Short- and long-term effects of exercise on neck muscle function in cervical radiculopathy:A randomized clinical trial

OBJECTIVE: To compare short- and long-term changes in neck muscle endurance, electromyography measures of neck muscle activation and fatigue and ratings of fatigue and pain after neck-specific training or physical activity in people with cervical radiculopathy.DESIGN: Randomized clinical trial.SUBJECTS/PATIENTS: Seventy-five patients with cervical radiculopathy.METHODS: Patients underwent neck-specific training in combination with a cognitive behavioural approach or prescribed physical activity over a period of 14 weeks. Immediately after the intervention and 12 months later, surface electromyography was recorded from neck flexor and extensor muscles during neck endurance tests. Time to task failure, amplitude and median frequency of the electromyography signal, and subjective fatigue and pain ratings were analysed in 50 patients who completed at least one follow-up.RESULTS: A significant increase in neck flexor endurance time was observed for both groups at 14 weeks compared with baseline and this was maintained at the 12-month follow-up (p &lt; 0.005). No change was identified for the slope of the median frequency. For the neck-specific training group, splenius capitis was less active during neck flexion at both follow-ups (p &lt; 0.01), indicating reduced muscle co-activation.CONCLUSION: Both specific and general exercise increased neck flexor endurance, but neck-specific training only reduced co-activation of antagonist muscles during sustained neck flexion.</p

Mechanisms of recovery after neck‐specific or general exercises in patients with cervical radiculopathy

Background The mechanisms of action that facilitate improved outcomes after conservative rehabilitation are unclear in individuals with cervical radiculopathy (CR). This study aims to determine the pathways of recovery of disability with different exercise programs in individuals with CR. Methods We analysed a dataset of 144 individuals with CR undergoing conservative rehabilitation. Eleven variables collected at baseline, 3, 6 and 12 months follow‐up were used to build a Bayesian Network (BN) model: treatment group (neck‐specific vs. general exercises), age, sex, self‐efficacy, catastrophizing, kinesiophobia, anxiety, neck–arm pain intensity, headache pain intensity and disability. The model was used to quantify the contribution of different mediating pathways on the outcome of disability at 12th months. Results All modelled variables were conditionally independent from treatment groups. A one‐point increase in anxiety at 3rd month was associated with a 2.45‐point increase in 12th month disability (p <.001). A one‐point increase in head pain at 3rd month was associated with a 0.08‐point increase in 12th month disability (p <.001). Approximately 83% of the effect of anxiety on disability was attributable to self‐efficacy. Approximately 88% of the effect of head pain on disability was attributable to neck–arm pain. Conclusions No psychological or pain‐related variables mediated the different treatment programs with respect to the outcome of disability. Thus, the specific characteristics investigated in this study did not explain the differences in mechanisms of effect between neck‐specific training and prescribed physical activity. The present study provides candidate modifiable mediators that could be the target of future intervention trials. Significance Psychological and pain characteristics did not differentially explain the mechanism of effect that two exercise regimes had on disability in individuals with cervical radiculopathy. In addition, we found that improvements in self‐efficacy was approximately five times more important than that of neck–arm pain intensity in mediating the anxiety‐disability relationship. A mechanistic understanding of recovery provides candidate modifiable mediators that could be the target of future intervention trials. Trials registration ClinicalTrials.gov identifier: NCT01547611

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements