• Baroreflex sensitivity and developmental coordination disorder

      Coverdale, Nicole; Applied Health Sciences Program (Brock University, 2011-03-08)
      Developmental coordination disorder (DCD) is a motor coordination disorder that is characterized by impairment of motor skills which leads to challenges with performing activities of daily living. Children with DCD have been shown to be less physically active and have increased body fatness. This is an important finding since a sedentary lifestyle and obesity are risk factors for cardiovascular disease. One indicator of cardiovascular health is baroreflex sensitivity (BRS), which is a measure of short term BP regulation that is accomplished through changes in HR. Diminished BRS is predictive of cardiovascular morbidity and mortality. The purpose of this study was to investigate BRS in 117 children aged 12 to 13 years with probable DCD (pOCO) and their matched controls with normal coordination. Following 15 minutes of supine rest, five minutes of continuous beat-by-beat blood pressure (Finapres) and RR interval were recorded (standard ECG). Spectral indices were computed using Fast Fourier Transform and transfer function analysis was used to compute BRS. High frequency and low frequency power spectral areas were set to 0.15-0.6 Hz and 0.04-0.15 Hz, respectively. BRS was compared between groups with an independent t-test and the difference was not significant. It is likely that a difference in BRS was not seen between groups since the difference in BMI between groups was small. As well, differences in BRS may not have manifested yet at this early age. However, the cardiovascular health of this population still deserves attention since differences in body composition and fitness were found between groups.
    • The Beneficial Effects of Motivational Self-Talk on Endurance Performance and Cognitive Function in the Heat

      Wallacep, Phillip Julian; Applied Health Sciences Program
      The role of psychological strategies on endurance performance and cognitive function in the heat is unclear. This thesis tested the effects of a two-week motivational self-talk (MST) intervention - specific to heat stress - on endurance capacity and cognitive function in the heat (35°C 50% RH). The study utilized a pre-test / post-test design testing endurance capacity using a time to exhaustion test (TTE) after exercise-induced hyperthermia. Cognitive function (e.g executive function) was tested at baseline in thermoneutral (22°C 30% RH), before (R1) and after the TTE (R2). MST led to a significant improvement (~30%) in TTE and significantly faster completion time with fewer errors made on executive function tasks at baseline and R2, but not in R1, while there were no differences in the control group. Overall, these results indicate that using a top-down regulation strategy consisting of self-contextualized MST can improve physical and cognitive performance in the heat.
    • Benefits of Using Target Activities to Assist in Improvement of Striking in Striking and Fielding Games for Individuals with Autism: A Comparative Case Study

      Hogan, Brittany; Applied Health Sciences Program (Brock University, 2013-10-11)
      The purpose of the research study was to increase understanding about the potential benefits of combining target activities with striking-fielding games for individuals with high functioning autism spectrum disorder. A comparative case study was conducted to understand if target activities can assist in improving the skills of striking and throwing, aid the learning of tactics and add to current understanding of how certain teaching skills might be linked to the transfer between target and striking-fielding games. Data was collected through observations, student journals and interviews and were analyzed using both inductive and deductive methods. Results show an appearance of improvement in throwing, striking, bowling and badminton for overall skill levels. In regards to teaching skills, appropriate and effective teaching techniques, appropriate and effective equipment, dynamic of participants and student-instructors and consistency of attendance are vital. Future research should further look at the transferability to outdoor settings and interview the participants.
    • Biological effects of resveratrol on skeletal muscle cells

