Abstract
The purpose of this study was to determine if differences occur in electrical activity of muscle at low levels of contraction in a 48-hour period following eccentric and concentric contractions. Specific purposes of this investigation were to determine: (a) the effects of eccentric and concentric exercise on the electrical activity during a 48-hour period, (b) the effects on the electrical activity when the exercise protocol is performed in the morning or at night, and (c) the effect of static stretching of sore muscles on the electrical activity at 48 hours following exercise. The 12 subjects who volunteered for this study were randomly assigned to 4 groups: (a) exercise that at night followed by a control test, (b) exercise test in the morning followed by a control test, (c) control test followed by a night exercise test, and (d) control test followed by a morning exercise test. Recordings of muscle electrical activity of the quadriceps muscles were made at zero hour, immediate post-exercise or no-exercise (NE), 1, 12, 24, and 48 hours post-exercise or NE. The recordings were made with the subjects seated with the leg being tested lifted just to the tip of the toe. After the 48-hour period, subjects performed a static stretching technique of the quadriceps muscles. Recordings were made of the electrical activity post-stretch. Univariate analyses of variance for a three-factor factorial with repeated measures on the last two factors were used in analyzing the dependent variables of rmsEMG and MPF. Results indicated no significant difference between any factors of the dependent variable rmsEMG. However, there was a significant three-way interaction (p < .05) between the factors of the dependent variables MPF; therefore, simple main effects were investigated. Results indicated a significant difference (p < .05) within the morning level; within all four levels of mode, control concentric, exercise concentric, control eccentric, and exercise eccentric; and within the zero and 24-hour levels of time. Results of the a priori contrasts between the post-stretch value of time and the average of the other time values indicated a significant (p < .05) decrease in electrical activity post-stretch for both rmsEMG and MPF.
Berry, Carolynn Blount (1985). The effects of eccentric and concentric contraction, testing time, and static stretching on the course of delayed muscle soreness. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -439093.