Short-term cutaneous vasodilatory and thermosensory effects of topical methyl salicylate.

Introduction: Methyl salicylate, the main compound of wintergreen oil, is widely used in topical applications. However, its vascular and thermosensory effects are not fully understood. The primary aim was to investigate the effects of topical methyl salicylate on skin temperature (Tskin), skin microcirculation (MCskin) and muscle oxygen saturation (SmO2) compared to a placebo gel. The secondary aim was to assess thermosensory responses (thermal sensation, thermal comfort) and to explore to which extent these sensations correspond to the physiological responses over time. Methods: 21 healthy women (22.2 ± 2.9 years) participated in this single-blind, randomized controlled trial. Custom-made natural wintergreen oil (12.9%), containing methyl salicylate (>99%) and a placebo gel, 1 g each, were applied simultaneously to two paravertebral skin areas (5 cm × 10 cm, Th4-Th7). Tskin (infrared thermal imaging), MCskin (laser speckle contrast imaging) and SmO2 (deep tissue oxygenation monitoring) and thermosensation (Likert scales) were assessed at baseline (BL) and at 5-min intervals during a 45 min post-application period (T0-T45). Results: Both gels caused an initial decrease in Tskin, with Tskin(min) at T5 for both methyl salicylate (BL-T5: Δ-3.36°C) and placebo (BL-T5: Δ-3.90°C), followed by a gradual increase (p < .001). Methyl salicylate gel resulted in significantly higher Tskin than placebo between T5 and T40 (p < .05). For methyl salicylate, MCskin increased, with MCskin(max) at T5 (BL-T5: Δ88.7%). For placebo, MCskin decreased (BL-T5: Δ-17.5%), with significantly lower values compared to methyl salicylate between T0 and T45 (p < .05). Both gels had minimal effects on SmO2, with no significant differences between methyl salicylate and placebo (p > .05). Thermal sensation responses to topical methyl salicylate ranged from "cool" to "hot", with more intense sensations reported at T5. Discussion: The findings indicate that topical methyl salicylate induces short-term cutaneous vasodilation, but it may not enhance skeletal muscle blood flow. This study highlights the complex sensory responses to its application, which may be based on the short-term modulation of thermosensitive transient receptor potential channels.

Intramuscular Oxygenation and Muscle Activity of Extensor Carpi Radialis Brevis During Piano Performance: An Observational Study.

BACKGROUND: Repetitive piano movements have been associated with playing-related musculoskeletal disorders (PRMDs) such as forearm myalgia and symptoms of lateral epicondylopathy. Despite the high prevalence of PRMDs among pianists, there is poor understanding regarding the underlying physiological mechanisms. Intramuscular oxygenation may play a role in the development of PRMDs. Therefore, this observational study aimed to explore the effect variability of playing piano repertoire on the oxygenation of the extensor carpi radialis brevis (ECRB). METHODS: Surface electromyography (EMG) activity and intramuscular oxygenation data (using near-infrared spectroscopy, NIRS) of the left and right ECRB were recorded in 13 conservatory piano students (8 female, 5 male, mean age 23.54 ± 3.24 years) while playing piano repertoire (virtuoso piece or études) for 20 minutes. From the oxygenation data, relative changes (in the percentage of the baseline measurements at rest) were calculated. RESULTS: For all participants, the oxygenated hemoglobin of the left ECRB over the piano play presented an averaged decline to the baseline resting value, with a sample mean for left ECRB of -7.48% and -11.88% for the right ECRB, ranging from -15.53% to -2.00% and -19.12% to -3.93%, respectively. The deoxygenated hemoglobin ranged in the left ECRB from -5.39% to 39.14% and from -9.37% to 54.01% in the right ECRB. The change in total hemoglobin ranged from -5.35% to 16.80% for the left ECRB and -12.10% to 10.37% for the right ECRB. EMG activity (in % maximal voluntary contraction) presented a mean of 16.85% (range 11.86 to 24.43) for the left ECRB and 23.65% (range 14.46 to 37.91) for the right ECRB. This pilot study presented a Pearson's r between the averaged oxygenated hemoglobin and EMG of -0.60 for the right ECRB and -0.48 for the left ECRB. CONCLUSION: Piano performance induced an average decline in oxygenated hemoglobin in the left and right ECRB, which differed largely between the specific pieces played. The EMG activity can partially explain these differences. Further research is needed to explore the impact of a 'dynamic index' reflecting the piece's dynamic characteristics and the individual oxygenation characteristics.

