The dynamic control ratio and its equilibrium point: A preliminary study of isokinetic fatiguing internal-external rotational effort of the shoulder joint in healthy subjects.

The shoulder joint-related dynamic control ratio (DCR) is derived by dividing the peak eccentric moment of the external rotators (ER) by the peak concentric moment of the internal rotators (IR). However, given the inherent limitation associated with a single value DCR, an alternative approach is to calculate it at fixed angular intervals. This preliminary study aimed at exploring the variation in the DCR at a resolution of 1° and under fatiguing external and internal rotation exertions. Eighteen young men, 10 experienced and 8 without experience in overhead sporting activities completed two separate series of 45 ER eccentric and 45 IR concentric isokinetic repetitions at 120°/s. The analysis focused on repetitions 1-3 (TR1), 21-23 (TR2) and 41-43 (TR3). The relative fatigue values for both muscle groups and for both E and NE participants were 25-40% with significantly higher fatigue resistance in eccentric compared with concentric exertions. The DCR traces varied substantially linearly for most of the internal rotation range of motion while significant differences (p < 0.001) were found in their values within group between TR1, TR2 and TR3 and between experienced and non-experienced participants. An antagonistic moment equilibrium (DCR = 1) was reached in all instances and for both groups only during TR3 with a significant progressive reduction in this moment as fatigue increased. Thus, considering the DCR as an angle-based variable rather than a single value isokinetic parameter, may add new insight regarding the interplay between the rotatory muscles of the shoulder joint.

A Thematic Survey on the Reporting Quality of Randomized Controlled Trials in Rehabilitation: The Case of Multiple Sclerosis.

BACKGROUND AND PURPOSE: Optimal reporting is a critical element of scholarly communications. Several initiatives, such as the EQUATOR checklists, have raised authors' awareness about the importance of adequate research reports. On these premises, we aimed at appraising the reporting quality of published randomized controlled trials (RCTs) dealing with rehabilitation interventions. Given the breadth of such literature, we focused on rehabilitation for multiple sclerosis (MS), which was taken as a model of a challenging condition for all the rehabilitation professionals.A thematic methodological survey was performed to critically examine rehabilitative RCTs published in the last 2 decades in MS populations according to 3 main reporting themes: (1) basic methodological and statistical aspects; (2) reproducibility and responsiveness of measurements; and (3) clinical meaningfulness of the change. SUMMARY OF KEY POINTS: Of the initial 526 RCTs retrieved, 370 satisfied the inclusion criteria and were included in the analysis. The survey revealed several sources of weakness affecting all the predefined themes: among these, 25.7% of the studies complemented the P values with the confidence interval of the change; 46.8% reported the effect size of the observed differences; 40.0% conducted power analyses to establish the sample size; 4.3% performed retest procedures to determine the outcomes' reproducibility and responsiveness; and 5.9% appraised the observed differences against thresholds for clinically meaningful change, for example, the minimal important change. RECOMMENDATIONS FOR CLINICAL PRACTICE: The RCTs dealing with MS rehabilitation still suffer from incomplete reporting. Adherence to evidence-based checklists and attention to measurement issues and their impact on data interpretation can improve study design and reporting in order to truly advance the field of rehabilitation in people with MS.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1 available at: http://links.lww.com/JNPT/A424 ).

Isokinetic Resistance Training for Ankle Plantarflexor Spasticity and Muscle Weakness in People With Multiple Sclerosis: A Proof-of-Concept Case Series.

