A 12-month prospective cohort study of symptoms of common mental disorders among professional rugby players
- Gouttebarge, Vincent, Hopley, Philip, Kerkhoffs, Gino, Verhagen, Evert, Viljoen, Wayne, Wylleman, Paul, Lambert, Mike
- Authors: Gouttebarge, Vincent , Hopley, Philip , Kerkhoffs, Gino , Verhagen, Evert , Viljoen, Wayne , Wylleman, Paul , Lambert, Mike
- Date: 2018
- Type: Text , Journal article
- Relation: European Journal of Sport Science Vol. 18, no. 7 (2018), p. 1004-1012
- Full Text:
- Reviewed:
- Description: The primary aims were to determine the 12-month incidence (and comorbidity) of symptoms of common mental disorders (CMD) among male professional rugby players and to explore their association with potential stressors. A secondary aim was to explore the view of male professional rugby players about the consequences of symptoms of CMD and related medical support/needs. An observational prospective cohort study with three measurements over a 12-month period was conducted among male professional rugby players from several countries. Symptoms of CMD (distress, anxiety/depression, sleep disturbance, eating disorders and adverse alcohol use) and stressors (adverse life events, rugby career dissatisfaction) were assessed through validated questionnaires. A total of 595 players (mean age of 26 years; mean career duration of 6 years) were enrolled, of which 333 completed the follow-up period. The incidence of symptoms of CMD were: 11% for distress, 28% for anxiety/depression, 12% for sleep disturbance, 11% for eating disorders and 22% for adverse alcohol use (13% for two simultaneous symptoms of CMD). Professional rugby players reporting recent adverse life events or career dissatisfaction were more likely to report symptoms of CMD but statistically significant associations were not found. Around 95% of the participants stated that symptoms of CMD can negatively influence rugby performances, while 46% mentioned that specific support measures for players were not available in professional rugby. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve not only awareness and psychological resilience of rugby players but also their rugby performance and quality-of-life. © 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
- Authors: Gouttebarge, Vincent , Hopley, Philip , Kerkhoffs, Gino , Verhagen, Evert , Viljoen, Wayne , Wylleman, Paul , Lambert, Mike
- Date: 2018
- Type: Text , Journal article
- Relation: European Journal of Sport Science Vol. 18, no. 7 (2018), p. 1004-1012
- Full Text:
- Reviewed:
- Description: The primary aims were to determine the 12-month incidence (and comorbidity) of symptoms of common mental disorders (CMD) among male professional rugby players and to explore their association with potential stressors. A secondary aim was to explore the view of male professional rugby players about the consequences of symptoms of CMD and related medical support/needs. An observational prospective cohort study with three measurements over a 12-month period was conducted among male professional rugby players from several countries. Symptoms of CMD (distress, anxiety/depression, sleep disturbance, eating disorders and adverse alcohol use) and stressors (adverse life events, rugby career dissatisfaction) were assessed through validated questionnaires. A total of 595 players (mean age of 26 years; mean career duration of 6 years) were enrolled, of which 333 completed the follow-up period. The incidence of symptoms of CMD were: 11% for distress, 28% for anxiety/depression, 12% for sleep disturbance, 11% for eating disorders and 22% for adverse alcohol use (13% for two simultaneous symptoms of CMD). Professional rugby players reporting recent adverse life events or career dissatisfaction were more likely to report symptoms of CMD but statistically significant associations were not found. Around 95% of the participants stated that symptoms of CMD can negatively influence rugby performances, while 46% mentioned that specific support measures for players were not available in professional rugby. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve not only awareness and psychological resilience of rugby players but also their rugby performance and quality-of-life. © 2018, © 2018 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
A prospective cohort study on symptoms of common mental disorders among Dutch elite athletes
- Gouttebarge, Vincent, Jonkers, Ruud, Moen, Maarten, Verhagen, Evert, Wylleman, Paul, Kerkhoffs, Gino
- Authors: Gouttebarge, Vincent , Jonkers, Ruud , Moen, Maarten , Verhagen, Evert , Wylleman, Paul , Kerkhoffs, Gino
- Date: 2017
- Type: Text , Journal article
- Relation: Physician and Sportsmedicine Vol. 45, no. 4 (2017), p. 426-432
- Full Text:
- Reviewed:
- Description: Objective: Scientific knowledge about symptoms of common mental disorders in elite sports is scarce. Consequently, the objectives of the study were to (i) establish the 12-month incidence of symptoms of common mental disorders (CMD; distress, anxiety/depression, sleep disturbance, adverse alcohol use, eating disorders) among Dutch elite athletes and (ii) explore their potential association with several stressors (being injured, recent life events, career dissatisfaction).Methods: A prospective cohort study with a 12-month follow-up period was conducted. The study used validated questionnaires to assess symptoms of common mental disorders (thus not clinically diagnosed) as well as several stressors; an electronic questionnaire was set up and repeatedly distributed.Results: A total of 203 elite athletes gave their written informed consent to participate in the study, from which 143 completed the 12-month follow-up period (follow-up rate of 70%). Incidence of symptoms of CMD ranged from 6% for adverse alcohol use to 57% for symptoms of anxiety/depression. Over the follow-up period, around 17% of the participants reported two simultaneous symptoms of CMD, and around 19% reported three simultaneous symptoms of CMD. Inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant.Conclusions: Substantial 12-month incidence rates of symptoms of CMD (self-reported and not clinically diagnosed) were found among Dutch elite athletes (especially for anxiety/depression), appearing similar to the ones found among athletes from other sports disciplines and the Dutch general population. Also, inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve awareness and psychological resilience of athletes, which would likely improve their performance and quality-of-life.
- Authors: Gouttebarge, Vincent , Jonkers, Ruud , Moen, Maarten , Verhagen, Evert , Wylleman, Paul , Kerkhoffs, Gino
- Date: 2017
- Type: Text , Journal article
- Relation: Physician and Sportsmedicine Vol. 45, no. 4 (2017), p. 426-432
- Full Text:
- Reviewed:
- Description: Objective: Scientific knowledge about symptoms of common mental disorders in elite sports is scarce. Consequently, the objectives of the study were to (i) establish the 12-month incidence of symptoms of common mental disorders (CMD; distress, anxiety/depression, sleep disturbance, adverse alcohol use, eating disorders) among Dutch elite athletes and (ii) explore their potential association with several stressors (being injured, recent life events, career dissatisfaction).Methods: A prospective cohort study with a 12-month follow-up period was conducted. The study used validated questionnaires to assess symptoms of common mental disorders (thus not clinically diagnosed) as well as several stressors; an electronic questionnaire was set up and repeatedly distributed.Results: A total of 203 elite athletes gave their written informed consent to participate in the study, from which 143 completed the 12-month follow-up period (follow-up rate of 70%). Incidence of symptoms of CMD ranged from 6% for adverse alcohol use to 57% for symptoms of anxiety/depression. Over the follow-up period, around 17% of the participants reported two simultaneous symptoms of CMD, and around 19% reported three simultaneous symptoms of CMD. Inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant.Conclusions: Substantial 12-month incidence rates of symptoms of CMD (self-reported and not clinically diagnosed) were found among Dutch elite athletes (especially for anxiety/depression), appearing similar to the ones found among athletes from other sports disciplines and the Dutch general population. Also, inferences between some stressors and symptoms of CMD were found but none of the associations were statistically significant. Supportive and preventive measures directed towards symptoms of CMD should be developed to improve awareness and psychological resilience of athletes, which would likely improve their performance and quality-of-life.
