Recent Submissions

  • Post-activation potentiation and potentiated motor unit firing patterns in boys and men

    European Journal of Applied Physiology, 2023-12-30
    Background: Post-activation potentiation (PAP) describes the enhancement of twitch torque following a conditioning contraction (CC) in skeletal muscle. In adults, PAP may be related to muscle fibre composition and is accompanied by a decrease in motor unit (MU) firing rates (MUFRs). Muscle fibre composition and/or activation is different between children and adults. This study examined PAP and MU firing patterns of the potentiated knee extensors in boys and men. Methods: Twenty-three boys (10.5±1.3 years) and 20 men (23.1±3.3 years) completed familiarization and experimental sessions. Maximal isometric evoked-twitch torque and MU firing patterns during submaximal contractions (20% and 70% maximal voluntary isometric contraction, MVIC) were recorded before and after a CC (5s MVIC). PAP was calculated as the percent-increase in evoked-twitch torque after the CC. MU firing patterns were examined during submaximal contractions before and after the CC using Trigno Galileo surface electrodes (Delsys Inc) and decomposition algorithms (NeuroMap, Delsys Inc). MU action potential amplitudes (MUAPamp) and MUFRs were calculated for each MU and exponential MUFR-MUAPamp relationships were calculated for each participant and trial. Results: PAP was higher in men than in boys (98.3±37.1% vs. 68.8±18.3%, respectively; p=0.002). Following potentiation, the rate of decay of the MUFR-MUAPamps relationship decreased in both contractions, with a greater decrease among boys during the high-intensity contractions. Conclusion: Lower PAP in the boys did not coincide with smaller changes in potentiated MU firing patterns, as boys had greater reductions in MUFRs with potentiation compared with men in high-intensity contractions.
  • Child-Adult differences in antagonist muscle coactivation: A systematic review

    Woods, Stacey; O'Mahoney, Caragh; McKiel, Andrew; Natale, Laurel; Falk, Bareket (Elsevier, 2023)
    Antagonist coactivation is the simultaneous activation of agonist and antagonist muscles during a motor task. Age-related changes in coactivation may contribute to observed differences in muscle performance between children and adults. Our aim was to systematically summarize age-related differences in antagonist muscle coactivation during multi-joint dynamic and single-joint isometric and isokinetic contractions. Electronic databases were searched for peer-reviewed studies comparing coactivation in upper or lower extremity muscles between healthy children and adolescents/young adults. Of the 1083 studies initially identified, 25 met eligibility criteria. Thirteen studies examined multi-joint dynamic movements, 10 single-joint isometric contractions, and 2 single-joint isokinetic contractions. Of the studies investigating multi-joint dynamic contractions, 83% (11/13 studies) reported at least one significant age-related difference: In 84% (9/11 studies) coactivation was higher in children, whereas 16% (2/11 studies) reported higher coactivation in adults. Among single-joint contractions, only 25% (3/12 studies) reported significantly higher coactivation in children. Fifty six percent of studies examined females, with no clear sex-related differences. Child-adult differences in coactivation appear to be more prevalent during multi-joint dynamic contractions, where generally, coactivation is higher in children. When examining child–adult differences in muscle function, it is important to consider potential age-related differences in coactivation, specifically during multi-joint dynamic contractions.
  • The September He Remembers

    Bolz, Cedric (2023-01-04)
    The Summit Series, a best-on-best hockey tournament played between the former-Soviet and Canadian men’s teams, occupies an outsized role in the Canadian sporting imagination. The September He Remembers: Josef Kompalla and the 1972 Summit Series reframes this famous Series in sport history through the story, experiences, and memories of Josef Kompalla, a German referee who played a key role in the events as one of the few esteemed officials selected to officiate during the Series. Given Kompalla’s important place in the history of the Summit Series, one of the most mythologized and celebrated tournaments in Canadian sport history, it should come as a surprise that his perspective on the events has not been previously documented. In this book, Bolz seeks to rectify this longstanding oversight through intrepid archival creation and analysis, as well as previously-untold stories from Kompalla himself. Although Kompalla’s role in the Summit Series has been largely omitted or obfuscated for the past half century, The September He Remembers is finally the first step in correcting a major historical oversight and adding a new chapter in the Summit Series’ growing legacy.
  • Proteomes Are of Proteoforms: Embracing the Complexity

