• Decision analysis of the effectiveness of lung cancer screening using autofluorescence bronchoscopy and computed tomography

      Tota, Joseph.; Applied Health Sciences Program (Brock University, 2008-06-15)
      Background: Lung cancer (LC) is the leading cause of cancer death in the developed world. Most cancers are associated with tobacco smoking. A primary hope for reducing lung cancer has been prevention of smoking and successful smoking cessation programs. To date, these programs have not been as successful as anticipated. Objective: The aim of the current study was to evaluate whether lung cancer screening combining low dose computed tomography with autofluorescence bronchoscopy (combined CT & AFB) is superior to CT or AFB screening alone in improving lung cancer specific survival. In addition, the extent of improvement and ideal conditions for combined CT & AFB screening were evaluated. Methods: We applied decision analysis and Monte Carlo simulation modeling using TreeAge Software to evaluate our study aims. Histology- and stage specific probabilities of lung cancer 5-year survival proportions were taken from Surveillance and Epidemiologic End Results (SEER) Registry data. Screeningassociated data was taken from the US NCI Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial (PLCO), National Lung Screening Trial (NLST), and US NCI Lung Screening Study (LSS), other relevant published data and expert opinion. Results: Decision Analysis - Combined CT and AFB was the best approach at Improving 5-year survival (Overall Expected Survival (OES) in the entire screened population was 0.9863) and in lung cancer patients only (Lung Cancer Specific Expected Survival (LOSES) was 0.3256). Combined screening was slightly better than CT screening alone (OES = 0.9859; LCSES = 0.2966), and substantially better than AFB screening alone (OES = 0.9842; LCSES = 0.2124), which was considerably better than no screening (OES = 0.9829; LCSES = 0.1445). Monte Carlo simulation modeling revealed that expected survival in the screened population and lung cancer patients is highest when screened using CT and combined CT and AFB. CT alone and combined screening was substantially better than AFB screening alone or no screening. For LCSES, combined CT and AFB screening is significantly better than CT alone (0.3126 vs. 0.2938, p< 0.0001). Conclusions: Overall, these analyses suggest that combined CT and AFB is slightly better than CT alone at improving lung cancer survival, and both approaches are substantially better than AFB screening alone or no screening.
    • Decreased motor unit firing rate in the potentiated tibialis anterior in humans

      Howard, Jon C.; Applied Health Sciences Program (Brock University, 2009-02-16)
      With repeated activity, force production, rate of force production, and relaxation time are impaired. These are characteristics ofa fatigued muscle (Vandenboom, 2004). However, brief bouts of near maximal to maximal activity results in the increased ability of the muscle to generate force, termed post activation potentiation (P AP)(V andervoort et aI., 1983). The purpose of the present study was to characterize motor unit firing rate (MUFR) in the unfatigued, potentiated tibialis anterior (TA). Using a quadrifilar needle electrode, MUFR was measured during a 5s 50% MVC in which the TA was either potentiated or unpotentiated; monopolar electrodes measured surface parameters. A lOs MVC was used to potentiate the muscle. Firing rate decreased significantly from 20.15±2.9Opps to 18.27±2.99pps, while mean power frequency decreased significantly from 60. 13±7.75 Hz to 53.62±8.56 Hz. No change in root mean square (RMS) was observed. Therefore, in the present study, MUFR decreases in response to a potentiated TA.
    • A denoising algorithm for surface EMG decomposition

      Kumar, Robert; Applied Health Sciences Program
      The goal of the present thesis was to investigate a novel motor unit potential train (MUPT) editing routine, based on decreasing the variability in shape (variance ratio, VR) of the MUP ensemble. Decomposed sEMG data from 20 participants at 60% MVC of wrist flexion was used. There were two levels of denoising (relaxed and strict) criteria for removing discharge times associated with waveforms that did not decrease the VR and increase its signal-to-noise ratio (SNR) of the MUP ensemble. The peak-to-peak amplitude and the duration between the positive and negative peaks for the MUP template were dependent on the level of denoising (p’s <0.05). The error-filtered estimation (EFE) algorithm was used to calculate the inter-discharge interval (IDI) for the denoised MUPTs. In total, VR decreased 24.88% and the SNR increased 6.0% (p’s < 0.05). The standard error of estimate (3.2 versus 3.69%) in mean IDI before and after denoising using the relaxed criteria, was very similar (p>0.05). The same was true between denoising criteria (p>0.05). Editing the MUPT based on MUP shape resulted in significant differences in measures extracted from the MUP template, with trivial difference between the standard error of estimate for mean IDIs between the complete and denoised MUPTs.
    • Determinants of left ventricular mass as measured by Doppler echocardiography in pre-adolescents