OBJECTIVE: To the best of the authors' knowledge, no data are available about the use of isokinetic resistance training for managing ankle plantarflexor spastic hypertonia in people with multiple sclerosis (MS). The aim of this proof-of-concept study was to explore the feasibility and effects of concentric contractions on spasticity-related resistance to passive motion, strength, and mobility in people with MS and ankle plantarflexor spasticity. METHODS: In this pretest/posttest case series, 5 people with MS (mean age = 53.6 [SD = 8.8] years; median Expanded Disability Status Scale score = 5; Modified Ashworth Scale range = 1-4) received 6 weeks of isokinetic resistance training of the spastic plantarflexors. Before and after the intervention, the following outcomes were assessed: average peak torque during passive robotic mobilization, isometric strength, surface electromyography (sEMG) from the spastic muscles, time to complete the 10-m Walk Test, and the Timed "Up & Go" Test. The standardized effect size was used to test pretest and posttest effects at the individual level. Group-level analyses were also performed. RESULTS: Following the training, the average peak torque recorded from the plantarflexors during passive motion at a velocity of 150 degrees per second was found to be decreased by at least 1 SD in all participants but 1, with a significant reduction at the group level of 23.8%. Conversely, no changes in sEMG activity were detected. Group-level analyses revealed that the maximal strength of the trained plantarflexors increased significantly (31.4%). Fast walking speed increased and time to complete the Timed "Up & Go" Test decreased in 4 participants, although not significantly at the group level. CONCLUSION: Isokinetic resistance training proved safe and feasible in people who had MS and ankle plantarflexor spasticity. The observed reductions in resistance to passive motion from the spastic plantarflexors in the absence of sEMG changes might suggest a mechanical rather than a neural effect of the training. IMPACT: Based on these preliminary findings, isokinetic resistance training does not exacerbate hypertonia in people with MS and ankle plantarflexor spasticity and could be safely used to manage muscle weakness in this population.

Center of pressure displacement due to graded controlled perturbations to the trunk in standing subjects: the force-impulse paradigm.

PURPOSE: Many studies have investigated postural reactions (PR) to body-delivered perturbations. However, attention has been focused on the descriptive variables of the PR rather than on the characterization of the perturbation. This study aimed to test the hypothesis that the impulse rather than the force magnitude of the perturbation mostly affects the PR in terms of displacement of the center of foot pressure (ΔCoP). METHODS: Fourteen healthy young adults (7 males and 7 females) received 2 series of 20 perturbations, delivered to the back in the anterior direction, at mid-scapular level, while standing on a force platform. In one series, the perturbations had the same force magnitude (40 N) but different impulse (range: 2-10 Ns). In the other series, the perturbations had the same impulse (5 Ns) but different force magnitude (20-100 N). A simple model of postural control restricted to the sagittal plane was also developed. RESULTS: The results showed that ΔCoP and impulse were highly correlated (on average: r = 0.96), while the correlation ΔCoP-force magnitude was poor (r = 0.48) and not statistically significant in most subjects. The normalized response, ΔCoPn = ΔCoP/I, was independent of the perturbation magnitude in a wide range of force amplitude and impulse and exhibited good repeatability across different sets of stimuli (on average: ICC = 0.88). These results were confirmed by simulations. CONCLUSION: The present findings support the concept that the magnitude of the applied force alone is a poor descriptor of trunk-delivered perturbations and suggest that the impulse should be considered instead.

Reporting quality of TMS studies in neurological conditions: A critical appraisal of the main gaps, challenges and clinical implications.

Transparent reporting of study methods and findings can dramatically expand the reliability and impact of health research. Evidence-based reporting checklists and guidelines, such as those hosted by the EQUATOR network, provide a framework for summarizing statistics, methods and data presentation. While being increasingly used in several research fields, such trend toward better control seems in its infancy in the field of transcranial magnetic stimulation (TMS). By the present work we aimed at assessing the quality of methodological and statistical reporting of TMS-based investigations in individuals with neurological motor impairments. We completed a methodological survey of all the studies conducted in the last two decades on the application of TMS to evaluate motor impairments in individual with neurological conditions. The pre-planned literature search of three major biomedical databases resulted in 1109 articles retrieved, 571 of which satisfied the eligibility criteria. The survey revealed that most of the studies suffered from relevant methodological and statistical issues, which potentially affect data interpretation and usability. Among these, sample size calculation, indices of change other than p values, reproducibility and clinical relevance/responsiveness emerged as those elements most commonly neglected. To increase research reliability of TMS data, we recommend adhering to international initiatives like the EQUATOR, that can impact clinical research by promoting adequate reporting. In particular, we advocate an update of the submission policies of the journals active in this field in line with adjacent areas, such as neurorehabilitation, that require the uploading of completed checklists that rationalize reporting.

