Research and News
Exercise Balls
Evidence-based Recommendations for Core Training with Unstable Surfaces
Sep 2nd
Core training has maintained its popularity in fitness and rehabilitation despite controversies over optimal training methods for “core stability.” Training with unstable surfaces such as Thera-Band® exercise balls, stability trainers, and balance boards have been recommended for core training, suggesting that such surfaces promote activation of core muscles. The “core” can be defined as the axial skeletal and its muscular and fascial attachments, including the pelvic and shoulder girdle.
Recently, resistance training while balancing on unstable surfaces such as exercise balls has become popular. Canadian researchers David Behm PhD and colleagues published a comprehensive review and position stand on the use of instability to train the core. Research has shown that exercises performed on unstable surfaces produce higher levels of muscle activation in both the core and extremity muscles compared to stable surfaces. However, force and power outputs are decreased while exercising on unstable surfaces, sometimes up to 70%. Interestingly, increasing levels of core muscle activation can also be achieved with free weight exercises such as squats and Olympic lifts without added instability.
In their article, the authors made several recommendations for both athletes and non-athletic conditioning based on their review of the literature. Dr. Behm et al. noted that athletes should emphasize “higher-intensity ground-based lifts” (such More >
Young women can gain as much strength using the Thera-Band® Exercise Station as training with free weights
Aug 18th
Dr. Juan Carlos Colado of the University of Valencia in Spain has published several excellent research papers on the effectiveness of Thera-Band® elastic resistance for fitness. In particular, he and his colleagues have shown that elastic resistance is as effective as isotonic machines for increasing strength in middle-aged women (Colado & Triplett 2008). In addition, they showed that elastic resistance exercise intensity can be regulated using “perceived exertion.”
Dr. Colado has continued his scientific investigations on the efficacy of elastic resistance, this time comparing free weight exercise training to elastic tubing exercises using the Thera-Band Exercise Station. His results are published in the International Journal of Sports Medicine. 42 women were randomly assigned to either a free weight exercise group, a Thera-Band exercise group, or a non-exercising control group. The two exercise groups performed the same 15 upper and lower body exercises using the OMNI perceived exertion scale to standardize intensity between the groups. The intervention lasted eight weeks for two to four sessions per week. Subjects were tested for muscular strength before and after the training program.
After the eight week program, both exercise groups reported up to 29% improvement in upper and lower body strength, while the control group did not. There was no More >
Exercise Ball Core Muscle Activation: Which exercises are best?
Jul 15th
Thera-Band® exercise balls are used by therapists and trainers around the world for therapy and fitness training. Despite its widespread use, the exercise ball has lacked in research to support its clinical application. Some studies have shown that abdominal exercises performed on exercise balls produce more muscle activation than the same exercise performed on a stable surface (Vera Garcia et al. 2000). In addition to traditional abdominal crunches, the exercise ball offers a variety of exercises aimed at activating the core muscles. With the variety of exercises being performed on exercise balls, more research is needed to prove or disprove the efficacy of specific exercises.
Roll Out
Physical therapy researchers quantified the electromyographic (EMG) activity of the abdominals, latissimus dorsi, lower back, and quadriceps muscles during eight “core” exercises on the exercise ball in 18 healthy subjects. They reported their findings in the Journal of Orthopedic and Sports Physical Therapy.
They found that the upper and lower rectus abdominus muscle were most activated during the roll-out (63% and 53% of maximum, respectively), and pike exercises (47% and 55%), while the internal and external obliques were most active during the pike (84% and 56% respectively) and skier exercises (73% and 47%). Not surprisingly, the lumbar paravertebral More >
Does the exercise ball enhance EMG activity during resistance training?
Jun 24th
When exercise balls became popular in the United States in the 1980s, it was thought that their instability promoted higher activation of the back and abdominal muscles for core stabilization. Several studies have shown that the exercise ball does increase muscle activation of the abdominal muscles compared to a stable surface.
As the exercise ball increased in popularity, trainers and therapists began performing traditional resistance training exercises such as the bench press with dumbbells on an exercise ball. Theoretically, the unstable surface would increase activation of both trunk and shoulder muscles. In addition to the increased risk of injuries associated with traditional resistance training on an exercise ball, researchers began to show that using an exercise ball for extremity exercises was not as effective as once thought.
Canadian researchers (Andersen & Behm 2002) were among the first to show that performing a chest press on an exercise ball significantly decreased force output by 60%. Interestingly, the muscle activation levels remained the same between surface types despite a decrease in force output, suggesting resistance training on an unstable surface may produce less efficient muscle contractions. Subsequently, other researchers (Marshall & Murphy 2006) reported an increase in EMG levels of the deltoid and abdominals More >
Why is force output decreased while sitting on an exercise ball? The core stability debate continues.
Jun 3rd
“Core Stability” has become a very popular term when discussing topics ranging from functional performance in athletes to rehabilitation for patients with low back pain. The exercise ball has long been used to promote core stability through specific exercises aimed at activating core muscles including the abdominals, low back, and pelvic stabilizers. The use of unstable surfaces such as a Thera-Band® exercise ball has been shown to increase muscle activity compared to a stable surface by providing additional challenge to postural stability. Researchers have shown, however, that exercises on an unstable surface reduce force output, suggesting that traditional resistance training exercises should not be performed on an unstable surface when the goal is to increase core activation. This lack of force output on unstable surfaces is thought to be related to a lack of core stability.
Researchers in New Zealand set out to determine if the loss in force output while performing an overhead press exercise on an exercise ball was related to core muscle endurance. They were interested in the ‘specificity vs. generality” of core stability; in other words, is core stability related to overall physical performance, or simply a measure of core muscle endurance?
30 resistance-trained, healthy young males participated in the study. More >
