Vibration-Induced Afferent Activity Augments Delayed Onset Muscle Allodynia

Susceptibility to movement-evoked pain following resistance exercise

Objective

To investigate the: (1) role of basic muscle pain sensitivity and psychological factors in the prediction of movement-evoked pain (MEP) following delayed onset muscle soreness (DOMS), and (2) association of MEP with changes in systemic muscle pain sensitivity following DOMS induction.

Methods

Fifty-one participants were assigned to either eccentric resistance exercise or control groups. They completed questionnaires evaluating psychological distress and underwent muscle pain sensitivity evaluation by the pressure pain threshold (PPT) test at the exercised and remote muscles, before and 24 hours following the intervention. MEP intensity was determined in response to lifting a 3kg canister using a visual analogue scale (VAS).

Results

The exercise group demonstrated MEP intensity of 5/10 on VAS and reduced PPTs at the main exercised muscle (p<0.001). A regression tree analyses revealed that the level of anxiety trait predicted a higher MEP intensity. A secondary analysis showed that 53% participants who were DOMS responders (MEP > mild intensity; ≥ 3/10 VAS) exhibited decreased PPTs in the exercised (p<0.001) and remote (p = 0.027) muscles following eccentric exercise. Characterization of DOMS responders revealed that, at baseline, they had lower PPTs in the exercised (p = 0.004) and remote (p = 0.001) muscles and reported higher psychological distress i.e., anxiety trait and depression symptoms (p<0.05), compared to non-responders. A regression analysis revealed that lower PPT or high levels of anxiety trait increased the probability to become a responder (p = 0.001).

Conclusions

Susceptibility to MEP following DOMS is determined by muscle pain hypersensitivity and high levels of anxiety trait. MEP at the early stage of DOMS is linked with an increase in systemic muscle pain sensitivity suggestive of central mechanisms. This knowledge is valuable in translating science into clinical musculoskeletal pain management.

Improving characterization and diagnosis quality of myofascial pain syndrome: a systematic review of the clinical and biomarker overlap with delayed onset muscle soreness

INTRODUCTION

Myofascial pain syndrome (MPS) is one of the most common conditions of chronic musculoskeletal pain, yet its mechanisms are still poorly understood. Delayed Onset Muscle Soreness (DOMS) is also a regional pain syndrome that has clinical similarities to MPS, but has been better investigated. Emerging research suggests that DOMS may be a valid experimental model for studying MPS; however, a comparison of the similarities and differences of these two conditions has previously not been performed. Herein, we aimed to identify the similarities and differences in the clinical features and biomarkers between DOMS and MPS in order to better define MPS and identify future areas of (DOMS-informed) MPS research.

EVIDENCE ACQUISITION

In order to identify similarities and differences in the clinical manifestation and biomarkers of DOMS and MPS, scoping literature searches were performed using Medline (1965-2019), Embase (1966-2019) and Central (1966-2019) databases. Fifty-three full-text articles were reviewed out of the 2836 articles retrieved in the search.

EVIDENCE SYNTHESIS

A scoping review of the literature demonstrated that DOMS and MPS similarly present as conditions of musculoskeletal pain that are associated with decreased strength and limited range of motion. However, while taut bands and discrete tender spots were described in DOMS, none of the studies reviewed have characterized whether these tender points represent the classic myofascial trigger point phenomenon observed in MPS. Certain systemic circulation biomarkers, including inflammatory cytokines and growth factors, were commonly elevated in MPS and DOMS; further research is needed to determine if other biomarkers that are currently characterized in DOMS are useful to enhance the clinical evaluation of MPS.

CONCLUSIONS

DOMS and MPS share clinical and biomarker similarities suggesting that DOMS may be a useful model for studying MPS.

Does vibration benefit delayed-onset muscle soreness?: a meta-analysis and systematic review

OBJECTIVE

Delayed-onset muscle soreness (DOMS) is a symptom of exercise-induced muscle injury that is commonly encountered in athletes and fitness enthusiasts. Vibration is being increasingly used to prevent or treat DOMS. We therefore carried out a meta-analysis to evaluate the effectiveness of vibration in patients with DOMS.