Effects of 3-week repeated cold water immersion on leukocyte counts and cardiovascular factors: an exploratory study.

Aim: This exploratory study aimed to investigate the effects of a 3-week repeated cold water immersion (CWI) intervention on leukocyte counts and cardiovascular factors (mean arterial pressure [MAP], heart rate [HR]) in healthy men. Methods: A total of n = 12, non-cold-adapted men (age: 25.2 ± 4.0 years; height: 177.8 ± 5.6 cm; weight: 73.8 ± 6.5 kg) were randomly allocated to the CWI or control (CON) group. The CWI group underwent a 3-week repeated CWI intervention (12min at 7°C, 4x/week). The CON group did not receive any cold exposure or therapy. Total leukocyte numbers and proportions (neutrophils, basophils, eosinophils, monocytes, lymphocytes) and cardiovascular factors (MAP, HR) were assessed at baseline and after the 3-week intervention period. Results: Total leukocyte count decreased in CWI (p = 0.027, 95% CI -2.35 to -0.20 × 103/µL) and CON (p = 0.043, 95% CI -2.75 to -0.50 × 103/µL). CWI showed a decrease in neutrophil number (p = 0.028, 95% CI -1.55 to -0.25 × 103/µL) and proportion (p = 0.046, 95% CI -6.42 to 0.56%). In contrast, CON showed no significant change (p > 0.05). No differences were found for other leukocyte subtypes in CWI or CON (all p > 0.05). MAP (p = 0.028, 95% CI -17 to -8 mmHg) and HR (p = 0.027, 95% CI -7 to -2 bpm) were reduced in CWI, whereas CON showed no change (p > 0.05). Conclusion: The results suggest no relevant effects of 3-week repeated CWI on leukocyte counts in healthy men. Due to methodological limitations, the effects on the investigated cardiovascular factors remain unclear. Further studies with larger sample sizes are needed to examine the effects on immune function and cardiovascular health.

The effects of normobaric and hypobaric hypoxia on cognitive performance and physiological responses: A crossover study.

This partially randomised controlled, crossover study sought to investigate the effects of normobaric hypoxia (NH) and hypobaric hypoxia (HH) on cognitive performance, the physiological response at rest and after a 3-min step-test. Twenty healthy participants (10 females and 10 males, 27.6±6.2yrs, 73.6±13.7kg, 175.3±8.9cm) completed a cognitive performance test, followed by the modified Harvard-step protocol, in four environments: normobaric normoxia (NN; PiO2: 146.0±1.5mmHg), NH (PiO2: 100.9±1.3mmHg), HH at the first day of ascent (HH1: PiO2 = 105.6±0.4mmHg) and HH after an overnight stay (HH2: PiO2 = 106.0±0.5mmHg). At rest and/or exercise, SpO2, NIRS, and cardiovascular and perceptual data were collected. The cerebral tissue oxygenation index and the cognitive performance (throughput, accuracy, and reaction time) were not different between the hypoxic conditions (all p>0.05). In NH, SpO2 was higher compared to HH1 (ΔSpO2 NH vs HH1: 1.7±0.5%, p = 0.003) whilst heart rate (ΔHR NH vs HH2: 5.8±2.6 bpm, p = 0.03) and sympathetic activation (ΔSNSi NH vs HH2: 0.8±0.4, p = 0.03) were lower in NH compared to HH2. Heart rate (ΔHR HH1 vs HH2: 6.9±2.6 bpm, p = 0.01) and sympathetic action (ΔSNSi HH1 vs HH2: 0.9±0.4, p = 0.02) were both lower in HH1 compared to HH2. In conclusion, cognitive performance and cerebral oxygenation didn't differ between the hypoxic conditions. SpO2 was only higher in NH compared to HH1. In HH2, heart rate and sympathetic activation were higher compared to both NH and HH1. These conclusions account for a PiO2 between 100-106 mmHg.

