Abstract:Objective: To determine whether multiple examiners could be trained to measure lower extremity anatomic characteristics with acceptable reliability and precision, both within (intratester) and between (intertester) testers. We also determined whether testers trained 18 months apart could perform these measurements with good agreement. Setting: University's Applied Neuromechanics Research Laboratory. Participants: Sixteen, healthy participants (7 men, 9 women). Assessment of Risk Factors: Six investigators measured 12 anatomic characteristics on the right lower extremity in the Fall of 2004. Four testers underwent training immediately preceding the study, and measured subjects on 2 separate days to examine intratester reliability. Two testers trained 18 months before the study (Spring 2002) measured each subject on day 1 to examine the consistency of intertester reliability when testers are trained at different times. Main Outcome Measurements: Knee laxity, genu recurvatum, quadriceps angle, tibial torsion, tibiofemoral angle, hamstring extensibility, pelvic angle, navicular drop, femur length, tibial length, and hip anteversion. Results: With few exceptions, all testers consistently measured each variable between test days (intraclass correlation coefficient>=0.80). Intraclass correlation coefficient values were lower for intertester reliability (0.48 to 0.97), and improved from day 1 to day 2. Intertester reliability was similar when comparing testers trained 18 months before those trained immediately before the study. Absolute measurement error varied considerably across individual testers. Conclusions: Multiple investigators can be trained at different times to measure anatomic characteristics with good to excellent intratester reliability. Intratester reliability did not always ensure acceptable intertester reliability or measurement precision, suggesting more training (or more experience) may be required to achieve acceptable measurement reliability and precision between multiple testers.Keywords: lower extremity alignment | risk factor assessment | posture | measurement stability Article:Little is known about the factors that predispose an individual to anterior cruciate ligament (ACL) injury.1,2 In part, this is because of the myriad of factors that have been proposed to explain the risk of ACL injury. Controlling and measuring multiple variables creates considerable challenges, as variables have the potential to interact with one another, and many of these variables are poorly defined or difficult to obtain reliably.3 Many of the potential risk factors cannot be measured after ACL disruption, because the injury modifies the risk factors, [4][5][6][7][8][9][10][11] and bilateral asymmetry cannot always be assumed. 12,13Because of these limitations, large prospective studies are recommended to identify ACL injury risk factors.14-17 However, prospective studies present their own challenges, as a large cohort of subjects is needed to yield sufficient ACL injuries. Uhorchak et al 16 prospectively fol...

Selected lower limb injuries and, in particular, those of the knee have been reported to occur in greater prevalence in females compared to males. 4,29,49,60,61,85 Sex differences in lower extremity alignment (LEA) have been included among a myriad of risk factors as a potential cause for the prevalence of knee injury in females. 21,29,34,33,47 Anecdotally, females have been cited as having greater anterior pelvic tilt, femoral anteversion, tibiofemoral angle, quadriceps angle, genu recurvatum, tibial torsion, and foot pronation. 21,29 However, apart from the measure of quadriceps angle, there is little empirical data to support these sex differences in a healthy population.While the literature consistently demonstrates greater mean quadriceps angles in females, 1,23,24,26,28,84 limited studies support a sex difference in mean pelvic tilt 24 and genu recurvatum. 81 Conversely, no sex differences have been observed with measures of tibial torsion 57,77 and foot pronation as measured by navicular drop 6,24,51,81 t StuDy DeSign: Descriptive, cohort design.t ObJectiveS: To comprehensively examine sex differences in clinical measures of static lower extremity alignment (LEA).t bAckgrOunD: Sex differences in LEA have been included among a myriad of risk factors as a potential cause for the increased prevalence of knee injury in females. While clinical observations suggest that sex differences in LEA exist, little empirical data are available to support these sex differences or the normal values that should be expected in a healthy population.t MethODS AnD MeASureS: The right and left static LEA of 100 healthy college-age participants (50 males [mean 6 SD age, 23.3 6 3.6 years; height, 177.8 6 8.0 cm, body mass, 80.4 6 11.6 kg] and 50 females [mean 6 SD age, 21.8 6 2.5 years; height, 164.3 6 6.9 cm; body mass, 67.4 6 15.2 kg]) was measured. Each alignment characteristic was analyzed via separate repeated-measures analyses of variance, with 1 between-subject factor (sex) and 1 within-subject factor (side).t reSultS: There were no significant sex-byside interactions and no differences between sides. Females had greater mean anterior pelvic tilt, hip anteversion, quadriceps angles, tibiofemoral angles, and genu recurvatum than males (P<.0001). No sex differences were observed in tibial torsion (P = .131), navicular drop (P = .130), and rearfoot angle (P = .590).t cOncluSiOn: Sex differences in LEA indicate that females, on average, have greater anterior pelvic tilt, thigh internal rotation, knee valgus, and genu recurvatum. These sex differences were not accompanied by differences in the lower leg, ankle, and foot. Understanding these collective sex differences in LEA may help us to better examine the influence of LEA on dynamic lower extremity function and clarify their role as a potential injury risk factor.

