Research and News
Posts tagged strength & conditioning
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 >
Elastic resistance exercise program effective in high school-based exercises for teens
Jun 22nd
Elastic tubing has been proven as effective as free weights again; this time, in teenagers. Several studies have shown that Thera-Band® elastic resistance has similar effects on muscle activation and strength as isotonic resistance (Andersen et al. 2010; Colado & Triplett 2008). Current physical activity guidelines recommend resistance training to improve muscular fitness in youths. A randomized, controlled study in Preventive Medicine by Australian researchers was performed to compare the effects of a resistance exercise program in 15 year old boys and girls using either elastic or isotonic free weight resistance compared to a control group. During the 8-week program, both groups trained twice a week with a PE teacher with a 1:15 instructor-to-participant ratio. They began each session with 5 minutes of aerobic activity and dynamic stretching. Resistance exercises were performed for 2 sets of 8 to 12 reps (Weeks 1-4 = 10-12 reps; Weeks 5-8 = 8-10 reps) with 60 second rests between sets. The 10 strengthening exercises were performed in 40-50 minutes in the same order. Both groups used the Borg scale at 15-18 with an 8-12RM; in other words, participants used a resistance with each exercise that caused fatigue with the last repetition with an exertion level of 15-18 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 >
Balance training program effective for basketball players
Apr 15th
Several studies have shown that balance exercises and “neuromuscular training” are effective at reducing injuries in athletes. Neuromuscular exercises typically incorporate products such as Thera-Band® Stability Trainers, Stability Discs, balance boards, and exercise balls. Athletic training researchers wanted to determine if a neuromuscular training program was effective at improving balance in high school athletes.
Two groups of female basketball players were assigned to either a 6-week neuromuscular exercise program or a control group (the subjects weren’t randomized; they were assigned to a group based on their school). Athletes were tested for their static balance and dynamic balance; the static balance test (BESS) used foam pads to create an unstable surface to evaluate postural stability.
The exercise group completed a twice a week, 6-week program that included 4 training stations: functional strengthening, plyometrics, agility training, and balance training. Each session lasted about 1.5 hours. The functional training station utilized elastic band loops and exercise balls, and the balance station utilized foam rolls.
After analysis of the 50 athletes completing the study, the authors found significant improvements in both static and dynamic balance. While these results may sound intuitive, other studies have shown no increase in balance with more simple balance exercises, possibly due to a More >
The Best Exercises for Rotator Cuff Strengthening
Mar 2nd
For years, the debate has continued on the ‘best’ exercises for strengthening shoulder muscles. Using electromyography (EMG) to measure muscle activity, researchers have attempted to determine which exercises have the highest levels of muscles activity for strengthening exercises. Several studies have examined EMG of common shoulder exercises to find the best exercises to strengthen the rotator cuff; in particular, the supraspinatus muscle. The “empty can” or “full can” exercises have been the most commonly performed exercise for supraspinatus strengthening, but controversy still exists in the literature.
While high muscle activation levels are often desirable, what’s more important is the relative activation of other muscles during the movement. For example, Dr. Michael Reinold and colleagues suggested in their 2007 paper that a good rotator cuff exercise should produce the greatest supraspinatus activity while minimizing the deltoid activation. Theoretically, reducing deltoid activation decreases the upward shear of the humerus during arm elevation, which may be desirable when prescribing exercise to strengthen the suprapsinatus in impingement patients.
In a study published in Medicine and Science and Sports and Exercise, subjects performed 5 isometric exercises in random order while measuring the EMG activity of the deltoid, supraspinatus, and infraspinatus. The exercises were: full can, empty can, prone elevation, elastic external More >