Coupling of a KERS power train and a downsized 1.2TDI diesel or a 1.6TDI-JI H2 engine for improved fuel economies in a compact car
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Recovery of braking energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Hybrid electric vehicles suffer the disadvantages of the four efficiency reducing transformations in each regenerative braking cycle. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to almost double values of about 70% avoiding all four of the efficiency reducing transformations from one form of energy to another and keeping the vehicle's energy in the same form as when the vehicle starts braking when the vehicle is back up to speed. With reference to the baseline configuration with a 1.6 liters engine and no recovery of kinetic energy, introduction of KERS reduces the fuel usage to 3.16 liters per 100 km, corresponding to 82.4 g of CO2 per km. The 1.6 liters Turbo Direct Injection (TDI) Diesel engine without KERS uses 1.37 MJ per km of fuel energy, reducing with KERS to 1.13 MJ per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, the fuel consumption is further reduced to 3.04 liters per 100 km, corresponding to 79.2 g of CO2 per km and 1.09 MJ per km of fuel energy. These CO2 and fuel usage values are 11% and 13% better than those of today’s highest fuel economy hybrid electric vehicle. The car equipped with a 1.6 liter Turbo Direct Injection Jet Ignition (TDI-JI) H2ICE engine finally consumes 8.3 g per km of fuel, corresponding to only 0.99 MJ per km of fuel energy.
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Recovery of braking energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Hybrid electric vehicles suffer the disadvantages of the four efficiency reducing transformations in each regenerative braking cycle. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to almost double values of about 70% avoiding all four of the efficiency reducing transformations from one form of energy to another and keeping the vehicle's energy in the same form as when the vehicle starts braking when the vehicle is back up to speed. With reference to the baseline configuration with a 1.6 liters engine and no recovery of kinetic energy, introduction of KERS reduces the fuel usage to 3.16 liters per 100 km, corresponding to 82.4 g of CO2 per km. The 1.6 liters Turbo Direct Injection (TDI) Diesel engine without KERS uses 1.37 MJ per km of fuel energy, reducing with KERS to 1.13 MJ per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, the fuel consumption is further reduced to 3.04 liters per 100 km, corresponding to 79.2 g of CO2 per km and 1.09 MJ per km of fuel energy. These CO2 and fuel usage values are 11% and 13% better than those of today’s highest fuel economy hybrid electric vehicle. The car equipped with a 1.6 liter Turbo Direct Injection Jet Ignition (TDI-JI) H2ICE engine finally consumes 8.3 g per km of fuel, corresponding to only 0.99 MJ per km of fuel energy.
Coupling of a KERS powertrain and a 4 Litre gasoline engine for improved fuel economy in a full size car
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Improvements of vehicle fuel economy are being considered using a mechanically driven flywheel to reduce the amount of mechanical energy produced by the thermal engine recovering the vehicle kinetic energy during braking. A mechanical system having an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids, is coupled to a naturally aspirated gasoline engine powering a full size sedan. Results of chassis dynamometer experiments and engine and vehicle simulations are used to evaluate the fuel benefits introducing a kinetic energy recovery system and downsizing of the engine. Preliminary results running the new European driving cycle (NEDC) show KERS may reduce fuel consumption by 25% without downsizing, and 33% with downsizing of the 4 litre engine to 3.3 litres.
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Improvements of vehicle fuel economy are being considered using a mechanically driven flywheel to reduce the amount of mechanical energy produced by the thermal engine recovering the vehicle kinetic energy during braking. A mechanical system having an overall efficiency over a full regenerative cycle of about 70%, about twice the efficiency of battery-based hybrids, is coupled to a naturally aspirated gasoline engine powering a full size sedan. Results of chassis dynamometer experiments and engine and vehicle simulations are used to evaluate the fuel benefits introducing a kinetic energy recovery system and downsizing of the engine. Preliminary results running the new European driving cycle (NEDC) show KERS may reduce fuel consumption by 25% without downsizing, and 33% with downsizing of the 4 litre engine to 3.3 litres.
Modelling of engine and vehicle for a compact car with a flywheel based kinetic energy recovery systems and a high efficiency small diesel engine
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Recovery of kinetic energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to values of about 70%. An engine and vehicle model is developed to simulate the fuel economy of a compact car equipped with a TDI Diesel engine and a KERS. Introduction of KERS reduces the fuel used by the 1.6L TDI engine to 3.16 liters per 100 km, corresponding to 82.4 g of CO2 per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, further reduces the fuel consumption to 3.04 liters per 100 km, corresponding to 79.2 g of CO2 per km. These CO2 values are 11% better than those of today’s most fuel efficient hybrid electric vehicle.
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Recovery of kinetic energy during driving cycles is the most effective option to improve fuel economy and reduce green house gas (GHG) emissions. Flywheel kinetic energy recovery systems (KERS) may boost this efficiency up to values of about 70%. An engine and vehicle model is developed to simulate the fuel economy of a compact car equipped with a TDI Diesel engine and a KERS. Introduction of KERS reduces the fuel used by the 1.6L TDI engine to 3.16 liters per 100 km, corresponding to 82.4 g of CO2 per km. Downsizing the engine to 1.2 liters as permitted by the torque assistance by KERS, further reduces the fuel consumption to 3.04 liters per 100 km, corresponding to 79.2 g of CO2 per km. These CO2 values are 11% better than those of today’s most fuel efficient hybrid electric vehicle.
Incidence, aetiology and prevention of musculoskeletal injuries in volleyball : A systematic review of the literature
- Kilic, O., Maas, Mario, Verhagen, Evert, Zwerver, Johannes, Gouttebarge, Vincent
- Authors: Kilic, O. , Maas, Mario , Verhagen, Evert , Zwerver, Johannes , Gouttebarge, Vincent
- Date: 2017
- Type: Text , Journal article , Review
- Relation: European Journal of Sport Science Vol. 17, no. 6 (2017), p. 765-793
- Full Text:
- Reviewed:
- Description: Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures of volleyball injuries. To this end, a highly sensitive search strategy was built based on two groups of keywords (and their synonyms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost. The results showed that ankle, knee and shoulder injuries are the most common injuries sustained while playing volleyball. Results are presented separately for acute and overuse injuries, as well as for contact and non-contact injuries. Measures to prevent musculoskeletal injuries, anterior knee injuries and ankle injuries were identified in the scientific literature. These preventive measures were found to have a significant effect on decreasing the occurrence of volleyball injuries (for instance on ankle injuries with a reduction from 0.9 to 0.5 injuries per 1000 player hours). Our systematic review showed that musculoskeletal injuries are common among volleyball players, while effective preventive measures remain scarce. Further epidemiological studies should focus on other specific injuries besides knee and ankle injuries, and should also report their prevalence and not only the incidence. Additionally, high-quality studies on the aetiology and prevention of shoulder injuries are lacking and should be a focus of future studies. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
- Authors: Kilic, O. , Maas, Mario , Verhagen, Evert , Zwerver, Johannes , Gouttebarge, Vincent
- Date: 2017
- Type: Text , Journal article , Review
- Relation: European Journal of Sport Science Vol. 17, no. 6 (2017), p. 765-793
- Full Text:
- Reviewed:
- Description: Currently, there is no overview of the incidence and (volleyball-specific) risk factors of musculoskeletal injuries among volleyball players, nor any insight into the effect of preventive measures on the incidence of injuries in volleyball. This study aimed to review systematically the scientific evidence on the incidence, prevalence, aetiology and preventive measures of volleyball injuries. To this end, a highly sensitive search strategy was built based on two groups of keywords (and their synonyms). Two electronic databases were searched, namely Medline (biomedical literature) via Pubmed, and SPORTDiscus (sports and sports medicine literature) via EBSCOhost. The results showed that ankle, knee and shoulder injuries are the most common injuries sustained while playing volleyball. Results are presented separately for acute and overuse injuries, as well as for contact and non-contact injuries. Measures to prevent musculoskeletal injuries, anterior knee injuries and ankle injuries were identified in the scientific literature. These preventive measures were found to have a significant effect on decreasing the occurrence of volleyball injuries (for instance on ankle injuries with a reduction from 0.9 to 0.5 injuries per 1000 player hours). Our systematic review showed that musculoskeletal injuries are common among volleyball players, while effective preventive measures remain scarce. Further epidemiological studies should focus on other specific injuries besides knee and ankle injuries, and should also report their prevalence and not only the incidence. Additionally, high-quality studies on the aetiology and prevention of shoulder injuries are lacking and should be a focus of future studies. © 2017 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
Sport injuries sustained by athletes with disability : A systematic review
- Weiler, Richard, van Mechelen, Willem, Fuller, Colin, Verhagen, Evert
- Authors: Weiler, Richard , van Mechelen, Willem , Fuller, Colin , Verhagen, Evert
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 8 (2016), p. 1141-1153
- Full Text:
- Reviewed:
- Description: Background Fifteen percent of the world's population live with disability, and many of these individuals choose to play sport. There are barriers to sport participation for athletes with disability and sports injury can greatly impact on daily life, which makes sports injury prevention additionally important. Objective The purpose of this review is to systematically review the definitions, methodologies and injury rates in disability sport, which should assist future identification of risk factors and development of injury prevention strategies. A secondary aim is to highlight the most pressing issues for improvement of the quality of injury epidemiology research for disability sport. Methods A search of NICE, AMED, British Nursing Index, CINAHL, EMBASE and Medline was conducted to identify all publications up to 16 June 2015. Of 489 potentially relevant articles and reference searching, a total of 15 studies were included. Wide study sample heterogeneity prevented data pooling and meta-analysis. Results Results demonstrated an evolving field of epidemiology, but with wide differences in sports injury definition and with studies focused on short competitions. Background data were generally sparse; there was minimal exposure analysis, and no analysis of injury severity, all of which made comparison of injury risk and injury severity difficult. Conclusion There is an urgent need for consensus on sports injury definition and methodology in disability sports. The quality of studies is variable, with inconsistent sports injury definitions, methodologies and injury rates, which prevents comparison, conclusions and development of injury prevention strategies. The authors highlight the most pressing issues for improvement of the quality in injury epidemiology research for disability sport.
- Authors: Weiler, Richard , van Mechelen, Willem , Fuller, Colin , Verhagen, Evert
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 8 (2016), p. 1141-1153
- Full Text:
- Reviewed:
- Description: Background Fifteen percent of the world's population live with disability, and many of these individuals choose to play sport. There are barriers to sport participation for athletes with disability and sports injury can greatly impact on daily life, which makes sports injury prevention additionally important. Objective The purpose of this review is to systematically review the definitions, methodologies and injury rates in disability sport, which should assist future identification of risk factors and development of injury prevention strategies. A secondary aim is to highlight the most pressing issues for improvement of the quality of injury epidemiology research for disability sport. Methods A search of NICE, AMED, British Nursing Index, CINAHL, EMBASE and Medline was conducted to identify all publications up to 16 June 2015. Of 489 potentially relevant articles and reference searching, a total of 15 studies were included. Wide study sample heterogeneity prevented data pooling and meta-analysis. Results Results demonstrated an evolving field of epidemiology, but with wide differences in sports injury definition and with studies focused on short competitions. Background data were generally sparse; there was minimal exposure analysis, and no analysis of injury severity, all of which made comparison of injury risk and injury severity difficult. Conclusion There is an urgent need for consensus on sports injury definition and methodology in disability sports. The quality of studies is variable, with inconsistent sports injury definitions, methodologies and injury rates, which prevents comparison, conclusions and development of injury prevention strategies. The authors highlight the most pressing issues for improvement of the quality in injury epidemiology research for disability sport.
Health and economic burden of running-related injuries in Dutch trailrunners : A prospective cohort study
- Hespanhol Junior, Luiz, van Mechelen, Willem, Verhagen, Evert
- Authors: Hespanhol Junior, Luiz , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article
- Relation: Sports Medicine Vol. 47, no. 2 (2017), p. 367-377
- Full Text:
- Reviewed:
- Description: Background: Trailrunning is becoming very popular. However, the risk and burden of running-related injuries (RRI) in trailrunning is not well established. Objective: To investigate the prevalence, injury rate, severity, nature, and economic burden of RRIs in Dutch trailrunners. Methods: This prospective cohort study included 228 trailrunners aged 18 years or over (range 23–67), and was conducted between October 2013 and December 2014. After completing the baseline questionnaire, the Oslo Sports Trauma Research Center Questionnaire on Health Problems was administered every 2 weeks to collect data on RRIs. Participants who reported RRIs were asked about healthcare utilization (direct costs) and absenteeism from paid work (indirect costs). RRI was defined as disorders of the musculoskeletal system or concussions experienced or sustained during participation in running. Results: The mean prevalence of RRIs measured over time was 22.4 % [95 % confidence interval (CI) 20.9–24.0], and the injury rate was 10.7 RRIs per 1000 h of running (95 % CI 9.4–12.1). The prevalence was higher for overuse (17.7 %; 95 % CI 15.9–19.5) than for acute (4.1 %; 95 % CI 3.3–5.0) RRIs. Also, the injury rate was higher for overuse (8.1; 95 % CI 6.9–9.3) than for acute (2.7; 95 % CI 2.0–3.4) RRIs. The median of the severity score was 35.0 [25–75 %, interquartile range (IQR) 22.0–55.7], and the median of the duration of RRIs was 2.0 weeks (IQR 2.0–6.0) during the study. The total economic burden of RRIs was estimated at €172.22 (95 % CI 117.10–271.74) per RRI, and €1849.49 (95 % CI 1180.62–3058.91) per 1000 h of running. An RRI was estimated to have a direct cost of €60.92 (95 % CI 45.11–94.90) and an indirect cost of €111.30 (95 % CI 61.02–192.75). Conclusions: The health and economic burden of RRIs presented in this study are significant for trailrunners and for society. Therefore, efforts should be made in order to prevent RRIs in trailrunners. © 2016, The Author(s).
- Authors: Hespanhol Junior, Luiz , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article
- Relation: Sports Medicine Vol. 47, no. 2 (2017), p. 367-377
- Full Text:
- Reviewed:
- Description: Background: Trailrunning is becoming very popular. However, the risk and burden of running-related injuries (RRI) in trailrunning is not well established. Objective: To investigate the prevalence, injury rate, severity, nature, and economic burden of RRIs in Dutch trailrunners. Methods: This prospective cohort study included 228 trailrunners aged 18 years or over (range 23–67), and was conducted between October 2013 and December 2014. After completing the baseline questionnaire, the Oslo Sports Trauma Research Center Questionnaire on Health Problems was administered every 2 weeks to collect data on RRIs. Participants who reported RRIs were asked about healthcare utilization (direct costs) and absenteeism from paid work (indirect costs). RRI was defined as disorders of the musculoskeletal system or concussions experienced or sustained during participation in running. Results: The mean prevalence of RRIs measured over time was 22.4 % [95 % confidence interval (CI) 20.9–24.0], and the injury rate was 10.7 RRIs per 1000 h of running (95 % CI 9.4–12.1). The prevalence was higher for overuse (17.7 %; 95 % CI 15.9–19.5) than for acute (4.1 %; 95 % CI 3.3–5.0) RRIs. Also, the injury rate was higher for overuse (8.1; 95 % CI 6.9–9.3) than for acute (2.7; 95 % CI 2.0–3.4) RRIs. The median of the severity score was 35.0 [25–75 %, interquartile range (IQR) 22.0–55.7], and the median of the duration of RRIs was 2.0 weeks (IQR 2.0–6.0) during the study. The total economic burden of RRIs was estimated at €172.22 (95 % CI 117.10–271.74) per RRI, and €1849.49 (95 % CI 1180.62–3058.91) per 1000 h of running. An RRI was estimated to have a direct cost of €60.92 (95 % CI 45.11–94.90) and an indirect cost of €111.30 (95 % CI 61.02–192.75). Conclusions: The health and economic burden of RRIs presented in this study are significant for trailrunners and for society. Therefore, efforts should be made in order to prevent RRIs in trailrunners. © 2016, The Author(s).
Modelling a biorefinery concept producing carbon fibre-polybutylene succinate composite foam
- Ghayur, Adeel, Verheyen, Vincent
- Authors: Ghayur, Adeel , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Chemical Engineering Science Vol. 209, no. (2019), p. 1-7
- Full Text:
- Reviewed:
- Description: In this study, a novel biorefinery concept producing carbon fibre-poly(butylene succinate) composite foam (CPC foam) from lignocellulose and CO 2 is modelled. The biodegradable nature of poly(butylene succinate) would allow for easy carbon fibre recovery from the CPC foam for reuse at the end of product lifecycle, thus allowing for a circular materials flow. Technical simulation results show the biorefinery consumes 417 kg of biomass, 33 kg of CO 2 , 86 kg of methanol, 23 kg of acetic anhydride, 130 kWh of electricity and 1166 kW of heat per hour. The facility generates 72 kg of CPC foam, 82 kg of carbon fibre, 24 kg of tetrahydrofuran and 50 kg of dimethyl ether (DME). DME is used to fulfil parasitic electricity requirement. These results demonstrate the technical viability of this biorefinery although, research is needed to reduce parasitic energy demand. This carbon negative biorefinery avoids carcinogens and halogens for polymeric materials synthesis by utilising green chemistry principles and lignocellulose feedstock.
- Authors: Ghayur, Adeel , Verheyen, Vincent
- Date: 2019
- Type: Text , Journal article
- Relation: Chemical Engineering Science Vol. 209, no. (2019), p. 1-7
- Full Text:
- Reviewed:
- Description: In this study, a novel biorefinery concept producing carbon fibre-poly(butylene succinate) composite foam (CPC foam) from lignocellulose and CO 2 is modelled. The biodegradable nature of poly(butylene succinate) would allow for easy carbon fibre recovery from the CPC foam for reuse at the end of product lifecycle, thus allowing for a circular materials flow. Technical simulation results show the biorefinery consumes 417 kg of biomass, 33 kg of CO 2 , 86 kg of methanol, 23 kg of acetic anhydride, 130 kWh of electricity and 1166 kW of heat per hour. The facility generates 72 kg of CPC foam, 82 kg of carbon fibre, 24 kg of tetrahydrofuran and 50 kg of dimethyl ether (DME). DME is used to fulfil parasitic electricity requirement. These results demonstrate the technical viability of this biorefinery although, research is needed to reduce parasitic energy demand. This carbon negative biorefinery avoids carcinogens and halogens for polymeric materials synthesis by utilising green chemistry principles and lignocellulose feedstock.
