Getting the ball rolling

The Swiss ball, which is also referred to as a gym or stability ball, has become an integral part of the physiotherapy clinic and the traditional gym setting. Some, however, still perceive the Swiss ball to be a gimmick, whilst others rely on it as being essential for managing low back disorders and increasing trunk control.

Low back pain is indicated to be a common complaint in 60-80% of the population and 60-86% of this group will experience more than one episode⁽¹⁾.Research has indicated that trunk stability exercise is effective in reducing low back pain compared to general exercise in the short term⁽²⁾. The Swiss ball has shown to be effective in enhancing control of the trunk stability muscles in healthy and low back pain populations⁽³⁾. However, research investigating changes in low back pain correlating with improved core muscle activity whilst using the Swiss ball is sparse. The purpose of the current text is to review the recent research pertaining to the use of the Swiss ball and how this key tool may influence core stability function.

The Swiss ball is used by physiotherapists and personal trainers worldwide to facilitate the stability muscles of the trunk to enhance core control. These ‘core’ muscles, which are active across the lumbopelvic and hip complex, include deep and superficial muscles (see table 1). The deeper muscles provide stability to the passive structures (vertebrae, intervertebral discs and ligaments) of the lower back while the superficial muscles facilitate trunk movement. For optimal pain-free movement to occur, both the deep and superficial core muscles must engage in unity with simultaneous timing and tension⁽⁴⁾. Failure of these muscles to activate in sequence may result in low back pain and compromise movement function.

Table 1: Trunk muscles

Core muscle recruitment

Researchers at California State University studied the muscle activity (electromyography, EMG) of the major trunk muscles during eight Swiss ball exercises (decline press-up, pike lift, reverse plank tuck/jack-knife with and without rotation, seated march, plank roll-out, prone hip extension left and right) and contrasted to a traditional floor-based abdominal crunch⁽⁴⁾. The rectus abdominis, internal and external oblique, latissimus dorsi, lumbar paraspinals and rectus femoris were normalised using a maximal voluntary isometric contraction (MVIC) and measured using surface EMG. Eighteen (nine male and nine female) healthy participants were assessed in each of the Swiss ball positions.

The results of the study indicated that the plank roll-out and pike lift were significantly more effective in activating the trunk muscles (see figures 1 and 2). The plank roll-out elicited a mean EMG signal of the upper rectus abdominis of 63% MVIC, lower rectus abdominis of 53% MVIC, external oblique of 46% MVIC and internal oblique of 46% MVIC. The pike lift elicited a mean EMG signal of the upper rectus abdominis of 46% MVIC, lower rectus abdominis of 55% MVIC, external oblique of 84% MVIC and internal oblique of 56% MVIC. The EMG activity of the trunk muscles was recorded at the lowest whilst in the seated march position and the floor based abdominal crunch of 7-8% MVIC respectively. In addition, the activity of the lumbar paraspinal muscles was relatively low with 10% MVIC activity through each of the exercises.

In addition, this study indicated that the plank roll-out and pike exercises were more effective in activating the internal and external obliques and the lower and upper rectus abdominis (see figures 1 and 2). The research, although useful, is limited as it lacks measurement of the deeper stabilisers such as the multifidi or the transverse abdominis.

Figure 1: Plank roll-out

Figure 2: Pike Lift

Researchers from Poland recently published an article measuring rectus abdominis, external oblique and internal oblique with transverse abdominis during Swiss ball bridging in prone, supine and side, lying on both stable and unstable surfaces⁽⁵⁾. This prospective study measured the trunk muscle activity of thirty-three healthy females, in each of the positions, by surface EMG and the results indicated that the trunk muscles were more active during Swiss ball prone bridging (plank). The MVIC of each of the individual muscles were rectus abdominis 44.7%, external oblique 54.7%, and internal oblique with transverse abdominis 36.8%. Supine bridging in comparison on a stable surface produced MVIC of less than 5% abdominal activity. From the previous two studies, a traditional plank exercise on the Swiss ball with the knees on or off the floor is suggestive of being one of the most effective in engaging trunk muscle activity^(4,5).

Single and double-leg squatting exercises are frequently recommended for patients with knee pain and other lower limb complaints also. The gluteus medius and maximus function, through its attachment, to increase stability through the hip and knee complex⁽⁶⁾. Researchers studied the effects of single and double squatting on gluteal maximus and medius activity using both a Swiss ball against the wall and in standing (see figure 3)⁽⁷⁾. An observational study measured the surface EMG of the gluteal muscles in nineteen healthy participants (11 male, 8 female) during the squat phase. Single-leg squatting was carried out with the participant standing sideways to the wall.

Figure 3: Double leg squat with and without Swiss ball. Bottom picture – single leg squat with and without Swiss ball

The results indicated that there was significantly greater gluteal maximus and medius muscle activity during single-leg squatting compared to double-leg squatting as measured as %MVC (see table 2). The results also found a significant difference in the glute max activity, compared to glute med, during single-leg squat with and without a ball, with greater activation with the Swiss ball. Although a significant difference wasn’t noted in the glute med, an increase in muscle activity was observed whilst using the Swiss ball.