METHOD

We searched nine databases for randomized controlled trials of vibration in DOMS, from the earliest date available to 30 May 2018. Visual analogue scale (VAS) and creatine kinase (CK) levels were set as outcome measures.

RESULTS

The review included 10 identified studies with 258 participants. The meta-analysis indicated that vibration significantly improved the VAS at 24, 48, and 72 hours after exercise, and significantly improved CK levels at 24 and 48 hours, but not at 72 hours.

CONCLUSION

Vibration is a beneficial and useful form of physiotherapy for alleviating DOMS. However, further studies are needed to clarify the role and mechanism of vibration in DOMS.

Parameters of vibration stimulation for the relief of pain of different origins and locations

The use of vibration stimulation in alleviating pain is an issue appearing more and more often in modern rehabilitation. The aim of the work was to review literature regarding the therapeutic usage of vibrations in analgesic activity. Searches based on the effect of alleviating pain with the help of vibrotherapy in the therapy of diseases of various origins and localizations, as well as with various physical therapy treatments and modalities. The most important parameters were determined, such as: frequency, amplitude, places of application, and exposure time, and were described on the basis of selected tests. Both the Polish and English-language literature has been discussed. Most of the studies were English-language (over 93%). The searches were carried out among the following databases: Medline, Embase, Cochrane, ScienceDirect, PubMed, IEEE Xplore, Wiley Online Library. The key words used were: pain, vibration, WBV, analgesics. The mentioned sources were qualified on the basis of: availability, data verification, selection of research material and regularity of update. While acute pain is, by definition, a short and self-limiting process, chronic pain begins to dominate life and concerns the patient and his/her family. In addition to significant deterioration in quality of life, chronic pain imposes a large financial burden. The use of vibrotherapy can be a solution. Therefore, it is proposed to further analyse the parameters of vibrotherapy in analgesic activity, which may lay the foundation for "personalized pain relief medicine", which will clearly define the standards of vibrational therapy parameters. pain, vibration, WBV, analgesics

No Effect of Acupuncture in the Relief of Delayed-Onset Muscle Soreness: Results of a Randomized Controlled Trial

BACKGROUND

Delayed-onset muscle soreness (DOMS) is a common symptom in people participating in exercise, sport, or recreational physical activities. Several remedies have been proposed to prevent and alleviate DOMS.

DESIGN AND METHODS

A five-arm randomized controlled study was conducted to examine the effects of acupuncture on eccentric exercise-induced DOMS of the biceps brachii muscle. Participants were recruited through convenience sampling of students and general public. Participants were randomly allocated to needle, laser, sham needle, sham laser acupuncture, and no intervention. Outcome measures included pressure pain threshold (PPT), pain intensity (visual analog scale), and maximum isometric voluntary force.

RESULTS

Delayed-onset muscle soreness was induced in 60 participants (22 females, age 23.6 ± 2.8 years, weight 66.1 ± 9.6 kg, and height 171.6 ± 7.9 cm). Neither verum nor sham interventions significantly improved outcomes within 72 hours when compared with no treatment control (P > 0.05).

CONCLUSIONS

Acupuncture was not effective in the treatment of DOMS. From a mechanistic point of view, these results have implications for further studies: (1) considering the high-threshold mechanosensitive nociceptors of the muscle, the cutoff for PPT (5 kg/cm) chosen to avoid bruising might have led to ceiling effects; (2) the traditional acupuncture regimen, targeting muscle pain, might have been inappropriate as the DOMS mechanisms seem limited to the muscular unit and its innervation. Therefore, a regionally based regimen including an intensified intramuscular needling (dry needling) should be tested in future studies, using a higher cutoff for PPT to avoid ceiling effects.

Whole-Body Vibration While Squatting and Delayed-Onset Muscle Soreness in Women

CONTEXT

Research into alleviating muscle pain and symptoms in individuals after delayed-onset muscle soreness (DOMS) has been inconsistent and unsuccessful in demonstrating a useful recovery modality.