Wrist flexion and extension strength in patients with work-related chronic elbow pain: the isokinetic effort factor and its implications.

BACKGROUND: The validity of isokinetic strength findings relating to forearm muscles in patients with chronic elbow pain and/or epicondylitis is not well established. Furthermore, given the nature of this disorder, ensuring maximal effort in performing the tests is an essential prerequisite. The isokinetic-based DEC parameter (defined as the difference between high- and low-velocity eccentric-to-concentric ratios of a given muscle) has been shown to efficiently detect maximal effort. The purpose of this study was therefore to assess the validity of isokinetic strength tests in patients with chronic elbow pain and/or epicondylitis. METHODS: A cohort consisting of 44 male patients with chronic elbow pain (average evolution time, 262 ± 193.04 days) was recruited. The wrist extensor and flexor concentric and eccentric isokinetic strength of the involved and uninvolved sides was measured. The involved-uninvolved and flexor-extensor (F/E) ratios, as well as the DEC (eccentric-concentric difference), were computed based on peak moment values. Work disability and relapse within the first year were registered. In maximal performers, associations between deficits, F/E ratios, work disability, and symptom relapse were explored applying multiple comparisons. RESULTS: Of the patients, 68.2% met the maximal-effort criteria, with the involved-side muscles being significantly weaker than their uninvolved-side counterparts in most cases. Although the mean deficit in this group was not associated with either work disability or relapse, patients with a relapse of symptoms within the first year had a significantly higher F/E ratio than those without relapse. CONCLUSION: In patients presenting with chronic elbow pain who perform at the maximal level of effort, high wrist F/E strength ratios may predict symptom relapse.

The association between specific temporomandibular disorders and cervicogenic headache.

BACKGROUND AND AIMS: Upper neck signs, symptoms and hypomobility have been shown to present with a higher prevalence in patients with temporomandibular disorders (TMDs). However, there is currently no evidence of an association between specific TMDs and cervicogenic headache (CGH). Therefore, the aim of this study was to evaluate the odds ratio and the relative risk of CGH in patients with specific TMDs. METHOD: 116 participants, including 74 patients with TMD (pain-related/intraarticular/mixed TMD) and 42 healthy controls took part in this study. The TMD diagnosis was made by senior faculty members of the Dental School according to the Diagnostic Criteria for TMD, while the cervical diagnosis was made by a qualified senior physical therapist. The analysis comprised the evaluation of the odds ratio of CGH among patients with TMD and the relative risk (RR) for CGH during 14-24 months of follow-up. RESULTS: Significantly higher odds ratios of cervicogenic headache were found among pain-related and mixed TMD (12.17 and 10.76, respectively) versus healthy controls. During the 14-24 months of follow-up, there was no significant difference of relative risk for CGH among patients with TMD versus healthy controls. SUMMARY AND CONCLUSIONS: The results support a clear clinical association between painful TMD (pain-related and mixed TMD) and cervicogenic headache.

Relationship between specific temporomandibular disorders and impaired upper neck performance.

Upper neck impairments are more prevalent in patients with temporomandibular disorders (TMDs) but the differences between specific types of TMDs are unclear. This study evaluated the distribution of such impairments among different forms of TMD. In total, 116 participants (86 women and 30 men, age range 21-75 yr) were investigated. Forty-two individuals had no TMDs and were assigned to the control group. The remaining 74 patients were assigned to one of three groups based on the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) findings: pain-related (n = 37); intra-articular (n = 17); or mixed (combined pain-related and intra-articular) (n = 20). Analyses of impairments included between-group comparisons of key parameters of upper neck performance (active/passive mobility and muscular capabilities) and pain (subjective neck disability and pain sensitivity). Patients in the pain-related and mixed TMD groups were found to have decreased upper neck mobility in the cervical flexion-rotation test compared with patients in intra-articular and control groups, as well as poorer capabilities of the deep neck flexor muscles in the cranio-cervical flexion test compared to the control group. It was concluded that patients with pain-related TMD diagnoses are more likely to experience significant upper-neck hypomobility and poor muscular capabilities than patients with intra-articular diagnoses of TMD.

