of DOMS remains unsettled, several treatments have been tried to help restore maximum fucntioning as quickly as possible.

  • Cryotheraphy (applying ice to the muscle) has not shown benefit in preventing and treating DOMS (although icing seems to help with acute traumatic injury).
  • Pre-exercise and post-exercise stretching has had inconsistent results at preventing DOMS. Stretching is often recommended to prevent injury, but its benefits have not been validated by research.
  • The administration of non-steroidal anti-inflammatory medications has shown mixed results in treating DOMS. In one study, taking ibuprofen three times a day prior to exercise resulted in greater declines in muscle soreness than taking it after exercise. However, the chronic overuse of NSAIDs can lead to increased incidence of stomach ulcers, kidney failures, and liver damage.
  • Ultrasound and electric current techniques such as transcutaneous electrical nerve stimulation (TENS) have shown mixed results in treating DOMS.
  • Using a homeopathic herb (arnica montana or Mountain Daisy) to treat DOMS dates back to the 16th century. However, current studies have shown it has little effect on DOMS.
  • Using massage to treat DOMS has shown varied results. In one study, sports massage administered two hours after eccentric exercise showed a significant reduction in DOMS. The timing of the massage seems to be the key to reducing DOMS. Using massage before exercise to prevent DOMS has not been studied.
  • One study showed that continuous compression helped reduce DOMS symptoms, but more studies are needed to confirm its benefits.
  • Exercise is one of the best interventions to alleviate DOMS; however, the pain relief is temporary and comes back quickly after stopping the exercise. Studies examining whether exercise can prevent DOMS have had mixed results.29
Practice Implications

Reviewing the research on whether lactic acid build-up causes pain following a workout and finding that it almost certainly does not has several implications for my future practice.

First, I will not perpetuate this myth by telling clients that lactic acid build-up is the cause of their sore muscles. I will explain that sore muscles are likely caused by a number of elements, but lactic acid build-up is not one of them. Now I know where to find research that  provides explanations with a scientific base. Being able to share these articles with clients helps improve my credibility because I can show that I pay attention to current clinical research and use it to develop my interventions.

Second, discovering that this widespread explanation for muscle soreness is really a myth emphasizes how important it is to be skeptical of commonly held beliefs. Questioning and taking a more analytical approach leads to practice advancement.

Finally, I will seek out opportunities to get involved in further research on massage–the opportunities seem wide open.

  1. Ed. Dryden, Trish and Christopher Moyer. "Massage Therapy: Integrating Research and Practice." Human Kinetics, 2012. Web. 12 May 2015. <>.
  2. Thompson, Diana. "Levels of Evidence: How to Learn What We Want to Know." Associated Bodywork and Massage Professionals, Mar/Apr 2010. Web. 11 May 2015 <>.
  3. Thompson.
  4. Thompson
  5. Chan, YH. "Randomized Controlled Trials (RCTs)–Sample Size: The Magic Number." Singapore Medical Journal, 2003. Web. 12 May 2015. <[1].pdf>.
  6. Thompson.
  7. Thompson
  8. "Qualitative and Quantitative Research." Business & IP Centre, The British Library. Web. 11 May 2015. <>.
  9. "Introduction to Quantitative Research." SAGE Publications, 2010. Web. 11 May 2015. <>.
  10. Andrade, Carla-Krystin. Outcome-Based Massage: Putting Evidence into Practice. Lippincott Williams & Wilkins, 2013.
  11. Andrade, Carla-Krystin, and Paul Clifford. "Qualitative Research Methods." Massage Therapy: Integrating Research and Practice. Human Kinetics, 2012.
  12. Kania, Ania, Antony Porcino, and Marja Vehoef. "Value of Qualitative Research in the Study of Massage Therapy." International Journal of Therapeutic Massage & Bodywork, 15 Dec 2008. Web. 13 May 2015. <>.
  13. Neufeld, April V., Beth Barberree, and Sandra K. Anderson. "Qualitative Research Furthers the Study of Massage Therapy." Massage Today, Oct. 2013. Web. 18 May 2015. <>.
  14. Neufeld et al.
  15. California State University Chico. "Evaluating Information-Applying the CRAAP Test." 17 Sep 2010. Web. 20 May 2015. <>.
  16. Grace, Sandra. "The Evidence for Massage." Foundations of Massage. Elsevier, 2009.
  17. Grace.
  18. Neufeld et. al.
  19. See Associated Bodywork & Massage Professionals (ABMP) Code of Ethics at and American Massage Therapy Association (AMTA) Code of Ethics at <>.
  20. Diamond, Irene. "To Bill or Not to Bill: Should You Accept Insurance?" Massage & Bodywork. Associated Bodywork & Massage Professionals. May/JUne 2015.
  21. Osborn, Karrie. "Who Do Your Clients Trust?" Massage & Bodywork. Associated Bodywork & Massage Professionals. May/June 2015.
  22. Gulick, Dawn T. and Iris F. Kimura. "Delayed Onset Muscle Soreness: What Is It and How Do We Treat It?" Journal of Sports Rehabilitation, 1996. Web. 26 May 2015. <>.
  23. Brummitt, Jason. "The role of massage in sports performance and rehabilitation: current evidence and future direction." North American Journal of Sports Physical Therapy, 2008. Web 26 May 2015.
  24. Cheung, Karoline, Patria A. Hume, and Linda Maxwell. "Delayed Onset Muscle Soreness: Treatment Strategies and Performance Factors." International SportMed Journal, 2003. Web 26 May 2015 .
  25. Cheung et al.
  26. Cheung et al.
  27. Cheung et al.
  28. Cheung et al.
  29. Cheung et al.


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