The purpose of this study was to calculate the coefficients of variation in jump performance for individual participants in multiple trials over time to determine the extent to which there are real differences in the error of measurement between participants. The effect of training phase on measurement error was also investigated. Six subjects participated in a resistance-training intervention for 12 wk with mean power from a countermovement jump measured 6 d/wk. Using a mixed-model meta-analysis, differences between subjects, within-subject changes between training phases, and the mean error values during different phases of training were examined. Small, substantial factor differences of 1.11 were observed between subjects; however, the finding was unclear based on the width of the confidence limits. The mean error was clearly higher during overload training than baseline training, by a factor of ×/÷ 1.3 (confidence limits 1.0–1.6). The random factor representing the interaction between subjects and training phases revealed further substantial differences of ×/÷ 1.2 (1.1–1.3), indicating that on average, the error of measurement in some subjects changes more than in others when overload training is introduced. The results from this study provide the first indication that within-subject variability in performance is substantially different between training phases and, possibly, different between individuals. The implications of these findings for monitoring individuals and estimating sample size are discussed.
Kristie-Lee Taylor, Will G. Hopkins, Dale W. Chapman and John B. Cronin
Amir K. Vafadar, Julie N. Cote and Philippe S. Archambault
Context: Joint-position sense (JPS) plays a critical role in the stability of shoulder joint. Restoration of JPS is essential to improve rehabilitation outcomes in individuals with shoulder injury. However, the number of affordable and reliable shoulder-JPS measurement methods for everyday clinical practice is limited. Objective:To estimate reliability and validity of 3 simple shoulder-JPS measurement methods. Design: Cross-sectional study. Participants: 25 healthy men and women. Main Outcome Measure: Absolute-error scores of JPS in 3 ranges of shoulder flexion (low, mid, and high), measured with a laser pointer, an inclinometer, and a goniometer in 2 separate sessions (48 h apart). Results: Overall interrater and intrarater intraclass correlation coefficients were .86 and .78 for the laser pointer, .67 and .70 for the inclinometer, and .60 and .50 for the goniometer, respectively. There was excellent reliability in the low range for the laser pointer and inclinometer methods, but fair to good and poor reliability in mid- and high ranges, respectively. All methods showed strong validity. Conclusion: The laser pointer and inclinometer JPS measurement methods are reliable and can be used by clinicians during rehabilitation of shoulder injuries.
Guilherme S. Nunes, Gabriela S. Bayer, Leticia M.R. da Costa and Marcos de Noronha
Context: Physical therapists often have to measure ankle range of motion (ROM) to decide on intervention and investigate improvements. The most common method of measurement is goniometry, but it has been questioned due to its unsatisfactory levels of reliability. Objective: To investigate the intraobserver and interobserver reliability of a new method of measuring plantar-flexion ROM. Design: Prospective and descriptive. Setting: Laboratory. Participants: 20 healthy participants (12 women and 8 men). Main Outcome Measurements: Ankle plantar flexion was measured by 3 observers (A, B, and C) with 3 methods (goniometry, measurement in hook-lying position [MHP], and static-image analysis [SIA]). Observer A was the most experienced therapist, and C, the least. MHP was performed with the participant in the supine position, knees flexed, and first and fifth metatarsals in contact with the treatment table. SIA was recorded and analyzed in the same position. Goniometry was performed with participant seated, lower legs unsupported, and axis positioned on the lateral malleolus. Results: For the interobserver analysis, the ICC2,1 was high for the MHP (.88), high for SIA (.87), and moderate for goniometry (.57). For the intraobserver analysis, the ICC2,1 was high or very high for MHP (.91-.92), high for SIA (.79-.83), and low to moderate for goniometry (.18-.60). Conclusion: MHP is inexpensive, fast, and more reliable than goniometry for measuring plantar-flexion ROM.
Paula M. Ludewig, Thomas M. Cook and Richard K. Shields
A common method of tracking humeral motion involves securing a thermoplastic cuff to the humerus with an electromagnetic sensor attached. The data on the accuracy of this technique are limited. This study addressed two questions: (a) How similar are surface and bone-fixed measurements of 3-D humeral rotations? (b) How similar are surface and bone-fixed measurements of 3-D humeral translations? Electromagnetic motion sensors were secured to a bone-fixed external humeral fixator, a surface humeral cuff, and the skin over the sternum and scapular acromion process. The 3-D data were collected during successive slow velocity (10–20°/second) repetitions of humeral active-assisted scapular plane abduction, sagittal plane flexion, and internal/external rotation with the arm adducted. Root mean square errors of surface measures compared to bone-fixed angular and translational values were calculated, and paired t-tests were computed between the two methods. Root mean square errors for humeral rotations ranged from 1° (1%) for humeral elevation during scapular plane abduction to 7.5° (9%) for humeral internal/external rotation. Peak errors were under-representations of 5.7° for internal/external rotation during scapular plane abduction and 15.6° for internal rotation with the arm adducted at the side. Average translation errors ranged from 0.1 to 2.1 mm. Data from this study suggest that dynamic measurement of humeral motion with a surface humeral cuff sensor can be performed for certain slow velocity motions with root mean square errors less than 8°. Caution is called for when interpreting internal/external rotation values, which were underrepresented. Results may vary with one’s age, weight, or general physical condition, with different velocities of movement, or with different movements.
