differences of sEMG signal characteristics. The calibration and training procedures are cumbersome and time consuming. Accordingly, a generalized model is required to further promote the sEMG-based movement classification in practical applications, such as virtual control equipment, intelligent prosthesis
Xiangyu Liu, Meiyu Zhou, Chenyun Dai, Wei Chen, and Xinming Ye
Pete Coffee and Tim Rees
This article reports initial evidence of construct validity for a four-factor measure of attributions assessing the dimensions of controllability, stability, globality, and universality (the CSGU). In Study 1, using confirmatory factor analysis, factors were confirmed across least successful and most successful conditions. In Study 2, following less successful performances, correlations supported hypothesized relationships between subscales of the CSGU and subscales of the CDSII (McAuley, Duncan, & Russell, 1992). In Study 3, following less successful performances, moderated hierarchical regression analyses demonstrated that individuals have higher subsequent self-efficacy when they perceive causes of performance as controllable, and/or specific, and/or universal. An interaction for controllability and stability demonstrated that if causes are perceived as likely to recur, it is important to perceive that causes are controllable. Researchers are encouraged to use the CSGU to examine main and interactive effects of controllability and generalizability attributions upon outcomes such as self-efficacy, emotions, and performance.
Razie J. Alibazi, Afsun Nodehi Moghadam, Ann M. Cools, Enayatollah Bakhshi, and Alireza Aziz Ahari
Generalized joint hypermobility (GJH) is a term used when the majority of synovial joints in the body can perform movements beyond the normal range of motion. 1 , 2 Several studies have shown that individuals with GJH have an increased risk of joint injury. 3 – 5 It is known that in
Byron Lai, Katie Cederberg, Kerri A. Vanderbom, C. Scott Bickel, James H. Rimmer, and Robert W. Motl
explore and describe the demographic and clinical characteristics of adults with neurologic disabilities who were enrolled in exercise trials and determine if the samples, and ultimately study results, may generalize to the broader population of individuals within each disability condition. Methods This
Tim Rees, Paul Freeman, Steve Bell, and Ross Bunney
Coaches are important providers of social support, but what influences us to perceive our coaches as supportive or unsupportive? We investigated the extent to which perceptions of coach support reflect characteristics of athletes and coaches, as well as relational components. In three studies, athletes judged the actual or hypothetical supportiveness of various coaches. The methods of generalizability theory permitted us to conclude that perceptions of coach support primarily reflected relational components, with characteristics both of athletes and coaches also independently playing (lesser) roles. These findings suggest that athletes may systematically disagree on the supportiveness of their coaches.
E. Andrew Pitchford, Leah R. Ketcheson, Hyun-Jin Kwon, and Dale A. Ulrich
Research measuring physical activity behaviors during infancy is critical for evaluation of early intervention efforts to reduce rapid weight gain. There is little known about the physical activity patterns of infants, due in part to limited evidence for measurement procedures. This study sought to determine the minimal number of days and hours of accelerometry needed to reliably measure daily physical activity in infants using Generalizability (G) theory.
A total of 23 infants (14 female, 9 male) wore an accelerometer on the right ankle and right wrist for 7 days. Data were manually cleaned to remove activity counts not produced by the infant. G theory analyses were conducted on the average counts per epoch.
Reliable estimates were observed with at least 2 days (G & Φ = .910) and 12 hours (G = .806, Φ = .803) at the ankle, and with at least 3 days (G & Φ = .906) and 15 hours (G = .802, Φ = .800) at the wrist.
These results provide some of the first guidelines for objective physical activity measurement during infancy. Accelerometer monitoring periods of at least 3 days including all daytime hours appear to be sufficient for reliable measurement.
Florence Guérin, Herbert W. Marsh, and Jean-Pierre Famose
Two studies tested the generalizability of support for within- and between-construct validity based on responses to a French translation of the Physical Self-Description Questionnaire (PSDQ) by high school students. The PSDQ is a multidimensional physical self-concept instrument designed to measure 11 components: health, coordination, physical activity, body fat, sports competence, global physical, appearance, strength, flexibility, endurance, and esteem. In the first study (N = 752), preliminary reliability analysis revealed strong internal consistency and overall stability. Confirmatory factor analysis provided support for structural equivalence with the original instrument. In the second study (N = 288), PSDQ factors were related to 13 external criteria of physical fitness; each was predicted a priori to be most highly correlated with one of the PSDQ scales. Bivariate correlations and CFA models supported both the convergent and discriminant validity of the PSDQ responses. These overall results demonstrated good support for the generalizability of the PSDQ with French adolescents.
Adam Howard Coussens, Tim Rees, and Paul Freeman
Although social support is integral to the coaching process, there is only a limited understanding of the antecedents of perceived coach support. We applied generalizability theory to examine perceived coach support and its antecedents at perceiver, provider, and relational levels of analysis. Two studies were conducted in which athletes rated the degree to which they identified with a selection of coaches, and the personality, competency, and supportiveness of those coaches. Univariate analyses demonstrated that the relational component accounted for a significant amount of variance in perceived coach support in both studies. Multivariate analyses demonstrated that when athletes perceive specific coaches to be highly agreeable, competent, and individuals with whom they share a common identity, they also perceive these same coaches to be particularly supportive in comparison with other coaches.
E. Andrew Pitchford and Joonkoo Yun
Pedometers are a common instrument used to measure walking activity, yet reliability evidence in disability populations, particularly Down syndrome (DS), has received little attention. There may be systematic and random sources of error that could influence reliability under natural walking conditions. The purpose of this study was to examine the sources of variance and estimate reliability coefficients of spring-levered (SL) and piezoelectric (PZ) pedometers for adults with DS during a free-walking bout.
Seventeen adults with DS and 23 adults without a disability walked continuously for a 20-minute period wearing 2 types of pedometers, SL and PZ. Step counts were analyzed using Generalizability theory to partition and quantify variance components and calculate reliability coefficients.
The largest variance component was due to individual participant differences. Adults with DS demonstrated greater intraindividual variability, but also had relatively low proportions of residual variance, or unexplained error. The SL pedometer showed problems with interunit variance while the PZ pedometer demonstrated little systematic error. Reliability coefficients were consistently higher for the PZ pedometer.
This study found minimal systematic error and moderate reliability evidence for the PZ pedometer. This type of pedometer may be used in future research for adults with DS.
Athanasios Kolovelonis and Marios Goudas
should be further explored in physical education. Does Students’ Calibration Generalize Across Sport Tasks? The three experiments provided rather mixed results for students’ calibration across dimensions of the same task and across tasks from different sports. In fact, the magnitude of calibration