Sex differences during a cold-stress test in normobaric and hypobaric hypoxia: A randomized controlled crossover study.

Cold and hypoxia are two stressors that are frequently combined and investigated in the scientific literature. Despite the growing literature regarding normobaric hypoxia (NH) and hypobaric hypoxia (HH), responses between females and males are less often evaluated. Therefore, this study aims to investigate the physiological sex differences following a cold-stress test under normoxia, normobaric- and hypobaric hypoxia. A total of n = 10 females (24.8 ± 5.1 years) and n = 10 males (30.3 ± 6.3 years) from a university population volunteered for this study. The cold-stress test (CST) of the right hand (15°C for 2 min) was performed using a randomised crossover design in normobaric normoxia, NH and HH. The change (∆) from baseline to post-CST up to 15 min was analysed for cutaneous vascular conductance (CVC) and the hands' skin temperature, whilst the mean values across time (post-CST up to 15 min) were assessed for peripheral oxygen saturation (SpO2), thermal sensation- and comfort. Pressure pain threshold (PPT) was assessed after the post-CST 15 min period. The hands' skin temperature drop was higher (p = 0.01) in the female group (∆3.3 ± 1.5°C) compared to the male group (∆1.9 ± 0.9°C) only in NH. Females (-0.9 ± 0.5) rated this temperature drop in NH to feel significantly colder (p = 0.02) compared to the males (-0.2 ± 0.7). No differences were observed between sexes in NN, NH, and HH for ∆CVC, SpO2, thermal comfort and PPT. In conclusion, females and males show similar reactions after a CST under normoxia and hypoxia. Sex differences were observed in the local skin temperature response and thermal sensation only in NH.

The Methodological Quality of Studies Investigating the Acute Effects of Exercise During Hypoxia Over the Past 40 years: A Systematic Review.

Exercise under hypoxia and the physiological impact compared to normoxia or hypoxia has gained attention in the last decades. However, methodological quality assessment of articles in this area is lacking in the literature. Therefore, this article aimed to evaluate the methodologic quality of trials studying exercise under hypoxia. An electronic search was conducted until December 2021. The search was conducted in PubMed, CENTRAL, and PEDro using the PICO model. (P) Participants had to be healthy, (I) exercise under normobaric or hypobaric hypoxia had to be (C) compared to exercise in normoxia or hypoxia on (O) any physiological outcome. The 11-item PEDro scale was used to assess the methodological quality (internal validity) of the studies. A linear regression model was used to evaluate the evolution of trials in this area, using the total PEDro score of the rated trials. A total of n = 81 studies met the inclusion criteria and were processed in this study. With a mean score of 5.1 ± 0.9 between the years 1982 and 2021, the mean methodological quality can be described as "fair." Only one study reached the highest score of 8/10, and n = 2 studies reached the lowest observed value of 3/10. The linear regression showed an increase of the PEDro score of 0.1 points per decade. A positive and small tendency toward increased methodologic quality was observed. The current results demonstrate that a positive and small tendency can be seen for the increase in the methodological quality in the field of exercise science under hypoxia. A "good" methodological quality, reaching a PEDro score of 6 points can be expected in the year 2063, using a linear regression model analysis. To accelerate this process, future research should ensure that methodological quality criteria are already included during the planning phase of a study.

Effects of Rehearsal Time and Repertoire Speed on Upper Trapezius Activity in Conservatory Piano Students.