    Carbonara, Katrina; Andonovski, Martin; Coorssen, Jens R. (MDPI AG, 2021-08-31)
    Proteomes are complex—much more so than genomes or transcriptomes. Thus, simplifying their analysis does not simplify the issue. Proteomes are of proteoforms, not canonical proteins. While having a catalogue of amino acid sequences provides invaluable information, this is the Proteome-lite. To dissect biological mechanisms and identify critical biomarkers/drug targets, we must assess the myriad of proteoforms that arise at any point before, after, and between translation and transcription (e.g., isoforms, splice variants, and post-translational modifications [PTM]), as well as newly defined species. There are numerous analytical methods currently used to address proteome depth and here we critically evaluate these in terms of the current ‘state-of-the-field’. We thus discuss both pros and cons of available approaches and where improvements or refinements are needed to quantitatively characterize proteomes. To enable a next-generation approach, we suggest that advances lie in transdisciplinarity via integration of current proteomic methods to yield a unified discipline that capitalizes on the strongest qualities of each. Such a necessary (if not revolutionary) shift cannot be accomplished by a continued primary focus on proteo-genomics/-transcriptomics. We must embrace the complexity. Yes, these are the hard questions, and this will not be easy…but where is the fun in easy?
  • Profit versus Quality: The Enigma of Scientific Wellness

    Carbonara, Katrina; MacNeil, Adam J.; O'Leary, Deborah D.; Coorssen, Jens R. (Journal of Personalized Medicine, 2022-01-03)
    The “best of both worlds” is not often the case when it comes to implementing new health models, particularly in community settings. It is often a struggle between choosing or balancing between two components: depth of research or financial profit. This has become even more apparent with the recent shift to move away from a traditionally reactive model of medicine toward a predictive/preventative one. This has given rise to many new concepts and approaches with a variety of often overlapping aims. The purpose of this perspective is to highlight the pros and cons of the numerous ventures already implementing new concepts, to varying degrees, in community settings of quite differing scales—some successful and some falling short. Scientific wellness is a complex, multifaceted concept that requires integrated experimental/analytical designs that demand both high-quality research/healthcare and significant funding. We currently see the more likely long-term success of those ventures in which any profit is largely reinvested into research efforts and health/healthspan is the primary focus.
  • Characterization of sclerostin’s response within white adipose tissue to an obesogenic diet at rest and in response to acute exercise in male mice

    Kurgan, Nigel; Baranowski, Bradley; Stoikos, Joshua; MacNeil, Adam J.; Fajardo, Val A.; MacPherson, Rebecca EK; Klentrou, Panagoita (Frontiers in Physiology, 2022)
    This study examined the effect of a high-fat diet (HFD) on sclerostin content within subcutaneous inguinal visceral white adipose tissue (iWAT), and visceral epididymal WAT (eWAT) depots at rest and in response to acute aerobic exercise. Male C57BL/6 mice (n=40, 18 weeks of age) underwent 10 weeks of either a low-fat diet (LFD) or HFD. Within each diet group, mice were assigned to either remain sedentary (SED) or perform 2h of endurance treadmill exercise at 15 m·min-1 with 5° incline (EX), creating 4 groups: LFD+SED (N=10), LFD+EX (N=10), HFD+SED (N=10), and HFD+EX (N=10). Serum and WAT depots were collected 2h post-exercise. Serum sclerostin showed a diet-by-exercise interaction, reflecting HFD+EX mice having higher concentration than HFD-SED (+31%, p=0.03), and LFD mice being unresponsive to exercise. iWAT sclerostin content decreased post-exercise in both 28 kDa (-31%, p=0.04) and 30 kDa bands (-36%, main effect for exercise, p=0.02). iWAT b-catenin (+44%, p=0.03) and GSK3b content were elevated in HFD mice compared to LFD (+128%, main effect for diet, p=0.005). Monomeric sclerostin content was abolished in eWAT of HFD mice (-96%, main effect for diet, p<0.0001), was only detectable as a 30 kDa band in LFD mice and was unresponsive to exercise. b-catenin and GSK3b were both unresponsive to diet and exercise within eWAT. These results characterized sclerostin’s mobilization to WAT depots in response to acute exercise, which appears to be specific to a reduction in iWAT and identified a differential regulation of sclerostin’s form/post-translational modifications depending on diet and WAT depot.
  • Reaching the Summit: Reimagining the Summit Series in the Canadian Cultural Memory

