Towards Upright Pedalling to drive recovery in people who cannot walk in the first weeks after stroke: movement patterns and measurement

Objectives: To examine whether people who are within 31 days of stroke onset are able to produce controlled lower limb movement, and phasic activity in antagonistic lower limb muscle groups, during Upright Pedalling (UP). Design: Observational study. Setting: Acute stroke unit within a University Hospital. Participants: Eight adults between 3 and 30 days from stroke onset, with unilateral lower limb paresis and unable to walk without assistance. Participants were considered fit to participate as assessed by a physician-led medical team and were able to take part in UP for one, one minute session. Intervention: Participants took part in one session of instrumented UP at their comfortable cadence, as part of a feasibility study investigating UP early after stroke. Outcome measures: Reciprocal activation of lower limb muscles derived from muscle activity recorded with surface EMG, quantified using Jaccards Coefficient (J); smoothness of pedalling determined from standard deviations of time spent in each of eight 45 degree wheel position bins (“S-Ped”). Motor behavioural measures: Motricity Index, Trunk Control Test, Functional Ambulatory Categories. Results: Participants were all unable to walk (FAC 0) with severe to moderate lower limb paresis (Motricity Index score/100 median 48.5, IQR 32-65.5). Smooth pedalling was observed; some participants pedalling similarly smoothly to healthy older adults, with a variety of muscle activation patterns in the affected and unaffected legs. Conclusion: These observational data indicate that people with substantial paresis early after stroke and who cannot walk, can produce smooth movement during UP using a variety of muscle activation strategies

Phenomenology of flavor-mediated supersymmetry breaking

The phenomenology of a new economical SUSY model that utilizes dynamical SUSY breaking and gauge-mediation (GM) for the generation of the sparticle spectrum and the hierarchy of fermion masses is discussed. Similarities between the communication of SUSY breaking through a messenger sector, and the generation of flavor using the Froggatt-Nielsen (FN) mechanism are exploited, leading to the identification of vector-like messenger fields with FN fields, and the messenger U(1) as a flavor symmetry. An immediate consequence is that the first and second generation scalars acquire flavor-dependent masses, but do not violate FCNC bounds since their mass scale, consistent with effective SUSY, is of order 10 TeV. We define and advocate a minimal flavor-mediated model (MFMM), recently introduced in the literature, that successfully accommodates the small flavor-breaking parameters of the standard model using order one couplings and ratios of flavon field vevs. The mediation of SUSY breaking occurs via two-loop log-enhanced GM contributions, as well as several one-loop and two-loop Yukawa-mediated contributions for which we provide analytical expressions. The MFMM is parameterized by a small set of masses and couplings, with values restricted by several model constraints and experimental data. The next-to-lightest sparticle (NLSP) always has a decay length that is larger than the scale of a detector, and is either the lightest stau or the lightest neutralino. Similar to ordinary GM models, the best collider search strategies are, respectively, inclusive production of at least one highly ionizing track, or events with many taus plus missing energy. In addition, D^0 - \bar{D}^0 mixing is also a generic low energy signal. Finally, the dynamical generation of the neutrino masses is briefly discussed.Comment: 54 pages, LaTeX, 8 figure

Reliability of maximal isometric knee strength testing with modified hand-held dynamometry in patients awaiting total knee arthroplasty: useful in research and individual patient settings? A reliability study

<p>Abstract</p> <p><b>Background</b></p> <p>Patients undergoing total knee arthroplasty (TKA) often experience strength deficits both pre- and post-operatively. As these deficits may have a direct impact on functional recovery, strength assessment should be performed in this patient population. For these assessments, reliable measurements should be used. This study aimed to determine the inter- and intrarater reliability of hand-held dynamometry (HHD) in measuring isometric knee strength in patients awaiting TKA.</p> <p><b>Methods</b></p> <p>To determine interrater reliability, 32 patients (81.3% female) were assessed by two examiners. Patients were assessed consecutively by both examiners on the same individual test dates. To determine intrarater reliability, a subgroup (n = 13) was again assessed by the examiners within four weeks of the initial testing procedure. Maximal isometric knee flexor and extensor strength were tested using a modified Citec hand-held dynamometer. Both the affected and unaffected knee were tested. Reliability was assessed using the Intraclass Correlation Coefficient (ICC). In addition, the Standard Error of Measurement (SEM) and the Smallest Detectable Difference (SDD) were used to determine reliability.</p> <p><b>Results</b></p> <p>In both the affected and unaffected knee, the inter- and intrarater reliability were good for knee flexors (ICC range 0.76-0.94) and excellent for knee extensors (ICC range 0.92-0.97). However, measurement error was high, displaying SDD ranges between 21.7% and 36.2% for interrater reliability and between 19.0% and 57.5% for intrarater reliability. Overall, measurement error was higher for the knee flexors than for the knee extensors.</p> <p><b>Conclusions</b></p> <p>Modified HHD appears to be a reliable strength measure, producing good to excellent ICC values for both inter- and intrarater reliability in a group of TKA patients. High SEM and SDD values, however, indicate high measurement error for individual measures. This study demonstrates that a modified HHD is appropriate to evaluate knee strength changes in TKA patient groups. However, it also demonstrates that modified HHD is not suitable to measure individual strength changes. The use of modified HHD is, therefore, not advised for use in a clinical setting.</p