OBJECTIVE

To investigate the effects of short-term whole-body vibration (WBV) on DOMS over a 72-hour period after a high-intensity exercise protocol.

DESIGN

Randomized controlled clinical trial.

SETTING

University laboratory.

PATIENTS OR OTHER PARTICIPANTS

Thirty women volunteered to participate in 4 testing sessions and were assigned randomly to a WBV group (n = 16; age = 21.0 ± 1.9 years, height = 164.86 ± 6.73 cm, mass = 58.58 ± 9.32 kg) or a control group (n = 14; age = 22.00 ± 1.97 years, height = 166.65 ± 8.04 cm, mass = 58.69 ± 12.92 kg).

INTERVENTION(S)

Participants performed 4 sets to failure of single-legged split squats with 40% of their body weight to induce muscle soreness in the quadriceps. The WBV or control treatment was administered each day after DOMS.

MAIN OUTCOME MEASURE(S)

Unilateral pressure-pain threshold (PPT), range of motion (ROM), thigh circumference, and muscle-pain ratings of the quadriceps were collected before and for 3 days after high-intensity exercise. Each day, we collected 3 sets of measures, consisting of 1 measure before the WBV or control treatment protocol (pretreatment) and 2 sets of posttreatment measures.

RESULTS

We observed no interactions for PPT, thigh circumference, and muscle pain (P > .05). An interaction was found for active ROM (P = .01), with the baseline pretreatment measure greater than the measures at baseline posttreatment 1 through 48 hours posttreatment 2 in the WBV group. For PPT, a main effect for time was revealed (P < .05), with the measure at baseline pretreatment greater than at 24 hours pretreatment and all other time points for the vastus medialis, greater than 24 hours pretreatment through 48 hours posttreatment 2 for the vastus lateralis, and greater than 24 hours pretreatment and 48 hours pretreatment for the rectus femoris. For dynamic muscle pain, we observed a main effect for time (P < .001), with the baseline pretreatment measure less than the measures at all other time points. No main effect for time was noted for thigh circumference (P = .24). No main effect for group was found for any variable (P > .05).

CONCLUSIONS

The WBV treatment approach studied did not aid in alleviating DOMS after high-intensity exercise. Further research is needed in various populations.

Suprathreshold heat pain response predicts activity-related pain, but not rest-related pain, in an exercise-induced injury model

Exercise-induced injury models are advantageous for studying pain since the onset of pain is controlled and both pre-injury and post-injury factors can be utilized as explanatory variables or predictors. In these studies, rest-related pain is often considered the primary dependent variable or outcome, as opposed to a measure of activity-related pain. Additionally, few studies include pain sensitivity measures as predictors. In this study, we examined the influence of pre-injury and post-injury factors, including pain sensitivity, for induced rest and activity-related pain following exercise induced muscle injury. The overall goal of this investigation was to determine if there were convergent or divergent predictors of rest and activity-related pain. One hundred forty-three participants provided demographic, psychological, and pain sensitivity information and underwent a standard fatigue trial of resistance exercise to induce injury of the dominant shoulder. Pain at rest and during active and resisted shoulder motion were measured at 48- and 96-hours post-injury. Separate hierarchical models were generated for assessing the influence of pre-injury and post-injury factors on 48- and 96-hour rest-related and activity-related pain. Overall, we did not find a universal predictor of pain across all models. However, pre-injury and post-injury suprathreshold heat pain response (SHPR), a pain sensitivity measure, was a consistent predictor of activity-related pain, even after controlling for known psychological factors. These results suggest there is differential prediction of pain. A measure of pain sensitivity such as SHPR appears more influential for activity-related pain, but not rest-related pain, and may reflect different underlying processes involved during pain appraisal.

