EMG Analysis and Motor Unit Recruitment in the Rectus Femoris of College Students

The rectus femoris works as part of the quadriceps muscle group to provide the force needed to generate very explosive movements during knee extension. Because many sports require explosive movements from the lower body, many strength coaches implement exercise routines that strengthen the muscles and prevent injuries. In the general population, activities using knee extension are essential in getting the full benefit of a designed exercise program. Muscle fibers provide the contractile force needed to accomplish a movement. Commonly, a deficiency is present in people who tend to favor one leg more than the other during activity. This is due to factors such as improper training, improper biomechanics, and joint injury. Having a strength imbalance from one leg to the other can strongly influence the amount of force generated, and therefore the amount of weight lifted. The purpose of this study was to determine whether these subjects had an imbalance in the contractile force of the rectus femoris. The participants were all kinesiology students in a Master’s degree program. Their age ranges from 22 years of age to 25 years of age. The instruments being used for this procedure are a leg extension machine and Biopac EMG. Each participant was required to perform five reps of a single leg extension for each leg, after determining maximum voluntary contraction. To analyze data that is collected. Data was analyzed using SPSS and Microsoft Excel. Muscle contractions were compared between and within subjects and compared from the participant’s dominant to non-dominant leg. For this particular study, the purpose was calculating whether the contractions are different from dominant leg to non-dominant leg. The results indicate that participants have a significant decrease in the contractile force from their dominant to non-dominant leg; significance was set at p\u3c.05. This study shows where coaches, trainers, and athletes need to focus on strength training to correct muscle imbalances. Imbalances could indicate that subjects are not trained properly, or they are favoring one leg while performing explosive maneuvers, or have an injury that prevents proper firing motor unit recruitment (1, 4)

Energy Expenditure and Economy During a Cycle Ergometer Test

Research has shown that submaximal cycle ergometer testing presents a reduced V02 max score when compared to that of the treadmill test. In this study, we compared a submaximal economy test on the Monark Cycle Ergometer. The purpose of this study was for each participant to perform the same test and compare economy, V02 ml/kg/min for a given workload, as well as calories burned between males and females during the nine minute test. By testing economy for each participant, we aim to determine whether males or females use oxygen more efficiently during testing. Before beginning the test, the Cosmed metabolic equipment was calibrated. The test was standardized to last for nine minutes at 70 rotations per minute and 1 kilopond of resistance. Based off of the comparison in V02 mL/kg/min and kCal mL/kg/min, the women had the highest V02 per given workload and also had the lowest calories burned. The women were the least efficient by having a higher V02 while working at the same intensity as the male participants. The research used to support this study indicates that there are two components for overall metabolic power during a dynamic leg exercise on the cycle ergometer; the power used to overcome the resistance applied to the ergometer and the rate of energy expenditure required to move the lower limbs without opposition against the opposition load (Girardis, Linnarsson, Moia, Pendergast, & Ferretti, 1999). It is also stated that during exercise at submaximal levels below lactate threshold the net V02 of the whole body is equivalent of the net rate of energy expenditure (Storer, Davis, & Caiozzo, 1990). The cycle ergometer is a good use to determine V02 by collecting expired air and the volume measured in the spirometer (Saltin & Astrand, 1967). For the results of this lab to be more accurate the resistance and intensity could have been changed at different stages of the test. This would have given and more accurate measure of the ability of each participant to reach the next stage of testing

Developing drowning prevention strategies for rivers through the use of a modified Delphi process

