Affiliation:
1. University Center for Assistance, Teaching and Research (CUADI) University of Gran Rosario Rosario Argentina
2. Institute for Research and Development on Bioengineering and Bioinformatics (IBB) CONICET‐UNER Oro Verde Argentina
3. Center for Rehabilitation Engineering and Neuromuscular and Sensory Research (CIRINS) National University of Entre Ríos (UNER) Oro Verde Argentina
4. Laboratory of Electromagnetic Fields in Biomedical Applications (LACEMAB) National University of Entre Ríos (UNER) Oro Verde Argentina
5. Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Faculty of Medicine Aalborg University (AAU) Aalborg Denmark
Abstract
AbstractBackgroundCommonly used models for eliciting muscle pain involve the injection of algesic substances or the induction of delayed onset muscle soreness. The former require invasive procedures, and the time frame for pain induction and subsidence in the latter can be inconvenient. This study presents a detailed spatiotemporal characterization of a new experimental model of muscle pain based on short‐wave diathermy (SWD), developed to overcome the limitations of existing models.MethodsThe shoulder was selected as target site and the effects of the model were tested in two sessions to assess its reliability. Pain intensity profiles were recorded during the application of SWD, and changes in pressure pain threshold (PPT) in the infraspinatus muscle, together with pain intensity, duration, and quality were assessed 30 min after induction.ResultsSWD‐induced pain intensity scores averaged 4 points on a visual analogue scale, whereas PPT showed a consistent decrease of about 25% relative to baseline values. Pain was localized in the shoulder area, and was described as continuous, dull, well‐delimited, heavy, and bearable. Pain lasted for an average of 145 min without requiring reinduction and was reliably elicited in both experimental sessions.ConclusionSWD can be used to elicit experimental muscle pain in a non‐invasive, long‐lasting, and reliable way and allows for repeated within‐ and between‐session testing in the shoulder.Significance StatementSWD produces deep heating in muscles by converting electromagnetic energy to thermal energy. It was previously shown that it can be used to elicit experimental pain in the forearm muscles, and the present study demonstrates that this can be reliably generalized to other body sites, such as the shoulder. Furthermore, SWD application is non‐invasive and presents a convenient time frame for pain induction and subsidence, thus overcoming limitations associated with traditional muscle pain models.