Interday Reliability Research Articles

The influence of input excitation on the inter- and intra-day reliability of the motor unit firing rate versus recruitment threshold relationship

Decomposition of the surface electromyographic (sEMG) signal is commonly used to examine motor unit (MU) firing behavior. However, the intra- and inter-day reliability of these measurements has yet to be quantified or reported. This investigation 1) examined the effect of input excitation on the mean firing rate (MFR) vs. recruitment threshold (RT) relationship and 2) determined the inter- and intra-day reliability of the MFR vs. RT relationship at 30%, 50%, and 70% of maximum voluntary isometric strength (MVIC). Twenty-eight healthy males (23 ± 3 yr) completed two experimental visits, during which they performed MVIC testing and isometric ramp contractions at 30%, 50%, and 70% MVIC. sEMG signals were recorded from the vastus lateralis during the ramp contractions and decomposed to establish the MFR vs. RT relationship for the detected MUs. Intra- and inter-day reliability was then established for the slopes and y-intercepts of the MFR vs. RT relationship at each contraction intensity. All participants displayed significant MFR vs. RT relationships ( r range: -0.662 to -0.999; P ≤ 0.001-0.006). Intra- and inter-day intraclass correlation coefficients (ICCs) ranged from 0.766-0.824 and 0.867-0.919 for the slopes and from 0.780-0.915 and 0.804-0.927 for the y-intercepts, respectively. Furthermore, the slope coefficient was significantly greater at 70% than at 30% MVIC, and the y-intercepts increased with increasing contraction intensities. Changes in input excitation to the MU pool alter the magnitude, but not the reliability, of the slopes and y-intercepts of the MFR vs. RT relationship. NEW & NOTEWORTHY The firing behavior of the motor unit (MU) pool is often characterized using the mean firing rate vs. recruitment threshold relationship of the active MUs. Although this relationship has been widely used, this is the first study to report the effects of input excitation (contraction intensity) on the intra- and inter-day reliability of this relationship. The criteria used for MU analysis and the model utilized in this study allow for generalization to outside investigators and laboratories.

The Validity and Reliability of the MyJump2 Application to Assess Vertical Jumps in Trained Junior Athletes

ABSTRACTThis study aimed to assess the validity and reliability of jump assessments using the MyJump2 application. Eleven junior athletes (15 ± 1.4 years) performed five countermovement (CMJ) and drop jumps (DJ) measured simultaneously by a force platform and MyJump2. Additionally, intra- and inter-day reliability was assessed over two sessions, 7 days apart. Extremely high agreement between MyJump2 and the force platform (intra-class correlation coefficient, ICC ≥ 0.99) and the intra- and inter-operator agreement (ICC = 0.98–0.99) confirmed the validity and reliability of MyJump2. Mean typical errors (coefficient of variation percentage, CV%) within the first and second sessions were 4.9% and 4.5% respectively for CMJs, and 8.0% to 11.8% for DJ outcomes. CMJ height held acceptable inter-day reliability (CV < 10%; ICC > 0.8), while DJ did not. Results supported MyJump2 to be a valid and reliable tool for assessing jumps; however, with variability in DJs in this cohort, appropriate caution should be taken if including in a junior assessment battery.

Intra- and interday reliability of the dynamic navicular rise, a new measure for dynamic foot function: A descriptive, cross-sectional laboratory study

BackgroundThe lack of reliable parameters to evaluate dynamic foot function, emphasizes the need for a deeper insight in foot biomechanics. The aims were to investigate the reliability of a new parameter (dynamic navicular rise dNR), and its relationship with the dynamic navicular drop (dND). MethodsTwenty healthy participants (mean age 30.2±8.1years) had to walk on even ground and downstairs. Data of ten trials per task on two measurement days were recorded. The dNR was defined as the difference in millimetres (mm) between the minimum navicular height (NH) during stance and the NH at toe off. To test intra- and interday reliability, Intraclass Correlation Coefficients (ICC2.1) and repeatability were calculated. To obtain the absolute repeatability (RP) in mm, the equation RP=1.96×SDdifferences was used. Furthermore, the relationship between the dNR and the dND was examined by calculating Pearson (r) or Spearman (rs) correlation coefficients. ResultsIncluded participants showed a mean dNR of (12.2±3.7) mm for level walking and (14.8±3.4) mm for stair descent. The ICC2.1 for the dNR were 0.98 (intraday), 0.91 (interday) for level walking and 0.97 (intraday), 0.94 (interday) for stair descent. The interday repeatability was 3.2mm (level walking), 2.7mm (stair descent) respectively. For level walking, r was 0.31 (p=0.049), and rs=0.88 (p<0.001) for stair descent. ConclusionsThe dNR seems to be highly reliable (ICCs), however, repeatability is unacceptable. For level walking, the dNR might be an independent measure, but not for stair climbing.

