The Bilateral Deficit Phenomenon in Elbow Flexion: Explanations for Its Inconsistent Occurrence and Detection

The underlying mechanism(s) of the Bilateral Deficit (BLD) phenomenon is without consensus. Methodological inconsistencies across prior works may be an important source of equivocal results and interpretations. Based on repeatability problems with the BLD measure and maximal force definition, the presence or absence of the BLD phenomenon is altered, shifting conclusions of its mechanistic cause. Our purpose in this study was to examine methodological inconsistencies in applying the BLD measure to establish optimal methods for evaluating the underlying mechanism. Eleven healthy participants engaged in one familiarity and five test sessions, completing bilateral and unilateral elbow maximal voluntary isometric contractions. We defined maximal force by averaged and absolute peak and plateau values. BLD was evident if the bilateral index (BI), the ratio of the bilateral over summed unilateral forces, was statistically different from zero. We addressed interclass correlations (ICC), Chronbach’s α, standard error of the mean, and minimal detectable change between and within sessions for all force measures and BI. We evaluated all combinations of sessions (i.e., 1–2, 3–5, 5–6) and maximal forces to establish the optimal number of sessions to achieve reliability. BLD was present for test sessions, but not for familiarization. All measures of maximal force were highly reliable between and within sessions (ICC(2,1) ≥ .895). BI was only considered significantly reliable in sessions 3–5 ( p < .027), defined by absolute and average plateau forces, but reliability was still quantifiably poor (absolute: ICC(2,1) = .392; average: ICC(2,1) = .375). These results demonstrate that high force reliability within and between sessions does not translate to stable and reliable BI, potentially exposing the lack of any defined BLD mechanism.

A portable isometric knee extensor strength testing device: test-retest reliability and minimal detectable change scores of the Q-Force ӀӀ in healthy adults

Background Although knee extensors are essential in daily activities (e.g. walking, climbing stairs), knee extensor strength is often not measured in clinical settings. Existing devices to test muscle strength are not always suitable to accurately measure the high forces of this muscle group. Therefore, a device to test muscle strength that is convenient, feasible, reliable, and valid in clinical settings is required. This study evaluated the reliability, responsiveness, and level of discomfort of the newly developed Q-Force ӀӀ (i.e. a portable device to measure isometric knee extensor strength) in healthy middle-aged and elderly adults. Methods Participants (n = 22) conducted two standardized test sessions on the Q-Force ӀӀ (five to ten days apart). Each session consisted of one familiarisation trial followed by three trials of peak isometric knee extension per each leg. Per trial, peak and mean knee extension force (N) and torque (Nm) were measured at 90° flexion. The level of discomfort was determined using a visual analog scale (VAS: 0-100). Intra Class Correlation (ICC, model: two-way mixed with absolute agreement), Standard Error of Measurement (SEM), and minimal detectable change (MDC) were determined. A repeated measures ANOVA was used to determine between-test variation. Results Excellent test-retest (ICC > 0.95) and inter-trial (ICC > 0.91) reliability for both legs were shown. No significant differences were found in peak and mean knee forces and torques between test and retest of both legs, indicating good test-retest reliability (P-value range: 0.360-0.538; F(1,21) range: 0.4-0.9). The SEM of the peak and mean forces and torques ranged from 28.0 to 30.4 N (6.0-6.8%) and from 9.2 to 10.4 Nm (6.4-7.7%), respectively. The MDC for these outcomes ranged respectively from 77.6 to 84.1 N (16.5-18.8%) and from 25.5 to 28.9 Nm (17.6-21.4%). The level of discomfort was low (median range: 7-10, IQR: 4-18). Conclusion The portable Q-Force ӀӀ is a comfortable, responsive, and relatively cheap device with excellent test-retest reliability. This device would be potentially suitable to measure isometric knee extensor strength in clinical settings.

