Effects of tai chi on pain and muscle activity in young males with acute low back pain.

[Purpose] This study was to examine the effects of tai chi on low back pain in young males.
[Subjects and Methods] Forty males in their 20s with low back pain were randomly assigned to two groups. Tai chi was applied to one group, and stretching was applied to the other group. The subjects conducted exercise for one hour, three times per week for four weeks. They performed warm-up exercises for 10 min at the beginning and end of the sessions and conducted the main exercise for 40 minutes. Wireless surface electromyography (sEMG) and a visual analogue scale (VAS) were employed to measure muscle activity and pain, respectively.
[Results] There were significant differences between the two groups in pain and muscle activity. The tai chi group's VAS decreased from 3.1 to 2.1, and its muscle activity decreased from 21.5% maximum voluntary isomeric contraction (MVIC) to 16.4% MVIC. The stretching group's VAS decreased from 3.4 to 2.8, and its muscle activity decreased from 24.1% MVIC to 22.1% MVIC.
[Conclusion] Tai chi is more effective for low back pain in males in their 20s than stretching. Tai chi can be considered an effective method to reduce low back pain in males in their 20s.

RCT Entities:   Population Interventions Outcomes

INTRODUCTION

Low back pain may be regarded as a personal problem, but it may trigger time and economic losses, thereby becoming a social problem. It is a serious disease that affects social productivity and may influence society in a large sense1). The principal cause of low back pain is poor posture. Other causes include weakened muscles, obesity, which affects many people today, weakened muscle strength resulting from insufficient exercise, and abnormal gait. Low back pain in the acute phase may result from abnormality in the back, lumbar, and abdominal muscles associated with problems with the ligaments, muscles, and intervertebral discs2). Imbalance between the trunk’s extensor muscles and flexor muscles is a common cause of low back pain. Those with chronic low back pain frequently have abnormalities in the spinal erector muscles, which are extensor muscles, relative to the trunk flexor muscles. Excessive movement and activity of the spinal erector muscles, which play an important role in postural maintenance and balance, may impede normal balance between the trunk extensor muscles and the trunk flexor muscles. Imbalance between the spinal erector muscles and the trunk flexor muscles reduces flexibility. Such imbalance is a cause of low back pain and may aggravate an existing problem3). Among the methods used to manage low back pain, physical therapy is the most commonly used method. Usually, the therapy involves stretching and lumbar flexion and extension exercises. In addition, exercise using a ball, aerobic exercise, yoga, and Pilates are often used. Recently, lumbar stabilization exercise, which is intended to strengthen the deep muscles of the trunk, has been frequently employed to manage low back pain. Lumbar stabilization exercise is effective for low back pain patients because it improves their muscle strength and range of motion4, 5). Tai chi has also been employed recently. Tai chi can be readily applied to improve postural balance in ordinary life. It has been reported to be helpful in improving muscle strength and enhancing balance ability. Tai chi, which originated from China, developed as a traditional military art for self-defense and health preservation and was widely popularized among the public. In addition to physical movements, tai chi places importance on normal elements to purify one’s mind by letting the hands fall, making the body upright, and putting the feet in order6). Due to tai chi’s very slow and smooth motions, many studies have included elderly subjects. According to one study, tai chi improved gait ability and muscle strength in elderly males7). Another study found that it is helpful in enhancing flexibility, muscle strength, and muscle endurance in middle-aged males8). Studies have investigated the effects of tai chi on specific diseases, as well as on elderly people. In a study in which tai chi and stretching were applied, tai chi was found to be effective for fibromyalgia9). In another study where tai chi was applied to knee osteoarthritis patients, they obtained better results than those who performed stretching exercises10). Previous studies have focused on elderly people, middle-aged males, or patients with specific diseases. Research on the potential benefits of tai chi for young adults is lacking. Therefore, this study compared changes in the pain and muscle activity of males in their 20s who conducted tai chi and examined how the exercise affected their bodies.

SUBJECTS AND METHODS

The total number of subjects was 40. They were divided into two groups: one group conducted tai chi, and the other group performed stretching. This study was conducted after obtaining approval of all procedures, safety, and ethics from the Research Ethics Committee of Kyungbuk University. All subjects agreed to participate in this research after receiving an explanation of its purpose and methods. The subjects had been diagnosed with acute low back pain by specialists and voluntarily consented to participate in this study. Those who had problems other than low back pain were excluded. Their muscle activity was measured using an MP150 (BIOPAC systems, Inc., Goleta, CA, USA), surface electromyography equipment, and Ag-Ag/Cl electrodes. To examine the activity of the spinal erector muscles of the dominant side, an active electrode was attached to the area 2 cm away from the side of the spinous process of vertebra L5 and slightly above the imaginary line connecting both anterior superior iliac spines. The ground electrode was attached to an area not associated with signals. Signals collected at a sampling rate of 1,000 Hz were notch filtered at 60 Hz after full-wave rectification to remove electrical noise. Then, 30 to 500 band-pass filtering was conducted. As muscle activity differed among individuals, %MVIC was employed for standardization. A maximal isometric contraction test was carried out based on the manual muscle test. The subjects walked on the spot for 10 sec, and their muscle activity for 6 sec, excluding the first and last 2 sec, was measured. Low back pain was measured with the visual analogue scale (VAS). The degree of pain was measured by the subjects putting a mark on a 100 mm stick on which the numbers 0 to 10 were written. Both groups performed the exercises three times per week, for one hour each time, for a total of four weeks. The two groups performed warm-up exercise for the first 10 min and cool-down exercise for the last 10 min. During the intervening 40 min period, each group carried out tai chi or stretching. Regarding tai chi, the subjects performed all motions, which took 20 minutes. The tai chi group performed the 20 min of exercise twice. The exercise was composed of various motions, including ya ma boon jong, boong ri je an, baek hak yang si, su whi bi pa, nu seul y obo, je su sang se, and yeo bong sap ye. The stretching group repetitively stretched their lower extremity joints, trunk joints, and upper extremity joints. SPSS was used for statistical analysis. To examine differences between the two groups in accordance with the interventions, a paired t-test was carried out. An independent t-test was performed to compare the groups. The significance level was set at 0.05.

