Effects of Powerchair Football: Contextual Factors That Impact Participation.

The aim of this study was to identify contextual factors that negatively affect activity and participation among powerchair football (PF) players. Thirty-seven semistructured interviews were conducted with PF players (Mage = 27.9 ± 8.2 years) in France (n = 18) and the United States (n = 19). Participants reported acute back and neck pain as the primary morbidities resulting from PF participation, with sustained atypical posture in the sport chair as the primary cause. Competition-related physical and mental stress were also identified as participation outcomes. Accompanying the many benefits of PF, participants recognized negative impacts of discomfort, physical fatigue, and mental fatigue. Interventions such as seating modifications, thermotherapy to combat pain, napping to combat acute physical stress, and mental preparation to manage state anxiety were all identified as prospective interventions.

Evidence-Based Classification in Powerchair Football: Determining the Determinants.

The purpose of this study was to initiate the development of an evidence-based sport classification system for powerchair football, a sport that serves athletes with physical impairments. Sport classification is designed to increase participation by minimizing the impact of impairment on competition outcome, and powerchair football lacks an evidence-based system of classification which is required of Paralympic sports. A number of approaches were used to build the theoretical model of sport performance (Step 2 of the International Paralympic Committee model). Key sport activities were identified through surveys of stakeholders and underlying determinants of those key activities were identified through game and database analyses. Current findings support drive control, ball control, communication, and adjustment to the ball as key activities in powerchair football with joint-specific strength and range of motion, sensory, and neurological variables identified as underlying determinants.

Measured and predicted resting energy expenditure in wheelchair rugby athletes.

Objective: Report measured resting energy expenditure (REE) in wheelchair rugby athletes and evaluate agreement between REE and the prediction models of Chun, Cunningham, Harris-Benedict, Mifflin, Nightingale and Gorgey, and Owen.Design: Cohort-based validation study.Setting. Paralympic team training camp.Participants: Fourteen internationally competitive athletes who play wheelchair rugby, 13 of whom had cervical spinal cord injuries (SCI).Outcome Measures: A portable metabolic analyzer was used to measure REE following an overnight fast and dual-energy X-ray absorptiometry (DXA) was used to assess lean body mass for the prediction equations.Results: REE in the current sample was 1735 ± 257 kcal × day-1 ranging from 1324 to 2068 kcal × day-1. Bland-Altman analyses revealed negative mean bias but similar limits of agreement between measured REE and scores predicted by Chun, Cunningham, Mifflin, Nightingale and Gorgey, and Owen models in elite athletes who play wheelchair rugby.Conclusion: Prediction models regressed on persons with and without SCI under-predicted REE of competitive wheelchair rugby athletes. This outcome may be explained by the higher REE/fat-free mass (FFM) ratio of current athletes compared to less active samples. Findings from the current study will help practitioners to determine nutrient intake needs on training days of varied intensity.

Physiological responses during a 25-km time trial in elite wheelchair racing athletes.

STUDY DESIGN: Observational study. OBJECTIVES: To characterize the cardiorespiratory and metabolic response of elite wheelchair racing (WCR) athletes during a 25 km, field-based time trial. SETTINGS: University laboratory and field racing course in Urbana, Illinois, USA. METHODS: Seven elite WCR athletes (4 men/3 women) with spinal cord injury completed an incremental exercise test to exhaustion on a computerized wheelchair roller system to determine peak cardiorespiratory capacity in the laboratory. The athletes then completed a long-distance, field-based time trial (i.e., 25 km) within 5 days. Energy expenditure was measured continuously during the time trial with a portable metabolic unit. Blood samples were collected to determine blood lactate and glucose concentrations. Core temperature was measured using an ingestible sensor thermistor. RESULTS: Five participants completed the long-distance time trial with usable cardiorespiratory data. Median heart rate and oxygen consumption during the time trial was 93.6% and 76.6% of peak values, respectively. Median energy expenditure was 504.6 kcal/h. There was a significant increase in blood lactate concentration from 0.7 to 4.0 mmol/L after the time trial (p = 0.03). There were no changes in blood glucose concentrations after the time trial (p = 0.27). Lastly, core temperature significantly increased from 37.1 at baseline to 38.7 °C immediately after the time trial (p = 0.01). CONCLUSIONS: Elite WCR athletes sustained a high exercise intensity that was consistent across the long-distance time trial, and exercise intensity outcomes were generally lower than those documented for elite able-bodied long-distance athletes in other studies. Our findings provide accurate estimates of energy expenditure that can be used to design effective training and racing strategies for elite WCR athletes.

