EFFECTIVENESS OF CHIROPRACTIC ADJUSTMENT IN LUMBAR PAIN IN CROSSFIT PRACTITIONERS

Objective: To evaluate the efficacy of acute chiropractic adjustment in individuals who practice CrossFit with regard to complaints of low back pain and the joint range of motion in this region. Methods: A randomized clinical trial comprised of CrossFit practitioners from a box in Novo Hamburgo-RS, of both sexes and aged 18 to 40 years who had low back pain at the time of the study. The following tools were used: Semi-structured Anamnesis Questionnaire, Visual Analog Scale, McGill Pain Questionnaire, and SF-36 Quality of Life Questionnaire. Individuals in the control group answered the questionnaires before and after CrossFit training. The chiropractic group performed the same procedure, plus pre-training chiropractic adjustment and joint range of motion (ROM) before and after lumbar adjustment. Results: There was a significant increase in pain in the control group, and a significant decrease in pain in the chiropractic group, including one day after the chiropractic adjustment. In the chiropractic group, the joint ranges of motion had a significant increase in flexion and extension of the lumbar spine after chiropractic adjustment. Conclusion: The chiropractic group achieved a significant improvement in pain level and joint range of motion, suggesting that acute chiropractic adjustment was effective in reducing low back pain.


INTRODUCTION
Physical activity is advocated as an important tool in preventing the emergence of diseases, controlling already existing diseases, and for the well-being and social life of human beings. 1,2Sports and physical activity do not seem to be the main cause of spine pain and injuries, but the frequent additional load on the biological structures of the spine during high-impact sports may be a prerequisite for injury.][5] Low back pain is one of the most common musculoskeletal conditions and the second most frequent reason that patients seek professional health care.][8] In CrossFit training, individuals perform repetitive movements of lifting weights, squatting, and improper posture, 9,10 and an evaluation of whether these movements are being performed incorrectly during training, whether from carelessness or lack of guidance, is extremely important.These activities, when repeated frequently, can lead to spine problems and intense pain, especially in the lumbar region, where most of the weight is normally supported. 11,127][18][19][20] It offers well-being to patients through pain relief, improved joint mobility, and muscle relaxation, 17,18 providing quality of life, reducing medication use, and avoiding unnecessary surgeries. 16,21,22he objective of this study is to evaluate the effectiveness of acute chiropractic adjustment in individuals who practice CrossFit training, in relation to complaints of pain and range of joint movement in the lumbar region.

METHODS
This study was a randomized clinical trial conducted at a CrossFit box in Novo Hamburgo/RS (Ultimate CrossFit Pirates).It was approved by the Institutional Review Board of the Centro Universitário Metodista (IPA) as opinion 1.440.851.All the participants signed the informed consent form.
During March and April of 2016, all individuals, males and females between the ages of 18 and 40 years, enrolled at the CrossFit box who had low back pain at the time of the study were invited to participate.Individuals involved in any type of physical rehabilitation, drug treatment for pain, with any contraindication to chiropractic adjustment, who had a history of lumbar spine surgery, and those who did not answer the questionnaire within 24 hours of the chiropractic adjustment were excluded.We used the study by Mascarenhas and Santos 13 as a reference for calculating the sample size.The calculation was performed using WinPEPI ® , version 4.0 software, with a confidence level of 95%, a coefficient of variation of 12%, and acceptable margin of error of 5%.Thus, 50 individuals were selected for the study, with 25 belonging to each of two groups.There were no exclusions in the study (Figure 1).
All 50 individuals who met the inclusion criteria were evaluated and randomized, using the online Research Randomizer, version 4.0 program (Social Psychology Network, http://www.randomizer.org),for the random allocation to the control and chiropractic groups.The individuals in the control group answered questionnaires both before and after CrossFit training.The chiropractic group followed the same procedure, with the addition of a chiropractic adjustment prior to training and the measurement of the range of motion (ROM) before and after the lumbar adjustment.
The whole procedure was conducted by two experienced researchers.The participants were properly positioned on the chiropractic table for one of the researchers to perform the high velocity low amplitude (HVLA) adjustment only to the lumbar region.The Diversified Technique was used, which, according to Cantera, 23 is used to correct segments that present specific biomechanical changes, with the goal of restoring joint mobility.The other researcher measured the ROM before and after the chiropractic adjustment by means of inclinometers.For this, the individuals were standing and performed flexion and extension of the trunk with the inclinometers positioned above the spinous process of T12 and at the sacral level, thus obtaining the angle of the amplitude of movement of the spine. 21his measurement was conducted twice, resulting in an average.
In this study, we used the Visual Analog Scale (VAS) and the validated Portuguese language versions of the McGill Pain Questionnaire and the 36-item Medical Outcomes Study -Short Form (SF-36).The first questionnaire administered in both groups was the Semi-Structured Anamnesis Form.This was prepared by the first researcher, served as a screening tool, and contained standard data for each individual such as age, sex, weight, profession, time experiencing pain in the lumbar region, time practicing and frequency of CrossFit training, among others.Afterwards, they responded to the VAS, which served as a parameter to measure the condition of pain and to quantify the intensity and the individual perception of their pain. 13,24This scale was also applied to the chiropractic group 24 hours after the adjustment to assess whether there was any change in the pain profile.
][27] The initial outcome of the study was a data comparison between the control and chiropractic groups to confirm whether chiropractic adjustment is capable of reducing low back pain.Then, we evaluated the before and after responses of the control and the chiropractic groups.Finally, we compared the ROM data before and after the chiropractic adjustment in the chiropractic group.
All the continuous data were described as averages, standard deviations, and the categorical data as frequencies and percentages.Normality was measured using the Shapiro-Wilk test.For the comparison of the groups, we used the Student's t-test for paired samples or the Mann-Whitney test.The data were organized in an Excel (2007 version) database and analyzed using the Statistical Package for the Social Sciences for Windows 20.0 (SPSS), adopting a level of significance of 5%.