The Athletic Shoulder (ASH) test: reliability of a novel upper body isometric strength test in elite rugby players

ObjectivesLower limb isometric tests are used to assess strength and strength asymmetries and monitor reductions in muscle force that may contribute to loss of performance and increase injury risk. Isometric...

Reliability of internal and external load parameters in 6 a-side and 7 a-side recreational football for health

Sedentariness and related chronic disorders have a massive impact on healthcare costs worldwide. Contrariwise to endurance-based activities, there are little information and evidence on recreational football amongst middle-aged healthy males. The aim of this study was to assess the reliability of internal and external load parameters during 6 a-side and 7 a-side recreational football formats. 20 subjects were enrolled (mean ± SDs; age = 37 ± 5 years, weight = 77 ± 12 kg, and height = 175 ± 10 cm). Participants completed a match (55 min) and replicated the same match (55 min) a week later. The football matches took place on an artificial grass outdoor field (pitch size of 40 × 25 m). The analysis performed using GPS considered several internal and external load parameters: heart rate (HR), total distance (TD), high speed running (HSR), number of accelerations (> 2 m s−2), and metabolic power (MT). We found good scores of reliability in several parameters in both 6 and 7 a-side, respectively: mean HR (ICC = 0.66 and 0.76), TD (ICC = 0.82 and 0.68, respectively), accelerations (ICC = 0.65 and 0.69, respectively), MT (ICC = 0.76 and 0.83), HSR (ICC = 0.79 and 0.78), and HMD (ICC = 0.80 and 0.78). This study revealed good/excellent scores of absolute reliability, a small mean of change, and small/trivial effect size for internal and external load parameters during the replication analysis of the football formats. Therefore, this study showed that 6 a-side and 7 a-sides are reliable recreational football formats (inter-day reliability). This new evidence can be utilised in the design of football protocols for health.

Intra-day And Inter-day Reliability Of A Combined Pre-planned And Reactive Agility Protocol

Intra-day And Inter-day Reliability Of A Combined Pre-planned And Reactive Agility Protocol

Test-retest reliability of the different dynamometric variables used to evaluate pelvic floor musculature during the menstrual cycle.

The aim of this study was to evaluate the reliability of different dynamometric variables of the pelvic floor muscles (PFM) in healthy women during different periods of menstrual cycle. Vaginal dynamometric equipment was developed by the authors and its reproducibility was tested. The PFM contractions of 20 healthy women were collected by two independent examiners over three consecutive weeks, always on the same day, with a seven-day interval between readings, starting from the first day after the end of the menstrual period. For the measurements, the branch of the dynamometer was positioned first on the sagittal plane and then on the frontal plane. Baseline, peak time, maximum PFM strength, impulse contraction, and average contraction force were calculated. Reproducibility was tested using the intra-class correlation coefficient (ICC) and standard error of measurement. Repeated-measures ANOVA was used to compare the data from different days. For intra-day and inter-day reliability between examiners, all the parameters collected on the sagittal plane presented good and excellent reproducibility (ICC2,1 = 0.60 to 0.98), whereas reproducibility on the frontal plane was respectively poor and excellent (ICC2,1 = 0.23 to 0.97). The ANOVA revealed significant differences between sessions only for the impulse of contraction for the sagittal (P = 0.005) and frontal (P = 0.03) planes. Time and contraction force parameters of the PFM are not influenced by hormonal alterations that occur during the menstrual cycle. The impulse of contraction was the only variable to demonstrate a significant difference between the first and second week of the data collection protocol. The baseline, maximum strength value, impulse of contraction, and average contraction force variables presented good to excellent reproducibility and can be safely used as a method of PFM evaluation.

