The BodPod® (COSMED, Concord, CA) uses predicted (pTGV) or measured thoracic gas volume (mTGV) during estimations of percentage body fat (%BF). In young adults, there is inconsistent evidence on the variation between pTGV and mTGV, and the effect of sex as a potential covariate on this relationship is unknown. This study examined the difference between TGV assessments and its effect on %BF and potential sex differences that may impact this relationship. A retrospective analysis of BodPod® pTGV and mTGV for 95 men and 86 women ages 18–30 years was performed. Predicted TGV was lower than mTGV for men (−0.49 ± 0.7 L; p < .0001). For men, %BF derived by pTGV was lower than that by mTGV (−1.3 ± 1.8%; p < .0001). For women, no differences were found between pTGV and mTGV (−0.08 ± 0.6 L; p > .05) or %BF (−0.03 ± 0.2%; p > .05). The two-predictor model of sex and height was able to account for 57.9% of the variance in mTGV, F(2, 178) = 122.5, p < .0001. Sex corrected for the effect of height was a significant predictor of mTGV (β = 0.483 L, p < .0001). There is bias for pTGV to underestimate mTGV in individuals with a large mTGV, which can lead to significant underestimations of %BF in young adults; this was especially evident for men in this study. Sex is an important covariate that should be considered when deciding to use pTGV. The results indicate that TGV should be measured whenever possible for both men and women ages 18–30 years.
Jeremy B. Ducharme, Ann L. Gibson, and Christine M. Mermier
Vitor de Salles Painelli, Emerson L. Teixeira, Bruno Tardone, Marina Moreno, Jonatas Morandini, Victória H. Larrain, and Flávio O. Pires
The long-standing caffeine habituation paradigm was never investigated in strength endurance and jumping exercise performance through a straightforward methodology. The authors examined if habitual caffeine consumption would influence the caffeine ergogenic effects on strength endurance and jumping performance as well as perceptual responses. Thirty-six strength-trained individuals were mathematically allocated into tertiles according to their habitual caffeine consumption: low (20 ± 11 mg/day), moderate (88 ± 33 mg/day), and high consumers (281 ± 167 mg/day). Then, in a double-blind, crossover, counterbalanced fashion, they performed a countermovement vertical jump test and a strength endurance test either after caffeine (6 mg/kg) and placebo supplementation or after no supplementation (control). Perceptual responses such as ratings of perceived exertion and pain were measured at the termination of the exercises. Acute caffeine supplementation improved countermovement vertical jump performance (p = .001) and total repetitions (p = .004), regardless of caffeine habituation. Accordingly, analysis of absolute change from the control session showed that caffeine promoted a significantly greater improvement in both countermovement vertical jump performance (p = .004) and total repetitions (p = .0001) compared with placebo. Caffeine did not affect the rating of perceived exertion and pain in any exercise tests, irrespective of tertiles (for all comparisons, p > .05 for both measures). Caffeine side effects were similar in low, moderate, and high caffeine consumers. These results show that habitual caffeine consumption does not influence the potential of caffeine as an ergogenic aid in strength endurance and jumping exercise performance, thus challenging recommendations to withdraw from the habitual caffeine consumption before supplementing with caffeine.
Bruno Ruiz Brandão da Costa, Rafaela Rocha Roiffé, and Márcia Nogueira da Silva de la Cruz
The growing consumer awareness regarding health and fitness has been leading to a huge rise in the consumption of nutritional supplements and, consequently, to an increase in concerns about their quality. In this sense, one of the most consumed products is protein supplements and, despite being safer than other types of supplements, there are several studies showing incompatibilities between what is present on the labels and their actual content. Therefore, this review is focused on gathering information about the problems arising from poor manufacturing practices and inadequate quality control of sport protein supplements. These issues are mainly related to three aspects: reduction of the supplements’ nutritional value, the presence of pharmacological substances, and contamination with microorganisms or toxic metals. Regarding the first aspect, reports about the “classic” addition of nitrogen-rich compounds to mask the protein content measured by the Kjeldahl method were discussed, as well as recent topics such as the addition of cheaper proteins to produce an “undetectable” adulteration in whey protein supplements. With respect to the presence of pharmacological compounds, it is a finding that is not very common in protein supplements; however, even trace amounts of foreign substances in this type of product may cause adverse effects to consumers, and, in the case of an elite athlete, may result in doping. Finally, we discuss about the contamination with microorganisms and toxic metals, this latter being a subject that should be further explored due to few studies in the literature.
Hans van der Mars, Hal A. Lawson, Murray Mitchell, and Phillip Ward
Notwithstanding the contributions of a few policy experts, overall physical education is constrained by policy illiteracy and neglect. A brief historical perspective on physical education policy provides a foundation for “a policy primer” founded on three recurring needs: (a) antecedent and corequisite factors meriting attention in support of policy improvement, (b) field-wide capacity-building in support of policy advocacy and improvement, and (c) specialized policy courses and seminars in physical education teacher education and doctoral physical education teacher education programs. Recommendations for policy-focused research and development structure a new agenda that merits attention and action.
