Core training

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 as Olympic lifts, squats and deadlifts) while including resistance exercises with unstable devices, as well as unilateral exercises that provide “transverse stress to the core musculature.” Furthermore, they stated that “unstable exercises should not be used when hypertrophy, absolute strength, or power is the primary training goal.”

Dr. David Behm

Similar recommendations were made for the general population, noting the benefits of both free weight and instability training on promoting spinal stability. It’s important to remember to decrease resistance loads on exercises performed on unstable surfaces.

During rehabilitation, unstable surfaces can be effective at improving muscle reaction time and co-contractions that protect joints. In addition, resistance training on unstable may provide localized muscle endurance training, beneficial for the high proportion of Type I “aerobic, slow-twitch” muscle fibers found in core muscles. Dr. Behm and colleagues recommend core endurance training exercises generally be performed at higher repetitions (greater than 15 per set), while athletes requiring more strength and power perform less than 6 repetitions per set. The authors further noted that unstable surfaces can provide musculoskeletal health benefits such as decreased injury risk and increased spinal stabilization as opposed to using free weights.

In summary, unstable exercise devices such as Thera-Band Exercise Balls and Stability Trainers should be included as part of a well-rounded conditioning program for athletes and non-athletes, but not for increasing primary strength and power. In addition, resistance exercises performed on an unstable surface should be performed at a reduced intensity level because of the reduction in force output.

REFERENCES:
Behm DG, et al. The use of instability to train the core musculature. Appl Physiol Nutr Metab. 2010 Feb;35(1):91-108.

Behm DG, et al. Canadian Society for Exercise Physiology position stand: The use of instability to train the core in athletic and nonathletic conditioning. Appl Physiol Nutr Metab. 2010 Feb;35(1):109-12.

Visit the Thera-Band Academy Stability Training portal here

Researchers at the University of Kentucky developed a progressive balance training program for patients with chronic ankle instability. The program lasted 4 weeks and focused on dynamic balance stabilization in single-leg stance. Exercises included progressions in hops and single-leg balance using foam pads and 6-pound medicine balls. The results of their first study, published in Medicine and Science in Sports and Exercise in 2008, found that their program significantly improved function and postural control in chronic ankle sprain patients. In their more recent study, 29 subjects with chronic ankle instability were randomly assigned to either an exercise group or control group. The authors reported improvements in gait kinematics, specifically the coupling of rearfoot and lower leg motion during walking. The researchers noted that the changes in gait kinematics following the exercise program were likely due to changes in sensorimotor function resulting from the 4- week balance training program, particularly since ligamentous laxity did not change.

In summary, a 4-week progressive balance training program implementing hops and single-leg balance exercises with Thera-Band Stability Trainers can help improve balance, function, and kinematics in patients with chronic ankle instability.

REFERENCES:

McKeon PO, et al. Effects of balance training on gait parameters in patients with chronic ankle instability: a randomized controlled trial. Clin Rehabil. 2009 Jul;23(7):609-21. Epub 2009 May 15.

McKeon PO, et al. Balance training improves function and postural control in those with chronic ankle instability. Med Sci Sports Exerc. 2008 Oct;40(10):1810-9.

Visit the Thera-Band Academy Stability Training Portal here

Their study using the “Tyler Twist” exercise for patients with tennis elbow showed significant improvements over tradition treatment. The study has been featured in the New York Times, Readers Digest and Consumer Health. Many patients have shared their success stories with us and interest continues to grow around the world!

Researchers at the University of Kentucky evaluated electromyographic (EMG) levels of 4 exercises in total hip patients between 7 and 32 weeks post-operative. Dr. Cale Jacobs and colleagues were interested to see if there was a progression of muscle activation to guide clinical decisions about hip abduction exercise prescription. They published their findings in the Journal of Arthroplasty. The 4 exercises included 2 non-weight bearing and 2 weight-bearing exercises:

• Standing hip abduction with cuff weight at 1% of bodyweight, lifted to 30 degrees
• Sidelying hip abduction with cuff weight at 0.5% of bodyweight, lifted to 50% of leg length
• Standing hip abduction with uninvolved leg to 30 degrees
• Lateral walk with Thera-Band resistance band attached with extremity straps around ankle

Researchers used a level of Thera-Band resistance that created the same torque as the standing hip abduction exercise (1% body weight) with stretch on the band at 50% elongation. The researchers used this chart of Thera-Band elastic resistance pull forces to prescribe the appropriate color of band.

Both the sidelying abduction and weight-bearing standing abduction with the other leg produced an average of 67% maximum voluntary isometric contraction (MVIC).  The Thera-Band resisted lateral walk exercise produced an average of 63% MVIC and the non-weight bearing standing abduction produced 58%. There was no significant difference in activation between exercises, indicating no clear order of exercise progression.  The researchers suggested these exercises can be used interchangeably, particularly when balance impairment or postural position may be an issue.

In conclusion, non-weight bearing exercises involving open-chain hip abduction provide no additional benefit of gluteus medius activation compared to more functional closed-chain exercises. Thera-Band loop resisted walking provides moderate (>60% MVIC) of gluteus medius activation in post-operative total hip replacement patients.

REFERENCE: Jacobs CA, et al. Electromyographic analysis of hip abductor exercises performed by a sample of total hip arthroplasty patients. J Arthroplasty. 2009 Oct;24(7):1130-6. Epub 2008 Aug 30.

Disclosure: Thera-Band Academy provided the bands used in this study, but did not provide monetary funding.

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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 significant difference in improvements between the two exercise groups. The researchers concluded, “…the use of elastic tubing in strength training in young adults is effective and can yield results that are equivalent to those obtained with weight machines and free weights.”

One of the most important advantages of the Exercise Station is the fact that there is no need for multiple weights, barbells or dumbbells of varying resistance. The Exercise Station, combined with a Thera-Band® Pro Series SCP Exercise Ball provides all the resistance necessary for an effective strength training program.  It requires no more than a 6’x6’ space and can easily be placed under a bed or against a wall when not in use.

REFERENCE: Colado JC et al. A comparison of elastic tubing and isotonic resistance exercises. International Journal of Sports Medicine. Published Online 2010.

Visit the Thera-Band Academy Exercise Station Resource Center here