ISOKINETIC ECCENTRIC EXERCISE

The development of active isokinetic dynamometers has allowed the asse ssment of muscular moment under eccentric activations that have differ ent characteristics to concentric actions. It is well documented that at a given angular velocity the eccentric moment is greater than the c orresponding concentric moment. The moment-velocity relationship under eccentric conditions has been investigated, with conflicting results. Particularly, eccentric moment was reported to remain similar to, or to increase or decrease with, increasing angular velocity. As with con centric actions, the reliability of isokinetic eccentric measurements is influenced by a number of factors such as gravity, preload force an d testing position. The velocity-specific effects of eccentric trainin g have not been extensively investigated. Based on current knowledge, eccentric exercise does not appear to be velocity-specific. Although t he mode specificity of both concentric and eccentric exercises have be en investigated, the resultant observations are conflicting. Eccentric training has been found to improve both concentric and eccentric stre ngth; yet, it has also been reported to improve only concentric or ecc entric strength. The reciprocal muscle group ratios under eccentric ac tions were found not to be influenced by angular velocity, but the sig nificant role of the eccentric/concentric moment ratio of each muscle has not been examined thoroughly. It is well documented that eccentric activations are associated with delayed muscle soreness and muscle da mage. A limited number of studies have reported that isokinetic eccent ric efforts may result in a lower amount of muscle soreness compared w ith other exercise modalities. Isokinetic dynamometers provide some un ique characteristics for rehabilitation applications. Examination of t he clinical application of eccentric exercise is limited. Consequently , the use of this exercise modality in prevention and assessment of mu sculoskeletal injuries should be investigated further.