Assessment of passive musculoarticular ankle stiffness in children, adolescents and young adults with haemophilic ankle arthropathy.

To measure passive musculoarticular ankle stiffness (PMAAS) and its intra- and interday reliability in adult control subjects without ankle disorders. We also sought to quantify PMAAS in children, adolescents and young adults with haemophilia (CAAwH) taking into account the accurate tibiotalar and subtalar joints structural status obtained by magnetic resonance imaging (MRI). We included 23 CAAwH and 23 typically developing boys (TDB) matched by age, weight and height, along with 25 healthy volunteers for reliability assessment. All CAAwH underwent bilateral ankle MRI, with anatomical status assessed using the International Prophylaxis Study Group MRI scale. All CAAwH underwent PMAAS testing for both sides randomly vs the dominant side (DS) in TDBs. For assessing viscous stiffness (VS) and elastic stiffness (ES), eight different oscillation frequencies were randomly repeated three times for each subject. Good-to-excellent intra- and interday reliability was observed for ES and VS variables. No relevant differences were observed between the ankle viscoelastic properties in CAAwH without joint damage and matched TDBs, whereas the study revealed significantly increased ES in the affected ankles of CAAwH with severe unilateral joint involvement compared to the non-affected joint. This study confirmed increased ES in the severely affected ankles of CAAwH compared to non-affected sides. No differences in the ankle viscoelastic properties of CAAwH with or without joint damage were observed, however, compared to matched TDB.

Congruent validity and inter-day reliability of two breath by breath metabolic carts to measure resting metabolic rate in young adults

Background & aimsAchieving high inter-day reliability is a key factor to analyze the magnitude of change in RMR, for instance after an intervention. The aims of this study were: i) to determine the congruent validity of RMR and respiratory quotient (RQ) with two breath by breath commercially available metabolic carts [CCM Express (CCM) and Ultima CardiO2 (MGU)]; and ii) to analyze the inter-day reliability of RMR and RQ measurements. Methods & resultsSeventeen young adults participated in the study. RMR measurements were performed during two consecutive 30-min periods, on two consecutive days with both metabolic carts. The 5-min period that met the steady state criteria [Coefficient of variance (CV) < 10% for VO2, VCO2, and VE, and CV<5% for RQ] and with the lowest CV average was included in further analysis. RMR values were higher with the MGU than with the CCM on both days (two-way ANOVA, P = 0.021), however, no differences were found on RQ values obtained by both metabolic carts (P = 0.642). Absolute inter-day RMR differences obtained with the MGU were higher than those obtained with the CCM (219 ± 185 vs. 158 ± 154 kcal/day, respectively, P = 0.002; 18.3 ± 17.2% vs. 13.5 ± 15.3%, respectively, P = 0.046). We observed a significant positive association of absolute inter-day differences in RMR obtained with both metabolic carts (β = 0.717; R2 = 0.743; P < 0.001). ConclusionsThe CCM metabolic cart provides lower RMR values and seems more reliable than the MGU in our sample of young adults. Our findings also suggest that a great part of inter-day variability is explained by the individuals.

Intra-session and Inter-day Reliability of the Myon 320 Electromyography System During Sub-maximal Contractions.

Electromyography systems are widely used within the field of scientific and clinical practices. The reliability of these systems are paramount when conducting research. The reliability of Myon 320 Surface Electromyography System is yet to be determined. This study aims to determine the intra-session and inter-day reliability of the Myon 320 Surface Electromyography System. Muscle activity from fifteen participants was measured at the anterior deltoid muscle during a bilateral front raise exercise, the vastus lateralis muscle during a squat exercise and the extensor carpi radialis brevis (ECRB) muscle during an isometric handgrip task. Intra-session and inter-day reliability was calculated by intraclass correlation coefficient, standard error of measurement and coefficient of variation (CV). The normalized root mean squared (RMS) surface electromyographic signals produced good intra-session and inter-day testing intraclass correlation coefficient values (range: 0.63–0.97) together with low standard error of measurement (range: 1.49–2.32) and CV (range: 95% Confidence Interval = 0.36–12.71) measures for the dynamic-and-isometric contractions. The findings indicate that the Myon 320 Surface Electromyography System produces good to fair reliability when examining intra-session and inter-day reliability. Findings of the study provide evidence of the reliability of electromyography between trials which is essential during clinical testing.