Phillip Ward, Hans van der Mars, Murray F. Mitchell, and Hal A. Lawson
Manifest challenges to physical education teachers merit identification, analysis, and strategic action. New designs for schools, threats to the well-being of a growing number of children and families, and financial problems confronting school systems are among the external challenges. Meanwhile, too many physical education teachers confront marginalization, isolation, and morale issues. Contributing causes include suboptimal policy; disagreements regarding subject matter, curriculum models, and purposes; working conditions that prevent teachers from implementing evidence-based practices; and two disconnects: (a) between physical education and health and (b) between school programs and community-based programs. Reflecting and fueling these challenges, the field lacks a common purpose and shared direction. This chapter addresses future alternatives for PK–12 physical education. Key recommendations include (a) integrating physical education and health, treating them both instructionally and as integrated content in the curriculum; (b) changing our focus on our instruction from a deficiency-based model to a salutogenic model of health, including stronger connections with the community in which schools exist; and (c) connecting to the community to leverage resources to support students, teachers, and schools. These alternatives derive from a grand claim: we cannot continue to do “business as usual,” producing the same results, because past–present results consistently have been suboptimal.
Phillip Ward, Murray F. Mitchell, Hal A. Lawson, and Hans van der Mars
The physical education teacher education (PETE) faculty charged with oversight and delivery of initial teacher licensure programs confront several challenges. Some necessitate responses to revised and new standards, while others can be reframed as timely opportunities for improvement and innovation, whether in response to or in anticipation of rapid, dramatic societal change. Six examples of challenges as opportunities are discussed in this chapter: (a) the need to determine the skills, essential knowledge, values, and sensitivities for work practices in the schools of the future; (b) the dual priority for evidence-based practices in PETE and in school programs; (c) PETE faculty members’ obligations to adapt their pedagogical practices and revise preservice programs in concert with expert, veteran teachers from schools with exemplary programs; (d) manifest needs to make choices among competing, evidence-supported physical education program models; (e) needs and opportunities to redesign PETE programs, especially those located in kinesiology departments; and (f) emergent policy imperatives to demonstrate the value-added effects, both short- and long-term, on tomorrow’s teachers.
Elanor E. Cormack and Jamie Gillman
There are few studies examining coaches’ awareness of their role in developing performance under pressure. This study has explored the application of implicit and explicit learning theory for skill execution under pressure through the understanding of coaches. Seven curling coaches who teach adult novices were interviewed using a semistructured approach. Interpretative phenomenological analysis was used to explore their experiences and beliefs around skill acquisition and pressure. Key factors that emerged from the analysis were the coaches’ lack of awareness of their role in developing skill execution under pressure and the importance of coach education in creating that awareness. The recognition of the pressure that players will face in games and the potential for implicit techniques to be employed by the coaches demonstrated positive prospects for the application of implicit/explicit skill acquisition theory. The coaches’ experiences highlighted aspects unique to curling that will need to be considered in progressing the study’s findings. The distinction between skill setup and execution was also raised by coaches and requires further study to identify whether it impacts the effectiveness of building robust skills and the resulting coaching advice. The study provides recommendations for application of the theory and suggestions for future research.
Edgar Schwarz, Liam D. Harper, Rob Duffield, Robert McCunn, Andrew Govus, Sabrina Skorski, and Hugh H.K. Fullagar
Purpose: To examine practitioners’, coaches’, and athletes’ perceptions of evidence-based practice (EBP) in professional sport in Australia. Methods: One hundred thirty-eight participants (practitioners n = 67, coaches n = 39, and athletes n = 32) in various professional sports in Australia each completed a group-specific online questionnaire. Questions focused on perceptions of research, the contribution of participants’ own experience in implementing knowledge to practice, sources, and barriers for accessing and implementing EBP, preferred methods of feedback, and the required qualities of practitioners. Results: All practitioners reported using EBP, while most coaches and athletes believed that EBP contributes to individual performance and preparation (>85%). Practitioners’ preferred EBP information sources were “peer-reviewed journals” and “other practitioners within their sport,” while athlete sources were “practitioners within their sport” and “other athletes within their sport.” As primary barriers to accessing and implementing research, practitioners highlighted “time constraints,” “poor research translation,” and “nonapplicable research.” Practitioners ranked “informal conversation” as their most valued method of providing feedback; however, coaches prefer feedback from “scheduled meetings,” “online reports,” or “shared database.” Both athletes and coaches value “excellent knowledge of the sport,” “experience,” and “communication skills” in practitioners disseminating EBP. Conclusion: Practitioners, coaches, and athletes believe in the importance of EBP to their profession, although practitioners reported several barriers to accessing and implementing research as part of EBP. Athletes place a high value on experienced practitioners who have excellent knowledge of the sport and communication skills. Collectively, these findings can be used to further stakeholder understanding regarding EBP and the role of research to positively influence athlete health.
Phillip Ward, Hal A. Lawson, Hans van der Mars, and Murray F. Mitchell
In this chapter, we examine the system of physical education with a Janus-like perspective. We focus on examining and learning from the past as we anticipate what society, school systems, and the physical education system might look like in the future. Drawing on futuristic scenarios developed for this special journal issue, we ask a timely, pivotal question. What does all of this mean for the future of the field of physical education, including its school programs, teacher education programs, doctoral programs, and salient public policies? The several chapters in this special issue can be viewed as a response to this question—and with a delimited focus on the unique context of the United States. This chapter is structured to provide an overall context for these other contributions. It includes a discussion of relevant theories provided in this special issue and a representative summary of the other articles. Selectivity is apparent and unavoidable in every article, and it can be viewed variously as a strength or limitation.