RESULTS
Fifty individuals were included in the study between March and April, 2016.The subjects were predominantly male (58%).The average age was 30 ± 4.89 years and the average BMI (body mass index) was 23.74 ± 2.87 kg/m 2 .The average daily workload was 8.24 ± 0.81 hours.Regarding CrossFit training, the time practicing was 16.02 ± 12.25 months, with a frequency of 3.1 ± 0.98 days with an average training time of 66.6 ± 12.43 minutes.In terms of low back pain, the average time experiencing pain was 12.33 ± 17.76 months and 58% of the subjects had undergone some type of treatment (Table 1).There were no significant changes in relation to the general characteristics in the comparison between the groups.In the control group, 64% of the individuals had already undergone some form of treatment, the most commonly reported being physical therapy.In the chiropractic group, 52% had already undergone treatment and the most commonly cited was chiropractic therapy itself (Table 2).
As for the pre-and post-training pain levels, we observed a significant increase in pain in the control group and a significant reduction in pain in the chiropractic group.The chiropractic group also experienced a reduction in pain on the day after the chiropractic adjustment (Figure 2).
In the chiropractic group, the amplitudes of articular movement had a significant increase in flexion and extension of the lumbar spine following the chiropractic adjustment (Figure 3).No significant changes were observed between the groups for the variables of the SF-36 Quality of Life Questionnaire or for the McGill Pain questionnaire, both with p > 0.05 (Table 3).Regarding the descriptive section of the McGill questionnaire, descriptors were chosen in all categories, however, in the "sensitive" pain category we observed a repeating pattern of characteristics of the type of low back pain, with descriptors like "stabbing" and "shooting" being used with more frequency, 22 (44%) and 19 (38%) times, respectively.