RESULTS

Pain and muscle activity decreased in both the tai chi group and the stretching group (p<0.05). The tai chi group’s muscle activity decreased from 22.2±3.5%MVIC to 17.8±3.9%MVIC, and its VAS decreased from 3.3±0.5 to 2.3±0.5, which was statistically significant. The stretching group’s muscle activity decreased from 24.1±3.7%MVIC to 22.1±3.6%MVIC, and its VAS decreased from 3.5±0.6 to 2.85±0.68, which was statistically significant (Table 1).

Table 1.

Differences in pain and muscle activity in the two groups (VAS, %MVIC)

	Group	Pre	Post
		M±SD	M±SD
Pain	Tai chi	3.1±0.6	2.1±0.5*
	Stretching	3.4±0.6	2.8±0.5*
Muscle activity	Tai chi	21.5±3.1	16.4±2.8*
	Stretching	24.1±3.9	22.1±3.6*

DISCUSSION

In this study, tai chi more effectively reduced pain in male patients with acute low back pain than stretching did. In addition to the decrease in pain, the decrease in muscle activity was greater in the tai chi group than in the stretching group. Different studies have applied diverse therapeutic methods to treat low back pain. Various physical therapy exercise methods have been employed, as well as physical manipulation. The application of an isotonic lumbar stretching exercise program using Mdex waist extension equipment to increase lumbar muscle strength in patients with chronic low back pain significantly improved their muscle strength and decreased their pain11). Conducting hip muscle exercise and lumbar stabilization exercise together enhanced lumbar stability in patients with chronic lumbar pain. The same study found that it may be helpful to conduct lumbar stabilization exercise with other exercise12). Lumbar stabilization exercise appears to improve lumbar pain by improving muscle strength and balance ability. However, in the case of the spinal erector muscles, which are important for postural maintenance, efficient utilization of them is crucial, unless great power is required. In contrast to previous studies, which focused on muscle strength, the present study investigated the relationship between the degree of lumbar pain and muscle mobilization after an appropriate tai chi exercise program. The present study also intended to examine whether tai chi, which has been applied many times to elderly individuals, was helpful in improving low back pain of males in their 20s when the exercise was used as an intervention to treat low back pain. Tai chi was applied to elderly subjects in many previous studies due to its slow and smooth characteristics, but in the present study, we established the hypothesis that it would be effective for young adults in their 20s as well and performed an experiment on them. In the present study, the degree of pain significantly decreased in both groups when tai chi and stretching were applied. The tai chi group’s VAS decreased from 3.1±0.6 to 2.1±0.5 after the intervention, which was a greater decrease than that in the stretching group, the VAS of which decreased from 3.4±0.6 to 2.8±0.5 after the intervention (p<0.05). The tai chi group’s muscle activity decreased from 21.5±3.1%MVIC to 16.4±2.8%MVIC after the intervention, and the stretching group’s muscle activity decreased from 24.1±3.9%MVIC to 24.1±3.9%MVIC after the intervention. Muscle activity decreased in both groups. These findings are likely due to stability affecting the muscle activity. Reduction in pain minimizes muscle mobilization, thereby enabling efficient movement. In previous studies, muscle activity decreased when stability was high. When subjects wearing a back belt stood holding an object, the muscle activity of the spinal erector muscles was lower in both anteversion and retroversion of the pelvis than when the subjects did not wear a back belt13). When subjects put on a back belt, their muscle activity was 175.1±30.3%RVC, but when they did not, their muscle activity was 190.0±31.7%RVC. When subjects move without wearing a back belt, their stability is lowered, and this increases muscle mobilization. In contrast, when they move while wearing a back belt, their stability increases, and therefore their muscle activity decreases. Conducting the same motion increases their stability and decreases the activity of their spinal erector muscles, which adjusts the body posture. Another study reported the same outcome. When the correlation between stability and muscle activity was compared, the higher stability was the lower muscle activity became14). Unlike the present study, research focusing on improvement in muscle strength noted that low back pain may be managed by enhancing muscle strength. A study of the direct effects of a tai chi intervention on males in their 40s with low back pain reported that muscle strength, which was measured using Mdex equipment, elements of physical strength, including balance at different angles (0°, 12°, 24°, 36°, 48°, 60°, and 72°), and lumbar muscle strength significantly increased. The study concluded that tai chi was well suited to managing low back pain among males in their 40s15). In that study, the subjects experienced maximal improvement in muscle strength through tai chi. In contrast, in the present study, the subjects had not efficiently used their muscles due to external factors, including pain, and they were able to perform the motions by exerting their muscles greatly. It is considered that because they were able to conduct motions with only a small amount of mobilization of the muscles, muscle activity decreased. Here, the reduction in muscle activity is not the same as a decrease in muscle strength. Muscle activity does not represent the degree of muscle strength but the degree of muscle mobilization. Therefore, the decrease in muscle activity should not be interpreted as a reduction in muscle strength. This study was conducted to examine the effects of tai chi on low back pain in males in their 20s. To determine the degree of the effect of tai chi, a stretching group was used as a control group, and pain and muscle activity were compared between the control group and a group that performed tai chi. Tai chi was effective in decreasing pain and muscle activity of males with low back pain in their 20s. If tai chi is used as an intervention instead of stretching for low back pain, it will become a very effective exercise program for males in their 20s with low back pain.