      Breen, Danna M.; Applied Health Sciences Program (Brock University, 2005-11-04)
      Resveratrol, a polyphenol found in red wine, has been reported to have antithrombotic, antiatherogenic, and anticancer properties both in vitro and III VIVO. However, possible antidiabetic properties of resveratrol have not been examined. The objective of this study was to investigate the direct effects of resveratrol on basal and insulin-stimulated glucose uptake and to elucidate its mechanism of action in skeletal muscle cells. In addition, the effects of resveratrol on basal and insulin- stimulated amino acid transport and mitogenesis were also examined. Fully differentiated L6 rat skeletal muscle cells were incubated with resveratrol concentrations ranging from 1 to 250 IlM for 15 to 120 min. Maximum stimulation, 201 ± 8.90% of untreated control, (p<0.001), of2eH] deoxy- D- glucose (2DG) uptake was seen with 100 IlM resveratrol after 120 min. Acute, 30 min, exposure of the cells to 100 nM insulin stimulated 2DG uptake to 226 ± 12.52% of untreated control (p<0.001). This appears to be a specific property of resveratrol that is not shared by structurally similar antioxidants such as quercetin and rutin, both of which did not have any stimulatory effect. Resveratrol increased the response of the cells to submaximal insulin concentrations but did not alter the maximum insulin response. Resveratrol action did not require insulin and was not blocked by the protein synthesis inhibitor cycloheximide. L Y294002 and wortmannin, inhibitors of PI3K, abolished both insulin and resveratrolstimulated glucose uptake while phosphorylation of AktlPKB, ERK1I2, JNK1I2, and p38 MAPK were not increased by resveratrol. Resveratrol did not stimulate GLUT4 transporter translocation in GLUT4cmyc overexpressing cells, in contrast to the significant translocation observed with insulin. Furthermore, resveratrol- stimulated glucose transport was not blocked by the presence of the protein kinase C (PKC) inhibitors BIMI and G06983. Despite that, resveratrol- induced glucose transport required an intact actin network, similar to insulin. In contrast to the stimulatory effect seen with resveratrol for glucose transport, e4C]methylaminoisobutyric acid (MeAIB) transport was inhibited. Significant reduction of MeAIB uptake was seen only with 100uM resveratrol (74.2 ± 6.55% of untreated control, p<0.05), which appeared to be maximum. In parallel experiments, insulin (100 nM, 30 min) increased MeAIB transport by 147 ± 5.77% (p<0.00l) compared to untreated control. In addition, resveratrol (100 JlM, 120 min) completely abolished insulin- stimulated amino acid transport (103 ± 7.35% of untreated control,p>0.05). Resveratrol also inhibited cell proliferation in L6 myoblasts with maximal inhibition of eH]thymidine incorporation observed with resveratrol at 50 J.LM after 24 hours (8 ± 1.59% of untreated control, p<O.OOI). Insulin (100 nM, 24 h) significantly increased thymidine incorporation (280 ± 9.92% of untreated control, p<O.OOI) and media containing 10% FBS resulted in stimulation of thymidine incorporation to 691 ± 36.92% of untreated control, p<O.OO1. Resveratrol (50JlM) completely abolished both insulin- (11 ± 1.26% of untreated control,p<O.OOI) and FBS- stimulated (36 ± 5.16% of untreated control, p<0.05) cell proliferation. These results suggest that resveratrol increases glucose transport in L6 skeletal muscle cells by a mechanism that is in4ependent of insulin and protein synthesis. Resveratrol- stimulated glucose uptake may be PI3K and actin cytoskeleton- dependent and independent of AktIPKB, PKC, ERK1I2, JNK1I2, p38 MAPK, and GLUT4 translocation. However, unlike glucose transport, resveratrol inhibits both basal and insulin- stimulated amino acid transport and mitogenesis.
    • Bone markers and cytokines in response to low-impact, high-intensity exercise

      Mezil, Yasmeen; Applied Health Sciences Program (Brock University, 2014-02-21)
      A low-impact, high-intensity interval exercise (HIE) bout was used to determine whether an association exists between cytokines and bone turnover markers following an acute bout of exercise. Twenty-three recreationally active males (21.8±2.4yr) performed a single HIE bout on a cycle ergometer at 90% relative intensity. Venous blood samples were collected prior to exercise, 5-minutes, 1-hour, and 24-hours post-exercise, and were analyzed for serum levels of pro-inflammatory (IL-6, IL-1α, IL-1β, and TNF-α) and anti- inflammatory cytokines (IL-10) and markers of bone formation (BAP, OPG) and resorption (NTX, RANKL). Significant effects were observed with all bone markers, especially 5-minutes post-exercise with BAP, OPG, and RANKL increasing from baseline (p<0.05). Significant effects were also observed for IL-1α, IL-1β, IL-6, and TNF-α (p<0.00, p=0.04, p=0.03, p<0.00). In addition, post-exercise changes in NTX, BAP, and OPG were significantly correlated pro- and anti-inflammatory cytokines, suggesting that an interaction exists between the immune and skeletal response to exercise.
    • Bone properties and skeletal maturity in adolescent males, as assessed by quantitative ultrasound