A Systematic Review of Dynamometry and its Role in Hand Trauma Assessment

The dynamometer was developed by American neurologists and came into general use in the late 19th century. It is still used in various ways as a diagnostic and prognostic tool in clinical settings. In this systematic review we assessed in detail the different uses of dynamometry, its reliability, different dynamometers used and the influence of rater experience by bringing together and evaluating all published literature in this field. It was found that dynamometry is applied in a wide range of medical conditions. Furthermore, the great majority of studies reported acceptable to high reliability of dynamometry. Jamar mechanical dynamometer was used most often in the studies reviewed. There were mixed results concerning the effect of rater experience. The factors influencing the results of dynamometry were identified as age, gender, body weight, grip strength, BMI, non/dominant hand, assessing upper/lower limbs, rater and patient’s strength and the distance from the joint where the dynamometer is placed. This review provides an understanding of the relevance and significance of dynamometry which should serve as a starting point to guide its use in hand trauma assessment. On the basis of our findings, we suggest that hand dynamometry has a great potential, and could be used more often in clinical practice

Measuring hip muscle strength in patients with femoroacetabular impingement and other hip pathologies

$\textbf{Objectives}$ The aim of this study was to systematically review the literature on measurement of muscle strength in patients with femoroacetabular impingement (FAI) and other pathologies and to suggest guidelines to standardise protocols for future research in the field. $\textbf{Methods}$ The Cochrane and PubMed libraries were searched for any publications using the terms ‘hip’, ‘muscle’, ‘strength’, and ‘measurement’ in the ‘Title, Abstract, Keywords’ field. A further search was performed using the terms ‘femoroacetabular’ or ‘impingement’. The search was limited to recent literature only. $\textbf{Results}$ A total of 29 articles were reviewed to obtain information on a number of variables. These comprised the type of device used for measurement, rater standardisation, the type of movements tested, body positioning and comparative studies of muscle strength in FAI $\textit{versus}$ normal controls. The studies found that hip muscle strength is lower in patients with FAI; this is also true for the asymptomatic hip in patients with FAI. $\textbf{Conclusions}$ Current literature on this subject is limited and examines multiple variables. Our recommendations for achieving reproducible results include stabilising the patient, measuring isometric movements and maximising standardisation by using a single tester and familiarising the participants with the protocol. Further work must be done to demonstrate the reliability of any new testing method

Testing knee extension and flexion strength at different ranges of motion: an isokinetic and electromyographic study.

The main objective of this study was to explore the mechanical and electrical output of thigh muscles derived from a range of motion (RoM) of 90 degrees (0-90 degrees flexion, LR) and the three successive RoMs: 0-30 degrees (SR1), 30-60 degrees (SR2) and 60-90 degrees (SR3). Thirteen men took part in the study. In view of the torque-velocity relationship and in order to render the test conditions as equivalent as possible, LR was tested at 90 degrees /s while the corresponding velocity for all SRs was 30 degrees /s. The findings indicated very good agreement between LR and SR2 in terms of absolute strength (particularly the concentric), within muscle eccentric to concentric strength ratios, between muscles (agonist to antagonist) strength ratios and the normalized IEMG (expressed in muV/Nm). An agreement was also noted between the mean eccentric peak torque of the knee flexors at LR and SR1 and between the mean eccentric peak torque of the knee extensors at LR and SR3. However, in general there was a lesser agreement between LR and SR1 or SR3. It is suggested that testing thigh muscles in the middle sector of knee motion (SR2) yields strength and EMG data that are close and well correlated with those derived from testing the knee along the commonly used (0-90 degrees ) RoM