Introduction Internationally, rivers are a leading drowning location, yet little evidence exists evaluating river drowning prevention strategies. This study aims to use expert opinion to identify strategies more likely to be effective. Methods Using a modified Delphi process, a virtual panel of 30 experts from 12 countries considered, grouped and prioritised strategies for river drowning prevention. Proposed strategies were assessed against known evidence and suitability in high-income countries (HICs) as well as low-income and middle-income countries (LMICs) using expert opinion. The final phase consolidated a list of strategies whose effectiveness was assessed against 10 evidence-based river drowning scenarios. Results An initial list of 424 prevention strategies was refined to 22. After being assessed against the 10 scenarios, a final list of 13 strategies was derived. Strategies addressed alcohol consumption around rivers, flood mitigation, improving child supervision, learning to swim, increased lifejacket wear and achieving community-wide resuscitation skills. Discussion While all 13 strategies were assessed as being effective in both LMICs and HICs by at least 60% of the respondents, further work is required to define river drowning at a country level and therefore allow for effective solutions to be developed, particularly in LMICs. No strategy will be effective in isolation and must be implemented alongside policy and behaviour change, public awareness and education. Evaluation should be incorporated as part of any future implementation of strategies. Conclusion This Delphi process identified 13 drowning prevention strategies for rivers. Further research is required to validate the efficacy of these findings through implementation and evaluation

Travel-weary to travel-worry: the epidemiology of injury-related traveller deaths in Australia, 2006-2017

Objective: To explore injury deaths in international and domestic interstate travellers, together with those newly arrived to Australia. Methods: A population-based cohort study of all injury-related deaths between 1January 2006 and 31 December 2017 registered with Births Death and Marriages in Australia was conducted using Australian Bureau of Statistics’ (ABS) Cause of Death information. Population data on travellers were obtained from Tourism Research Australia. Results: There were 4,503 injury-related traveller deaths (domestic interstate:3,055; international:934; new arrivals:514). The average annual age-standardised mortality rates in domestic interstate travellers was 0.75 per 100,000, compared with 2.22 per 100,000 in international travellers. Leading causes of injury-related death were land transport incidents (n=1495, 33.2%), self-harm (n=786, 17.5%) and falls (n=513, 11.4%), with differences in mechanism by state/territory, traveller type and age group. Intentional self-harm was common amongst all visitor types, however, it was the primary cause of death in new arrivals Conclusion: Age-standardised mortality rates were almost three-fold higher in international than domestic travellers. New arrivals, international and domestic travellers have different injury profiles, and each require specific prevention strategies. Implications for public health: While COVID has restricted travel to and within Australia, this has provided an opportunity for exploration, reflection, and consideration of risk factors for travellers, and to develop targeted injury prevention strategies for visitor types, so travel experience can be optimised and the magnitude of harm can be reduced

Epidemiology of unintentional fatal drowning among migrants in Australia

Objective: This study aimed to describe the epidemiology and risk factors contributing to drowning among migrants in Australia. Methods: A total population retrospective epidemiological study of unintentional drowning deaths in Australia between 1 July 2009 and 30 June 2019 of people born outside Australia (migrants). Cases were extracted from the National Coronial Information System. Descriptive statistics, chi-square and relative risk were calculated. Crude drowning rates were based on country of birth and population in Australia. Results: There were 572 migrant deaths over the study period, 28.9% of total drowning deaths, 82.9% were male. Twenty-one per cent were aged 25–34 years and 40.8% had lived in Australia for 20+ years. Migrants at highest risk of drowning were from: South Korea (2.63/100,000 95%CI: 0.85–8.25), Taiwan (2.29/100,000 95%CI: 0.27–13.44), and Nepal (2.15/100,000 95%CI: 0.23–11.55). Migrants were more likely to drown when around rocks (p<0.001) compared with Australian-born people, who most frequently drowned in rivers (p<0.001). Conclusions: Migrants are not over-represented in drowning statistics. However, unique trends were found for drowning among migrants based on country of birth and length of time in Australia. Implications for public health: Holistic drowning prevention strategies and policies are required to effectively lower drowning risk among migrant communities

Challenges in the delivery of sex education for people with intellectual disabilities: A Chinese cultural-contextual analysis

