Massage reduces pain perception and hyperalgesia in experimental muscle pain: a randomized, controlled trial

Heightened pain sensitivity in individuals with signs and symptoms of carpal tunnel syndrome and the relationship to clinical outcomes following a manual therapy intervention

Neurophysiological responses related to lessening of pain sensitivity are a suggested mechanism of manual therapy. Prior studies have observed generalized lower pain thresholds associated with carpal tunnel syndrome (CTS) in comparison to healthy controls. The present study sought to determine whether similar findings were present in suprathreshold measures and measures specific to central integration of pain (temporal summation and after sensations). Additionally, we wished to determine whether measures of pain sensitivity were related to clinical outcomes in participants with signs and symptoms of CTS receiving a manual therapy intervention. Individuals with signs and symptoms of CTS reported greater pain sensitivity to suprathreshold measures of mechanical pain, temporal summation, and after sensation in comparison to healthy controls. Immediate lessening of mechanical pain sensitivity and after sensations in response to a manual therapy intervention and 3-week attenuation of temporal summation following a 3-week course of manual therapy were associated with 3-week changes in clinical pain intensity in participants with signs and symptoms of CTS. These findings suggest heightened pain sensitivity across several parameters may be associated with CTS. Furthermore, changes in mechanical pain, after sensation, and temporal summation may be related to improvements in clinical outcomes.

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.

The influence of a series of five dry cupping treatments on pain and mechanical thresholds in patients with chronic non-specific neck pain--a randomised controlled pilot study

Background

In this preliminary trial we investigated the effects of dry cupping, an ancient method for treating pain syndromes, on patients with chronic non-specific neck pain. Sensory mechanical thresholds and the participants' self-reported outcome measures of pain and quality of life were evaluated.

Methods

Fifty patients (50.5 ± 11.9 years) were randomised to a treatment group (TG) or a waiting-list control group (WL). Patients in the TG received a series of 5 cupping treatments over a period of 2 weeks; the control group did not. Self-reported outcome measures before and after the cupping series included the following: Pain at rest (PR) and maximal pain related to movement (PM) on a 100-mm visual analogue scale (VAS), pain diary (PD) data on a 0-10 numeric rating scale (NRS), Neck Disability Index (NDI), and health-related quality of life (SF-36). In addition, the mechanical-detection thresholds (MDT), vibration-detection thresholds (VDT), and pressure-pain thresholds (PPT) were determined at pain-related and control areas.

Results

Patients of the TG had significantly less pain after cupping therapy than patients of the WL group (PR: Δ-22.5 mm, p = 0.00002; PM: Δ-17.8 mm, p = 0.01). Pain diaries (PD) revealed that neck pain decreased gradually in the TG patients and that pain reported by the two groups differed significantly after the fifth cupping session (Δ-1.1, p = 0.001). There were also significant differences in the SF-36 subscales for bodily pain (Δ13.8, p = 0.006) and vitality (Δ10.2, p = 0.006). Group differences in PPT were significant at pain-related and control areas (all p < 0.05), but were not significant for MDT or VDT.

Conclusions

A series of five dry cupping treatments appeared to be effective in relieving chronic non-specific neck pain. Not only subjective measures improved, but also mechanical pain sensitivity differed significantly between the two groups, suggesting that cupping has an influence on functional pain processing.

Trial registration

The trial was registered at clinicaltrials.gov (NCT01289964).

Pressure and activity-related allodynia in delayed-onset muscle pain

OBJECTIVES

Muscle pain from different activities was tested with the muscle pain expected to vary in ways that may clarify mechanisms of activity-induced exacerbation of myofascial pain.

METHODS

Participants [N=20; 45% women; 23 y old (SD=2.09)] consented to participate in a 6 session protocol. Bilateral muscle pain ratings and pressure pain thresholds (PPTs) were collected before and for 4 days after lengthening (ie, eccentric) muscle contractions were completed with the nondominant elbow flexors to induce delayed-onset muscle pain. The muscle pain ratings were collected with the arms in several conditions (eg, resting, moving, and contracting in a static position) and PPTs were collected with the arms.

RESULTS

In the ipsilateral arm, muscle pain ratings at rest and during activity significantly increased whereas PPTs significantly decreased after the eccentrics (ηs=0.17 to 0.54). The greatest increases in pain occurred during arm extension without applied load, in which there was more stretching but less force than isometrics. In the contralateral arm, neither muscle pain nor PPTs changed from baseline.

DISCUSSION

These results resemble earlier electrophysiology studies showing differential sensitization across stimuli and support that increased depth of information about aggravating activities from clinical patients is needed.