Circulating Progenitor Cell Response to Exercise in Wheelchair Racing Athletes.

INTRODUCTION: Circulating progenitor cells (CPC) are a heterogeneous population of stem/progenitor cells in peripheral blood that participate in tissue repair. CPC mobilization has been well characterized in able-bodied persons but has not been previously investigated in wheelchair racing athletes. The purpose of this study was to characterize CPC and CPC subpopulation mobilization in elite wheelchair racing athletes in response to acute, upper-extremity aerobic exercise to determine whether CPC responses are similar to ambulatory populations. METHODS: Eight participants (three females; age = 27.5 ± 4.0 yr, supine height = 162.5 ± 18.6 cm, weight = 53.5 ± 10.9 kg, V˙O2peak = 2.4 ± 0.62 L·min, years postinjury = 21.5 ± 6.2 yr) completed a 25-km time trial on a road course. Blood sampling occurred before and immediately after exercise for quantification of CPC (CD34), hematopoietic stem and progenitor cells (HSPC) (CD34/CD45), hematopoietic stem cells (HSC) (CD34/CD45/CD38), CD34 adipose tissue (AT)-derived mesenchymal stromal cells (MSC) (CD45/CD34/CD105/CD31), CD34 bone marrow (BM)-derived MSC (CD45/CD34/CD105/CD31), and endothelial progenitor cells (EPC) (CD45/CD34/VEGFR2) via flow cytometry. Blood lactate was measured before and after trial as an indicator of exercise intensity. RESULTS: CPC concentration increased 5.7-fold postexercise (P = 0.10). HSPC, HSC, EPC, and both MSC populations were not increased postexercise. Baseline HSPC populations were significantly positively correlated to absolute V˙O2peak (rho = 0.71, P < 0.05) with HSC trending to positively correlate to V˙O2peak (rho = 0.62, P = 0.10). AT-MSC populations were trending to be negatively correlated to baseline V˙O2peak (rho = -0.62, P = 0.058). The change in CPC, EPC, and AT-MSC pre- and postexercise significantly positively correlated to the change in lactate concentrations (rho = 0.91 P = 0.002, 0.71 P = 0.047, 0.81 P = 0.02, respectively, all P < 0.05). CONCLUSION: These data suggest that CPC content in wheelchair racing athletes is related to cardiorespiratory fitness, and responses to exercise are positively related to exercise intensity.

Communication, Sport and Disability: The Case of Power Soccer.

No abstract available for this article.

Exercise Intensity During Power Wheelchair Soccer.

OBJECTIVE: To determine exercise intensity during power wheelchair soccer among a sample of persons with mobility impairments. DESIGN: Cross-sectional descriptive. SETTING: On-site training facilities of multiple power wheelchair soccer teams. PARTICIPANTS: Participants with severe mobility impairments (N=30) (mean ± SD, age: 29.40±15.51y, body mass index: 24.11±6.47kg/m2, power soccer experience: 7.91±3.93y, disability sport experience: 12.44±9.73y) were recruited from multiple power wheelchair soccer teams. INTERVENTIONS: Portable metabolic carts were used to collect oxygen consumption (V˙o2) data during resting and game play conditions. MAIN OUTCOME MEASURES: Average V˙o2 (expressed in metabolic equivalent tasks [METs]) during resting and game play conditions and rating of perceived exertion for game play. RESULTS: V˙o2 increased from 1.35±0.47 METs at rest to 1.81±0.65 METs during game play. This 34% increase in exercise intensity was significant (P<.01) and supported by a mean perceived exertion score of approximately 13 (somewhat hard). CONCLUSIONS: Although not able to sustain an intensity associated with reduced secondary disease risk (ie, 3 METs), the documented light-intensity exercise in the current study surpassed an intensity threshold associated with improved functional capacity and performance of daily living activities (ie, 1.5 METs).

