Force-velocity and length-tension properties of stimulated human quadriceps muscle in spinal cord injured children

The force-velocity and length-tension properties of electrically stimulated quadriceps muscles were determined in a pilot study with two teenage subjects with midthoracic spinal cord injuries. Percutaneous intramuscular electrodes were used to elicit maximal isometric and concentric isokinetic contractions over angles range from 20 degrees to 80 degrees of knee flexion and over speeds from 30 degrees to 150 degrees per second. Submaximal contractions were generated both eccentrically and concentrically. Maximal concentric moment-velocity-angle surfaces were found to be similar in all respects to force-velocity-length surfaces reported for isolated animal preparations. Submaximal profiles grossly approximated the characteristics of maximal contractions. For any joint angle, eccentric moments were generally greater than those produced isometrically or concentrically.<
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