      Peralta-Huertas, Jose.; Applied Health Sciences Program (Brock University, 2006-06-04)
      This study examined factors contributing to the differences in left ventricular mass as measured by Doppler echocardiography in children. Fourteen boys (10.3 ± 0.3 years of age) and 1 1 girls (10.5 ± 0.4 years of age) participated in the study. Height and weight were measured, and relative body fat was determined from the measurement of skinfold thickness according to Slaughter et al. (1988). Lean Body Mass was then calculated by subtracting the fat mass from the total body mass. Sexual maturation was self-assessed using the stages of sexual maturation by Tanner (1962). Both pubic hair development and genital (penis or breast for boys and girls respectively) development were used to determine sexual maturation. Carotid Pulse pressure was assessed by applanation tomometry in the left carotid artery. Cardiac mass was measured by Doppler Echocardiography. Images of cardiac structures were taken using B-Mode and were then translated to M- Mode. The dimensions at the end diastole were obtained at the onset of the QRS complex of the electrocardiogram in a plane through a standard position. Measurements included: (a) the diameter of the left ventricle at the end diastole was measured from the septum edge to the endocardium mean border, (b) the posterior wall was measured as the distance from to anterior wall to the epicardium surface, and (c) the interventricular septum was quantified as the distance from the surface of the left ventricle border to the right ventricle septum surface. Systolic time measurements were taken at the peak of the T-wave of the electrocardiogram. Each measurement was taken three to five times before averaging. Average values were used to calculate cardiac mass using the following equation (Deveraux et al. 1986). Weekly physical activity metabolic equivalent was calculated using a standardize activity questionnaire (Godin and Shepard, 1985) and peakV02 was measured on a cycloergometer. There were no significant differences in cardiovascular mesurements between boys and girls. Left ventricular mass was correlated (p<0.05) with size, maturation, peakV02 and physical activity metabolic equivalent. In boys, lean body mass alone explained 36% of the variance in left ventricular mass while weight was the single strongest predictor of left ventricular mass (R =0.80) in girls. Lean body mass, genital developemnt and physical activity metabolic equivalent together explained 46% and 81% in boys and girls, respectively. However, the combination of lean body mass, genital development and peakV02 (ml kgLBM^ min"') explained up to 84% of the variance in left ventricular mass in girls, but added nothing in boys. It is concluded that left ventricular mass was not statistically different between pre-adolescent boys and girls suggesting that hormonal, and therefore, body size changes in adolescence have a main effect on cardiac development and its final outcome. Although body size parameters were the strongest correlates of left ventricular mass in this pre-adolescent group of children, to our knowledge, this is the first study to report that sexual maturation, as well as physical activity and fitness, are also strong associated with left ventricular mass in pre-adolescents, especially young females. Arterial variables, such as systolic blood pressure and carotid pulse pressure, are not strong determinants of left ventricular mass in this pre-adolescent group. In general, these data suggest that although there is no gender differences in the absolute values of left ventricular mass, as children grow, the factors that determine cardiac mass differ between the genders, even in the same pre-adolescent age.
    • Determining If Lowering the Level of Dietary Calcium and Vitamin D in AIN-93G Diet Supports Normal Bone Development and Intestinal Integrity in Female CD-1 Mice

      Yumol, Jenalyn; Applied Health Sciences Program
      Current levels of vitamin D (vit D) and calcium (Ca) in the reference AIN-93G rodent diet may be higher than required for healthy bone structure and bone mineral density (BMD). Other studies suggest that intestinal integrity may be altered by lowering levels of vit D or Ca. The study objective was to determine if lower diet levels of Ca and vit D support development of healthy bone structure and BMD in female CD-1 mice at 2 and 4 months of age without altering intestinal integrity. Lowering the levels of vit D (100 IU/kg) and Ca (3.5 g/kg) did not alter bone structure or BMD. Effects on intestinal integrity are less clear and requires further study using more comprehensive measures. Findings from this study suggest that dietary Ca and/or vit D at current levels in the AIN-93G reference diet may mask potential benefits of nutritional interventions aimed at promoting bone health.
    • The Development of a Novel Pitching Assessment Tool