      Braid, Sarah Anne.; Applied Health Sciences Program (Brock University, 2007-06-04)
      ABSTRACT Background: Previous studies have implied that weight-bearing, intense and prolonged physical activities optimize bone accretion during the grow^ing years. The majority of past inquiries have used dual-energy X-ray absorptiometry (DXA) to examine bone strength and hand-wrist radiography to determine skeletal maturity in children. Recently, quantitative ultrasound (QUS) technologies have been developed to examine bone properties and skeletal maturity in a safe, noninvasive and cost-effective manner. Objective: The purpose of this study was to compare bone properties and skeletal maturity in competitive male child and adolescent athletes with minimallyactive, age-matched controls, using QUS technology. >. Methods: In total, 224 males were included in the study. The 115 pre-pubertal boys aged 10-12 years consisted of control, minimally-active children (n=34), soccer players (n=26), gymnasts (n=25) and hockey players (n=30). In addition, the 109 late-pubertal boys aged 14-16 years consisted of control, minimally-active adolescents (n=31), soccer players (n=30), gymnasts (n=17) and hockey players (n=31). The athletic groups were elite level players that predominantly trained year-round. Physical activity, nutrition and sports participation were assessed with various questionnaires. Anthropometries, such as height, weight and relative body fat percentage (BF%) were assessed using standard measures. Skeletal strength and age were evaluated using bone QUS. Lastly, salivary testosterone (sT) concentration was measured using Radioimmunoassay (RIA). Results: Within each age group, there were no significant differences between the activity groups in age and pubertal stage. An age effect was apparent in all variables, as expected. A sport effect was noted in all physical characteristics: the child and adolescent gymnasts were shorter and lighter than other sports groups. Adiposity was greater in the controls and in the hockey players. All child subjects were pubertal stage (fanner) I or II, while adolescent subjects were pubertal stage IV or V. There were no differences in daily energy and mineral intakes between sports groups. In both age groups, gymnasts had a higher training volume than other athletic groups. Bone speed of sound (50s) was higher in adolescents compared with the children. Gymnasts had signifieantly higher radial 50S than controls, hockey and soccer players in both age cohorts. Hockey athletes also had higher radial 50S than controls and soccer players in the child and adolescent groups, respectiyely. Child gymnasts and soccer players had greater tibial 50S compared with the hockey players and control groups. Likewise, adolescent gymnasts and soccer players had higher tibial SoS compared with the control group. No interaction was apparent between age and type of activity in any of the bone measures. » Lastly, maturity as assessed by sT and secondary sex characteristics (Tanner stage) was not different between sports group within each age group. Despite the similarity in chronological age, androgen levels and sexual maturity, differences between activity groups were noted in skeletal maturity. In the younger group, hockey players had the highest bone age while the soccer players had the lowest bone age. In the adolescent group, gymnasts and hockey players were characterized by higher skeletal maturity compared with controls. An interaction between the age and sport type effects was apparent in skeletal maturity, reflecting the fact that among the children, the soccer players were significantly less mature than the rest of the groups, while in the adolescents, the controls were the least skeletally mature. Summary and Conclusions: In summary, radial and tibial SOS are enhanced by the unique loading pattern in each sport (i.e, upper and lower extremities in gymnastics, lower extremities in soccer), with no cumulative effect between childhood and adolescence. That is, the effect of sport participation on bone SOS was apparent already among the young athletes. Enhanced bone properties among athletes of specific sports suggest that participation in these sports can improve bone strength and potential bone health.
    • Bone speed of sound in overweight and normal-weight girls and adolescents

      Yao, Matthew W.; Applied Health Sciences Program (Brock University, 2009-02-01)
      Over the last two decades, the prevalence of obesity in the general population has been steadily increasing. Obesity is a major issue in scientific research because it is associated with many health problems, one of which is bone quality. In adult females, adiposity is associated with increased bone mineral density, suggesting that there is a protective effect of fat on bone. However, the association between adiposity and bone strength during childhood is not clear. Thus, the purpose of this study was to compare bone strength, as reflected by speed of sound (SOS), of overweight and obese girls and adolescents with normal-weight age-matched controls. Data from 75 females included normal-weight girls (G-NW; body fat:::; 25%; n = 21), overweight and obese girls (GOW; body fat ~ 28%; n = 19), normal-weight adolescents (A-NW, body fat:::; 25%; n = 13) and overweight and obese adolescents (A-OW; body fat ~ 28%; n = 22). Nutrition was assessed with a 24-hour recall questionnaire and habitual physical activity was measured for one week using accelerometry. Using quantitative ultrasound (QUS; Sunlight Omnisense™), bone SOS was measured at the distal radius and mid-tibia. No differences were found between groups in daily total energy, calcium or vitamin D intake. However, all groups were below the recommended daily calcium intake of 1300 mg (Osteoporosis Canada, 2008). Adolescents were significantly less active than girls (14.7 ± 0.6 vs. 6.3 ± 0.6% active for G and A, respectively). OW accumulated significantly less minutes of moderate-to-very vigorous physical activity per day (MVPA) than NW in both age groups (114 ± 6 vs. 57 ± 5 min/day for NW and OW, i respectively). Girls had significantly lower radial SOS (3794 ± 87 vs. 3964 ± 64 mls for G-NW and A-NW, respectively), and tibial SOS (3678 ± 86 vs. 3878 ± 52 mls for G-NW and A-NW, respectively) than adolescents. Radial SOS was similar in the two adiposity groups within each age group. However, tibial SOS was lower in the two overweight groups (3601 ± 75 mls vs. 3739 ± 134 mls for G-OW and A-OW, respectively) compared with the age-matched normal-weight controls. Body fat percentage negatively correlated with tibial SOS in the study sample as a whole (r = -0.30). However, when split into groups, percent bo~y fat correlated with tibial SOS only in the A-OW group (r = -0.53). MVPA correlated with tibial SOS (r = 0.40), once age was partialed out. In conclusion, in contrast withthe higher bone strength characteristic of obese adult women, overweight and obese girls and adolescents are characterized by low tibial bone strength, as assessed with QUS. The differences between adiposity groups in tibial SOS may be at least partially due to the reduced weight-bearing physical activity levels in the overweight girls and adolescents. However, other factors, such as hormonal influences associated with high body fat may also playa role in reducing bone strength in overweight girls. Further research is required to reveal the mechanisms causing low bone strength in overweight and obese children and adolescents.
    • Bone speed of sound, biochemical markers of bone turnover and IGF-1 in competetive synchronized swimmers

      Ludwa, Izabella Atena.; Applied Health Sciences Program (Brock University, 2009-07-14)
      The purpose of this study was to compare bone speed of sound (SOS) measured by quantitative ultrasound, circulating levels of IGF- 1 and biochemical markers of bone turnover in pre- (Pr) and post-menarcheal (Po) synchronized swimmers (SS) and controls (NS). Seventy participants were recruited: 8 PrSS, 22 PoSS, 20 PrNS, and 20 PoNS. Anthropometric measures of height, weight, skeletal maturity and percent body fat were taken, and dietary intake evaluated using 24-hour recall. Bone SOS was measured at the distal radius and mid-tibia and blood samples analyzed for IGF-1, osteocalcin, NTx, and 25-OH vitamin D. Results demonstrated maturational effects on bone SOS, IGF-1 and bone turnover (p<0.05), with no differences observed between SS and NS. Main effects were observed for a reduced caloric intake in SS compared to NS (p<0.05). Therefore, SS does not offer additive affects on bone strength but imparts no adverse affects to skeletal health in these athletes.
    • Can Attention Focus Instructions Reduce the Effects of Fatigue on Balance Control?

      Huff, Richard; Applied Health Sciences Program (Brock University, 2014-09-10)
      Localized muscular fatigue has been identified to have detrimental effects on balance control, an important skill for everyday life. Manipulation of attention focus instructions has been shown to benefit performance of various motor skills including balance and has been found to facilitate endurance during fatiguing tasks. The purpose of this thesis was to determine if the use of attention focus instructions could attenuate the effects of muscular fatigue on balance control. Twenty-four participants performed a balance task (two-legged stance on an unstable platform) before and after a fatigue protocol. Trunk sway, platform excursions, and lower limb muscle activity was measured. Results suggest that use of either internal or external attention focus instructions can reduce the immediate effects of muscular fatigue of the lower limb on balance control as shown through reduced trunk sway and platform excursions. These results have relevance for individuals performing balance tasks in a fatigued state.
    • Capacity and transformational development within the 2005 Canada Summer Games host society

      Marunchak, Katrusia.; Applied Health Sciences Program (Brock University, 2006-05-19)
      Although capacity has been used in recent federal government accords and policies related to the voluntary and amateur sport sectors, there is little consensus over the meaning of the term. Consequently, the purpose of this qualitative case study was to explore the concept of organizational capacity within a temporary voluntary sport organization. Specifically, the nature of organizational capacity was examined within the case of the Volunteers Division of the 2005 Canada Summer Games (CSG) Host Society. Data were collected from executive planning and middle management CSG volunteers through the use of a variety of methods: verbal journals, interviews, observations, documents and a focus group. Findings indicated several challenges associated with the volunteer management model utilized by the host society, varying levels of importance among six elements of capacity, and key aspects of the relationship between organizational capacity and transformational development. Implications focused upon the importance of highlighting individuals rather than the organizational as a whole in order to build capacity, and utilizing a brain or hybrid brain-machine organizational form to enhance capacity. Recommendations are provided for both the Canada Games Council and Canada Games host societies.
    • The capillary supply of human skeletal muscle in health and disease

      Kadyan, Mamta.; Applied Health Sciences Program (Brock University, 2006-06-04)
      BACKGROUND: Capillaries function to provide a surface area for nutrient and waste exchange with cells. The capillary supply of skeletal muscle is highly organized, and therefore, represents an excellent choice to study factors regulating diffusion. Muscle is comprised of three specific fibre types, each with specific contractile and metabolic characteristics, which influence the capillary supply of a given muscle; in addition, both environmental and genetic factors influence the capillary supply, including aging, physical training, and various disease processes. OBJECTIVE: The present study was undertaken to develop and assess the functionality of a data base, from which virtual experiments can be conducted on the capillary supply of human muscle, and the adaptations of the capillary bed in muscle to various perturbations. METHODS: To create the database, an extensive search of the literature was conducted using various search engines, and the three key words - "capillary, muscle, and human". This search yielded 169 papers from which the data for the 46 variables on the capillary supply and fibre characteristics of muscle were extracted for inclusion in the database. A series of statistical analyses (ANOVA) were done on the capillary database to examine differences in skeletal muscle capillarization and fibre characteristics between young and old individuals, between healthy and diseased individuals, and between untrained, endurance trained, endurance welltrained, and resistance trained individuals, using SAS. RESULTS: There was a significantly higher capillarization in the young compared to the old individuals, in the healthy compared to the diseased individuals, and in the endurance-trained and endurance well-trained compared to the untrained individuals. CONCLUSIONS: The results of this study support the conclusion that the capillary supply of skeletal muscle is closely regulated by factors aimed at optimizing oxygen and nutrient supply and/or waste removal in response to changes in muscle mass and/or metabolic activity.
    • Carbohydrate refeeding rapidly reverses the adaptive upregulation of human skeletal muscle pyruvate dehydrogenase kinase following a high fat diet

      Bigrigg, Jonathan Kent.; Applied Health Sciences Program (Brock University, 2004-07-14)
      The time course for the reversal of the adaptive increase in pyruvate dehydrogenase kinase (PDK) activity following a 6d high fat diet (HP: 4.2 ± 0.2 % carbohydrate; 75.6 ± 0.4 % fat; 19.5 ± 0.8 % protein) was investigated in human skeletal muscle (vastus lateralis). HF feeding increased PDK activity by 44% (from 0.081 ± 0.025 min"' to 0.247 ± 0.025 mm\p < 0.05). Following carbohydrate re-feeding, (88% carbohydrate; 5% fat; 7% protein), PDK activity had returned to baseline (0.111 ± 0.014 min"') within 3h of re-feeding. The active fraction of pyruvate dehydrognease (PDHa) was depressed following 6d of the HF diet (from 0.89 ± 0.21 mmol/min/kg WW to 0.32 ± 0.05 mmol/min/kg ww,p <0.05) and increased to pre-HF levels by 45 min of post re-feeding (0.74 ±0.19 mmol/min/kg ww) and remained elevated for 3h. Western blotting analysis of the PDK isoforms, PDK4 and PDK2, revealed a 31% increase in PDK4 protein content following the HF diet, with no change in PDK2 protein. This adaptive increase in PDK4 protein content was reversed with carbohydrate re-feeding. It was concluded that the adaptive up-regulation in PDK activity and PDK4 protein content was fiilly reversed by 3h following carbohydrate re-feeding.
    • Cardiovascular and Cognitive Adaptations Following Isometric Handgrip Exercise Training in Hypertensive Adults