Spinal postural changes during the modified Matthiass test in healthy children : Interday and interrater reliability of dynamic rasterstereographic measurements.

The Matthiass test serves to identify postural insufficiencies by evaluating the sagittal posture but this subjective assessment may be responsible for different reports on the prevalence of postural insufficiencies in children. Previously, rasterstereography was used to objectify this clinical test. Until now, the coupling of the Matthiass test with rasterstereography has not yet been applied to children and the reliability is unknown; therefore, the objective of our study was to provide interday and interrater reliability of rasterstereographic measurements during dynamic (modified Matthiass test) and static trials (only interday) in healthy children. Trunk inclination, kyphotic, and lordotic angles were measured using rasterstereography during static and dynamic trials (modified Matthiass test: 90° shoulder flexion, hand-held load, 5% of body weight). Intraclass correlation coefficients (ICC) were calculated using atwo-way mixed model (absolute agreement, average measure). In this study 21healthy children were assessed (age range 10-12years). Dynamic rasterstereographic measurements showed fair to good interday and interrater reliability (ICC 0.46-0.70) and static measurements good to excellent interday reliability (ICC 0.63-0.91). Dynamic rasterstereography during the modified Matthiass test furnishes reliable data serving to objectify spinal changes of healthy children and detect postural insufficiencies. Additional efforts are needed to investigate how the early detection of postural insufficiencies can help to prevent back pain in children, adolescents and adults.

Reliability and Sensitivity of Neuromuscular and Perceptual Fatigue Measures in Collegiate Men's Basketball.

The purpose of this study was to establish the reliability and sensitivity of a countermovement jump (CMJ) and perceptual wellness questionnaire in NCAA Division I men's basketball players. Twelve male collegiate basketball athletes completed 3 maximal CMJ's on a portable force plate and a customized perceptual wellness questionnaire prior to training on non-consecutive days. CMJ variables were derived from computer software and used in analysis. All CMJ variables expressed acceptable trial-to-trial reliability (CV < 8%) except eccentric duration (CV = 8.3%). Peak absolute and relative power, and absolute mean power and force were capable of detecting small performance changes with CV% < SWC%. Similar trends were observed for interday reliability with the exception of flight time to contraction time (FT:CT) (CV = 10.9%), jump height (CV =12.1%), concentric duration (CV = 9.1%) and total duration (CV = 13.6%). Perceptual wellness showed acceptable interday reliability (CV = 6.9%), however was unable to detect the SWC. When assessing the CMJ, selected variables can be used to monitor acute and chronic changes in performance. CMJ variables relating to the eccentric phase may respond differently to typical CMJ variables and may provide insight into the loading mechanisms of response. Perceptual wellness questionnaires also prove to be a reliable subjective fatigue monitoring tool.

Assessment of the test-retest reliability of human gingival blood flow measurements by Laser Speckle Contrast Imaging in a healthy cohort.

The reliability of gingival blood flow measured by Laser Speckle Contrast Imaging is unknown. Our aim was to investigate the effect of factors inherent in oral mucosa measurement on intra-day and inter-day reliability. Gingival blood flow was measured in seventy healthy subjects. First, measurements were obtained by varying the incidence angle of imaging, using a lip retractor. Second, 3 snapshots were taken with closure of the mouth in-between, and lips were retracted by a dental mirror. These were repeated 1week later. Third, snapshots were taken either by direct view or using a mirror. Reliability was assessed based on coefficient of variation. Unlike retraction of the lips and the mirror, the incidence angle had an effect on mean blood flow. The coefficient of variation within a subject was 6.4% with the mouth constantly open. With retraction, the intra-session, and the inter-day coefficient of variation were 8.3% and 10.5%, respectively. The coefficient of variation was 11.9% by alternating direct and indirect imaging. Laser Speckle Contrast Imaging has good short- and long-term reliability regardless of lip retraction or an indirect view. This technique seems to be appropriate for the long-term clinical non-invasive follow-up of gingival microcirculation.