Listening to music while running alters ground reaction forces: a study of acute exposure to varying speed and loudness levels in young women and men.

PURPOSE: Music listening while running enhances physiological and psychological features, resulting in a more enjoyable experience. The possible influence of music on ground reaction forces (GRF) during running, however, is unknown. Considering the 'distracting' role of music on runner's attention, we hypothesized that music would cover foot impacts against the ground. This study verified such hypothesis by testing the effects of different music volumes while running at different velocities. METHODS: Fifty fit volunteers (F:M = 22:8; 23 ± 2 years) performed 2-min running stints over 3 random conditions (80-dB, 85-dB music; 'no music'), at 3 velocities (8, 10, 12 km/h). Participants ran on a sensorized treadmill that recorded GRF during all experiments. RESULTS: Listening to 85-dB music resulted in greater GRF at 8 (p = 0.0005) and 10 km/h (p = 0.04) but not 12 km/h (p = 0.35) and not with 80-dB volume. Gender-based analyses revealed significant Condition × gender interactions only for 85-dB music vs. 'no music'. Bonferroni-adjusted comparisons revealed significant music-induced increases in GRF only in men at 8 km/h (+ 4.1 kg/cm2, p < 0.0005; women: + 0.8 kg/cm2, p = 0.47) and 10 km/h (+ 3.3 kg/cm2, p = 0.004; women: + 0.8 kg/cm2, p = 0.51) but not at 12 km/h. CONCLUSION: In active men, listening to loud music while running results in increased GRF, whereas no effect was observed in women. The lack of music effect in women may be related to structural factors, such as larger hip width-to-femoral length ratio, possibly resulting in different loading patterns. The present preliminary findings introduce high-volume music listening as a new potential risk factor for injury in young runners.

Linearity and repeatability of postural responses in relation to peak force and impulse of manually delivered perturbations: a preliminary study.

PURPOSE: Postural reactions (PR) of standing subjects have been mostly investigated in response to platform displacements or body perturbations of fixed magnitude. The objective of this study was to investigate the relationship between PR and the peak force and impulse of the perturbation. METHODS: In ten healthy young men, standing balance was challenged by anteriorly directed perturbations (peak force: 20-60 N) delivered to the back, at the lumbar (L) or inter-scapular (IS) level, by means of a manual perturbator equipped with a force sensor. Postural reactions as expressed by the displacement of the center of pressure (CoP) were recorded using a force platform. Two sets of 20 randomly ordered perturbations (10 to each site) were delivered in two separate testing sessions. RESULTS: The magnitude of CoP response (∆CoP) was better correlated with the impulse (I) than with the peak force of the perturbation. The normalized response, ∆CoPn = ∆CoP/I, exhibited good reliability (ICCs of 0.93 for IS and 0.82 for L), was higher with IS than with L perturbations (p < 0.01), and was significantly correlated with the latency of CoP response: r = 0.69 and 0.71 for IS and L, respectively. CONCLUSION: These preliminary findings support the concept that manually delivered perturbations can be used to reliably assess individual PR and that ∆CoPn may effectively express a relevant aspect of postural control.

Multiple-Joint Isokinetic Dynamometry: A Critical Review.