      Dempster, Kylie Samantha; Applied Health Sciences Program
      Isometric handgrip (IHG) exercise training is an effective method of blood pressure (BP) reduction in clinical and non-clinical populations. The efficacy of IHG on cardiovagal baroreflex sensitivity (cvBRS) and systemic arterial stiffness (i.e. carotid-toe pulse wave velocity (ctPWV)) is less well understood, especially in hypertensive populations who demonstrate increased arterial stiffness and decreased BRS. Furthermore, hypertension is considered an accelerated model of cognitive decline, often attributed to the effects of increased BP and arterial stiffness. This study utilized IHG (n=8) and CON groups (n=4) to examine the effects of 8-weeks of IHG training or no IHG training on arterial stiffness, cvBRS, and cognitive function in hypertensive adults. Significant group differences in SBP and ctPWV change was observed (p<0.05) indicating that IHG training reduced SBP and systemic arterial stiffness compared to no IHG training. Moreover, although not significant (p>0.05), the IHG group demonstrated an ~53% increase in BRS. Lastly, a significant difference in Trail Making Test Part A (TMT-A) time (p<0.001) was observed in the IHG group, suggesting that IHG training improved motor, and visual control and speed. These findings suggest that IHG training can improve systemic arterial stiffness and possibly cvBRS in a hypertensive population, in addition to the new potential for improving specific aspects of cognitive function.
    • The cardiovascular hemodynamic responses to various levels of orthostatic stress in children

      Livingstone, Kristina.; Applied Health Sciences Program (Brock University, 2007-06-09)
      The ability of the cardiovascular system to quickly and efficiently adapt to an orthostatic stress is vital for the human body to function on earth. The way in which the various aspects of the cardiovascular system work together to counteract an orthostatic stress has been previously quantified in the adult population. However, there are still many unknowns surrounding the topic of how the cardiovascular system functions to cope with this same stress in children. The purpose of this study was to describe the cardiovascular hemodynamic adaptations to various levels of orthostatic stress induced using a lower body negative pressure (LBNP) chamber in pre-pubertal boys. A secondary purpose was to determine indices of baroreceptor sensitivity (BRS) at both rest and during low levels of LBNP in this same pediatric sample. Finally, this study aimed to compare the relative responses to LBNP between the children and adults. To complete the study 20 healthy pre-pubertal boys and adult males (9.3 ± 1.1 and 23 ± 1.8 years of age respectively) were recruited and randomly exposed to three levels of LBNP (15, 20 and 25 mmHg). At rest and during the application of the LBNP heart rate (HR), manual and bcat-by-beat systolic (SBP), diastolic (DBP) and mean arterial blood pressure (MAP) were monitored continuously. Aortic diameter was measured at rest and peak aortic blood velocity (PV) was recorded continuously for at least I minute during each baseline and LBNP condition. From the raw data HR, stroke volume (SV), cardiac output (Q), total peripheral resistance (TPR), low frequency baroreceptor sensitivity (LF BRS), high frequency baroreceptor sensitivity (HF BRS) and LFIIIF ratio were calculated. At rest, llR wa'i higher and SBP, SV, Q and LF/HF ratio were lower in the children compared to the adult males (pgJ.05). In response to the increasing LEN!> IIR and TPR increased, and LF BRS. SV and Q decreased in the adult group (pSf).05). while the same levels of LBNP caused an increase in TPR and a decrease in SBP, SV and Q in the children (pSf).05). Although not significant, the LF/HF ratio in the adult group showed an increasing trend in response to increased negative pressure (p=O.088). As for resting BRS, there were no significant differences in LF or HF BRS between the children and the adults despite a tendency for both measures to be 18% lower in the children. Also the LF/HF ratio was almost significantly greater in the adults compared to the children (p=O.057). In addition, a comparison between the relative adult and child responses to LBNP yielded no significant group by level interactions. This result should be taken with caution though, as the low sample size and high measurement variability generated very low statistical power for this analysis. In conclusion, the results of this study suggest that the hemodynamic adaptations to an orthostatic stress were less pronounced in the prepubertal males, most likely due to an underdeveloped autonomic system. These results need to be strengthened by further research before any implications can be derived for health care purposes.
    • A Case Study to Explore Women's Body Image Experiences Practicing Hot Yoga

