Research and News
Posts tagged core training
Muscle activation levels for advanced exercises using the Exercise Ball
Dec 1st
If you're new here, you may want to subscribe to our email updates for new blog posts. Thanks for visiting!
Several EMG studies have been performed in the past decade to quantify and validate claims of “core stability” exercises. Despite few controlled, clinical outcome studies on using an exercise ball, its use in clinics and gyms remains steady. Because the Thera-Band® exercise ball can be used for both rehabilitation and fitness, different exercises and levels of muscle activation may be best for specific patients and clients. It’s important to know that an exercise provides enough EMG activation for strength training (greater than 60% maximal contraction), or if it’s more endurance-based (less than 25%).
In an article published in the Journal of Strength and Conditioning Research, researchers were interested in determining the EMG levels of ‘advanced’ exercises using an exercise ball. The authors noted that most exercise ball EMG studies have evaluated basic exercises, finding few exercises with a ball that activate core muscles more than traditional resistance exercises at training effect levels.
In the study, 14 healthy subjects performed 6 advanced exercises in random order. The exercises involved were more “whole-body” movements compared to traditional stabilization exercises focusing on the core. Surface EMG data More >
Exercise on unstable surfaces increases trunk muscle activation
Nov 4th
Unstable surfaces have become more popular for balance and stabilization training. Thera-Band® Exercise Balls and Stability Discs offer multiple options for unstable surface training. These unstable surfaces are thought to increase muscle activation and co-contraction, particularly for core stabilization training. Japanese researchers investigated the effect of unstable surface training on trunk muscle activity during common lumbar stabilization exercises in 19 healthy subjects. Their findings were published in the Journal of Orthopedic and Sports Physical Therapy.
The researchers used surface electromyography (EMG) to assess the “global” muscles: rectus abdominus, erector spinae, and external obliques, and fine-wire EMG for the deeper “local” muscles: transverse abdominus and multifidus. The subjects performed 5 lumbar stabilization exercises for 3-second holds, both on stable and unstable surfaces. The exercises were: prone plank on elbows, supine bridge, quadruped arm-and-leg, side bridge, and curl-up. EMG levels were normalized to maximal contraction.
The prone plank exercise on unstable surfaces (including an exercise ball and stability disk) produced significantly more muscle activity of all core muscles. High levels of oblique and rectus muscles were noted in both conditions for the prone plank exercise. The supine bridge exercise performed on an unstable surface did not significantly increase the activation of any muscle; the levels remained More >
Is resistance training on unstable surfaces effective?
May 6th
Instability training, or exercising while on unstable surfaces, has become both popular and controversial. Performing resistance training on unstable surfaces such as exercise balls, balance boards, stability disks, and foam pads has been shown to reduce force output, but increase activation of “core” muscles of the trunk (Behm and Anderson 2006). No studies, however, have directly compared training outcomes on stable and unstable surfaces.
In a paper published in the Journal of Strength and Conditioning Research, researchers performed a 7 week study of resistance training exercises in 2 groups: one using unstable surfaces and the other on stable surfaces. The researchers hypothesized that the instability resistance training group would demonstrate significantly greater gains in functional testing after the program.
Forty, college-aged, healthy untrained subjects volunteered for the study. Subjects performed squats and vertical jumps, as well as 3 machine-resisted upper body exercises: lat pull down, butterfly, and bench press. Both groups performed upper body exercises at 70% of 1RM. The stable surface training group performed squats at 75% 1RM, and the instability group performed squats at 50% 1RM while balancing on wobble boards, stability discs, or a BOSU ball. The instability group also performed 4 trunk stabilization exercises on an exercise ball. Subjects More >
Stable vs. Unstable: Using Exercise Balls with the Overhead Press Exercise
Apr 29th
“Functional Training” has become increasingly popular in both rehabilitation and fitness. “Core training” has often been considered a component of functional training because of the transfer of force through the trunk to the extremities. Unstable surfaces such as Thera-Band® Exercise Balls and Stability Trainers are often used with traditional exercise movements to integrate training of the trunk and extremities.
Canadian researchers Anderson and Behm have shown that instability training can provide similar muscle activation levels at lower resistance levels compared to training on stable surfaces. Unfortunately, however, unstable surface training also results in a decrease force output of prime movers. California State University researchers set out to evaluate the electromyographic (EMG) activity of prime movers and core stabilizers during a seated overhead press exercise. 30 healthy, resistance-trained subjects performed an overhead press with dumbbells and barbells while sitting on a stable surface and on an exercise ball. The investigators were interested in looking for differences in EMG levels between the stable load (barbell) and unstable load (dumbbell), on both stable (bench) and unstable surfaces (exercise ball). Subjects used a 10RM resistance (maximum amount of weight lifted for 10 repetitions) for each of the 4 conditions; thus, each condition had a slightly different absolute load.
As expected, More >
Exercise ball more effective at activating abdominal muscles
Apr 8th
The exercise ball is a popular device for core training, and is often used to increase muscle activation, particularly of the abdominals. Most studies have concluded that the exercise ball increases electromyographic (EMG) activity of the abdominal muscles. In England, Dr. Michael Duncan investigated the muscle activation in 2 different parts of the rectus abdominus muscle (the upper and lower portions) during exercise both on and off an exercise ball. The 3 exercises were the abdominal curl-up, roll-out, and jack knife. Subjects also performed a curl-up on the floor.
The exercise ball consistently had significantly more rectus activation than the curl-up on the floor. The chart below provides the percent of maximal contraction (MVIC) of each portion of the abdominals during each exercise:
Floor Curl-up Ball Curl-up Jack knife Roll-out Upper Rectus 68% 84% 93% 104% Lower Rectus 64% 93% 111% 98%The study also found that the jack knife was the best exercise for lower abdominal activation compared to all other exercises. This may help clinicians choose an exercise that specifically targets one portion of the abdominals over another. However, some researchers suggest that isolating one muscle may not be beneficial for core stabilization, instead focusing on quick and strong activation of More >