Dvir, Z and Müller, S. Multiple-joint isokinetic dynamometry: a critical review. J Strength Cond Res 34(2): 587-601, 2020-Angular isokinetic dynamometry (AID) is widely regarded as the gold standard for dynamic muscle performance testing. Based on the rotational movement of its actuator, AID targets "single-joint" (knee, shoulder, hip, etc.) configurations namely measurement of muscle potential while it moves the lever arm-limb assembly ostensibly around a single fixed axis. On the other hand, the application of multiple-joint isokinetic dynamometry (MID) is relatively narrow, both in research and in practice. This situation is due, possibly, to the fact that these dynamometers are generally more limited in scope namely to testing/conditioning of combined hip, knee, ankle motion (leg press), combined shoulder, elbow motion, and lifting motion patterns, despite the fact that all 3 are associated with higher functionality. However, with the emerging importance of MID, this critical review takes a fresh look at its various aspects including the terminology and classification of multiple-joint isokinetic dynamometers; the problem of scaling namely the need to adjust the range of motion and linear velocities to subjective anthropometric measures; specific technical and methodological issues that underlie the valid application of these dynamometers; available reference values; and the reproducibility of MID-based test findings. Analysis of these topics indicates that MID may validly and effectively be applied for the assessment and conditioning of specific muscle action patterns. However, there is a clear need for standardization of tests and for conditioning protocols alongside research into the use of this method in various clinical cohorts.

The application of the Neurac technique vs. manual therapy in patients during the acute phase of subacromial impingement syndrome: A randomized single-blinded controlled trial.

BACKGROUD: Although the effect of exercise in patients during the subacute and/or chronic subacromial impingement syndrome has been reported, only a few studies have examined the effect of pain free exercise in the acute phase of this disorder. OBJECTIVE: To compare the effect of training using the Neurac technique which combines body segments suspension and vibration vs. manual therapy, on various relevant outcome parameters in patients with acute subacromial impingement syndrome (PASIS). METHOD: Twenty-six patients underwent a 4 week intervention program. Using random assignment, half of the patients were treated using the Neurac device while the other half was treated using manual therapy. The outcome parameters consisted of shoulder pain, shoulder function, range of motion (ROM) and the isokinetic strength of the external and internal rotators at 60 and 180∘/s. RESULTS: Following either modes of interventions, the pain, function, and ROM improved significantly compared to pre-intervention levels in both groups. Time-by-group interaction was observed for the rotational strength which increased significantly and exclusively in the Neurac group. CONCLUSIONS: Given its positive effect on shoulder pain, function, ROM and the isokinetic strength of the external and internal rotators, we recommend the application of the Neurac technique in PASIS.

Isokinetic predictors of gait speed increase following high-intensity resistance training of the ankle dorsiflexors in people with multiple sclerosis: A pilot study.

BACKGROUND: Maximal strength is a predictor of functional capacity for people with multiple sclerosis (PwMS), who frequently exhibit unilateral weakness of the ankle dorsiflexors. Aims of this study were to investigate the relationships between dorsiflexors' weakness and gait speed, the effects of high-intensity training of the affected dorsiflexors on gait performance and to identify isokinetic predictors of changes in gait speed in PwMs. METHODS: Twenty patients aged 45 (10.3) years, illness duration 14.9 (8.5) years, median EDSS 3, underwent isokinetic dorsiflexors' strength testing at 10°/s and 45°/s angular velocities and gait analysis before and after a 6-week training of dorsiflexors. Pre-to-post differences in strength and gait parameters were analyzed by paired t-test; association between gait speed and isokinetic parameters was tested through correlation and regression analyses. FINDINGS: Dorsiflexors' strength (peak moment at 10°/s: +14.9%, p = 0.02; at 45°/s: +21.7%, p = 0.03) and gait parameters (speed: +9.6%; p = 0.004; stride time: -5.7%; p = 0.01; cadence: +6.2%; p = 0.001; ankle power: +27.5%, p = 0.003) increased significantly. Of the thirteen isokinetic descriptors of strength, only peak moment, maximal and total work significantly correlated with gait speed increase. Regression analyses revealed high beta coefficients only for maximal work (10°/s: B = -6.528; beta = -1.825; p = 0.008; 45°/s: B = -1.466; beta = -1.364; p = 0.03). INTERPRETATION: In PwMS, high-intensity training of weakened ankle dorsiflexors induced significant improvements in maximal strength and gait speed. The finding of maximal work as a significant predictor of training-induced changes in gait speed suggests that PwMS with reduced muscle work may benefit from strength training approaches aimed at increasing gait speed. Registration number: ClinicalTrials.gov Identifier: NCT02010398.

Meta-analytic and Scoping Study on Strength Training in People With Multiple Sclerosis.