BACKGROUND: Repetitive piano play may overload neck and shoulder muscles and tendons, leading to playing-related musculoskeletal disorders (PRMDs). METHODS: In this pilot study (EMG data of the extensor carpi radialis have been published separately), surface electromyography (sEMG) activity of the upper trapezius (UT) was captured in 10 conservatory piano students while playing a fast and a slow music score selected from the individual's repertoire, each 3 minutes long. Measurements were made at baseline and again after 2 hrs and 4 hrs of rehearsal time of the piano études. The amplitude of the sEMG signal was processed by a smoothing algorithm, and the frequency component with a non-orthogonal wavelets procedure. Amplitude of the sEMG was expressed in percent of maximal voluntary contraction (%MVC) at baseline, and the frequency component using median frequency based on the frequency band powers. Statistical analysis encompassed repeated measures ANOVAs for the amplitude and frequency components of the sEMG signal (set at 5%). The students also rated the intensity of rehearsals using a visual analog scale (VAS). RESULTS: The median values for the %MVC presented a global mean for the left trapezius of 5.86 (CI90% 4.71, 6.97) and 5.83 for the right trapezius (CI90% 4.64, 7.05). The rehearsals at moderate intensity increased the amplitude of %MVC of the upper trapezius by around 50% and decreased the median frequency. CONCLUSIONS: Playing faster presented higher magnitudes of activity of the upper trapezius. The decrease in the median frequency in response to long rehearsals may be a sign of muscle fatigue.

Local Heat Applications as a Treatment of Physical and Functional Parameters in Acute and Chronic Musculoskeletal Disorders or Pain.

OBJECTIVES: The aim of this systematic review and meta-analysis was to evaluate the effectiveness of local heat applications (LHAs) in individuals with acute or chronic musculoskeletal disorders. DATA SOURCES: An electronic search was conducted on MEDLINE, Cochrane Controlled Register of Trials, Current Nursing and Allied Health Literature, and the Physiotherapy Evidence databases up to December 2019. STUDY SELECTION: Studies incorporating adults with any kind of musculoskeletal issues treated by LHA compared with any treatment other than heat were included. DATA EXTRACTION: Two authors independently performed the methodological quality assessment using the Cochrane Risk of Bias tool. DATA SYNTHESIS: LHA showed beneficial immediate effects to reduce pain vs no treatment (P<.001), standard therapy (P=.020), pharmacologic therapy (P<.001), and placebo/sham (P=.044). Physical function was restored after LHA compared with no treatment (P=.025) and standard therapy (P=.006), whereas disability improved directly after LHA compared with pharmacologic therapy (P=.003) and placebo/sham (P<.028). Quality of life was improved directly after LHA treatment compared with exercise therapy (P<.021). Range of motion increased and stiffness decreased after LHA treatment compared with pharmacologic therapy (P=.009, P<.001) and placebo/sham (P<.001, P=.023). The immediate superior effects of LHA on muscular strength could be observed compared with no treatment (P<.001), cold (P<.001), and placebo/sham (P=.023). CONCLUSIONS: Individuals with acute musculoskeletal disorders might benefit from using LHA as an adjunct therapy. However, the studies included in this meta-analysis demonstrated a high heterogeneity and mostly an unclear risk of bias.

An Exploratory Meta-Analytic Review on the Empirical Evidence of Differential Learning as an Enhanced Motor Learning Method.

Background: Differential learning (DL) is a motor learning method characterized by high amounts of variability during practice and is claimed to provide the learner with a higher learning rate than other methods. However, some controversy surrounds DL theory, and to date, no overview exists that compares the effects of DL to other motor learning methods. Objective: To evaluate the effectiveness of DL in comparison to other motor learning methods in the acquisition and retention phase. Design: Systematic review and exploratory meta-analysis. Methods: PubMed (MEDLINE), Web of Science, and Google Scholar were searched until February 3, 2020. To be included, (1) studies had to be experiments where the DL group was compared to a control group engaged in a different motor learning method (lack of practice was not eligible), (2) studies had to describe the effects on one or more measures of performance in a skill or movement task, and (3) the study report had to be published as a full paper in a journal or as a book chapter. Results: Twenty-seven studies encompassing 31 experiments were included. Overall heterogeneity for the acquisition phase (post-pre; I 2 = 77%) as well as for the retention phase (retention-pre; I 2 = 79%) was large, and risk of bias was high. The meta-analysis showed an overall small effect size of 0.26 [0.10, 0.42] in the acquisition phase for participants in the DL group compared to other motor learning methods. In the retention phase, an overall medium effect size of 0.61 [0.30, 0.91] was observed for participants in the DL group compared to other motor learning methods. Discussion/Conclusion: Given the large amount of heterogeneity, limited number of studies, low sample sizes, low statistical power, possible publication bias, and high risk of bias in general, inferences about the effectiveness of DL would be premature. Even though DL shows potential to result in greater average improvements between pre- and post/retention test compared to non-variability-based motor learning methods, more high-quality research is needed before issuing such a statement. For robust comparisons on the relative effectiveness of DL to different variability-based motor learning methods, scarce and inconclusive evidence was found.