      Birfer, Richard; Applied Health Sciences Program
      Posture based ergonomic assessment tools are widely used to evaluate posture and injury risk for many workplace/occupational tasks. To date, there is no validated equivalent that can be used to assess the posture of a pitcher during baseball pitching. Therefore, the purpose of this study was to develop an inexpensive tool which can allow for the rapid assessment of a pitcher’s posture at lead foot strike, and establish the inter- and intra- rater reliability of the tool. For this study, 11 participants threw 30 pitches (15 fastballs, 15 curveballs) off an indoor pitching. Full body 3D kinematics were measured using reflective markers attached to anatomical landmarks and rigid bodies attached to body segments using a 10-camera Vicon Motion Capture system along with two high-speed video cameras (rear and side view) to record each pitch during the experimental trials. The kinematic data was analyzed, after which the highest velocity fastball of each of the 11 pitchers was selected for further analysis. A Pitching Mechanics Tool was designed to evaluate 16 different parameters at lead foot strike. Each of the 16 parameters had posture ranges or categories established based on scientific literature. Six evaluators with at least five years of experience working with adult pitchers completed the Pitching Mechanics Tool. Findings showed moderate to good levels of repeatability across multiple sessions as well as across multiple evaluators. Additionally, PMT results suggested that 2D qualitative analysis is a viable alternative to 3D motion capture.
    • Dietary Intakes and Periodontal Outcomes After Sanative Therapy

      Dodington, David; Applied Health Sciences Program (Brock University, 2014-09-02)
      Diet has an important role in the maintenance of oral health, but the relationship between diet and clinical outcomes following sanative therapy (ST) has not been investigated. Due to their antioxidant and anti-inflammatory properties, we hypothesized that periodontal patients with higher intakes of vitamin C, vitamin D, eicosapentaenoic acid (EPA) or docosahexaenoic acid (DHA) would have greater reductions in probing depth (PD) after ST. Patients completed the Block food frequency questionnaire, a supplement use questionnaire and had their serum 25-hydroxyvitamin D measured. There were no significant associations between intakes of vitamin C, vitamin D, EPA, DHA and PD. There were, however, negative associations between intakes of linoleic acid, α- linolenic acid or total vegetable intake and PD, as well as a positive association between the total omega-6/omega-3 ratio and PD (p < 0.05). Therefore, dietary intakes of essential fatty acids and vegetables may be important modulators of periodontal outcomes following ST.
    • A discursive analysis of children's recreational adult-organized sport : when do children get to play?

      Gracey, Bonita.; Applied Health Sciences Program (Brock University, 2008-06-01)
      Adult-organized children's sport attracts millions of participants in Canada and the United States each year. Though there is a great deal of research that considers children's sport, little of it focuses on recreational or house league sport and less of it offers a deep examination of children's experience of their participation. Using observations, interviews, and focus groups involving ten participants in mixed-gender recreational basketball, this qualitative research project examined their experiences. With Foucault's concepts of correct training and the panoptic gaze in mind, I used discourse and deconstruction analyses to consider the children's descriptions along with my observations of their basketball experience. I was particularly looking for prevalent discourses on sport, childhood, and gender and how they affected their experiences. Despite the league's discursive emphasis on fun, participation, fairness, and respect, that was not necessarily what the children experienced. While most stated they enjoyed their season many also expressed serious disappointments. Size and particularly skill very much determined who was most involved in the action and thus actually played baskethaW. Gender also played a significant role in their sport experiences. My findings invite questions about what genuine sport participation actually is and how it might be alternatively imagined.
    • Do You See What I See: The Influence of Self-Objectification on Appearance Anxiety, Intrinsic Motivation, Interoceptive Awareness, and Physical Performance

