Introduction: Delayed onset muscle soreness (DOMS) is caused by increased intensity or
volume of exercise. It most commonly occurs after eccentric muscle contraction, 8 to 20 hours
after exercise, peaks between 24 and 48 hours after, and then slowly subsides. It manifests as
muscle pain with signs of inflammation, decreased strength, and reduced range of motion.
DOMS is usually alleviated once it has developed but there are some methods we can use to
prevent or at least limit the development. One of the newest techniques is local vibration therapy
(LVT) but there is not enough experimental evidence of its effectiveness. Purpose: This study
of several cases aims to pilot a research protocol for studying the effects of preventive local
vibration therapy on the development of DOMS and potential changes in voluntary contractility
of skeletal muscles after intensive eccentric exercise. Methods: There were four subjects in this
study. DOMS in their elbow flexors of both upper limbs was induced with four sets of ten
repetitions of supramaximal eccentric elbow extensions. Before exercise, we measured
pressure-pain threshold and muscle performance using an isokinetic dynamometer. These
measures were repeated 24, 48, and 72 hours later when we also measured DOMS intensity
using a visual analog scale. Just before the exercises, one minute of vibration therapy was
applied to the elbow flexors of the experimental arm while the control arm did not receive any
intervention. Results: Pain during isometric and isokinetic contractions was more intense on
the control arm but there were small differences. The changed time course of DOMS was
noticeable. The pressure-pain threshold was higher on the experimental arm than on the control
arm. Mean values of voluntary muscle contractions did not show visible improvements on the
experimental arm versus the control arm. Discussion and conclusion: The results show that
the use of vibration therapy slightly reduces the intensity of DOMS during voluntary
contractions but has no effects on maximal torque and strength during voluntary muscle
contraction. The pilot protocol showed that changes in unconscious and volunatry muscle
contractility can be detected after intense eccentric exercise, however a different application
protocol of vibration therapy needs to be used in the future to determine its effectiveness. The
results of the present pilot study show large individual differences, therefore testing on a larger
sample is necessary.
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