An investigation into the peripheral substrates involved in the tactile modulation of cutaneous pain with emphasis on the C-tactile fibres

We recently demonstrated the emergence of touch-evoked pain (allodynia) during innocuous tactile stimulation of the skin overlying a painful muscle. This effect appeared to depend on a class of low-threshold unmyelinated mechanoafferents, termed C-tactile fibres (CT). In this study, we investigated the peripheral neurocircuitry of allodynia when pain originates in the skin. Psychophysical observations were carried out in 28 healthy subjects. Cutaneous pain was induced by infusing hypertonic saline (HS: 5 %) into the hairy skin overlying tibialis anterior muscle. An innocuous tactile stimulus (sinusoidal vibration: 200 Hz-200 μm) was concurrently applied to the hairy skin ~90 mm distal to the HS-infusion site. The contribution of different fibre classes to allodynia was determined by employing conduction blocks of myelinated (sciatic nerve compression) and unmyelinated (intradermal anaesthesia, Xylocaine 0.25 %) fibres. In absence of background nociceptive input, vibration was reported as non-painful. During cutaneous pain, vibration evoked a significant and reproducible increase in the overall pain intensity (allodynia). The blockade of myelinated fibres abolished the vibration sense, but the vibration-evoked allodynia persisted. Conversely, the blockade of unmyelinated cutaneous fibres abolished the allodynia (while the myelinated fibres were conducting or not). On the basis of these findings, in addition to our earlier work, we conclude that the allodynic effect of CT-fibre activation is not limited to nociceptive input arising from the muscle, but can be equally realized when pain originates in the skin. These results denote a broader role of CTs in pain modulation.

Human experimental pain models for assessing the therapeutic efficacy of analgesic drugs

Pain models in animals have shown low predictivity for analgesic efficacy in humans, and clinical studies are often very confounded, blurring the evaluation. Human experimental pain models may therefore help to evaluate mechanisms and effect of analgesics and bridge findings from basic studies to the clinic. The present review outlines the concept and limitations of human experimental pain models and addresses analgesic efficacy in healthy volunteers and patients. Experimental models to evoke pain and hyperalgesia are available for most tissues. In healthy volunteers, the effect of acetaminophen is difficult to detect unless neurophysiological methods are used, whereas the effect of nonsteroidal anti-inflammatory drugs could be detected in most models. Anticonvulsants and antidepressants are sensitive in several models, particularly in models inducing hyperalgesia. For opioids, tonic pain with high intensity is attenuated more than short-lasting pain and nonpainful sensations. Fewer studies were performed in patients. In general, the sensitivity to analgesics is better in patients than in healthy volunteers, but the lower number of studies may bias the results. Experimental models have variable reliability, and validity shall be interpreted with caution. Models including deep, tonic pain and hyperalgesia are better to predict the effects of analgesics. Assessment with neurophysiologic methods and imaging is valuable as a supplement to psychophysical methods and can increase sensitivity. The models need to be designed with careful consideration of pharmacological mechanisms and pharmacokinetics of analgesics. Knowledge obtained from this review can help design experimental pain studies for new compounds entering phase I and II clinical trials.

Muscle soreness and delayed-onset muscle soreness

Immediate and delayed-onset muscle soreness differ mainly in chronology of presentation. Both conditions share the same quality of pain, eliciting and relieving activities and a varying degree of functional deficits. There is no single mechanism for muscle soreness; instead, it is a culmination of 6 different mechanisms. The developing pathway of DOMS begins with microtrauma to muscles and then surrounding connective tissues. Microtrauma is then followed by an inflammatory process and subsequent shifts of fluid and electrolytes. Throughout the progression of these events, muscle spasms may be present, exacerbating the overall condition. There are a multitude of modalities to manage the associated symptoms of immediate soreness and DOMS. Outcomes of each modality seem to be as diverse as the modalities themselves. The judicious use of NSAIDs and continued exercise are suggested to be the most reliable methods and recommended. This review article and each study cited, however, represent just one part of the clinician's decisionmaking process. Careful affirmation of temporary deficits from muscle soreness is not to be taken lightly, nor is the advisement and medical management of muscle soreness prescribed by the clinician.