Despite the common use of elastic resistance in training, only the static loading characteristics have been studied, whereas the dynamic components remain undetermined. The purpose was to determine the effect of two movement strategies on the shoulder resultant joint moment (RJM) during internal/external rotation exercise with elastic load. Ten healthy subjects performed sweep and step movement strategies over a constant range of motion and cadence (1:1). Shoulder RJM was determined using a Newtonian model with elastic force measured by force transducer, joint angle by electrogoniometer, and limb acceleration by accelerometer. Relative to the sweep strategy, the step strategy revealed a 49% increase in angle-specific RJM during the initial phase, RJM was reduced to 67–69% during midrange, and increased to over 110% at the end of the repetition. These RJM differences were wholly attributable to strategy-dependent changes in limb acceleration. Shoulder RJM in the sweep strategy was almost entirely explained by moment of elastic force. Movement strategy can substantially alter shoulder loading despite constant range of motion and cadence, impacting the magnitude and nature of the stimulus for neuromuscular adaptation. These acceleration-dependent changes in shoulder RJM may be important to consider for exercise efficacy and safety.
Gregory Neil Hodges and Dean Johannes Kriellaars
John Cairney, Heather Clark, Dean Dudley and Dean Kriellaars
Purpose: Physical literacy (PL) has been proposed as a key construct for understanding participation in physical activity. However, the lack of an agreed-upon definition and measure has hindered research on the topic. The current study proposed and analyzed the construct validity of a PL model comprised of motor competence, perceived competence, motivation, and enjoyment. Method: The authors tested three different models in two samples: Grade 5 (N = 1,448) and Grade 7 students (N = 698). Results: The PL construct was best represented as a hierarchical model in both the Grade 5, X2(295) = 791.90, p < .001; root mean square error of approximation = .035; and comparative-fit index = .97, and the Grade 7 samples, X2(295) = 557.21, p < .001; root mean square error of approximation = .036; and comparative-fit index = .98, samples. Discussion: Future work is needed to design and evaluate a PL measure consistent with our model. Such work will help generate further research and understanding of PL.
John Cairney, Tia Kiez, E. Paul Roetert and Dean Kriellaars
While it is commonly thought that physical literacy is an early 21st-century construct and is often credited to Margaret Whitehead, in fact, the term physical literacy can be traced back to the late 1800s. In this narrative, the authors review descriptions of physical literacy that appeared in the late 19th and early to mid-20th century literature and show how physical literacy is historically tied to the reoccurring contextual issue of threats to active lifestyles and how definitional components of the construct have both remained consistent, while others changed over the course of the century. They conclude by discussing some tensions that have arisen with the Whiteheadian construction of the term, as well as the conflation of the term with fitness or physical education. In doing so, the authors hope to open up greater discussion of the multidisciplinary potential of this construct.
Dean J. Kriellaars, John Cairney, Marco A.C. Bortoleto, Tia K.M. Kiez, Dean Dudley and Patrice Aubertin
Objective: To examine the impact of circus arts instruction in physical education (PE) on the physical literacy of children in Grades 4 and 5. Methods: A clustered, quasi-experimental design was used comparing children in schools with circus arts instruction in physical education (n = 101) with children in socioeconomic status-matched schools using standard PE instruction (n = 110). Physical literacy assessments performed at the beginning and end of one semester using the Physical Literacy Assessment for Youth tools. Results: Significant improvements in motor competence for both groups; endpoint differences favored the circus arts instruction in physical education schools for 15 of 18 movement skills for Grade 5 and 7 of 18 skills for Grade 4 (p < .05), with corresponding increases in children’s confidence and comprehension of movement terminology, as well as active participation. The gap in motor competence between girls and boys in the circus arts instruction in physical education schools was smaller than in standard PE schools. Conclusions: Circus arts instruction enriched PE can effectively aid in the development of physical literacy in children with greater gender equity.
Danny P. Goel, Jonathan D. Geiger, Jacqueline J. Shan, Dean Kriellaars and Grant N. Pierce
Nutraceuticals may induce doping infractions through contamination of the product itself or their ingestion might be metabolized within the body to create a positive doping control test. We tested this possibility using a commercially available, proprietary ginseng root extract (Cold-FX®, CV Technologies Inc., Edmonton, AB). After athletes ingested Cold-FX© for 28 d at 400 mg/d, urine samples were collected and processed under strict IOC doping control guidelines and then analyzed for a full screen of IOC banned/restricted substances by an IOC-approved laboratory. There were no positive tests for any banned substances in any of the subjects. Our study demonstrates that ingestion of Cold-FX® for 28 d at 400 mg/d does not represent a doping concern for athletes. Carefully controlled clinical studies like this one are necessary to provide the athlete, the nutraceutical industry and IOC regulatory bodies with information to avoid inadvertent exposure to banned/restricted or potentially unhealthy substances.