COMPARATIVE STUDY
JOURNAL ARTICLE

Muscle activation differences between eccentric and concentric isokinetic exercise

E Kellis, V Baltzopoulos
Medicine and Science in Sports and Exercise 1998, 30 (11): 1616-23
9813875

PURPOSE: The purpose of this study was to compare electromyographic (EMG) activity and joint moment of agonists and antagonists between isokinetic eccentric and concentric knee muscle actions.

METHODS: Twelve females (20.5 +/- 2.9 yr) performed maximum knee extension and flexion effort on a Biodex dynamometer isometrically and at concentric and eccentric angular velocities ranging from 30 degrees.s-1 to 150 degrees.s-1. EMG activity of vastus lateralis, rectus femoris, vastus medialis, and hamstrings was also recorded. The moment and agonist EMG values were normalized as a percentage of the maximum isometric values. The antagonist EMG was normalized as a percentage of the IEMG activity of the same muscle group when acting as agonist at the same angular velocity and angular position and taking into consideration the effects of muscle action.

RESULTS: Three-way ANOVA designs indicated significantly greater normalized eccentric moments compared with concentric moments (P < 0.05), whereas the eccentric normalized integrated EMG (IEMG) of agonists and antagonists was significantly lower compared with the respective concentric IEMG values (P < 0.05). These differences were more evident at fast angular velocities.

CONCLUSIONS: The present results demonstrate that neural activation and the resulting muscular action are different between isokinetic eccentric and concentric tests and depend also on the angular velocity of the movement. The antagonist IEMG activity is different depending on the muscle examined. The IEMG activity of the antagonists in this study indicate that the antagonist activity is an important factor that affects the resultant joint moment during isolated isokinetic maximum voluntary joint movements.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Trending Papers

Remove bar
Read by QxMD icon Read
9813875
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"