Detecting change in community participation with the Enfranchisement scale of the community participation indicators

Objective This study determined the sensitivity to change of the Enfranchisement scale of the Community Participation Indicators in people with stroke. Data sources We analyzed data from two studies of participants with stroke: an intervention study and an observational study. Main measures The Enfranchisement Scale contains two subscales: the Importance subscale (feeling valued by and contributing to the community; range: 14–70) and the Control subscale (choice and control: range: 13–64). Data analysis Assessments were administered 6 months apart. We calculated minimum detectable change and minimal clinically important difference. Results The Control subscale analysis included 121 participants with a mean age of 61.2 and mild-moderate disability (Functional Independence Measure, mean = 97.9, SD = 24.7). On the Control subscale, participants had a mean baseline score of 51.4 (SD = 10.4), and little mean change (1.3) but with large variation in change scores (SD = 11.5). We found a minimum detectable change of 9 and a minimum clinically important difference of 6. The Importance subscale analysis included 116 participants with a mean age of 60.7 and mild-moderate disability (Functional Independence Measure, mean = 98.9, SD = 24.5). On the Importance subscale, participants had a mean baseline score of 44.1 (SD = 12.7), and again demonstrated little mean change (1.08) but with large variation in change scores (SD = 12.6). We found a minimum detectable change of 11 and a minimum clinically important difference 7. Conclusions The Control subscale required 9 points of change, and the Importance subscale required 11 points of change, to achieve statistically and clinically meaningful changes, suggesting adequate sensitivity to change.

Reliability of Repeated Trials Protocols for Body Composition Assessment by Air Displacement Plethysmography

Air displacement plethysmography (ADP) is fast, accurate, and reliable. Nevertheless, in about 3% of the cases, standard ADP tests provide rogue results. To spot these outliers and improve precision, repeated trials protocols have been devised, but few works have addressed their reliability. This study was conducted to evaluate the test–retest reliabilities of two known protocols and a new one, proposed here. Ninety-two healthy adults (46 men and 46 women) completed six consecutive ADP tests. To evaluate the reliability of single measurements, we used the results of the first two tests; for multiple measures protocols, we computed the test result from trials 1–3 and the retest result from trials 4–6. Bland–Altman analysis revealed that the bias and the width of the 95% interval of agreement were smaller for multiple trials than for single ones. For percent body fat (%BF)/fat-free mass, the technical error of measurement was 1% BF/0.68 kg for single trials and 0.62% BF/0.46 kg for the new protocol of multiple trials, which proved to be the most reliable. The minimal detectable change (MDC) was 2.77% BF/1.87 kg for single trials and 1.72% BF/1.26 kg for the new protocol.

French translation and validation of the Keele STarT MSK Tool

Background The Keele STarT MSK Tool is a 10-item questionnaire developed to classify patients suffering from one of the five most common types of musculoskeletal pain into 3 sub-groups of risk of chronic pain (i.e. low risk, medium risk and high risk). Objective The objective of the present study was to translate the Keele STarT MSK Tool into French and to evaluate its main psychometric properties. Methods The translation and intercultural adaptation of the questionnaire were carried out using a 6-step process. The following psychometric properties were investigated: floor and ceiling effects, construct validity, internal consistency and test-retest reliability including Standard Error of Measurement and Smallest Detectable Change. Results 101 patients suffering from musculoskeletal pain participated in the study. No floor nor ceiling effects were observed. A Cronbach’s alpha of 0.65 was found, revealing a moderate internal consistency. Nevertheless, all items were demonstrated to be significantly correlated with the total score (range of correlations: r=0.2 for item 7 to r=0.78 for item 1). A good construct validity was also found with a significant correlation of r=0.78 between the French Keele STarT MSK Tool and the ÖMPSQ-short. Test-retest reliability was excellent (Intraclass Correlation Coefficient 0.97). A Standard Error of Measurement of 0.42 and a Smallest Detectable Change of ±1.17 were measured. Conclusion A validated French version of the Keele STarT MSK Tool is now available and can be used by health practitioners to stratify patients as being at low, medium or high risk of persistent musculoskeletal pain.