Intramuscular Temperature Changes in the Quadriceps Femoris Muscle After Post-Exercise Cold-Water Immersion (10°C for 10 min): A Systematic Review With Meta-Analysis.

Post-exercise cold-water immersion (CWI) is a widely accepted recovery strategy for maintaining physical performance output. However, existing review articles about the effects of CWI commonly pool data from very heterogenous study designs and thus, do rarely differentiate between different muscles, different CWI-protocols (duration, temperature, etc.), different forms of activating the muscles before CWI, and different thickness of the subcutaneous adipose tissue. This systematic review therefore aimed to investigate the effects of one particular post-exercise CWI protocol (10°C for 10 min) on intramuscular temperature changes in the quadriceps femoris muscle while accounting for skinfold thickness. An electronic search was conducted on PubMed, LIVIVO, Cochrane Library, and PEDro databases. Pooled data on intramuscular temperature changes were plotted with respect to intramuscular depth to visualize the influence of skinfold thickness. Spearman's rho (rs) was used to assess a possible linear association between skinfold thickness and intramuscular temperature changes. A meta-analysis was performed to investigate the effect of CWI on pre-post intramuscular temperature for each measurement depth. A total of six articles met the inclusion criteria. Maximum intramuscular temperature reduction was 6.40°C with skinfold thickness of 6.50 mm at a depth of 1 cm, 4.50°C with skinfold thickness of 11.00 mm at a depth of 2 cm, and only 1.61°C with skinfold thickness of 10.79 mm at a depth of 3 cm. However, no significant correlations between skinfold thickness and intramuscular temperature reductions were observed at a depth of 1 cm (r s = 0.0), at 2 cm (r s = -0.8) and at 3 cm (r s = -0.5; all p > 0.05). The CWI protocol resulted in significant temperature reductions in the muscle tissue layers at 1 cm (d = -1.92 [95% CI: -3.01 to -0.83] and 2 cm (d = -1.63 [95% CI: -2.20 to -1.06]) but not at 3 cm (p < 0.05). Skinfold thickness and thus, subcutaneous adipose tissue, seems to influence temperature reductions in the muscle tissue only to a small degree. These findings might be useful for practitioners as they demonstrate different intramuscular temperature reductions after a specific post-exercise CWI protocol (10°C for 10 min) in the quadriceps femoris muscle.

Assessment of neuropathic pain after spinal cord injury using quantitative pain drawings.

STUDY DESIGN: Clinimetric cross-sectional cohort study in adults with paraplegic spinal cord injury (SCI) and neuropathic pain (NP). OBJECTIVE: To assess the reliability of standardized quantitative pain drawings in patients with NP following SCI. SETTING: Hospital-based research facility at the Spinal Cord Injury Center, Balgrist University Hospital, Zurich, Switzerland. METHODS: Twenty individuals with chronic thoracic spinal cord injury and neuropathic pain were recruited from a national and local SCI registry. A thorough clinical examination and pain assessments were performed. Pain drawings were acquired at subsequent timepoints, 13 days (IQR 7.8-14.8) apart, in order to assess test-retest reliability. RESULTS: The average extent [%] and intensity [NRS 0-10] of spontaneous NP were 11.3% (IQR 4.9-35.8) and 5 (IQR 3-7), respectively. Pain extent showed excellent inter-session reliability (intraclass correlation coefficient 0.96). Sensory loss quantified by light touch and pinprick sensation was associated with larger pain extent (rpinprick = -0.47, p = 0.04; rlight touch = -0.64, p < 0.01). CONCLUSION: Assessing pain extent using quantitative pain drawings is readily feasible and reliable in human SCI. Relating information of sensory deficits to the presence of pain may provide distinct insights into the interaction of sensory deafferentation and the development of neuropathic pain after SCI.