Derek N. Pamukoff, Sarah E. Bell, Eric D. Ryan and J. Troy Blackburn
Hamstring musculotendinous stiffness (MTS) is associated with lower-extremity injury risk (ie, hamstring strain, anterior cruciate ligament injury) and is commonly assessed using the damped oscillatory technique. However, despite a preponderance of studies that measure MTS reliably in laboratory settings, there are no valid clinical measurement tools. A valid clinical measurement technique is needed to assess MTS and permit identification of individuals at heightened risk of injury and track rehabilitation progress.
To determine the validity and reliability of the Myotonometer for measuring active hamstring MTS.
Descriptive laboratory study.
33 healthy participants (15 men, age 21.33 ± 2.94 y, height 172.03 ± 16.36 cm, mass 74.21 ± 16.36 kg).
Main Outcome Measures:
Hamstring MTS was assessed using the damped oscillatory technique and the Myotonometer. Intraclass correlations were used to determine the intrasession, intersession, and interrater reliability of the Myotonometer. Criterion validity was assessed via Pearson product–moment correlation between MTS measures obtained from the Myotonometer and from the damped oscillatory technique.
The Myotonometer demonstrated good intrasession (ICC3,1 = .807) and interrater reliability (ICC2,k = .830) and moderate intersession reliability (ICC2,k = .693). However, it did not provide a valid measurement of MTS compared with the damped oscillatory technique (r = .346, P = .061).
The Myotonometer does not provide a valid measure of active hamstring MTS. Although the Myotonometer does not measure active MTS, it possesses good reliability and portability and could be used clinically to measure tissue compliance, muscle tone, or spasticity associated with multiple musculoskeletal disorders. Future research should focus on portable and clinically applicable tools to measure active hamstring MTS in efforts to prevent and monitor injuries.
Tom G.A. Stevens, Cornelis J. de Ruiter, Cas van Niel, Roxanne van de Rhee, Peter J. Beek and Geert J.P. Savelsbergh
A local position measurement (LPM) system can accurately track the distance covered and the average speed of whole-body movements. However, for the quantification of a soccer player’s workload, accelerations rather than positions or speeds are essential. The main purpose of the current study was therefore to determine the accuracy of LPM in measuring average and peak accelerations for a broad range of (maximal) soccerspecific movements.
Twelve male amateur soccer players performed 8 movements (categorized in straight runs and runs involving a sudden change in direction of 90° or 180°) at 3 intensities (jog, submaximal, maximal). Position-related parameters recorded with LPM were compared with Vicon motion-analysis data sampled at 100 Hz. The differences between LPM and Vicon data were expressed as percentage of the Vicon data.
LPM provided reasonably accurate measurements for distance, average speed, and peak speed (differences within 2% across all movements and intensities). For average acceleration and deceleration, absolute bias and 95% limits of agreement were 0.01 ± 0.36 m/s2 and 0.02 ± 0.38 m/s2, respectively. On average, peak acceleration was overestimated (0.48 ± 1.27 m/s2) by LPM, while peak deceleration was underestimated (0.32 ± 1.17 m/s2).
LPM accuracy appears acceptable for most measurements of average acceleration and deceleration, but for peak acceleration and deceleration accuracy is limited. However, when these error margins are kept in mind, the system may be used in practice for quantifying average accelerations and parameters such as summed accelerations or time spent in acceleration zones.