Evaluation of slug flow-induced flexural loading in pipelines using a surrogate model
- Sultan, Ibrahim, Reda, Ahmed, Forbes, Gareth
- Authors: Sultan, Ibrahim , Reda, Ahmed , Forbes, Gareth
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Offshore Mechanics and Arctic Engineering Vol. 135, no. 3 (2013), p. 8
- Full Text:
- Reviewed:
- Description: Slug flow induces vibration in pipelines, which may, in some cases, result in fatigue failure. This can result from dynamic stresses, induced by the deflection and bending moment in the pipe span, growing to levels above the endurance limits of the pipeline material. As such, it is of paramount importance to understand and quantify the size of the pipeline response to slug flow under given speed and damping conditions. This paper utilizes the results of an optimization procedure to devise a surrogate closed-form model, which can be employed to calculate the maximum values of the pipeline loadings at given values of speed and damping parameters. The surrogate model is intended to replace the computationally costly numerical procedure needed for the analysis. The maximum values of the lateral deflection and bending moment, along with their locations, have been calculated using the optimization method of stochastic perturbation and successive approximations ( SPSA). The accuracy of the proposed surrogate model will be validated numerically, and the model will be subsequently used in a numerical example to demonstrate its applicability in industrial situations. An accompanying spreadsheet with this worked example is also given.
- Description: C1
The limacon of Pascal : mechanical generation and utilization for fluid processing
- Authors: Sultan, Ibrahim
- Date: 2005
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers Part C-Journal of Mechanical Engineering Science Vol. 219, no. 8 (Aug 2005), p. 813-822
- Full Text:
- Reviewed:
- Description: The limaçon of Pascal is a plane curve that possesses some characteristics which qualify it for fluid processing applications. However, the curve has not yet attracted enough attention, neither from industry nor from the mechanical engineering research community, despite the few attempts that have been conducted over the past century. The work presented here is intended to explore various mechanical linkages that can be employed to produce the limaçon and the aspects of these linkages. Mathematical analysis will show that machines based on the limaçon curve possess sinusoidal volumetric relationships and hence, simplified pressure and torque equations can be obtained in closed forms. The concepts discussed here will be demonstrated by using a compressor as a sample application
- Description: C1
- Description: 2003001087
Telomere length maintenance and cardio-metabolic disease prevention through exercise training
- Denham, Joshua, O'Brien, Brendan, Charchar, Fadi
- Authors: Denham, Joshua , O'Brien, Brendan , Charchar, Fadi
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 9 (2016), p. 1213-1237
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Telomeres are tandem repeat DNA sequences located at distal ends of chromosomes that protect against genomic DNA degradation and chromosomal instability. Excessive telomere shortening leads to cellular senescence and for this reason telomere length is a marker of biological age. Abnormally short telomeres may culminate in the manifestation of a number of cardio-metabolic diseases. Age-related cardio-metabolic diseases attributable to an inactive lifestyle, such as obesity, type 2 diabetes mellitus and cardiovascular disease, are associated with short leukocyte telomeres. Exercise training prevents and manages the symptoms of many cardio-metabolic diseases whilst concurrently maintaining telomere length. The positive relationship between exercise training, physical fitness and telomere length raises the possibility of a mediating role of telomeres in chronic disease prevention via exercise. Further elucidation of the underpinning molecular mechanisms of how exercise maintains telomere length should provide crucial information on how physical activity can be best structured to combat the chronic disease epidemic and improve the human health span. Here, we synthesise and discuss the current evidence on the impact of physical activity and cardiorespiratory fitness on telomere dynamics. We provide the molecular mechanisms with a known role in exercise-induced telomere length maintenance and highlight unexplored, alternative pathways ripe for future investigations.
- Authors: Denham, Joshua , O'Brien, Brendan , Charchar, Fadi
- Date: 2016
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 46, no. 9 (2016), p. 1213-1237
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text:
- Reviewed:
- Description: Telomeres are tandem repeat DNA sequences located at distal ends of chromosomes that protect against genomic DNA degradation and chromosomal instability. Excessive telomere shortening leads to cellular senescence and for this reason telomere length is a marker of biological age. Abnormally short telomeres may culminate in the manifestation of a number of cardio-metabolic diseases. Age-related cardio-metabolic diseases attributable to an inactive lifestyle, such as obesity, type 2 diabetes mellitus and cardiovascular disease, are associated with short leukocyte telomeres. Exercise training prevents and manages the symptoms of many cardio-metabolic diseases whilst concurrently maintaining telomere length. The positive relationship between exercise training, physical fitness and telomere length raises the possibility of a mediating role of telomeres in chronic disease prevention via exercise. Further elucidation of the underpinning molecular mechanisms of how exercise maintains telomere length should provide crucial information on how physical activity can be best structured to combat the chronic disease epidemic and improve the human health span. Here, we synthesise and discuss the current evidence on the impact of physical activity and cardiorespiratory fitness on telomere dynamics. We provide the molecular mechanisms with a known role in exercise-induced telomere length maintenance and highlight unexplored, alternative pathways ripe for future investigations.
Turnpike theorem for an infinite horizon optimal control problem with time delay
- Authors: Mammadov, Musa
- Date: 2014
- Type: Text , Journal article
- Relation: SIAM Journal on Control and Optimization Vol. 52, no. 1 (2014), p. 420-438
- Full Text:
- Reviewed:
- Description: An optimal control problem for systems described by a special class of nonlinear differential equations with time delay is considered. The cost functional adopted could be considered as an analogue of the terminal functional defined over an infinite time horizon. The existence of optimal solutions as well as the asymptotic stability of optimal trajectories (that is, the turnpike property) are established under some quite mild restrictions on the nonlinearities of the functions involved in the description of the problem. Such mild restrictions on the nonlinearities allowed us to apply these results to a blood cell production model. © 2014 Society for Industrial and Applied Mathematics.
- Authors: Mammadov, Musa
- Date: 2014
- Type: Text , Journal article
- Relation: SIAM Journal on Control and Optimization Vol. 52, no. 1 (2014), p. 420-438
- Full Text:
- Reviewed:
- Description: An optimal control problem for systems described by a special class of nonlinear differential equations with time delay is considered. The cost functional adopted could be considered as an analogue of the terminal functional defined over an infinite time horizon. The existence of optimal solutions as well as the asymptotic stability of optimal trajectories (that is, the turnpike property) are established under some quite mild restrictions on the nonlinearities of the functions involved in the description of the problem. Such mild restrictions on the nonlinearities allowed us to apply these results to a blood cell production model. © 2014 Society for Industrial and Applied Mathematics.