A case report of shoulder fatigue imbalance in wheelchair rugby: implications to pain and injury.

The purpose of this case-control study was to examine potential agonist-antagonist fatigue imbalance during wheelchair rugby activity. A 16-channel NORAXON electromyography (EMG) system 1400A with telemetry was used to assess EMG activity in a 39-year-old male with a C6 complete spinal cord injury (American Spinal Injury Association Impairment Scale (AIS) A), 17.5 years post injury. Mean amplitude and median frequency were determined for push-phase agonists (anterior deltoid and pectoralis major) and antagonist (posterior deltoid) across four training sessions at a community fitness and Paralympic training facility. Unlike continuous wheelchair pushing, acute muscle imbalances between agonists and antagonists (that is, push and recovery muscles) were not demonstrated. Wheelchair sports such as rugby may reduce risk of shoulder pain and overuse injury due to intermittent activity rather than continuous pushing. The current study is one of the first to document sport fatigue through electromyography during intermittent, live play rather than clinical conditions (that is, continuous pushing).

Perceived exercise benefits and barriers among power wheelchair soccer players.

Lack of exercise is a major risk factor for secondary conditions among persons dependent upon motorized wheelchairs. Power wheelchair soccer is a unique exercise opportunity for this population, and understanding factors that influence exercise decision-making is necessary for clinicians to help those in motorized chairs reduce their secondary risk. Therefore, this study examined differences in perceived benefits and barriers to exercise among power wheelchair soccer players using a mixed-methods analysis. The most common perceived benefit to exercise was "Exercising lets me have contact with friends and persons I enjoy." Post hoc comparisons of quantitative data indicated that persons with muscular dystrophy perceived exercise to be significantly less important than did other disability groups (p < 0.05). "Exercise is hard work for me," "Exercise tires me," and "There are too few places for me to exercise" were the most common perceived barriers. These findings can assist with development of exercise opportunities for power wheelchair users.

Perceived benefits and barriers to exercise among persons with physical disabilities or chronic health conditions within action or maintenance stages of exercise.

BACKGROUND: Information regarding factors that affect the initial step to exercise behavior change among persons with physical disabilities or chronic health conditions is available in the literature but much less is known regarding perceived benefits and barriers to exercise among those who are regularly active. OBJECTIVE: The purpose of this study was to examine the perceived benefits and barriers to exercise among persons with physical disabilities or chronic health conditions within action or maintenance stages of exercise. METHODS: Participants (n = 152) completed the Exercise Benefits and Barriers Scale (EBBS). For data analyses, disabilities and health conditions were grouped as neuromuscular, orthopedic, cardiovascular/pulmonary, or multiple conditions. Multivariate analysis of variance (MANOVA) was conducted to determine if mean differences on EBBS benefits and barriers scores existed among disability types, between sexes, among age groups, and between physical activity levels. Sum scores were computed to determine the strongest benefit and barrier responses. RESULTS: No significant mean differences in EBBS scores were found between disability types, sexes, age groups, or physical activity levels (p > 0.05). Strongest benefit responses varied by group. Strongest barrier responses were the same for all demographic groups: "Exercise tires me," "Exercise is hard work for me," and "I am fatigued by exercise." CONCLUSIONS: EBBS scores were similar across disability/health condition, sex, age, and physical activity level. Primary benefits reported were in the areas of improved physical performance and psychological outlook whereas the primary barriers were in the area of physical exertion.

Differences between African-American and Caucasian students on enrollment influences and barriers in kinesiology-based allied health education programs.