Background: Staff members' views can have a significant impact on sexuality issues of people with intellectual disabilities. Research on the impact of sociocultural factors in this area in the Chinese context is sparse. Methods: Semi-structured interviews were conducted with seven professionals (social worker, nurse, life skills trainer and manager) to explore their experiences of and attitudes towards the sexual needs of people with intellectual disabilities by applying interpretative phenomenological analysis. Results: The study identified two major themes, each with two sub-themes: 1. Professional handling of the sexual needs of people with intellectual disabilities (sex education and intervention); 2. Barriers (incompatible approaches and parental resistance). Participants also experienced feelings of resignation facing the barriers they encountered. Collectivism and cultural view about sex are potentially the influencing factors. Conclusion: This study highlights the need to adopt an evidence-based sex education programme whose content and delivery should take account of cultural factors

Observing patterns of river usage

Rivers are a leading location for drowning, yet little is known about people’s usage of these waterways. This pilot study aimed to test the use of direct observations to calculate river usage. Direct observations were conducted at regular intervals within defined zones at four river drowning locations in Australia (including weekends and the Australia Day national public holiday). Data recorded were date and time of observation; total people (including males, females, children, and adults); and number of people on, in, and beside the water. Univariate analysis with mean (SD) and range was conducted. Interrater reliability for observations was determined using the intraclass correlation coefficient (ICC) (one-way random-effects, average measures model), with a 95% confidence interval (CI). Across 149 time points, 309 observations resulted in 13,326 river interactions observed by multiple observers. There was an average of 39 people (M = 39.4, SD = 29.4, range = 0–137) per observation, 44 people (M = 44.2, SD = 32.7, range = 0–37) on an average weekend, and 97 people (M = 96.8, SD = 58.1, range = 20–190) on Australia Day. More females (M = 20.6, SD = 16.0, range = 0–83) than males (M = 18.3, SD = 14.5, range = 0–68) were observed. More people were observed in the water (M = 20.6, SD = 20.4, range = 0–84) than beside or on the water. Interrater reliability was excellent, consistently above 0.900 for all variables collected (apart from the variable of beside the river). Despite males accounting for 80% of river drowning fatalities, more females were observed than males. Increased visitation on the Australia Day public holiday may be linked to increased drowning risk. This study detailed a simple approach to data collection, exploring exposure within a defined zone at river locations. River usage is dynamic, with people’s movement in and out of the water changing their risk exposure. Observational-based data collection for drowning, particularly for rivers, is an important yet highly neglected area of research

Road traffic fatalities in rural and remote Australia from 2006 to 2017: The need for targeted action

OBJECTIVE: To explore rural motor vehicle collision (MVC) fatalities by trends over time, mode of transport, age, state, sex, and Aboriginal and Torres Strait Islander status. DESIGN: A retrospective total population‐based time series was conducted using the Australian Bureau of Statistics (ABS) death registration data. SETTING: All statistical local area (SLA) within Australia from 2006 to 2017. PARTICIPANTS: Australian residents whose deaths were registered with the ABS between 01 January 2006 and 31 December 2017 where the underlying cause of death was related to unintentional transport accidents. MAIN OUTCOME MEASURES: Fatality rates were determined using population data collected from the 2006, 2011 and 2016 census. Trends over time by rurality were analysed by financial year. Rates of transport deaths by vehicle type were determined by rurality. Risk ratios were calculated to compare demographic groups based on sex, Aboriginal and Torres Strait Islander status and age. A 3‐year scorecard was organised by state and rurality using 99.7% confidence intervals. RESULTS: Motor vehicle collision fatalities increase with increasing remoteness. Females, children from 0 to 14 years, pedestrians, and Aboriginal and Torres Strait Islander peoples are at a significantly higher risk of fatal MVCs than their respective metropolitan counterparts. The 3‐year scorecard indicates that road fatality rates in the NT, WA, and all rural and remote areas required immediate attention and targeted action. CONCLUSIONS: There is a need for investment in MVC fatality prevention in rural Australia from inner regional to remote areas in order to meet the road safety targets established by the National Road Safety Strategy