Geometric design of the limaçon-to-circular fluid processing machine
- Phung, Truong, Sultan, Ibrahim
- Authors: Phung, Truong , Sultan, Ibrahim
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Mechanical Design, Transactions of the ASME Vol. 143, no. 10 (2021), p.
- Full Text:
- Reviewed:
- Description: A limaçon machine is a rotary positive displacement device, in which the housing and rotor are constructed of limaçon of Pascal curves. Previous works have been published to investigate the working of these machines in two applications: gas expanders and compressors. This article presents a theoretical investigation into the potential of modifying the rotor profile of the limaçon machines to simplify the machine's manufacturing process and to reduce production cost. The proposed modification will produce new characteristics for the housing-rotor interaction. An outcome that motivates the need to obtain new mathematical models to investigate the housing-rotor interference and describe the volumetric relationship of the new machine. This article also employs an optimization approach to design the best machine for a given set of operating conditions, i.e., expander, compressor, and pump. The outcome of this study confirms the validity of the proposed modification and its potential to produce a limaçon machine with favorable characteristics. Copyright © 2021 by ASME
- Authors: Phung, Truong , Sultan, Ibrahim
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Mechanical Design, Transactions of the ASME Vol. 143, no. 10 (2021), p.
- Full Text:
- Reviewed:
- Description: A limaçon machine is a rotary positive displacement device, in which the housing and rotor are constructed of limaçon of Pascal curves. Previous works have been published to investigate the working of these machines in two applications: gas expanders and compressors. This article presents a theoretical investigation into the potential of modifying the rotor profile of the limaçon machines to simplify the machine's manufacturing process and to reduce production cost. The proposed modification will produce new characteristics for the housing-rotor interaction. An outcome that motivates the need to obtain new mathematical models to investigate the housing-rotor interference and describe the volumetric relationship of the new machine. This article also employs an optimization approach to design the best machine for a given set of operating conditions, i.e., expander, compressor, and pump. The outcome of this study confirms the validity of the proposed modification and its potential to produce a limaçon machine with favorable characteristics. Copyright © 2021 by ASME
A numerical control algorithm for a B-double truck-trailer with steerable trailer wheels and active hitch angles
- Authors: Percy, Andrew , Spark, Ian
- Date: 2012
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 226, no. 3 (2012), p. 289-300
- Full Text:
- Reviewed:
- Description: This paper presents a new algorithm for the control of a B-double truck–trailer with steerable trailer wheels and active hitch angles, designed to minimize both off-tracking and scuffing. Each trailer has six autonomously steered double wheels, although each double wheel is modelled by a centrally placed single wheel. Each hitch point, joining truck to first trailer and first trailer to second trailer, as well as a nominated point central to the axles of the second trailer, traverses the same path which is determined by an operator controlling the path curvature and truck speed. The algorithm approximates the ideal solution in which all wheels on each trailer have the same centre of curvature. The actively controlled hitch angles, satisfying the path-following constraints, provide a further level of cooperative redundancy of steering systems. Simulations are carried out to show the effects of changing curvature and front hitch speed on hitch path, wheel angles, and hitch angles as well as the accuracy of the algorithm. Further simulation is carried out to show the improvement in off-tracking of the new control system over current B-double fixed-wheel systems.
- Authors: Percy, Andrew , Spark, Ian
- Date: 2012
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering Vol. 226, no. 3 (2012), p. 289-300
- Full Text:
- Reviewed:
- Description: This paper presents a new algorithm for the control of a B-double truck–trailer with steerable trailer wheels and active hitch angles, designed to minimize both off-tracking and scuffing. Each trailer has six autonomously steered double wheels, although each double wheel is modelled by a centrally placed single wheel. Each hitch point, joining truck to first trailer and first trailer to second trailer, as well as a nominated point central to the axles of the second trailer, traverses the same path which is determined by an operator controlling the path curvature and truck speed. The algorithm approximates the ideal solution in which all wheels on each trailer have the same centre of curvature. The actively controlled hitch angles, satisfying the path-following constraints, provide a further level of cooperative redundancy of steering systems. Simulations are carried out to show the effects of changing curvature and front hitch speed on hitch path, wheel angles, and hitch angles as well as the accuracy of the algorithm. Further simulation is carried out to show the improvement in off-tracking of the new control system over current B-double fixed-wheel systems.
Aerobic training protects cardiac function during advancing age : A meta-analysis of four decades of controlled studies
- Beaumont, Alexander, Grace, Fergal, Richards, Joanna, Campbell, Amy, Sculthorpe, Nicholas
- Authors: Beaumont, Alexander , Grace, Fergal , Richards, Joanna , Campbell, Amy , Sculthorpe, Nicholas
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 49, no. 2 (2019), p. 199-219
- Full Text:
- Reviewed:
- Description: Background: In contrast to younger athletes, there is comparatively less literature examining cardiac structure and function in older athletes. However, a progressive accumulation of studies during the past four decades offers a body of literature worthy of systematic scrutiny. Objectives: We conducted a systematic review, meta-analysis and meta-regression of controlled echocardiography studies comparing left ventricular (LV) structure and function in aerobically trained older athletes (> 45 years) with age-matched untrained controls, in addition to investigating the influence of chronological age. Methods: Electronic databases were searched from inception to January 2018 before conducting a random-effects meta-analysis to calculate pooled differences in means, effect size and 95% confidence intervals (CIs). Study heterogeneity was reported using Cochran’s Q and I2 statistic. Results: Overall, 32 studies (644 athletes; 582 controls) were included. Athletes had greater LV end-diastolic diameter (3.65 mm, 95% CI 2.66–4.64), interventricular septal thickness (1.23 mm, 95% CI 0.85–1.60), posterior wall thickness (1.20 mm, 95% CI 0.83–1.56), LV mass (72 g, 95% CI 46–98), LV mass index (28.17 g·m2, 95% CI 19.84–36.49) and stroke volume (13.59 mL, 95% CI 7.20–19.98) (all p < 0.01). Athletes had superior global diastolic function [ratio of early (E) to late (A) mitral inflow velocity (E/A) 0.18, 95% CI 0.13–0.24, p < 0.01; ratio of early (e′) to late (a′) diastolic annular tissue velocity (e′/a′) 0.23, 95% CI 0.06–0.40, p = 0.01], lower A (−8.20 cm·s−1, 95% CI −11.90 to −4.51, p < 0.01) and a′ (−0.72 cm·s−1, 95% CI −1.31 to −0.12, p = 0.02), and more rapid e′ (0.96 cm·s−1, 95% CI 0.05–1.86, p = 0.04). Meta-regression for chronological age identified that athlete–control differences, in the main, are maintained during advancing age. Conclusions: Athletic older men have larger cardiac dimensions and enjoy more favourable cardiac function than healthy, non-athletic counterparts. Notably, the athlete groups maintain these effects during chronological ageing. © 2018, The Author(s).