    JESS Press, 2022-10-03
    Reimagining the '72 Summit Series in the Canadian Cultural Memory.
  • Oxygen toxicity: cellular mechanisms in normobaric hyperoxia

    Alva, Ricardo; Baiton, Adam; Bobinski, Ava; Mirza, Maha; Lazaran, Lucas; Samokysh, Lyuda; Obioru, Dede; Stuart, Jeffrey A.; Al Makhoul, Tala (Springer, 2022)
    In clinical settings, oxygen therapy is administered to preterm neonates and to adults with acute and chronic conditions such as COVID-19, pulmonary fibrosis, sepsis, cardiac arrest, carbon monoxide poisoning, and acute heart failure. In non-clinical settings, divers and astronauts may also receive supplemental oxygen. In addition, under current standard cell culture practices, cells are maintained in atmospheric oxygen, which is several times higher than what most cells experience in vivo. In all the above scenarios, the elevated oxygen levels (hyperoxia) can lead to increased production of reactive oxygen species from mitochondria, NADPH oxidases, and other sources. This can cause cell dysfunction or death. Acute hyperoxia injury impairs various cellular functions, manifesting ultimately as physiological deficits. Chronic hyperoxia, particularly in the neonate, can disrupt development, leading to permanent deficiencies. In this review, we discuss the cellular activities and pathways affected by hyperoxia, as well as strategies that have been developed to ameliorate injury.
  • sidelines

    Reid, Brittany (JESS Press, 2021-06-21)
    Sidelines is a collection of poetic memories about sport. Each narrative poem features a recollected moment, based on personal experiences, misremembered histories, or imaginative guessing games. In the process, Sidelines explores the complex contradictions of living and loving through sport by extending the concept of “participation” to include sporting culture’s more marginal players. As a work of sport literature, this poetic biomythography considers how the sidelines are a liminal space that is peripheral, yet central to the world of sport. As a poetic memoir, it is a longing but hopeful account of how sports can inform your self-conception, even when you believe you are out of play.
  • Association of Functional Screening Tests and Noncontact Injuries in Division I Women Student-Athletes

    Warren, Meghan; Lininger, Monica R.; Smith, Craig A.; Copp, Adam J.; Chimera, Nicole J. (Lippincott, Williams & Wilkins, 2020)
    To determine the association between functional screening tests and lower-body, noncontact injuries in Division I women basketball, soccer, and volleyball student-athletes (SA). Sixty-eight injury-free women SA (age19.1 ± 1.1 years, height171.3 ± 8.7 cm, and mass68.4 ± 9.5 kg) were tested preseason with single hop (SH), triple hop (TH), and crossover hop (XH) for distance, and isometric hip strength (abduction, extension, and external rotation) in randomized order. The first lower-body (spine and lower extremity), noncontact injury requiring intervention by the athletic trainer was abstracted from the electronic medical record. Receiver operating characteristic and area under the curve (AUC) were calculated to determine cut-points for each hopping test from the absolute value of between-limb difference. Body mass–adjusted strength was categorized into tertiles. Logistic regression determined the odds of injury with each functional screening test using the hopping tests cut-points and strength categories, adjusting for previous injury. Fifty-two SA were injured during the sport season. The cut-point for SH was 4 cm (sensitivity = 0.77, specificity = 0.43, and AUC = 0.53), and for TH and XH was 12 cm (sensitivity = 0.75 and 0.67, specificity = 0.71 and 0.57, AUC = 0.59 and 0.41, respectively). A statistically significant association with TH and injuries (adjusted odds ratio = 6.50 [95% confidence interval1.69–25.04]) was found. No significant overall association was found with SH or XH, nor with the strength tests. Using a clinically relevant injury definition, the TH showed the strongest predictive ability for noncontact injuries. This hopping test may be a clinically useful tool to help identify increased risk of injury in women SA participating in high-risk sports.
  • Predicting Lower Quarter Y-Balance Test Performance from Foot Characteristics