      Dimas, Michelle A; Applied Health Sciences Program
      Objectification theory suggests that when individuals take on an observer’s perspective of their physical appearance (known as self-objectification), they experience an increase in body shame and anxiety and a decrease in motivation and bodily awareness. The purpose of this study was to determine if self-objectification could impact social physique anxiety, intrinsic motivation, and bodily awareness as well as physical performance. Undergraduate female students (N=54) were recruited to participate in a Consumer Behaviour study (cover story). Participants were randomly assigned to a swimsuit or sweater condition, completed cover story and body image measures, changed into the clothing based upon randomization, then completed state body image measures and performed a series of balance tasks. Women in the swimsuit group experienced greater state self-objectification and reported greater amounts of body-related shame and appearance anxiety and lower amounts of intrinsic motivation. In addition, self-objectification led to restricted arms, trunk, and leg movements during a 1-leg stand. Findings could have implications for promoting positive experiences during physical activity, such as sport, exercise or rehabilitation settings.
    • Does altering brachial artery tone with lower-body negative pressure and flow-mediated dilation affect arterial stiffness?

      Goswami, Ruma.; Applied Health Sciences Program (Brock University, 2006-06-04)
      Although medium sized, muscular vessels normally respond to sympathetic stimulation by reducing compliance, it is unclear whether the large brachial artery is similarly affected by sympathetic stimulation induced via lower-body negative pressure (LBNP). Similarly, the impact of flow-mediated dilation (FMD) on brachial artery compliance and distensibility remains unresolved, hi addition, before such measures can be used as prognostic tools, it is important to investigate the reliability and repeatability of both techniques. Using a randomized order design, the effects of LBNP and FMD on the mechanical properties of the brachial artery were examined in nine healthy male subjects (mean age 24y). Non-invasive Doppler ultrasound and a Finometer were used to measure simultaneously the variation in systolic and diastolic diameter, and brachial blood pressure, respectively. These values were used to calculate compliance and distensibility values at baseline, and during both LBNP and FMD. The within-day and between-day repeatability of arterial diameter, compliance, distensibility, and FMD measures were assessed using the error coefficient and intra-class correlation coefficient (ICC). While heart rate (P<0.01) and peripheral resistance increased during LBNP (P<0.05), forearm blood flow and pulse pressure decreased (P<0.01). hi terms of mechanical properties, vessel diameters decreased (P<0.05), but both compliance and distensibility were not changed. On the other hand, FMD resulted in a significant increase in diameter (P<0.001), with no change in compliance or distensibility. hi summary, LBNP and FMD do not appear to alter brachial artery compliance or distensibility in young, healthy males. Whereas measures ofFMD were not found to be repeatable between days, the ICC indicated that compliance and distensibility were repeatable only within-day.
    • Does Bracing affect Bone Health in Females with adolescent Idiopathic Scoliosis?

      Akseer, Nasreen; Applied Health Sciences Program (Brock University, 2013-09-11)
      This study examined the bone mineral content (BMC) in young women with Adolescent Idiopathic Scoliosis (AIS), treated with a brace (27.9 ±21.6 months, for 18.0±5.4 h/d) during adolescence (AIS-B, n = 15, 25.6 ±5.8 yrs), versus women with AIS but no treatment (AIS-NB, n = 15, 24.0 ±4.0 yrs), and women without AIS (C, n = 19, 23.5 ±3.8 yrs). After controlling for lean body mass, calcium and vitamin D daily intake, and strenuous physical activity, femoral neck BMC was lower in the AIS-B compared with AIS-NB and C (all p’s < .05). In summary, women with AIS, braced during their growing years are characterized by low lower limb BMC. However, the lack of a relationship between brace treatment duration and BMC, suggests that bracing was not the likely mechanism.
    • Don’t Stop the Music: Does the Thin Ideal in Pop Music Lyrics Affect Women’s Body Image During Exercise?

      Jackson, Alyssa; Applied Health Sciences Program
      Viewing music videos emphasizing the thin ideal female body has been shown to have a negative impact on body image in young women, including increased body dissatisfaction, social comparisons, self-objectifications and body size discrepancies. However, it is unclear whether the changes in body image outcomes are due to the highly objectified images of women representing the thin ideal or the lyrics of the songs. This study aimed to explore the effects of music lyrics on body image during exercise in physically active female university students. A repeated measures design was used; 29 women completed two conditions in which they were asked to walk or run for 30 minutes while listening to music. In one condition, the negative music lyric condition, songs referred explicitly to women’s appearance, objectified the female body, or referenced the thin ideal. In the neutral music lyric condition, the songs did not refer to appearance at all. Participants completed state measures of mood, body satisfaction, self-objectification and body appreciation prior to and following each of their walks/runs. Rating of perceived exertion (RPE) was assessed following each walk/run and total distance traveled was recorded. Results indicated a statistically significant time effect (all ps < 0.05) for all outcomes except self-objectification, with women reporting feeling more confident, physically attractive, appreciative of their body, happier and feeling less fat, anxious, depressed and angry from pre- to post-exercise following both conditions. There were no effects of condition and no interaction effects. There were no differences between condition for RPE or distance travelled. This study highlights the positive effects exercise has on body image and mood outcomes and suggests that exercise may buffer the possible negative effects of objectifying lyrics. Music that is motivational, even with appearance-focused lyrics, may not be harmful to body image in exercise settings and may be used to keep women happier and more positive about their body following exercise.
    • Drumming toward communitas : a case study of facilitated recreational music making and the Arthurian method

      Cunningham, Amy.; Applied Health Sciences Program (Brock University, 2008-06-01)
      The phenomenon of communitas has been described as a moment 'in and out of time' in which a collective of individuals may be experienced by one as equal and individuated in an environment stripped of structural attributes (Turner, 1 969). In these moments, emotional bonds form and an experience of perceived 'oneness' and synergy may be described. As a result of the perceived value of these experiences, it has been suggested by Sharpe (2005) that more clearly understanding how this phenomenon may be purposefully facilitated would be beneficial for leisure service providers. Consequently, the purpose of this research endeavor was to examine the ways in which a particular leisure service provider systematically employs specific methods and sets specific parameters with the intention of guiding participants toward experiences associated with communitas or "shared spirit" as described by the organization. A qualitative case study taking a phenomenological approach was employed in order to capture the depth and complexity of both the phenomenon and the purposefiil negotiation of experiences in guiding participants toward this phenomenon. The means through which these experiences were intentionally facilitated was recreational music making in a group drumming context. As such, an organization which employs specific methods of rhythm circle facilitation as well as trains other facilitators all over the world was chosen purposely for their recognition as the most respectable and credible in this field. The specific facilitator was chosen based on high recommendation by the organization due to her level of experience and expertise. Two rhythm circles were held, and participants were chosen randomly by the facilitator. Data was collected through observation in the first circle and participant- observation in the second, as well as through focus groups with circle participants. Interviews with the facilitator were held both initially to gain broad understanding of concepts and phenomenon as well as after each circle to reflect on each circle specifically. Data was read repeatedly to drawn out patterns which emerged and were coded and organized accordingly. It was found that this specific process or system of implementation lead to experiences associated with communitas by participants. In order to more clearly understand this process and the ways in which experiences associated with communitas manifest as a result of deliberate facilitator actions, these objective facilitator actions were plotted along a continuum relating to subjective participant experiences. These findings were then linked to the literature with regards to specific characteristics of communitas. In so doing, the intentional manifestation of these experiences may be more clearly understood for ftiture facilitators in many contexts. Beyond this, findings summarized important considerations with regards to specific technical and communication competencies which were found to be essential to fostering these experiences for participants within each group. Findings surrounding the maintenance of a fluid negotiation of certain transition points within a group rhythm event overall were also highlighted, and this fluidity was found to be essential to the experience of absorption and engagement in the activity and experience. Emergent themes of structure, control, and consciousness have been presented as they manifested and were found to affect experiences within this study. Discussions surrounding the ethics and authenticity of these particular methods and their implementation has also been generated throughout. In conclusion, there was a breadth as well as depth of knowledge found in unpacking this complex process of guiding individuals toward experiences associated with communitas. The implications of these findings contribute in broadening the current theoretical as well as practical understanding as to how certain intentional parameters may be set and methods employed which may lead to experiences of communitas, and as well contribute a greater knowledge to conceptualizing the manifestation of these experiences when broken down.
    • Dynamic Upper Leg Strength and Neuromuscular Function in Children, Adolescents and Adults

      Jenkins, Glenn; Applied Health Sciences Program (Brock University, 2013-01-14)
      This study examined muscle strength, muscle performance, and neuromuscular function during contractions at different velocities across maturation stages and between sexes. Participants included pre-pubertal, late-pubertal and adult males and females. All completed 8 isometric and 8 isokinetic leg extensions at two different velocities. Peak torque (PT), rate of torque development (PrTD), electromechanical-day (EMD), rate of muscle activation (Q30), muscle activation efficiency and coactivation were determined. Sex, maturity, and velocity main effects were found in PT and PrTD, reflecting greater values in men, adults, and isometric contractions respectively. When values were normalized to quadriceps cross-sectional area (qCSA), there was still an increase with maturity. EMD decreased with maturity. Adults had greater activation efficiency than children. Overall, differences in muscle size and neuromuscular function failed to explain group differences in PT or PrTD. More research is needed to investigate why adults may be affected to a greater extent by increasing movement velocity.
    • The effect of 17-B estradiol therapy on bone mineral density and structure of alveolar bone in the ovariectomized rat model of postmenopausal osteoporosis

      Johnston, Bryan; Applied Health Sciences Program (Brock University, 2015-01-23)
      The ovariectomized (OVX) rat, a preclinical model for studying postmenopausal bone loss, may also be used to study differences in alveolar bone (AB). The objectives of this study were to quantify the differences in AB following estrogen replacement therapy (ERT), and to investigate the relationship between AB structure and density, and trabecular bone at the femoral neck (FN) and third lumbar vertebral body (LB3). Estrogen treated rats had a higher bone volume fraction (BV/TV) at the AB region (9.8% P < 0.0001), FN (12% P < 0.0001), and LB3 (11.5% P < 0.0001) compared to the OVX group. BV/TV of the AB was positively correlated with the BV/TV at the FN (r = 0.69 P < 0.0001) and the LB3 (r = 0.75 P < 0.0001). The trabecular number (Tb.N), trabecular separation (Tb.Sp), and structure model index (SMI) were also positively correlated (P < 0.05) between the AB and FN (r = 0.42, 0.49, and 0.73, respectfully) and between the AB and LB3 (r = 0.44, 0.63, and 0.69, respectfully). Given the capacity of AB to respond to ERT, future preclinical drug/nutritional intervention studies aimed at improving skeletal health should include the AB as a region of interest (ROI).
    • Effect of a high fat maternal diet on body composition and bone development in male offspring

      Miotto, Paula; Applied Health Sciences Program (Brock University, 2014-08-29)
      Direct high fat (HF) feeding has adverse effects on body composition and bone development in rodents. However, it is unclear whether maternal HF feeding has similar effects in male rat offspring. The objectives of this thesis were to determine if maternal HF feeding altered body composition, plasma hormones, bone development, and bone fatty acid composition in male offspring at weaning and 3 months of age. Maternal HF feeding increased bone mass and altered femur fatty acid composition at weaning, without differences in fat mass, lean mass, plasma hormones, or bone mass (femur or lumbar vertebrae). However, early differences did not persist at 3 months of age or contribute to lower bone strength – following consumption of a control diet post-weaning. These findings suggest that maternal HF feeding can alter body composition and bone development in weanling male offspring, without long-lasting effects if a healthy control diet is consumed post-weaning.
    • The effect of a segmental, localized lower limb cooling protocol on muscular strength and balance

      Montgomery, Roger Edward; Applied Health Sciences Program (Brock University, 2012-11-27)
      The human neuromuscular system is susceptible to changes within the thermal environment. Cold extrinsic temperatures can significantly reduce muscle and nervous system function and communication, which can have consequences for motor performance. A repeated measures design protocol exposed participants to a 12°C cold water immersion (CWI) up to the ankle, knee, and hip to determine the effect that reduced skin and muscle temperature had on balance and strength task execution. Although a linear reduction in the ability to perform balance tasks was seen from the control condition through to the hip CWI, results from the study indicated a significant reduction in dynamic balance (Star Excursion Balance Test reach distance) performance from only the hip CWI (P<0.05). This reduced performance could have been due to an increase in joint stiffness, increased agonist-antagonist co-contraction, and/or reduced isokinetic muscular strength. Reduced physical performance due to cold temperature could negatively impact outdoor recreational athletics.
    • The Effect of a Stickhandling and Puck Control (SPC) Training Intervention on SPC Skills and Wrist Shot Performance Variables in Female Collegiate Ice Hockey Players