- Authors: Beaumont, Alexander , Grace, Fergal , Richards, Joanna , Campbell, Amy , Sculthorpe, Nicholas
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 49, no. 2 (2019), p. 199-219
- Full Text:
- Reviewed:
- Description: Background: In contrast to younger athletes, there is comparatively less literature examining cardiac structure and function in older athletes. However, a progressive accumulation of studies during the past four decades offers a body of literature worthy of systematic scrutiny. Objectives: We conducted a systematic review, meta-analysis and meta-regression of controlled echocardiography studies comparing left ventricular (LV) structure and function in aerobically trained older athletes (> 45 years) with age-matched untrained controls, in addition to investigating the influence of chronological age. Methods: Electronic databases were searched from inception to January 2018 before conducting a random-effects meta-analysis to calculate pooled differences in means, effect size and 95% confidence intervals (CIs). Study heterogeneity was reported using Cochran’s Q and I2 statistic. Results: Overall, 32 studies (644 athletes; 582 controls) were included. Athletes had greater LV end-diastolic diameter (3.65 mm, 95% CI 2.66–4.64), interventricular septal thickness (1.23 mm, 95% CI 0.85–1.60), posterior wall thickness (1.20 mm, 95% CI 0.83–1.56), LV mass (72 g, 95% CI 46–98), LV mass index (28.17 g·m2, 95% CI 19.84–36.49) and stroke volume (13.59 mL, 95% CI 7.20–19.98) (all p < 0.01). Athletes had superior global diastolic function [ratio of early (E) to late (A) mitral inflow velocity (E/A) 0.18, 95% CI 0.13–0.24, p < 0.01; ratio of early (e′) to late (a′) diastolic annular tissue velocity (e′/a′) 0.23, 95% CI 0.06–0.40, p = 0.01], lower A (−8.20 cm·s−1, 95% CI −11.90 to −4.51, p < 0.01) and a′ (−0.72 cm·s−1, 95% CI −1.31 to −0.12, p = 0.02), and more rapid e′ (0.96 cm·s−1, 95% CI 0.05–1.86, p = 0.04). Meta-regression for chronological age identified that athlete–control differences, in the main, are maintained during advancing age. Conclusions: Athletic older men have larger cardiac dimensions and enjoy more favourable cardiac function than healthy, non-athletic counterparts. Notably, the athlete groups maintain these effects during chronological ageing. © 2018, The Author(s).
Intervention strategies used in sport injury prevention studies : A systematic review identifying studies applying the Haddon matrix
- Vriend, Ingrid, Gouttebarge, Vincent, Finch, Caroline, van Mechelen, Willem, Verhagen, Evert
- Authors: Vriend, Ingrid , Gouttebarge, Vincent , Finch, Caroline , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 47, no. 10 (2017), p. 2027-2043
- Full Text:
- Reviewed:
- Description: Background: Prevention of sport injuries is crucial to maximise the health and societal benefits of a physically active lifestyle. To strengthen the translation and implementation of the available evidence base on effective preventive measures, a range of potentially relevant strategies should be considered. Objective: Our aim was to identify and categorise intervention strategies for the prevention of acute sport injuries evaluated in the scientific literature, applying the Haddon matrix, and identify potential knowledge gaps. Methods: Five electronic databases were searched (PubMed, EMBASE, SPORTDiscus, CINAHL, Cochrane) for studies that evaluated the effect of interventions on the occurrence of acute sport injuries. Studies were required to include a control group/condition, prospective data collection, and a quantitative injury outcome measure. Results: A total of 155 studies were included, mostly randomised controlled trials (43%). The majority of studies (55%) focussed on strategies requiring a behavioural change on the part of athletes. Studies predominantly evaluated the preventive effect of various training programmes targeted at the ‘pre-event’ phase (n = 73) and the use of equipment to avoid injury in the ‘event phase’ (n = 29). A limited number of studies evaluated the preventive effect of strategies geared at rules and regulations (n = 14), and contextual modifications (n = 18). Studies specifically aimed at preventing re-injuries were a minority (n = 8), and were mostly related to ankle sprains (n = 5). Conclusions: Valuable insight into the extent of the evidence base of sport injury prevention studies was obtained for 20 potential intervention strategies. This approach can be used to monitor potential gaps in the knowledge base on sport injury prevention. © 2017, The Author(s).
- Authors: Vriend, Ingrid , Gouttebarge, Vincent , Finch, Caroline , van Mechelen, Willem , Verhagen, Evert
- Date: 2017
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 47, no. 10 (2017), p. 2027-2043
- Full Text:
- Reviewed:
- Description: Background: Prevention of sport injuries is crucial to maximise the health and societal benefits of a physically active lifestyle. To strengthen the translation and implementation of the available evidence base on effective preventive measures, a range of potentially relevant strategies should be considered. Objective: Our aim was to identify and categorise intervention strategies for the prevention of acute sport injuries evaluated in the scientific literature, applying the Haddon matrix, and identify potential knowledge gaps. Methods: Five electronic databases were searched (PubMed, EMBASE, SPORTDiscus, CINAHL, Cochrane) for studies that evaluated the effect of interventions on the occurrence of acute sport injuries. Studies were required to include a control group/condition, prospective data collection, and a quantitative injury outcome measure. Results: A total of 155 studies were included, mostly randomised controlled trials (43%). The majority of studies (55%) focussed on strategies requiring a behavioural change on the part of athletes. Studies predominantly evaluated the preventive effect of various training programmes targeted at the ‘pre-event’ phase (n = 73) and the use of equipment to avoid injury in the ‘event phase’ (n = 29). A limited number of studies evaluated the preventive effect of strategies geared at rules and regulations (n = 14), and contextual modifications (n = 18). Studies specifically aimed at preventing re-injuries were a minority (n = 8), and were mostly related to ankle sprains (n = 5). Conclusions: Valuable insight into the extent of the evidence base of sport injury prevention studies was obtained for 20 potential intervention strategies. This approach can be used to monitor potential gaps in the knowledge base on sport injury prevention. © 2017, The Author(s).