Pressure pain threshold mapping of the trapezius muscle reveals heterogeneity in the distribution of muscular hyperalgesia after eccentric exercise

This study aimed at investigating in details the spatial characteristics of muscular hyperalgesia after development of delayed onset muscle soreness (DOMS) in the trapezius muscle. High density pressure pain mapping consisting of 36 pain pressure threshold (PPT) recording points were assessed over the trapezius muscle from 20 subjects. PPT were recorded before, immediately after and 24h after eccentric exercise/rest for the exercise group (N=10) and the control group (N=10). A 36 points geometric grid was used on both the exercise and control groups. The eccentric exercise used to elicit DOMS consisted of 50 contractions against a downward pressing force at 100% maximum voluntary contraction in bouts of 10 contractions followed by 2 min break. For the exercise group, PPT values decreased significantly over time for all points (P<0.001) but not for the control group. At baseline, both muscle belly sites and upper part of the trapezius were more sensitive than muscle belly sites and middle and lower parts (P<0.001 for both). The hyperalgesia was also mostly developed in the muscle belly sites (P<0.001), further enhancing its position as the most sensitive part of the muscle. The present results showed the topographical distribution of pressure pain sensitivity over the trapezius muscle and also that hyperalgesia developed in a heterogeneous manner over the trapezius muscle in response to eccentric exercise underlining sensory partitioning of the muscle. The technique of high density pressure pain topographical mappings can be helpful in characterizing muscle hyperalgesia and its heterogeneity.

A randomized sham-controlled trial of a neurodynamic technique in the treatment of carpal tunnel syndrome

STUDY DESIGN

Randomized, controlled trial.

OBJECTIVES

To assess the believability of a novel sham intervention for a neurodynamic technique (NDT) in participants with signs and symptoms of carpal tunnel syndrome (CTS). Additionally, we wished to assess a potential mechanism of NDT (hypoalgesia) and to compare outcomes related to clinical pain and upper extremity disability between NDT and a sham intervention.

BACKGROUND

Preliminary evidence suggests that NDT is effective in the treatment of CTS. A sham-controlled study is lacking from the literature and could provide insight to the efficacy of NDT, as well as the corresponding mechanisms.

METHODS

Participants with signs and symptoms consistent with CTS provided baseline measures of expectation, clinical pain intensity, upper extremity disability, and experimental pain sensitivity. Participants were then randomly assigned to receive either a NDT known to anatomically stress the median nerve or a sham technique intended to minimize stress to the median nerve. Following brief exposure to the assigned technique, expectation was reassessed to observe for group-dependent changes. Participants received the assigned intervention over 3 weeks. Additionally, all participants received a prefabricated wrist splint for their involved hands, with instructions to sleep in the splint and to wear it during painful activities when awake. Following 3 weeks of the assigned intervention and splint wear, baseline measures were reassessed and participants were asked which intervention they believed they had received.

RESULTS

Forty females agreed to participate. Expectations for pain relief and perceived group assignment were similar between the groups. Within-session decreases in clinical pain intensity and pressure pain sensitivity were observed independent of group assignment. Reduction of temporal summation was observed only in participants receiving NDT. Significant improvements in clinical pain intensity and upper extremity disability were observed at 3 weeks, independent of group assignment.

CONCLUSION

The sham intervention was successful in blinding the participants. Immediate changes in pain sensitivity and intensity and 3-week changes in clinical pain intensity and upper extremity disability associated with NDT were equivalent to a sham intervention to which the participants were adequately blinded. Conversely, reduction of temporal summation was only observed in participants receiving the NDT, suggesting the potential of a favorable neurophysiological effect.

BounceBack capsules for reduction of DOMS after eccentric exercise: a randomized, double-blind, placebo-controlled, crossover pilot study

BACKGROUND

Delayed onset muscle soreness (DOMS) is muscle pain and discomfort experienced approximately one to three days after exercise. DOMS is thought to be a result of microscopic muscle fiber tears that occur more commonly after eccentric exercise rather than concentric exercise. This study sought to test the efficacy of a proprietary dietary supplement, BounceBack, to alleviate the severity of DOMS after standardized eccentric exercise.

METHODS

The study was a randomized, double-blind, placebo-controlled, crossover study. Ten healthy community-dwelling untrained subjects, ranging in age from 18-45 years, were enrolled. Mean differences within and between groups were assessed inferentially at each data collection time-point using t-tests for all outcome measures.

RESULTS

In this controlled pilot study, intake of BounceBack capsules for 30 days resulted in a significant reduction in standardized measures of pain and tenderness post-eccentric exercise compared to the placebo group. There were trends towards reductions in plasma indicators of inflammation (high sensitivity C-reactive protein) and muscle damage (creatine phosphokinase and myoglobin).

CONCLUSION

BounceBack capsules were able to significantly reduce standardized measures of pain and tenderness at several post-eccentric exercise time points in comparison to placebo. The differences in the serological markers of DOMS, while not statistically significant, appear to support the clinical findings. The product appears to have a good safety profile and further study with a larger sample size is warranted based on the current results.