      Rose, Hannah; Applied Health Sciences Program
      Yoga is an embodying activity associated with positive body image; however, hot yoga may have differing impacts on body image and embodiment than traditional yoga, as several features of hot yoga differ from traditional yoga (e.g., heat, clothing worn, emphasis on fitness) and may influence women’s body image and practice of hot yoga. Using an exploratory case study approach, one hot yoga studio (Modo Yoga St. Catharines) was chosen for this study. The research questions pertaining to this case were: 1) In what ways is body image related to women’s practice of hot yoga? 2) What are women’s experiences practicing hot yoga at Modo Yoga studio St. Catharines? Ten women were recruited from the yoga studio and interviewed about their body image and experience practicing yoga at Modo Yoga. Four women, with differing experiences and body image, completed a follow-up interview to further clarify their experiences. Overall, it was found that women tended to emphasize the fitness aspects of hot yoga, which impacted their body image and undermined some benefits of yoga. However, there were also positive effects on body image and mental health as a result of the practice. Case-specific features, specifically related to the physical characteristics of the studio (e.g., large mirrors in the studio) and the social environment within the studio (i.e., instructor cues and other members) impacted women’s body image both positively and negatively. Further, some differences based on age and experience at the studio were also identified, with long-term members (6 months+) experiencing more psychological benefits (e.g., mindfulness, feeling less anxious, body acceptance, body responsiveness), with the physical challenges of hot yoga being an additional benefit. Overall, hot yoga had a complex impact on women’s body image and experience practicing hot yoga through a larger focus on the fitness elements of the practice.
    • Changes in mitochondrial PLIN3 and PLIN5 protein content in rat skeletal muscle following acute contraction and endurance training

      Ramos, Sofhia; Applied Health Sciences Program (Brock University, 2014-11-03)
      Surrounding lipid droplets in skeletal muscle are the perilipin (PLIN2-5) family of proteins, regulating lipid droplet metabolism. During exercise lipid droplets provide fatty acids to the mitochondria for oxidation while increasing their proximity to each other. Whether PLIN3 and PLIN5 associate with mitochondria following contraction has not been examined. To determine whether contraction altered mitochondrial PLIN3 and PLIN5 content, sedentary and endurance trained rats underwent acute contraction. The main outcomes are; 1) mitochondrial PLIN3 content is unaltered while mitochondrial PLIN5 content is increased following an acute contraction 2) mitochondrial PLIN3 content is higher in endurance trained rats when compared to sedentary and mitochondrial PLIN5 content is similar in both conditions 3) only PLIN5 mitochondrial content is increased similarly in both groups following acute contraction. This work highlights the dynamics of these two PLIN proteins, which may have roles not only on the lipid droplet but also on the mitochondria.
    • Characterization of Neutral Sphingomyelinase Isoforms in Skeletal Muscle Mitochondria

      Silvera, Sebastian; Applied Health Sciences Program
      Skeletal muscle is composed of fiber types that differ in mitochondrial content, antioxidant capacity, and susceptibility to apoptosis. Ceramides have been linked to apoptosis by increasing mitochondrial permeability, a common hallmark of apoptotic signalling. The enzyme neutral sphingomyelinase (nSMase) generates ceramides by hydrolysing sphingomyelin. Despite the role of ceramides in mediating apoptosis, there is a gap in the literature regarding nSMase in skeletal muscle mitochondria. This study aimed to characterize activity and content of nSMase isoforms in isolated subsarcolemmal (SS) mitochondria from soleus, diaphragm, plantaris, and extensor digitorum longus (EDL). Total nSMase activity did not differ between isolated SS mitochondria. nSMase2 content was higher in SS mitochondria from EDL compared to soleus or diaphragm, and positively correlated to total nSMase activity in soleus. nSMase3 was undetectable in all samples, suggesting it is not associated with SS mitochondria, and likely does not contribute to total nSMase activity in SS mitochondria.
    • Characterizing the role of tafazzin in allergically activated mast cells

      Maguire, Aindriu; Applied Health Sciences Program
      Introduction & Aim: Allergic inflammatory diseases are a constantly growing health concern in westernized societies. Mast cells, the driving force behind many allergic diseases, modulate various metabolic pathways to carry out their various functions following IgE-FceRI-mediated activation. Tafazzin is a cardiolipin transacylase that works to remodel cardiolipin into its mature form of tetralinoleoyl-cardiolipin. Mature cardiolipin is important for efficient energy production through oxidative phosphorylation. The aim of this project is to study the effects of a reduction in tafazzin protein content on IgE-mediated mast cell activation. Methods: Fetal liver-derived mast cells (FLMCs) were treated with 1 μg/mL doxycycline for 5 days to initiate the tafazzin knockdown. Western blotting was used to confirm a reduction in tafazzin protein content. Flow cytometry was used to ensure that the FLMCs expressed both c-kit and FceRI receptors, and that receptor expression was not impacted by the doxycycline treatment. Oxygen consumption rate was measured using a Clark-type electrode. b-hexosaminidase release assays were utilized to assess degranulation during the early phase of the allergic reaction. ELISA assays were used to examine secretion of de novo synthesized inflammatory mediators, while qPCR assays were used to examine gene transcription of these mediators. Results: The doxycycline inducible tafazzin knockdown resulted in a 99.5% reduction in tafazzin protein content. This reduction was accompanied by a 25% reduction in oxygen consumption and a 31.4% reduction in degranulation. Secretion of CCL1, CCL2, and TNF was significantly reduced, CCL9 secretion levels showed a decrease that approached significance. Secretion of CCL3 and IL-6 was not impacted. Gene expression was not impacted for any of the inflammatory mediators measured. Conclusion & Significance: These results suggest that tafazzin may play a role in mast cell oxidative phosphorylation. Functionally, the results suggest that tafazzin plays a role in degranulation and mediator secretion. However, since gene expression was not impacted it is thought that the tafazzin reduction causes these decreases due to an impairment of the exocytosis mechanism. This work adds to the growing field of immunometabolism and improves our understanding of how mast cells modulate metabolic pathways during an allergic inflammatory event.
    • Chronic versus acute ingestion of sodium citrate: a randomized placebo controlled cross-over trial for swimming 200 metres in well-trained swimmers age 13-17