    Chimera, Nicole J.; Larson, Mallorie (Human Kinetics, 2020)
    The lower quarter Y-Balance Test (YBT-LQ) is associated with injury risk; however, ankle range of motion impacts YBT-LQ. Arch height and foot sensation impact static balance, but these characteristics have not yet been evaluated relative to YBT-LQ. Determine if arch height index (AHI), forefoot sensation (SEN), and ankle dorsiflexion predict YBT-LQ composite score (CS). Descriptive cohort. Athletic training laboratory. Twenty general population (14 females and 6 males; mean [SD]: age 35 [18] y, weight 70.02 [16.76] kg, height 1.68 [0.12] m) participated in this study. AHI measurement system assessed arch height in 10% (AHI10) and 90% (AHI90) weight-bearing. Two-point discrim-a-gon discs assessed sensation (SEN) at the plantar great toe, third and fifth metatarsal heads. Biplane goniometer and weight-bearing lunge tests were used to measure static and weight-bearing dorsiflexion, respectively. The YBT-LQ assessed dynamic single-leg balance. For right-limb dynamic single-leg balance, AHI90 and SEN were included in the final sequential prediction equation; however, neither model significantly (P = .052 and .074) predicted variance in YBT-LQ CS. For left-limb dynamic single-leg balance, both SEN and weight-bearing lunge test were included in the final sequential prediction equation. The regression model (SEN and weight-bearing lunge test) significantly (P = .047) predicted 22% of the variance in YBT-LQ CS. This study demonstrates that foot characteristics may play a role in YBT-LQ CS. The authors did not assess limb dominance in this study; therefore, the authors are unable to determine which limb would be the stance versus kicking limb. However, altered SEN and weight-bearing dorsiflexion appear to be contributing factors to YBT-LQ CS.
  • Colorectal cancer screening behaviors among South Asian immigrants in Canada: a qualitative study

    Crawford, Joanne; Ahmad, Farah; Beaton, Dorcas E.; Bierman, Arlene S. (Emerald, 2015)
    The purpose of this paper is to gain an in-depth understanding of beliefs, attitudes, and reasons for decision making about colorectal cancer (CRC) screening among South Asian (SA) immigrants. Design/methodology/approach – Six focus groups conducted in English, Punjabi, and Urdu were held with 42 SA immigrants, 50-74 years old and at average risk for CRC, from November 2012 to May 2013. All focus group discussions were audio-taped and transcribed verbatim. Data analysis used an inductive and systematic approach employing constant comparison techniques. Findings – Three dominant themes emerged. Beliefs and attitudes towards cancer and screening represented SA immigrant’s perceptions that early detection was beneficial; screening was not necessary in the absence of symptoms; cancer was scary; and the loss of previously established bowel practices upon immigration as potential risks for CRC. Knowledge and awareness focused on unscreened participants’ cancer stories; screened participants’ knowledge of CRC, risk factors, and screening; experiential learning from focus groups; and screened participants’ strategies to promote screening. Support and accessibility concentrated on physician support and responsibility to provide information, explanation, and recommend screening to facilitate access. Originality/value – Findings provide novel insights on socio-cultural context, beliefs, and barriers to CRC screening among SA immigrants. Culturally appropriate community-based strategies included story-telling, the use of social networks, and greater physician engagement. Enhancing collaborative partnerships with physicians and public health may minimize structural barriers and reduce health disparities. Future research could explore effectiveness of outreach strategies including these collaborations.
  • Home Care Nursing Visits and Same-Day Emergency Department Use: Which Patients Are Most at Risk?

    Schumacher, Connie; Jones, Aaron; Costa, Andrew P. (Sage Publications, 2020)
    Background Home care patients are a growing group of community-dwelling older adults with complex care needs and high health service use. Adult home care patients are at high risk for emergency department (ED) visits, which is greater on the same day as a nursing visit. The purpose of this study was to examine whether common nursing indicators modified the association between nursing visits and same-day ED visits. Methods A case-crossover design within a retrospective cohort of adult home care patients in Ontario. Results A total of 11,840 home care nursing patients were analyzed. Home care patients who received a home nursing visit were more likely to go the ED after hours on the same day with a stronger association for visits not admitted to the hospital. Having a urinary catheter increased the risk of a same-day ED visit (OR: 1.78 (95% CI 1.15–1.60) vs. 1.21 (95% CI 1.15–1.28)). No other clinical indicator modified the association. The findings of this study can be used to inform care policies and practices for home care nurses in the management of indwelling urinary catheter complications. Further examination of system factors such as capacity and resources available to respond to catheter related complications in the community setting are recommended.
  • Against limits: A post-structural theorizing of resistance in leisure