Table 2: Percentage maximal voluntary contraction(MVC) of the glute max and glute med in single and double leg squat positions with and without the Swiss ball

Case study 1: Clinic visits

The first case study involves a 55-year-old male with a history of recurring back and neck pain with referred leg pain. The patient had been treated for his symptoms since 1977 with muscle-relaxing techniques and exercises in a chiropractic clinic. His symptoms were aggravated by standing at work on a concrete floor, bending and lifting, which he did for 25 years. Although his back symptoms were improved by chiropractic treatments, his symptoms became more profound and positive results harder to achieve. A rapid increase in clinic visits was reported and in January 2002 sitting on the ball for 20 minutes was recommended daily. After a short time he stopped because it increased his back pain frequency and severity. X-ray images in March 2003 revealed mild degenerative change at the level of L3–L4, L4–L5 with moderate disc space narrowing at L3–L4.

Treatment continued and he was encouraged to try to sit on the Swiss ball again. In 2005 he stated that he could only sit on the Swiss ball for two minutes and it began to increase his symptoms. Treatment continued, and in May 2005 he was instructed to sit on the ball for two minutes or until it was uncomfortable and to increase the time he used the ball, as comfort dictated. At the end of eight weeks he was able to sit on the ball for 20 minutes.

The patient was rewarded for his persistence with a considerable reduction in all symptoms. He experienced a reduction in the severity and frequency of episodes of back pain, and the sharp back pain and leg pain were completely gone. The constant backache gradually improved and is now not a problem. He now experiences only occasional low back discomfort and no severe back pain or leg pain.

Multifidus

The lumbar multifidus muscle has been recognized as an important stabilizer of the lumbar spine⁽⁸⁾. The most superficial fibers arise from the spinous process and also the lamina of the vertebrae and descend towards the pelvis where they insert whilst crossing up to five segments. The deeper fibers attach at the inferior edge of the spinous process and also the inferior border lamina of the vertebrae and attach distally at the mamillary process and facet joint capsule of the vertebrae at least two levels below. The superficial fibers are active during lumbar extension whilst the deeper fascicles don’t possess the moment arm and therefore assist in segmental control.

A research study recently published in Physical Therapy in Sport studied the muscle activity of the lumbar multifidus during sitting exercises whilst on either a stable or unstable surface using the Swiss ball⁽³⁾. A cross-sectional design of 40 patients, 20 healthy and 20 with chronic low back pain (CLBP), found that the lumbar multifidus was significantly more active during sitting exercises on the Swiss ball in both healthy and CLBP groups than the stable surface was. The results, although positive, should be viewed with caution as muscle activity was measured using ultrasound with no implementation of electromyography (EMG). Pain levels weren’t recorded in this particular study, and therefore no correlation between increased multifidus activity and low back pain reduction. However, it does indicate that sitting is effective in both cohorts and provides support for using the Swiss ball as a chair.

Case study 2: Clinic visits

The second case study involves a 52-year-old female office worker. Her complaint on the first visit was recurring bouts of severe pain involving her lower back, upper back and neck. A chiropractor had previously recommended a gym ball as a chair to use at work. This had helped reduce the recurrence of back and neck pain, and also seemed to reduce the severity of the episodes of pain as well.

At the time of her first visit, she had been using the ball as a chair at work for about one year and felt that it was helping. Over the course of time, gym ball exercises were added to the treatment regime. In the past four years, her treatment history shows a reduction in patient visits from 17 in 2002 to 4 in 2005.

Due to pressure from within her workplace, the patient has tried to return to a regular office chair on several occasions. Each time there has been an exacerbation of her symptoms, which were relieved by her returning to sitting on the gym ball and more frequent visits to the chiropractor.

For this patient, a combination of chiropractic care, gym ball exercise and the use of a gym ball as a chair at work have contributed to a significant reduction in symptoms of low back pain and reduced frequency of office visits. She has had not only a significant reduction in episodes of back pain but also a reduction in the severity of the episodes and this is illustrated in the number.

The Swiss ball as a chair

It is not uncommon for a Swiss ball to be used instead of a traditional desk chair in an office or staff meeting to manage pain and improve muscle control. Some have questioned this method as the quality of the research in pertaining to this method is limited. A research paper published in the Journal of Canadian Chiropractic Association provided two case studies on the use of sitting on a Swiss ball during daily tasks⁽⁹⁾.

Summary

The research indicates that the Swiss ball is effective in improving control of the core stability muscles in a variety of positions. The quality of the available evidence is limited at present and further studies, using random allocation, should endeavor to measure for a correlation between core muscle activity and pain reduction. It is desirable to use systematic reviews and randomized controlled trials where possible, but is also important to review case studies to monitor the effects of an intervention. The case studies referred to, provide qualitative evidence of how the Swiss ball may be used in managing CLBP. The Swiss ball is a cost-effective, safe and easily accessible tool to use in the home, gym or workplace and the research available is supportive of its inclusion for both healthy and low back pain populations.