      Russell, Colin; Applied Health Sciences Program (Brock University, 2013-07-19)
      A double-blinded, placebo controlled, cross-over design was used to investigate sodium citrate dihydrate (Na-CIT) supplementation improve 200m swimming performance. Ten well-trained, male swimmers (14.9 ± 0.4y; 63.5 ± 4kg) performed four 200m time trials: acute (ACU) supplementation (0.5g/kg), acute placebo (PLC-A), chronic (CHR) (0.1g/kg for 3 days and 0.3g/kg on the 4th day pre-trial), and chronic placebo (PLC-C). Na-CIT was administered 120min pre-trial in solution with 500mL of flavored water; placebo was flavored water. Blood lactate, base excess (BE), bicarbonate, pH, and PCO2 were analyzed at basal, 100min post-ingestion, and 3min post-trial via finger prick. Time, lactate, and rate of perceived exertion were not different between trials. BE and bicarbonate were significantly higher for the ACU and CHR trials compared to placebo. “Responders” improved by 1.03% (P=0.043) and attained significantly higher post-trial lactate concentrations in the ACU versus PLC-A trials and compared to non-responders in the ACU and CHR trials.
    • Clinical Depression, Antidepressant Use, and Metabolic Syndrome-related Comorbidities among Canadian Older Adults: A Cross-sectional Analysis of Baseline Data from the Canadian Longitudinal Study of Aging

      Son, Surim; Applied Health Sciences Program
      Background: Clinical depression is associated with a number of biological alterations and behaviours that can increase the risk of metabolic syndrome (MetS). Antidepressant medications (AD) are frequently used to treat depressed patients, but it often has side effects such as metabolic abnormalities. MetS is a well-known risk factor for multiple chronic diseases including cancer, and cardiovascular disease (CVD). However, it is unclear how clinical depression, AD use, and MetS are associated with cancer and CVD. Objective: To explore the relationship between clinical depression, AD use, and MetS-related chronic disorders, with a specific focus on cancer and CVD, and to assess how associations differ by MetS status, among Canadian older adults. Methods: The baseline data of the Canadian Longitudinal Study on Aging Comprehensive Cohort of 29,366 men and women aged 45 years and older was used in the analysis. Clinical depression was defined by self-reported clinical diagnosis of depression. Current depression treatment type was categorized into three groups: AD use only, other types of depression therapy, and no current depression therapy. MetS was defined by the harmonized criteria developed by the International Diabetes Federation, and American Health Association/National Heart, Lung, and Blood Institute. Logistic regression was used to estimate the associations of cancer or CVD on the basis of distribution of depression, current treatment types, and MetS. Results: The overall prevalence of clinical depression was 17.3%, and AD use was 8.1%. Compared to non-depressed individuals, depressed individuals taking AD had higher odds of colorectal cancer, and lung cancer. Depressed individuals using AD had higher odds of CVD, except peripheral vascular disease. Regardless of depression status, MetS showed no association with cancers. Among non-depressed individuals, MetS was associated with CVD compared to those without MetS. Within depressed individuals using AD, MetS did not appear to be associated with CVD. Conclusion: Clinical depression and AD use are associated with colorectal cancer, but the association may be independent of MetS. The positive associations between clinical depression, AD, and lung cancer or CVD were mitigated by comorbidity. MetS did not appear to play a role in the association between clinical depression, AD, and MetS-related chronic diseases.