Manca, A, Dvir, Z, and Deriu, F. Meta-analytic and scoping study on strength training in people with multiple sclerosis. J Strength Cond Res 33(3): 874-889, 2019-Aim of the study was to determine a pooled estimate of effect on muscle strength and functional capacity induced by strength training in people with multiple sclerosis (PwMS). Five databases and 2 public registries were searched from inception to May 2017. Indexing terms used were: "multiple sclerosis," "resistance training," and "strength training." After title/abstract screening, 2 independent reviewers evaluated the studies' eligibility, which were retained if PwMS were randomly assigned to strength training or to a no intervention group. Of the 1,467 items retrieved, 30 randomized controlled trials formed the initial database with 11 trials (426 subjects) entering the final meta-analysis. The quality of the included studies was assessed by the PEDro scale and the risk of bias using the Cochrane Risk-of-Bias tool. All meta-analyses were conducted using a random effects model. After interventions, PwMS increased strength by 23.1% (confidence interval [CI] 11.8-34.4; +12.1 N; CI 4.5-19.8; p = 0.002; n = 366 subjects) at a small-to-moderate effect size (0.37; CI 0.2-0.6). Walking speed increased by 16.3 ± 10.7% (p = 0.0002; effect size 0.54; n = 275 subjects), distance covered in the 2-minute walking test by 6.7 ± 6.4% (p = 0.04; effect size 0.50; n = 111 subjects). People with MS respond to resistance training with consistent strength gains. Methodological inconsistencies among studies and inadequate reporting of the findings limited a comprehensive determination of the impact of strength improvements on patient functioning, except for walking performance which seemed significantly improved. Methodological steps and scoping lines are provided to establish a common platform for future trials.

Non-corresponding authors in the era of meta-analyses.

BACKGROUND AND OBJECTIVE: The exponential growth of the global scientific output requires review articles that summarize such escalating knowledge. The rate of growth in the number of published meta-analyses in the last decade is impressive, with meta-analyses being the most cited form of scientific article. The validity of the pooled estimates of effect heavily rely on the availability of data in the included articles. Unfortunately, inadequate reporting of the findings is common and often makes data extraction cumbersome. However, the response rate of corresponding authors to data requests is dangerously low, which threatens the validity of meta-analytic estimates. The aim of the present communication is to ignite a thoughtful debate to stimulate a higher level of responsibility and correspondence commitment from published authors. METHODS: Commentary on our personal experience as meta-analysts. RESULTS: In line with previous surveys, we observed a low response rate from corresponding authors, typically less than 50%. CONCLUSIONS: Lack of publication follow-up is a serious threat not only to meta-analysts and systematic reviewers, whose incomplete data pooling may lead to biased and misleading estimates of effect, but also to clinical practitioners, who heavily rely on the findings generated by meta-analyses for informing and driving their clinical practice.

Cervical flexion-rotation test and physiological range of motion - A comparative study of patients with myogenic temporomandibular disorder versus healthy subjects.

BACKGROUND: Temporomandibular Disorders (TMD) refer to several common clinical disorders which involve the masticatory muscles, the temporomandibular joint (TMJ) and the adjacent structures. Although neck signs and symptoms are found with higher prevalence in TMD patients compared to the overall population, whether limitation of cervical mobility is an additional positive finding in this cohort is still an open question. OBJECTIVE: To compare the physiological cervical range of motion (CROM) and the extent of rotation during cervical flexion (flexion-rotation test, FRT) in people with TMD (muscular origin) and healthy control subjects. METHOD: The range of motion of the neck and FRT was measured in 20 women with myogenic TMD and 20 age matched healthy controls. RESULTS: Women with myogenic TMD had significantly lower FRT scores compared to their matched healthy women. No difference was found between groups in CROM in any of the planes of movement. The FRT was positive (less than 32°) in 90% of the TMD participants versus 5% in the healthy control but the findings were not correlated with TMD severity. CONCLUSION: The results point out a potential involvement of the upper cervical joints (c1-c2) in women with myogenic TMD.