ABSTRACT:We examined sex differences in general joint laxity (GJL), and anterior-posterior displacement (ANT-POST), varus-valgus rotation (VR-VL), and internal-external rotation (INT-EXT) knee laxities, and determined whether greater ANT and GJL predicted greater VR-VL and INT-EXT. Twenty subjects were measured for GJL, and scored on a scale of 0-9. ANT and POST were measured using a standard knee arthrometer at 133 N. VR-VL and INT-EXT were measured using a custom joint laxity testing device, defined as the angular displacements (deg) of the tibia relative to the femur produced by 0-10 Nm of varus-valgus torques, and 0-5 Nm of internalexternal torques, respectively. INT-EXT were measured during both non-weight-bearing (NWB) and weight-bearing (WB ¼ 40% body weight) conditions while VR-VL were measured NWB. All laxity measures were greater for females compared to males except for POST. ANT and GJL positively predicted 62.5% of the variance in VR-VL and 41.8% of the variance in WB INT-EXT. ANT was the sole predictor of INT-EXT in NWB, explaining 42.3% of the variance. These findings suggest that subjects who score higher on clinical measures of GJL and ANT are also likely to have greater VR-VL and INT-EXT knee laxities. ß

ABSTRACT:We examined the capabilities of the Vermont Knee Laxity Device (VKLD) in measuring varus (VR)-valgus (VL) and internal (INT)-external (EXT) rotational laxities by quantifying measurement consistency and absolute measurement error (N ¼ 10). Based on the expected measurement error, we then examined side-to-side differences (N ¼ 20). For all measures, the knee was flexed 208, the thigh securely fixed, and counterweights applied to the thigh and shank to create an initial zero shear and compressive load across the tibiofemoral joint. A 10-Nm torque was applied to the knee for VL and VR during non-weight-bearing, and a 5-Nm torque was applied for INT and EXT during non-weight-bearing and weight-bearing conditions. Position sensors measured angular displacements (deg). Except for INT during weight bearing, measurement consistency was good to excellent (range, 0.68-0.96), with absolute measurement errors generally less than 28 for VR-VL and 3-48 for INT-EXT. Although side-to-side differences were observed, they did not exceed absolute measurement errors. The VKLD yields reliable measures of VR-VL and INT-EXT laxities, with sufficient measurement precision to yield clinically relevant differences. ß

No abstract

The rapid development of telecommunication and Internet services enables smartphone users to access online services faster and create more demand for using high-speed data services. The third generation (3G) mobile services have become the pioneer for the trend of high speed data transmission for years. This study aims to explore the factors that affect behavioral intention of adopting 3G mobile telecommunications. After implementing a structural equation modeling to analyze the data collection of 223 self-administered correspondents, we found that perceived factors, including ease of use, usefulness and enjoyment have a significantly positive relationship with attitude and while the attitude is positively associated with behavioral intention to use 3G. Based on the results, the research enables us to propose several practical recommendations to 3G providers in Vietnam such as 3G providers should provide more interesting and entertaining contents in their 3G applications and services, which charge appropriate fees and are easy to use for customers. In addition, 3G providers should focus on customers' attitude by listening and receiving customers' feedbacks to improve 3G technological solutions and value-added services.

Background-Torsional joint stiffness is thought to play in role in the observed sex bias in noncontact ACL injury rates.

Changes in anterior knee laxity (AKL), genu recurvatum (GR) and general joint laxity (GJL) were quantified across days of the early follicular and early luteal phases of the menstrual cycle in 66 females, and the similarity in their pattern of cyclic variations examined. Laxity was measured on each of the first 6 days of menses (M1-M6) and the first 8 days following ovulation (L1-L8) over two cycles. The largest mean differences were observed between L5 and L8 for AKL (0.32 mm), and between L5 and M1 for GR (0.56 • ) and GJL (0.26) (p < 0.013). At the individual level, mean absolute cyclic changes in AKL (1.8 ± 0.7 mm, 1.6 ± 0.7 mm), GR (2.8 ± 1.0 • , 2.4 ± 1.0 • ), and GJL (1.1 ± 1.1, 0.7 ± 1.0) were more apparent, with minimum, maximum and delta values being quite consistent from month to month (ICC 2,3 = 0.51-0.98). Although the average daily pattern of change in laxity was quite similar between variables (Spearman correlation range 0.61 and 0.90), correlations between laxity measures at the individual level were much lower (range −0.07 to 0.43). Substantial, similar, and reproducible cyclic changes in AKL, GR, and GJL were observed across the menstrual cycle, with the magnitude and pattern of cyclic changes varying considerably among females. © Joint laxity continues to be a variable of interest as we seek to uncover the underlying risk factors for ACL injury in females.