Criteria Used for the Diagnosis of Myofascial Trigger Points in Clinical Trials on Physical Therapy: Updated Systematic Review.

OBJECTIVE: The objective of this study was to conduct an updated systematic review of diagnostic criteria for myofascial trigger points (MTrPs) used in clinical trials of physical therapy interventions from 2007 to 2019. METHODS: MEDLINE and Physiotherapy Evidence Database (PEDro) were searched using the following MeSH keywords: "trigger points," "trigger point," "myofascial trigger point," "myofascial trigger points," "myofascial pain," and "myofascial pain syndrome." The MeSH keywords were combined by using Boolean operators "OR"/"AND." All physiotherapy clinical trials including patients with musculoskeletal conditions characterized by at least 1 active MTrP or latent MTrP in any body area were selected. We pooled data from an individual criterion and criteria combinations used to diagnose MTrPs. The protocol was developed in accordance with the PRISMA-P guidelines. RESULTS: Of 478 possibly relevant publications, 198 met the inclusion criteria. Of these 198 studies, 129 studies (65.1%) stated specifically the diagnostic criteria used for MTrPs in the main text, 56 studies (28.3%) failed to report any method whereby MTrP was diagnosed, and 13 studies (6.6%) adopted expert-based definitions for MTrPs without specification. Of 129 studies, the 6 criteria applied most commonly were: "spot tenderness" (n=125, 96.9%), "referred pain" (95, 73.6%), "local twitch response" (63, 48.8%), pain recognition (59, 45.7%), limited range of motion" (29, 22.5%), and "jump sign" (10, 7.8%). Twenty-three combinations of diagnostic criteria were identified. The most frequently used combination was "spot tenderness," "referred pain," and "local twitch response" (n=28 studies, 22%). CONCLUSIONS: A number of the included studies failed in properly reporting the MTrP diagnostic criteria. Moreover, high variability in the use of MTrP diagnostic was also observed. Spot tenderness, referred pain, and local twitch response were the 3 most popular criteria (and the most frequently used combination). A lack of transparency in the reporting of MTrP diagnostic criteria is present in the literature. REGISTRY: This systematic review was registered under the Centre for Reviews and Dissemination, PROSPERO number: CRD42018087420.

Effects of Rehearsal Time and Repertoire Speed on Extensor Carpi Radialis EMG in Conservatory Piano Students.

BACKGROUND: Repetitive actions while playing piano may overload forearm muscles and tendons, leading to playing-related musculoskeletal disorders (PRMDs), including lateral epicondylitis. METHODS: In this pilot study, surface electromyography (sEMG) activity of the extensor carpi radialis (ECR) was captured in 10 conservatory piano students while playing a fast and a slow music score selected from the individual's repertoire, each 3 minutes long. Measurements were made at baseline and again after 2 hrs and 4 hrs of rehearsal time of the piano études. The amplitude of the sEMG signal was processed by a smoothing algorithm, and the frequency component with a non-orthogonal wavelets procedure. Amplitude of the sEMG was expressed in percent of maximal voluntary contraction (%MVC) at baseline. Statistical analysis encompassed 2-way repeated measures ANOVAs for the amplitude and frequency components of the sEMG signal (a set at 5%). The students also rated the intensity of rehearsals using a VAS. RESULTS: The ECR presented with a mean amplitude of 23%MVC for the slow scores, which increased significantly to 36%MVC for the fast scores. The sEMG signal presented a significant though small decrease of 1.9%MVC in amplitude between baseline and 4 hrs of rehearsal time and no shift in frequency, which may indicate that the rehearsals were held at a physiological steady-state and suggesting optimization or complementary muscle loading. CONCLUSIONS: These data accentuated that the loading of the ECR (as reflected in the amplitude component) was higher than that seen for computer keyboard workers. The augmented loading of the ECR and reduced blood flow to forearm muscles may be a factor in the development of PRMDs in pianists.