    Sharpe, Erin K (Palgrave Macmillan, 2017)
    In its recognition of oppositional behavior as informed and political, resistance offers us a way to explore the interconnections between leisure and politics in meaningful ways. However, for the concept to have utility for theorizing theses interconnections, it needs to be located within broader theorizations of power. Drawing on the work of Foucault, this chapter offers a post-structural theorizing of power and resistance. In contrast to modernist binary conceptualizations of power and resistance, Foucault conceptualized power as circulating through a culture or a system and exercised at innumerable points and times. To Foucault, resistance was power exercised in the attempt to destabilize the limits of the present order. The chapter applies Foucault’s perspective of resistance as “against limits” to leisure, and argues that we can think of leisure as resistance when it expands the possibilities for what we can do and who we might imagine ourselves to be.
  • A Good Place for What? Placing ‘Value’ in Youth Centres

    Sharpe, Erin K; Lashua, Brett; van Ingen, Cathy (Taylor and Francis, 2019-07-02)
    In this paper, we investigate the discursive context of community-based youth centres to critically interrogate ideas and practices concerning leisure, youth, and youth centres. Using publicly available documents and data collected with youth at two community-based youth centres, we ask, what is the “good”’ that they do for young people, and how do young people negotiate these discourses? We argue that the youth centres operate in a discursive tension, constructed as a place to change by the (organizational) bodies that established them, and a place to chill by the (youth) bodies that used them. We trace how these discourses entered into the everyday lived contexts of youth centres including their program logics, measures of success, and constructions of youthful subjectivities. We close with a discussion of the implications of the research in terms of how youth and recreation practitioners might use youth centres to support young people’s leisure.
  • Risk, nostalgia, and the production of the ideal childhood in online commentary on children’s outdoor play

    Sharpe, Erin K; Litwiller, Fenton; Gallant, Karen (Taylor and Francis, 2019-11-25)
    We use Foucauldian discourse analysis to examine comments posted online in response to news articles that reported on one Canadian neighbourhood’s ‘ban’ on children’s outdoor play. Our analysis showed that reader comments, both for and against the ban on street play, accessed discourses of risk that produced an idealized childhood based on close parental supervision. Additionally, nostalgic discourse, the feeling that unfettered, wholesome outdoor play has been lost and cannot be reclaimed, also made claims about who the ideal childhood is for. While marginalized children continue to experience disadvantage that inherently exposes them to risks daily, White, middle class children already have access to safer streets, both parent presence or unquestioned but appropriate parental absence, and play in the streets can be part of their everyday lives. We consider how the idealized childhoods produced by discourses of risk and nostalgia influence the materiality of children’s outdoor play, including how children’s time is organized and who gets to organize it, how play is experienced and who gets to experience it; in ideal ways, in ideal spaces, and for the ideal child.
  • Comparison of different wheelchair seating on thermoregulation and perceptual responses in thermoneutral and hot conditions in children

    Mallette, Matthew M.; Hodges, Gary J.; Klentrou, Panagiota; Cheung, Stephen S.; Falk, Bareket (Elsevier Ltd, 2019-04-24)
    We examined the effects of 4 different wheelchair seatings on physiological and perceptual measures in 21 healthy, pre-pubertal children (9 ± 2 years). Participants were able-bodied and did not regularly use a wheelchair. Participants sat for 2 h in Neutral (∼22.5 °C, ∼40%RH) and Hot (∼35 °C, ∼37%RH) conditions. Four seating technologies were: standard incontinent cover and cushion (SEAT1); standard incontinent cover with new cushion (SEAT2) were tested in Neutral and Hot; new non-incontinent cover with new cushion (SEAT3); new incontinent cover and new cushion (SEAT4) were tested in Neutral only. Measurements included skin blood flow (SkBF), sweating rate (SR) and leg skin temperature (TlegB) on the bottom of the leg (i.e. skin-seat interface), heart rate (HR), mean skin temperature, tympanic temperature, thermal comfort, and thermal sensation. During Neutral, SkBF and TlegB were lower (∼50% and ∼1 °C, respectively) and SR higher (∼0.5 mg cm−2·min−1) (p < 0.05) with SEAT3 compared to all other seats. SkBF was ∼30% lower (p p > 0.05). During Hot, HR and temperatures were higher than in Neutral but there were no differences (p > 0.05) between SEATs. New cover and cushion improved thermoregulatory responses during Neutral but not Hot. An impermeable incontinent cover negated improvements from cushion design. Seat cover appears more important than seat cushion during typical room conditions.
  • Parenting Teamwork: The impact of a fathering intervention on mothers and infants in Vietnam