      Komenda, Briar; Applied Health Sciences Program (Brock University, 2011-04-11)
      The purpose of the study was to investigate the effect of a 16 session stickhandling and puck control (SPC) off-ice training intervention on SPC skills and wrist shot performance variables. Eighteen female collegiate ice hockey players participated in a crossover design training intervention, whereby players were randomly assigned to two groups. Each group completed 16 SPC training sessions in two conditions [normal vision (NV) and restricted vision (RV)]. Measures obtained after the training intervention revealed significant improvements in SPC skills and wrist shot accuracy. Order of training condition did not reach significance, meaning that SPC improvement occurred as a result of total training volume as opposed to order of training condition. However, overall changes in the RV-NV condition revealed consistently higher effect sizes, meaning a greater improvement in performance. Therefore, support can be provided for this technical approach to SPC training and an alternative method of challenging SPC skills.
    • The effect of a weighted-vest strength and balance training program on obstructed walking in postmenopausal women

      Slack, Jill Patricia.; Applied Health Sciences Program (Brock University, 2003-05-21)
      SUMMARY Background: Age related declines in lower extremity strength have been associated with impaired mobility and changes in gait patterns, which increase the likelihood of falls. Since community dwelling adults encounter a wide range of locomotor challenges including uneven and obstmcted walking surfaces, we examined the effect of a strength 11 and balance exercise program on obstructed walking in postmenopausal women. Objectives: This study examined the effect of a weighted-vest strength and balance exercise program on adaptations of the stance leg during obstacle walking in postmenopausal women. Methods: Eighteen women aged 44-62 years who had not engaged in regular resistance training for the past year were recruited from the St. Catharines community to participate in this study. Eleven women volunteered for an aerobic (walking), strength, and balance training program 3 times per week for 12 weeks while 7 women volunteered as controls. Measurements included: force platform dynamic balance measure of the center of pressure (COP) and ground reaction forces (GRFs) in the stance leg while going over obstacles of different heights (0,5, 10,25 and 30 cm); and isokinetic strength measures of knee and ankle extension and flexion. Results: Of the 18 women, who began the trial, 16 completed it. The EX group showed a significant increase of 40% in ankle plantar flexion strength (P < 0.05). However, no improvements in measures of COP or GRFs were observed for either group. Failure to detect any changes in measures of dynamic balance may be due to small sample size. Conclusions: Postmenopausal women experience significant improvements in ankle strength with 12 weeks of a weighted-vest balance and strength training program, however, these changes do not seem to be associated with any improvement in measures of dynamic balance.
    • The effect of acute low-load resistance exercise with the addition of blood flow occlusion on muscle function in children and adults

      Bax, Alyssa; Applied Health Sciences Program
      Background: Resistance training recommendations to increase muscular strength suggest using high loads. However, some individuals cannot withstand high mechanical stress. Thus, in adults, low-load training is used with blood flow occlusion (BFO), to mimic strength increases from high-load training. Due to differing physiological responses to exercise, children may respond differently to BFO than adults. This study compares the effect of low-load exercise with BFO on maximal voluntary contraction (MVC) and electromyographical (EMG) activity in children and adults. Methods: 16 men (24.4±2.5y) and 14 boys (10.7±2.0y) performed two experimental conditions: (1) occlusion and (2) control. During the occlusion condition, a blood pressure cuff on the upper arm was inflated above systolic pressure during 25 wrist flexions at 35% MVC. Participants then performed an MVC and rated their perceived exertion (RPE). The control condition was the same as the occlusion condition but without the use of BFO. EMG signal was recorded from the flexor carpi radialis (FCR). Results: Men displayed a 16.9±7.1% increase in FCR EMG amplitude across the occlusion (p=0.005) but not the control condition (p=0.919). The boys did not show a change in EMG amplitude between time points (p=0.576) or conditions (p=0.549). Across both age groups, EMG mean power frequency was influenced by a condition-x-time interaction, with a larger decrease across the occlusion (-20.1±9.6%; p<0.001) than the control condition (-5.6±9.7%; p=0.002). Furthermore, across both age groups, MVC torque decreased more following the occlusion (-18.7±12.8%; p<0.001) than the control condition (-6.7±12.5%; p<0.001). Discussion: Based on our findings, a partial explanation for increases in EMG amplitude in the men but not the boys may be that the men recruited more of their higher-threshold motor units than the boys. However, not all measures were consistent in showing child-adult differences, as BFO caused similar decreases in MPF for both groups. Thus, while adults use low-loads with BFO to simulate high-load training, it remains unclear whether this form of training would be as effective for children.