Tendon morphological changes after a prolonged ski race can be detected by ultrasound echo intensity.

BACKGROUND: Ultrasound imaging techniques have been used to assess the characteristics of skeletal muscles and tendons. Such techniques (gray scale analysis) allow qualitative evaluation and have been used recently to assess the internal structure of muscles and tendons by computer-aided gray scale analysis. We hypothesized that changes in the internal structure of the Achilles and patellar tendons after a ski mountaineering race competition could be detected with ultrasound. METHODS: Twenty athletes were recruited during the 19th Millet Tour du Rutor extreme, a three-day ski mountaineering competition. Ultrasound measurements of the Achilles and patellar tendons were carried out before the first race and immediately after each of the three competition days. Tendon thickness, cross-sectional area (CSA), and ultrasound gray scale analysis were calculated. RESULTS: Significant differences (p < 0.05) were observed between the pre- and post-race measurements for the Achilles tendon thickness and CSA, while no significant differences were noted for the patellar tendon thickness and CSA. However, gray scale analysis of both the Achilles and patellar tendons showed significantly higher post-race values, than the pre-race values (p < 0.05). CONCLUSIONS: Achilles and patellar tendons of healthy athletes are highly responsive to an acute increase in mechanical load. Those changes can be detected from classical (thickness and CSA) and innovative (gray scale) ultrasound-based parameters. TRIAL REGISTRATION: This study was approved by the Azienda USL Valle d'Aosta Ethics Committee (protocol no. 23/03/2018.0026243.I).

Physical Management of Scar Tissue: A Systematic Review and Meta-Analysis.

Objective: The aim of this systematic review with meta-analysis was to describe the status on the effects of physical scar treatments on pain, pigmentation, pliability, pruritus, scar thickening, and surface area. Design: Systematic review and meta-analysis. Subjects: Adults with any kind of scar tissue. Interventions: Physical scar management versus control or no scar management. Outcome measures: Pain, pigmentation, pliability, pruritus, surface area, scar thickness. Results: The overall results revealed that physical scar management is beneficial compared with the control treatment regarding the management of pain (p = 0.012), pruritus (p < 0.001), pigmentation (p = 0.010), pliability (p < 0.001), surface area (p < 0.001), and thickness (p = 0.022) of scar tissue in adults. The observed risk of bias was high for blinding of participants and personnel (47%) and low for other bias (100%). Conclusions: Physical scar management demonstrates moderate-to-strong effects on improvement of scar issues as related to signs and symptoms. These results show the importance of specific physical management of scar tissue.

Comparison of two skin temperature assessment methods after the application of topical revulsive products: Conductive iButton data logger system vs contact-free infrared thermometry.

BACKGROUND: Skin temperature assessments comprise conductive and contact-free techniques. Comparison between conductive data loggers and contact-free thermometry after the application of revulsive products is scarce. This study aimed to compare iButton data loggers with an infrared thermometer after the application of two revulsive products. Secondly, the relation between skin temperature kinetics with skin's perfusion of microcirculation was investigated. MATERIALS AND METHODS: Healthy females (n = 25) were randomly allocated to two groups, representing the products A and B. Skin temperature was measured with "iButtons" and an infrared pistol at baseline and up to 1 hour after application. Skin's perfusion of microcirculation was monitored with a laser speckle contrast imager. RESULTS: Baseline "iButton" temperature values were significantly lower compared with infrared pistol values in both groups. After application of the products, skin temperature decreased as recorded with both devices followed by an increase to baseline values when measured with the pistol. The results obtained by the "iButtons" reached values above baseline in both products towards the end of the follow-up period. A moderate correlation was found between infrared pistol and "iButton" system in product A, with a weak negative correlation between skin's perfusion of microcirculation and temperature devices. For product B, the correlation between the devices was moderate and between skin's perfusion and temperature devices weak and positive. CONCLUSION: Both devices produced similar kinetics, except at baseline, where they may differ as metallic loggers have been insufficiently adapted to skin temperature. Skin's perfusion of microcirculation could not explain skin temperature changes.