Bram L. Newman, Courtney L. Pollock and Michael A. Hunt
Context: Lateral trunk-flexion strength is an important determinant of overall trunk stability and function, but the reliability in measuring this outcome clinically in athletic individuals is not known. Objective: To determine the interrater and intrarater reliability of lateral trunk-flexion strength measurement in athletic individuals using handheld dynamometry. Design: Reliability study. Setting: Research laboratory. Participants: 12 healthy, athletic individuals. Intervention: Lateral trunk-flexion strength was measured using handheld dynamometry across 2 different trunk placements (lateral aspect of the axilla and laterally at the level of the midtrunk) and 2 testing occasions by 2 therapists. Three maximum-effort trials during a "make test" at each placement were completed for each therapist on both occasions. Main Outcome Measures: Maximum force output was identified and converted to a torque. Intraclass correlation coefficients (ICC2,1) were calculated for each dynamometer placement, therapist, and test occasion to determine intrarater and interrater reliability. Results: Intrarater reliability was moderate to good (ICC2,1 = .53-.77), while interrater reliability was good to very good (ICC2,1 = .79-81) at the axilla position. For the midtrunk position, intrarater reliability was good to very good (ICC2,1 = .80-.86), while interrater reliability was good on both days (ICC2,1 = .87-.88). Finally, the standard errors of measurement were low for the axilla position (0.20 Nm/kg; 95% CI .15, .28) and midtrunk position (0.09 Nm/kg; 95% CI .07, .12). Conclusions: Maximum lateral trunk-flexion strength can be reliably measured in athletic individuals with greater overall strength. Based on the 2 positions used in this study, measurement with a dynamometer placement at the midtrunk may be more reliable than that obtained at the axilla.
Sinem Suner-Keklik, Gamze Cobanoglu-Seven, Nihan Kafa, Mustafa Ugurlu and Nevin Atalay Guzel
Context: Proprioception is the basic element of the spontaneous control of movement, balance and joint stability. Therefore, it is necessary for the execution of walking and daily and sport activities. Loss of proprioception of the knee, which may cause a new injury, is important to evaluate the position sense of the joint during the rehabilitation period. However, the evaluation methods that are used are very expensive, complicated and nonportable, or the measuring method is difficult to implement. Objective: We demonstrated the validity and reliability of knee proprioception measurements performed in the open kinetic chain position and closed kinetic chain position with a dual inclinometer. Design: We assessed the validity and intratester reliability of a digital inclinometer for measuring the knee joint position sense in different positions. Setting: Clinical laboratory. Participants: We enrolled 22 participants (age = 21.8 ± 0.95 y, height = 172 ± 9.1 cm, weight = 64.9 ± 14 kg) into the study. Intervention: The same investigator used an inclinometer to take knee proprioception measurements in open and closed kinetic chain positions. Main Outcome Measures: The relative angular error was calculated by taking the arithmetic average of the difference between the target angle and reproduced angle and was the main outcome measure. Results: We found that the dynamometer-inclinometer had a moderate ICC value (ICC = 0.594, SEM = 1.60, P = .005), whereas inclinometer t1 vs inclinometer t2 (ICC = 0.778, SEM = 0.62, P < 0.001) and closed kinetic chain position t1 and closed kinetic chain position t2 (ICC = 0.888, SEM = 0.63, P < 0.001) had high ICC values. Conclusion: Knee proprioception measurements performed with a dual inclinometer were reliable in the closed kinetic chain position in healthy, sedentary individuals and were valid and reliable in the open kinetic chain position.
Stephen Silverman and Prithwi Raj Subramaniam
This paper reviews the literature on student attitude in physical education. First, an overview of the concept of attitude is presented followed by a discussion of why we need to investigate student attitude. Next, there is a detailed discussion of issues related to attitude measurement—factors that often are problematic in research in this area. Both quantitative and qualitative tools are discussed with a particular focus on developing an instrument that has the properties of reliability and validity. The third major section of the paper presents an overview of the results of attitude research in physical education. Finally, the paper concludes with implications for research in this area.
Saryn R. Goldberg, Thomas M. Kepple and Steven J. Stanhope
We increased the accuracy of an instrumented treadmill’s measurement of center of pressure and force data by calibrating in situ and optimizing the transformation between the motion capture and treadmill force plate coordinate systems. We calibrated the device in situ by applying known vertical and shear loads at known locations across the tread surface and calculating a 6 × 6 calibration matrix for the 6 output forces and moments. To optimize the transformation, we first estimated the transformation based on a locating jig and then measured center-of-pressure error across the treadmill force plate using the CalTester tool. We input these data into an optimization scheme to find the transformation between the motion capture and treadmill force plate coordinate systems that minimized the error in the center-of-pressure measurements derived from force plate and motion capture sources. When the calibration and transformation optimizations were made, the average measured error in the center of pressure was reduced to approximately 1 mm when the treadmill was stationary and to less than 3 mm when moving. Using bilateral gait data, we show the importance of calibrating these devices in situ and performing transformation optimizations.