THE INFLUENCE OF EXERCISE ON THE SONOGRAM OF SKELETAL-MUSCLES

Aim The purpose of this study was to examine quantitatively the change of muscle thickness and echo intensity caused by muscle exercise in h ealthy persons. Method 16 healthy volunteers (7 women, 9 men), aged 23 to 37 years, underwent static exercises of the rectus abdominis, rect us femoris/vastus intermedius, and tibialis anterior muscles. In addit ion, the rectus femoris/vastus intermedius muscles were exercised dyna mically. Thicknesses of these muscles were measured before and during/ after exercise using the electronic caliper and computer-assisted gray -scale analysis of the echo signals. Results Short, maximal isometric contraction resulted in an increase of thickness by 5 to 18% depending on the examined muscle (p < 0.01). The echo intensity of the rectus f emoris and vastus intermedius muscles decreased significantly (-8% and -26%, p < 0.01). The increase of muscle thickness immediately after i sometric exercise for up to 90 s was significantly correlated to the d uration of contraction (r = 0.26 to 0.49, p < 0.05). Muscle echo inten sities did not significantly correlate with the duration of the contra ction. After dynamic exercise on a bicycle ergometer both thickness of the rectus femoris/vastus intermedius muscles (+12.5%, p < 0.01) and echo intensity of the vastus intermedius muscle increased (+ 19.5%, p < 0.01). The change of echo intensity of the vastus intermedius muscle after static and dynamic exercise was significantly different (-26% v s. + 18%, p < 0.001). Conclusion Muscle thickness increases during and after static its well as dynamic exercise. Echo intensity may be unch anged, decreased or increased, depending on the exercised muscle and m ode of exercise.