Myotonometry for the evaluation of Achilles tendon mechanical properties: a reliability and construct validity study.

OBJECTIVE: This study evaluates the intra-rater and inter-rater reliability of the MyotonPRO and its construct validity for the assessment of Achilles tendon stiffness. DESIGN: Reliability and construct validity study. METHODS: Forty healthy participants were assessed using the MyotonPRO by two raters on two different occasions. Tendon was evaluated in three different positions (relaxed, 0° plantarflexion and standing) and during different isometric contractions (range 0-3 kg). Reliability was calculated using intraclass correlation coefficient (ICC and 95% CI) standard error of measurement and minimal detectable change. Construct validity was evaluated between the different positions and the different contraction intensities using Friedman test. RESULTS: Intra-rater reliability was very high ICC2,k 0.87-0.98. The reliability of the 0.5 kg contraction was moderate with an ICC2,k of 0.59. Inter-rater reliability ranged from high to very high with an ICC2,k of 0.76-0.86. The reliability of the 0.5 kg, 1 kg contraction and the standing position was moderate with an ICC2,k of 0.55, 0.54 and 0.56 respectively. Inter-session reliability ranged from high to very high with an ICC2,k of 0.70-0.89. The reliability of the 0.5 kg contraction was moderate with an ICC2,k of 0.54. Construct validity was demonstrated between different contraction levels and different positions. CONCLUSION: MyotonPRO is a reliable tool for the evaluation of Achilles tendon stiffness during different contraction levels and in different positions. Construct validity was supported by changes of tendon stiffness during the explored conditions. MyotonPRO can be implemented, as a ready to use device, in the evaluation of tendon tissue mechanical properties.

Upper and lower limb performance fatigability in people with multiple sclerosis investigated through surface electromyography: a pilot study.

OBJECTIVE: Fatigue experienced by people with multiple sclerosis (pwMS) is multidimensional, consisting of different components, such as perceived, physical and cognitive fatigue and performance fatigability. At present, there is no gold standard to assess performance fatigability in pwMS; therefore, we aimed to determine whether, during a fatiguing task, average rectified value (ARV), mean frequency of the power spectrum (MNF), muscle fiber conduction velocity (CV) and fractal dimension (FD) of surface electromyography (sEMG) may be used as indirect indices of performance fatigability. Moreover, we analyzed whether a three-week rehabilitation program impacts on performance fatigability in pwMS, and whether a relationship between sEMG parameters and trait levels of perceived fatigability, before and after rehabilitation, does exist. APPROACH: Twenty-one pwMS performed a 20% maximal voluntary contraction (MVC) of 1 min, and afterwards a 60% MVC held until exhaustion. sEMG signals were detected from the biceps brachii, vastus medialis and vastus lateralis. Performance fatigability was determined at entry to (t 0) and discharge from (t 1) rehabilitation. Perceived fatigability was measured at t 0 and t 2, one month after rehabilitation. MAIN RESULTS: ARV, MNF, CV and FD rates of change showed significant changes at t 0 and t 1 (p < 0.05) during the high-level contraction in the BB, but rather limited in the vastii muscles. Moreover, rehabilitation did not induce any reductions in either perceived or performance fatigability. No significant correlations between ARV, MNF, CV and FD rates of change during the 60% MVC and perceived fatigability, at t 0 and t 2, were found. SIGNIFICANCE: Our findings suggest that the sEMG parameters are useful for indirectly assessing performance fatigability in pwMS during sub-maximal fatiguing contractions, particularly in the biceps brachii.