A Novel Method to Reduce the Impact of Countermovement Jump Monitoring In Professional Rugby Athletes

The countermovement jump (CMJ) is widely used to monitor jump performance, with greater interest being demonstrated in the propulsive phase. When landing from a CMJ, high forces are produced; this can increase the risk of injury. The present study aimed to test the validity and reliability of a countermovement jump to a box (CMBJ) where the forces associated with the landing are reduced. Eighteen professional rugby athletes (age=22 ± 2 years; body mass=104.2 ± 13.0 kg; height=187.4 ± 7.1 cm) performed 3 CMJ’s and 3 CMBJ’s on 3 different occasions. Net impulse (N.s), peak and mean absolute and relative force (N; N/kg) were obtained from a force plate system. The kinetic validity of the CMBJ was assessed by calculating the intraclass correlation coefficient, Pearson product-moment correlation, Cohen’s effect sizes and statistical hypothesis testing (paired t-test) in comparison to the CMJ. Intraday and interday reliability was assessed for each variable for both jumping conditions by calculating typical error, within subject coefficient of variation and intraclass correlation coefficient. Nonsignificant, trivial differences between the CMJ and CMBJ were observed for all jump variables. Low within-subject variability was observed between the CMJ and CMBJ for all variables. Interday and intraday variability showed good reliability and an almost perfect interday agreement score. In conclusion, net impulse, peak and mean force and relative peak and mean force obtained from a CMBJ are valid and reliable to monitor jump performance. This data demonstrates that the CMBJ is a viable alternative to monitor jump performance in athletes.

A minimal markerset for three-dimensional foot function assessment: measuring navicular drop and drift under dynamic conditions

BackgroundThe validity of predicting foot pronation occurring mainly at the midfoot by surrogate measures from the rearfoot, like eversion excursion, is limited. The dynamic navicular mobility in terms of vertical navicular drop (dNDrop) and medial navicular drift (dNDrift) may be regarded as meaningful clinical indicators to represent overall foot function. This study aimed to develop a minimal approach to measure the two parameters and to examine their intra- and interday reliability during walking.MethodsThe minimal markerset uses markers at the lateral and medial caput of the 1st and 5th metatarsals, respectively, at the dorsal calcaneus and at the tuberosity of the navicular bone. Dynamic navicular drop and drift were assessed with three-dimensional motion capture in 21 healthy individuals using a single-examiner test-retest study design.ResultsIntra- and interday repeatability were 1.1 mm (ICC21 0.97) and 2.3 mm (ICC21 0.87) for dynamic navicular drop and 1.5 mm (ICC21 0.96) and 5.3 mm (ICC21 0.46) for dynamic navicular drift. The contribution of instrumental errors was estimated to 0.25 mm for dynamic navicular drop and 0.86 mm for dynamic navicular drift.ConclusionsInterday reliability was generally worse than intraday reliability primary due to day-to-day variations in movement patterns and the contribution of instrumental errors was below 23% for dynamic navicular drop but reached 57% for dynamic navicular drift. The minimal markerset allows to simply transfer the known concepts of navicular drop and drift from quasi-static clinical test conditions to functional tasks, which is recommended to more closely relate assessments to the functional behavior of the foot.

VARIABILIDADE E CONFIABILIDADE DOS PARÂMETROS CINEMÁTICOS DA MARCHA DE IDOSOS APÓS UM TROPEÇO CONTROLADO: ESTUDO PRELIMINAR

Approximately 21% of the falls in older adults occur due to tripping, while walking. There is a paucity of information regarding the gait variability and reliability when a tripping is induced in different days mainly with elderly. It was aimed to analyze the variability and the reliability (intra- and inter-day) of spatiotemporal gait parameters and joint angles after controlled tripping in older adults. Eight healthy older women participated. The trip was induced during the early-mid swing phase on the transposing segment and the kinematic data was obtained from trials. The variability and reliability of spatiotemporal gait parameters and joint angles during the gait cycle were checked through the coefficient of variation (CV), the intraclass coefficient correlation (ICC) and the standard error of measurement (SEM). The variability of spatiotemporal and intra- and inter-day angular parameters was low for most variables, except for plantar flexion. The SEM was low for all parameters. Intra-day reliability was moderate to high for the spatiotemporal and angular parameters. Inter-day reliability was considered low to moderate for all parameters. The variables did not differ between instants and days. Experimental procedures demonstrate that the walking pattern did not change, but should be considered with caution in studies that include intervention, particularly for angular parameters during gait.