DISCUSSION
The overall average age of the subjects was approximately 30 years and the average BMI was normal according to the Brazilian Association for the Study of Obesity (ABESO). 28Males were predominant in both groups, accounting for 58% of the total sample, corroborating findings in the literature that report that the modalities most practiced by men aiming to improve health and performance are those that involve lifting weights, such as body building. 29     Of the 50 subjects, 58% had received some form of treatment, the most common of which was chiropractic therapy (51.72%) followed by physical therapy (48.27%).Chiropractic therapy is considered a primary treatment and the literature affirms that spine pain is the most common reason that patients use complementary and alternative therapies like chiropractic therapy, massotherapy, and acupunture. 30,31In a randomized clinical trial, Giles and Muller 32 compared the efficacy of spine manipulation, medications, and acupuncture in patients with cervical and lumbar pain.They concluded that, if there were no contraindications, manipulation generates a reduction in pain and an increase in joint mobility.Other studies have evaluated the efficacy of other forms of treatment to reduce lumbalgia, such as trunk exercises to prevent and treat low back pain, but approaches that use mobilizations and manipulations significantly reduce low back pain. 33,34][40][41] Manipulation of the spine causes changes in the musculoskeletal system.Experimental evidence indicates that the impulse load of spine manipulation influences the primary proprioceptive afferent neurons of the paraspinal tissues. 42In addition, vertebral manipulation may possibly affect the pain process, changing the central state of facilitation of the spinal cord, and it can affect the motor control system. 42,43atients with acute or chronic pain have relevant and statistically significant clinical improvement in all spinal structures following chiropractic manipulation. 39The control group had an increase in pain level following training, reinforcing the findings in the literature where weight lifting has been widely associated with lumbalgia. 44,45he average measurement of the lumbar ROM agrees with that found in the literature, both in movements of flexion and extension. 21,46,47he significant increase in the flexion and extension of the lumbar spine following chiropractic adjustment is in accordance with a study that showed that vertebral manipulation can improve joint mobility and restore movement in all anatomical planes, thus serving to eliminate the kinesiopathological component of the vertebral subluxation complex. 48hen we analyzed the quality of life of the subjects included in the study, we observed an excellent score in the area of functional capacity in both groups, which was to be expected since the sample was made up of people who participate in regular physical activities and are in good physical health.The general state of health also received a high score.The individuals had chronic pain, but of low intensity, which interfered less with the quality and emotional aspects of their lives when regular physical activity was included.
Chronic non-specific low back pain is rarely related to total disability in performing a person's daily activities.However, it may cause partial and temporary, and many times recurring, limitations. 49This fact corroborates our finding that complaints of pain in the lumbar region was not seen as a factor causing disability in the individuals, but rather as a limitation to performing certain daily activities.
In the McGill Pain Questionnaire, the "sensitive" category was checked by 100% of the sample, as similar to the literature where this category is the most cited. 50,51In the study by Gonçalves, 50 99% of the subjects reported the lumbosacral zone as the most affected region, and "uncomfortable" is among the words most often cited.In the study by Bermudez and Bontempo 51 one of the most frequently used words, in the sensory subclass, is "sore".The sensory category refers to the mechanical, thermal, and spatial properties and vividness of the pain, 13 demonstrating that in this study the subjects were successful in characterizing their pain, indicating a pain of mainly physical origin.In contrast to the results of the studies cited above, in our study, the most frequently used descriptors were words like "stabbing" and "shooting", although they are all part of the same "sensory" category.
There are some aspects of this study that need to be taken into consideration.First, the VAS used to measure the perception of pain may reveal a subjective and placebo effect of pain, given that the participants had access to their previous level of pain.Second, the control group was not evaluated for the post-training pain level, since there was no ROM measurement or chiropractic adjustment in this group.It might be interesting to have this value, since CrossFit is an impact physical activity that can lead to peaks of muscle pain in the 24 hours following the exercise.

CONCLUSION
Acute chiropractic adjustment (HVLA -Diversified Technique) was shown to be effective in reducing the perception of lumbar pain and in improving the amplitude of joint movement in individuals who practice CrossFit training with complaints of low back pain.
All authors declare no potential conflict of interest related to this article.

Figure 1 .
Figure 1.Flowchart of the individuals included in the study.MA -amplitude of joint movement.

Figure 2 .
Figure 2. Pain level of the Control Group (white) and the Chiropractic Group (grey).

Figure 3 .
Figure 3. Evaluation of the Amplitude of Joint Movement in the Chiropractic Group.

FC = functional
capacity; LPA = limitations from physical aspects; P = pain; GSH = general state of health; V = vitality; SA = social aspects; LEA = limitations from emotional aspects; MH = mental health.

Table 1 .
Characteristics of the individuals included in the study Data expressed as averages ± standard deviation and number (%).BMI -Body Mass Index.

Table 2 .
Characteristics of the individuals in the Control Group (n=25) and the Chiropractic Group (n=25).
Data expressed as averages ± standard deviation and number (%).BMI -Body Mass Index.

Table 3 .
Evaluation of the SF-36 Quality of Life Scale and the McGill Pain Questionnaire in the Control Group and the Chiropractic Group (n=50).