Use of variable valve actuation to control the load in a direct injection, turbocharged, spark-ignition engine
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Downsizing and Turbo Charging (TC) and Direct Injection (DI) may be combined with Variable Valve Actuation (VVA) to better deal with the challenges of fuel economy enhancement. VVA may control the load without throttle; control the valve directly and quickly; optimize combustion, produce large volumetric efficiency. Benefits lower fuel consumption, lower emissions and better performance and fun to drive. The paper presents an engine model of a 1.6 litre TDI VVA engine specifically designed to run pure ethanol, with computed engine maps for brake specific fuel consumption and efficiency. The paper also presents driving cycle results obtained with a vehicle model for a passenger car powered by this engine and a traditional naturally aspirated gasoline engine. Preliminary results of the VVA system coupled with downsizing, turbo charging and Direct Injection permits significant driving cycle fuel economies.
- Authors: Boretti, Alberto
- Date: 2010
- Type: Text , Conference paper
- Relation: Paper presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, San Diego, USA : 25th-27th October 2010
- Full Text:
- Description: Downsizing and Turbo Charging (TC) and Direct Injection (DI) may be combined with Variable Valve Actuation (VVA) to better deal with the challenges of fuel economy enhancement. VVA may control the load without throttle; control the valve directly and quickly; optimize combustion, produce large volumetric efficiency. Benefits lower fuel consumption, lower emissions and better performance and fun to drive. The paper presents an engine model of a 1.6 litre TDI VVA engine specifically designed to run pure ethanol, with computed engine maps for brake specific fuel consumption and efficiency. The paper also presents driving cycle results obtained with a vehicle model for a passenger car powered by this engine and a traditional naturally aspirated gasoline engine. Preliminary results of the VVA system coupled with downsizing, turbo charging and Direct Injection permits significant driving cycle fuel economies.
Injuries in field hockey players : A systematic review
- Barboza, Saulo, Joseph, Corey, Nauta, Joske, van Mechelen, Willem, Verhagen, Evert
- Authors: Barboza, Saulo , Joseph, Corey , Nauta, Joske , van Mechelen, Willem , Verhagen, Evert
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 48, no. 4 (2018), p. 849-866
- Full Text:
- Reviewed:
- Description: Background: To commence injury prevention efforts, it is necessary to understand the magnitude of the injury problem. No systematic reviews have yet investigated the extent of injuries in field hockey, despite the popularity of the sport worldwide. Objective: Our objective was to describe the rate and severity of injuries in field hockey and investigate their characteristics. Methods: We conducted electronic searches in PubMed, Embase, SPORTDiscus, and CINAHL. Prospective cohort studies were included if they were published in English in a peer-reviewed journal and observed all possible injuries sustained by field hockey players during the period of the study. Results: The risk of bias score of the 22 studies included ranged from three to nine of a possible ten. In total, 12 studies (55%) reported injuries normalized by field hockey exposure. Injury rates ranged from 0.1 injuries (in school-aged players) to 90.9 injuries (in Africa Cup of Nations) per 1000 player-hours and from one injury (in high-school women) to 70 injuries (in under-21 age women) per 1000 player-sessions. Studies used different classifications for injury severity, but—within studies—injuries were included mostly in the less severe category. The lower limbs were most affected, and contusions/hematomas and abrasions were common types of injury. Contact injuries are common, but non-contact injuries are also a cause for concern. Conclusions: Considerable heterogeneity meant it was not possible to draw conclusive findings on the extent of the rate and severity of injuries. Establishing the extent of sports injury is considered the first step towards prevention, so there is a need for a consensus on injury surveillance in field hockey. © 2018, The Author(s).
- Authors: Barboza, Saulo , Joseph, Corey , Nauta, Joske , van Mechelen, Willem , Verhagen, Evert
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Sports Medicine Vol. 48, no. 4 (2018), p. 849-866
- Full Text:
- Reviewed:
- Description: Background: To commence injury prevention efforts, it is necessary to understand the magnitude of the injury problem. No systematic reviews have yet investigated the extent of injuries in field hockey, despite the popularity of the sport worldwide. Objective: Our objective was to describe the rate and severity of injuries in field hockey and investigate their characteristics. Methods: We conducted electronic searches in PubMed, Embase, SPORTDiscus, and CINAHL. Prospective cohort studies were included if they were published in English in a peer-reviewed journal and observed all possible injuries sustained by field hockey players during the period of the study. Results: The risk of bias score of the 22 studies included ranged from three to nine of a possible ten. In total, 12 studies (55%) reported injuries normalized by field hockey exposure. Injury rates ranged from 0.1 injuries (in school-aged players) to 90.9 injuries (in Africa Cup of Nations) per 1000 player-hours and from one injury (in high-school women) to 70 injuries (in under-21 age women) per 1000 player-sessions. Studies used different classifications for injury severity, but—within studies—injuries were included mostly in the less severe category. The lower limbs were most affected, and contusions/hematomas and abrasions were common types of injury. Contact injuries are common, but non-contact injuries are also a cause for concern. Conclusions: Considerable heterogeneity meant it was not possible to draw conclusive findings on the extent of the rate and severity of injuries. Establishing the extent of sports injury is considered the first step towards prevention, so there is a need for a consensus on injury surveillance in field hockey. © 2018, The Author(s).
- Joseph, Corey, Bradshaw, Elizabeth, Kemp, Justin, Clark, Ross
- Authors: Joseph, Corey , Bradshaw, Elizabeth , Kemp, Justin , Clark, Ross
- Date: 2014
- Type: Text , Journal article
- Relation: Sports Biomechanics Vol. 13, no. 3 (2014), p. 241-258
- Full Text:
- Reviewed:
- Description: Eccentric contractions that provide spring energy can also cause muscle damage. The aim of this study was to explore leg and vertical stiffness following muscle damage induced by an eccentric exercise protocol. Twenty active males completed 60 minutes of backward-walking on a treadmill at 0.67 m/s and a gradient of − 8.5° to induce muscle damage. Tests were performed immediately before; immediately post; and 24, 48, and 168 hours post eccentric exercise. Tests included running at 3.35 m/s and hopping at 2.2 Hz using single- and double-legged actions. Leg and vertical stiffness were measured from kinetic and kinematic data, and electromyography (EMG) of five muscles of the preferred limb were recorded during hopping. Increases in pain scores (over 37%) occurred post-exercise and 24 and 48 hours later (p < 0.001). A 7% decrease in maximal voluntary contraction occurred immediately post-exercise (p = 0.019). Changes in knee kinematics during single-legged hopping were observed 168 hours post (p < 0.05). No significant changes were observed in EMG, creatine kinase activity, leg, or vertical stiffness. Results indicate that knee mechanics may be altered to maintain consistent levels of leg and vertical stiffness when eccentric exercise-induced muscle damage is present in the lower legs. © 2014 Taylor & Francis.