Kinesiology departments have recently started to offer allied health education programs to attract additional students to teacher education units (9). Although allied health professions offer increased work opportunities, insufficient enrollment and training of minority students in these academic fields contribute to underrepresentation in the workforce (3). To improve workforce diversity, kinesiology departments must understand how enrollment influences and barriers differ by race among prospective students. Therefore, the purpose of this study was to identify differences in allied health education enrollment influences and enrollment barriers between minority and Caucasian students. Participants (n = 601) consisted of students enrolled in kinesiology-based allied health education programs. Multivariate ANOVA was used to compare group differences in enrollment decision making. "Personal influence," "career opportunity," and "physical self-efficacy" were all significantly stronger enrollment influences among African-American students than among Caucasian students, and "social influence," "experiential opportunity," "academic preparation," and "physical self-efficacy" were all perceived as significantly greater barriers compared with Caucasian students. Findings support the need to recruit African-American students through sport and physical education settings and to market program-based experiential opportunities.

Factors associated with enrollment in allied health education programs: development of a predictive scale.

UNLABELLED: The purpose of this study was to identify factors related to a student's decision to enroll in college/university allied health education programs. The secondary purpose was to create a scale that can be used by colleges and universities to assess decision-making among prospective and current allied health education students. METHODS: We identified factors and developed the scale in 4 stages: 1) review of the literature, 2) focus group studies, 3) pilot testing, and 4) administration of the scale and testing of measurement properties. Research participants (n = 1,123) were students enrolled in allied and non-allied health education programs in Tennessee. RESULTS: In exploratory and confirmatory factor analyses, this study identified six factors linked to the decision to enroll in allied health education programs: personal influence, social influence, academic preparation, career opportunity, individual aspiration, and self-efficacy. Discriminant function analyses further revealed that these factors predicted program enrollment status. CONCLUSION: Although this scale may not be generalizable to all allied health education fields, it may assist universities and colleges in targeting and recruiting students into their allied health education programs.

Exercise intensity during wheelchair rugby training.

The purpose of this study was to determine the ability of individuals with a cervical spinal cord injury to achieve and sustain a cardiorespiratory training intensity during wheelchair rugby. Nine wheelchair rugby players completed a continuous peak exercise test on a SciFit Pro I arm ergometer with stage increases each minute to determine peak heart rate and power output. Approximately one week after peak exercise testing, heart rate was recorded (every 5 s) during three regularly scheduled rugby training sessions. Data were analysed to determine the number of continuous minutes that participants spent above 70% of heart rate reserve under various rugby training activities. The percent of time spent at or above 70% heart rate reserve varied across participants and conditions. Continuous pushing was the least variable training condition among participants with the sample averaging greater than 73% of time above the target heart rate. Scrimmage training was highly variable across participants with a range of 0% to 98% of time above the criterion. Results of this study indicate that wheelchair rugby training enables some participants to reach a training intensity associated with improved cardiorespiratory fitness, and that the type (or kind) of training activity dictates the extent to which individuals sustain such a threshold.

Comparison of heart rate response to tennis activity between persons with and without spinal cord injuries: implications for a training threshold.

The purpose of this study was to evaluate the ability of individuals with spinal cord injury (SCI) to reach a training threshold during on-court sport activity. Monitors collected heart rate (HR) data every 5 s for 11 wheelchair tennis players (WCT) with low paraplegia and 11 able-bodied controls matched on experience and skill level (ABT). Average HR was determined for time spent in practice (e.g, drills) and game (i.e., a competitive set), and the ability to surpass 50% peak HR (HRpeak) and 64% HRpeak in each condition was evaluated. Average exercise intensity (%HRpeak) was not significantly different between the groups during practice (M WCT = 68.18, SD = 7.53%, M ABT = 68.78, SD = 5.44%; t = .22, p = .83) or game (M WCT = 68.17, SD = .17%, M ABT = 71.55, SD = 4.75%; t = 1.12, p =.28). Allparticipants averaged an intensity > or = 50% HR-peak during practice and game, and the difference between group participants averaging an intensity > or = 64% HRpeak was not significant during practice (chi2 = .92, p = .34) or game (chi2 = 3.85, p = .05). In terms of reaching a health and fitness training threshold during tennis, individuals with low-level SCI are similar to matched controls.

Effect of dehydration prior to cryopreservation of large equine embryos.

Cryopreservation of equine embryos>300microm in diameter results in low survival rates using protocols that work well for smaller equine embryos. These experiments tested the potential benefit of incorporating a dehydration step prior to standard cryopreservation procedures. Forty-six, day 7-8, grade 1, equine embryos 300-1350microm in diameter were subjected to one of the following treatments: (A) 2 min in 0.6M galactose, 10min in 1.5M glycerol, slow freeze (n=21); (B) 10min in 1.5M glycerol, slow freeze (n=15); (C) 2min in 0.6M galactose, 10min in 1.5M glycerol, followed by exposure to thaw solutions, then culture medium (n=5); (D) transferred directly to culture medium (n=5). Frozen embryos were thawed and subjected to a three-step cryoprotectant removal. Five embryos from each treatment were evaluated morphologically after 24 and 48h culture (1=excellent, 5=degenerate/dead). All treatments had at least 4/5 embryos with a quality score >or=3 at these time points except treatment B (2/5 at 24h, 1/5 at 48h). Subsequent embryos from treatment A (n=16) or B (n=10) were matched in sets of two for size and treatment, thawed, and immediately transferred in pairs to 13 recipients. Only two recipient mares were pregnant; one received two 400microm embryos from treatment A, and the other one 400 and one 415microm embryo from treatment B. There was no advantage of incorporating a 2min dehydration step into the cryopreservation protocol for large equine embryos.

Effect of Olympic and traditional resistance training on vertical jump improvement in high school boys.

The purpose of this study was to compare the effects of a ballistic resistance training program of Olympic lifts with those of a traditional resistance training program of power lifts on vertical jump improvement in male high school athletes. Twenty-seven male student athletes were recruited from a high school football program at a small, rural school in the Southeast. The subjects were divided into an Olympic training group (OT, n = 11), a power training group (PT, n = 10), and a control group (n = 6). Analysis of variance was used to determine whether a significant mean difference existed among groups on vertical jump improvement after 8 weeks of group-specific training. Effect size of vertical jump improvement between groups, and correlations between strength and vertical jump performance, were also examined. There was no significant mean difference (p >or= 0.05) among OT, PT, and control groups, but large effect sizes between OT and control (d = 1.06) and PT and control (d = 0.94) demonstrate that both OT and PT are effective in improving vertical jump performance in male high school athletes. Moderate to high correlations were noted between squat score and vertical jump after adjusting for body weight (r = 0.42) and between power clean and vertical jump after adjusting for body weight (r = 0.75). Findings from the current study indicate that Olympic lifts as well as power lifts provide improvement in vertical jump performance and that Olympic lifts may provide a modest advantage over power lifts for vertical jump improvement in high school athletes.

The tonicity of murine epididymal spermatozoa and their permeability towards common cryoprotectants and epididymal osmolytes.

The permeability of murine cauda epididymidal spermatozoa was determined from the swelling caused by penetrating agents at isotonicity, which lies between 422 and 530 mmol/kg. Spermatozoa were permeable to a range of solutes with size <200 Da. Relative entry rates of cryoprotective agents (CPAs) were ethylene glycol approximately DMSO>propane-1,2-diol>glycerol>propane-1,3-diol. More polar compounds including major epididymal secretions were impermeant. None of the compounds entered spermatozoa through quinine-sensitive channels; rather, quinine increased the size of solute-swollen spermatozoa, suggesting that regulatory volume decrease and osmolyte loss occurred under these conditions. Volume responses to lowered osmolality revealed a greater volume-regulating ability of spermatozoa from the B6D2F1 strain than the C57BL6 strain. As the former strain displays better post-thaw fertility, their spermatozoa may have greater osmolyte loads enabling them to cope better with osmotic stress. Inadequate volume regulation, due to CPA-induced osmolyte loss, may affect post-thaw fertility. Knowing the permeability towards cryoprotectants will help to make a better choice of CPAs that are less damaging to sperm during cryopreservation.

Physiological volume regulation by spermatozoa.