    Rempel, John K.; Rempel, Lynn A.; Hoa, Dinh Thi Phuong; Vui, Le Thi; Long, Tran Khanh (Child Development, 2019-04-01)
    A multi-faceted, relationally-focused intervention involving group and individual pre-and post-natal counseling, print resources, and community resources encouraged 390 fathers of newborn infants in Vietnam to responsively support mothers and work with them as a parenting team. Both partners completed questionnaires pre-birth and 1, 4, and 9-months post-birth on measures of breastfeeding support, exclusive breastfeeding duration, relationship quality, and infant development. Compared to 412 comparison group couples, intervention couples evidenced greater father support, especially in terms of helping and responsiveness to the mother’s needs. This support predicted longer exclusive breastfeeding duration, improved relationship quality, and higher levels of infant development at 9 months. Sensitively working together with mothers as a coordinated team enhanced couple’s relationship functioning and improved children’s developmental outcomes.
  • What is the effect of ADHD stimulant medication on Heart Rate and Blood Pressure in a Community Sample of Children?

    St Amour, Meagan; O'Leary, Deborah D; Cairney, John; Wade, Terrance J (Springer International Publishing, 2018)
    OBJECTIVE: This study examines the effect of ADHD diagnosis and stimulant medication for ADHD treatment on child heart rate (HR) and blood pressure (BP) in a community sample compared to children without ADHD. METHODS: Data came from the HBEAT Study. 2,013 participants from 49 schools from southern Ontario in grades 5-8 were included. Linear regression analyses examined the effects of ADHD medications on systolic blood pressure, diastolic blood pressure, and heart rate adjusting for age, sex, and body mass index (BMI). RESULTS: Compared to non-ADHD children and adjusting for age, sex and BMI, children with ADHD on stimulant medication had a 12.3 bpm higher HR, and 3.0 mmHg higher SBP and DBP (all statistically significant). Children with ADHD on no stimulant medication had no differences in HR and BP compared to those children without a diagnosis of ADHD. CONCLUSION: Stimulant medications used to treat ADHD are associated with elevated HR and higher BP. While it is unknown if children on ADHD medications may be at risk for longer term cardiovascular issues, this study supports the need to examine the long-term consequences of ADHD medication.
  • Influence of father-infant relationship on infant development: A father-involvement intervention

    Rempel, Lynn A.; Rempel, John K.; Khuc, Toan Nang; Vui, Le Thi (APA, 2017)
    We examined the extent to which fathers can be taught and encouraged to develop positive relationships with their children, especially in infancy, and the effects of this fathering intervention on infant development. A multi-faceted relationally-focused intervention was used to assist fathers in Vietnam to engage in responsive direct and indirect involvement with their infants and work together with the mother as part of a parenting team. Fathers and mothers from 13 communes in a rural and semi-urban district were recruited to the intervention group. Intervention fathers received group and individual counseling before and after birth, an interactive print resource, community messages about fathering, and the opportunity to participate in a Fathers Club. Couples from 12 comparable communes in a non-contiguous district were recruited to the control group. Fathers and mothers completed questionnaires at the pre-birth recruitment and at 1, 4, and 9-months post-birth. Intervention fathers demonstrated greater increase in knowledge and attitudes regarding father-infant relationships. Both fathers and mothers reported that fathers engaged in more affection, care-taking, and play in the early months of their infants’ lives and fathers felt more attached to their infants right from birth. A developmental assessment at 9 months showed that intervention infants demonstrated higher levels of motor, language, and personal/social development. This study demonstrated that fathers can be taught to interact more sensitively, responsively, and effectively with their newborn infants. Their increased interaction and emotional attachment appears to lay the foundation for enhanced infant development.

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