Number of trials necessary to achieve reliable change-of-direction measurement in amateur basketball players

This study examined the inter-day reliability and repeatability of change-of-direction (COD) performance to determine the minimum number of measurement trials required to represent a stable athlete...

Inter-day reliability of a Wattbike cycle ergometer sprint protocol in male rugby players

Inter-day reliability of a Wattbike cycle ergometer sprint protocol in male rugby players

Inter-day reliability of surface electromyography recordings of the lumbar part of erector spinae longissimus and trapezius descendens during box lifting

BackgroundLow back pain and neck-shoulder pain are the most reported types of work-related musculoskeletal disorders, and performing heavy lifting at work and working with trunk rotation increase the risk of developing work-related musculoskeletal disorders. Surface electromyography (sEMG) provides information about the electrical activity of muscles. Thus it has the potential to retrieve indirect information about the physical exposure of specific muscles of workers during their actual work. This study aimed to investigate the inter-day reliability of absolute and normalized amplitude of sEMG measurements obtained during repeated standardized reference lifts.MethodsThe inter-day reliability of sEMG of the erector spinae longissimus and trapezius descendens muscles was tested during standardized box lifts. The lifts were performed with loads of 3, 15 and 30 kg from floor to table and from table to table in three conditions, i.e., forearm length (short reaching distance), ¾ arm length (long reaching distance) and forearm length with trunk rotation. Absolute and normalized root mean square (absRMS and normRMS) values were extracted. In line with the guidelines for reporting reliability and agreement studies, we reported relative and absolute reliability estimated by intra class correlation (ICC3,K), standard error of measurement (SEM) and minimal detectable change in percent (MDC).ResultsThe ICC3,K was higher for absRMS compared with normRMS while SEM and maximal voluntary contraction (MVC) were similar. A total of 50 out of 56, i.e., 89%, and 41 out of 56, i.e., 73%, of the lifting situations were in the range from moderate to almost perfect for absRMS and normRMS, respectively. The SEM and MDC shoved more variation in the lifting situations performed from floor to table and in the trapezius descendens muscle than in the erector spinae longissimus muscle.ConclusionThis reliability study showed that maximum absRMS and normRMS were found to have a fair to substantial relative inter-day reliability for most lifts but were more reliable when lifting from table to table than from floor to table for both trapezius descendens and erector spinae muscles. The relative inter-day reliability was higher for absolute compared with normalized sEMG amplitudes while the absolute reliability was similar.

Inter-Day Reliability of Finapres ® Cardiovascular Measurements During Rest and Exercise.

This study evaluated the inter-day test-retest reliability of the Finapres ® finger pulse pressure measuring device during rest and exercise. Eight male participants visited the laboratory twice for evaluation of the inter-day reliability of the Finapres ® finger-pulse pressure device to measure: heart rate (HR), stroke volume (SV), cardiac output (Q̇) and mean arterial pressure (MAP) at rest, and treadmill walking at 3 km/h on 1% and 5% inclines. There were no systematic biases for any of the variables between days. The coefficient of variation (CV%) and 95% limits of agreement (95% LoA) was smallest for MAP (CV%=1.6–3.2%; LoA total error=4.6–12 mmHg) and HR (CV%=3.2–3.9%; LoA total error=6.8–11.9 b/min), increasing with exercise intensity (gradient). The pattern of error was different for Q̇, with decreasing CV% (4.8–3.8%) and LoA (4.2–5.7 L/min) from rest to 5% gradient, with the larger errors occurring for resting SV (CV=7.4%; LoA total error=21.5 ml). The device measures MAP and HR reliably between days; however, error increases at higher intensities. The measurement of SV is less reliable, probably owing to underlying algorithmic assumptions.