Maturing spermatozoa passing through the epididymis experience increasing osmolality in the luminal environment and mature cells are stored in fluids hyper-osmotic to serum. When ejaculated into the female tract, they encounter a hypo-osmotic challenge which initiates the process of regulatory volume decrease (RVD). Defects in RVD result in hindrance of mucus penetration in man and failure of utero-tubal passage in mice. Epididymal sperm from the mouse and cynomolgus monkey and ejaculated sperm from man and monkey have been isolated and dispersed in media with osmolalities mimicking those of uterine fluid or cervical mucus. The effects of specific and broad-spectrum ion channel blockers indicate the involvement of separate K+ and Cl- channels as well as organic osmolytes in physiological sperm RVD, with mechanisms developed during epididymal maturation. Western blotting and immuno-cytochemistry identify and localise some of these channels which play a crucial role in fertilisation in vivo and could be targets for post-testicular contraception.

Chloride channels in physiological volume regulation of human spermatozoa.

As with other mammalian species, human spermatozoa experience a decrease in extracellular osmolarity in cervical mucus upon ejaculation, which requires the efflux of osmolytes and water to counteract swelling that hinders mucus penetration. Recent evidence for the operation of K+ channels in the process of volume regulation suggests parallel involvement of Cl-/anion channels for electro-neutrality as in somatic cells. This was studied using ejaculated spermatozoa washed at seminal osmolality and incubated for 30 min in a medium of mucus osmolality in the presence of Cl- channel blockers. Increases in cell size measured as laser forward-scatter by flow cytometry were detected in the presence of 100 microM 5-nitro-2(3-phenylpropylamino) benzoic acid, 400 microM diisothiocyanato-stilbene-2,2'-disulphonic acid, and 20 microM tamoxifen. No volume changes were found with 400 microM 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulphonic acid, 200 microM verapamil, or niflumic acid, whereas 1 mM niflumic acid induced shrinkage. Among the candidate channel proteins, Western blotting revealed the presence of ClC-3 (CLCN3) at 87 kDa, but the absence of ClC-2 (CLCN2) from sperm proteins in all samples tested. ICln (CLNS1A) was found in only one of eight samples. Immunocytochemistry localized CLCN3 to the sperm tail. To confirm molecular identities, sperm mRNA was extracted and checked for quality by the presence of protamine 2 transcripts and the absence of sperm DNA and leukocyte mRNA using reverse transcription-polymerase chain reaction. Transcripts of Clcn3 were found in all samples and that of Clns1a in some but not all samples. Clcn3 was therefore considered the most likely candidate of Cl- channel involved in volume regulation of human sperm.

Disability type influences heart rate response during power wheelchair sport.

PURPOSE: The purpose of this study was to determine the influence of disability type on exercise response during power wheelchair competition. The secondary purpose was to determine the extent to which heart rate responses during competition meet cardiorespiratory fitness training intensities for the general population. METHODS: Forty-eight athletes who had cerebral palsy (CP, N = 31), spinal cord injury (SCI, N = 10), or muscular dystrophy (MD, N = 7), and were competing in the 2003 Power Soccer National Tournament, volunteered to participate. Heart rate was recorded every 5 s throughout pre-game and game conditions by Polar S610 monitors. Average heart rate (HR) values were determined for GAME and RESPONSE (change score between GAME HR and pre-game HR). The Kruskal-Wallis nonparametric test was used to determine whether a significant difference among group medians existed on the dependent measure, RESPONSE (P < 0.05). RESULTS: A significant difference on RESPONSE (P < 0.05) existed among athletes with CP (29 bpm), SCI (17 bpm), and MD (26 bpm). The median RESPONSE for athletes with CP was 12 bpm higher than athletes with SCI, and this difference was significant (P < 0.01). Further, 22 athletes with CP (71%), 5 athletes with MD (71%), and 1 athlete with SCI (10%) exceeded 55% of estimated HR(max) for at least 30 min during competition. CONCLUSION: Disability type influences the heart rate response to power wheelchair sport, and may affect the ability to sustain training intensities associated with fitness improvement.