Skip header and navigation

Refine By

110 records – page 1 of 11.

Acceleration and sprint profiles of a professional elite football team in match play.

https://arctichealth.org/en/permalink/ahliterature267270
Source
Eur J Sport Sci. 2015;15(2):101-10
Publication Type
Article
Date
2015
Author
Jørgen Ingebrigtsen
Terje Dalen
Geir Håvard Hjelde
Barry Drust
Ulrik Wisløff
Source
Eur J Sport Sci. 2015;15(2):101-10
Date
2015
Language
English
Publication Type
Article
Keywords
Acceleration
Athletic Performance
Football
Humans
Movement
Norway
Physical Exertion
Running
Soccer
Walking
Abstract
The aim of this study was to characterise the acceleration and sprint profiles of elite football match play in one Norwegian elite football team (Rosenborg FC). Fifteen professional players in five playing positions took part in the study (n = 101 observations). Player movement was recorded during every domestic home game of one full season (n = 15) by an automatic tracking system based on microwave technology. Each player performed 91 ± 21 accelerations per match, with a lower number in the second compared with the first half (47 ± 12 vs. 44 ± 12). Players in lateral positions accelerated more often compared to players in central positions (98.3 ± 20.5 vs. 85.3 ± 19.5, p
PubMed ID
25005777 View in PubMed
Less detail

Age and gender differences in youth physical activity: does physical maturity matter?

https://arctichealth.org/en/permalink/ahliterature163872
Source
Med Sci Sports Exerc. 2007 May;39(5):830-5
Publication Type
Article
Date
May-2007
Author
Lauren B Sherar
Dale W Esliger
Adam D G Baxter-Jones
Mark S Tremblay
Author Affiliation
College of Kinesiology, University of Saskatchewan, Saskatoon, Saskatchewan, Canada. lauren.sherar@usask.ca
Source
Med Sci Sports Exerc. 2007 May;39(5):830-5
Date
May-2007
Language
English
Publication Type
Article
Keywords
Acceleration
Adolescent
Age Factors
Aging
Child
Exercise
Female
Humans
Male
Monitoring, Physiologic - instrumentation
Ontario
Sex Factors
Abstract
To investigate whether observed gender differences in objectively measured physical activity (PA) in children (8-13 yr) are confounded by physical maturity differences.
Four hundred and one children (194 boys and 207 girls) volunteered for this study. An Actigraph accelerometer was used to obtain seven consecutive days of minute-by-minute PA data for each participant. Minutes of moderate to vigorous PA per day (MVPA), continuous minutes of MVPA per day (CMVPA), and minutes of vigorous PA per day (VPA) were derived from the accelerometer data. Age at peak height velocity (APHV), an indicator of somatic maturity, was predicted in all individuals. Gender differences in the PA variables were analyzed using a two-way (gender x age) ANOVA.
Levels of PA decreased with increasing chronological age in both genders (P
Notes
Comment In: Med Sci Sports Exerc. 2008 May;40(5):979; author reply 98018418241
PubMed ID
17468582 View in PubMed
Less detail

An expert judgment model applied to estimating the safety effect of a bicycle facility.

https://arctichealth.org/en/permalink/ahliterature198108
Source
Accid Anal Prev. 2000 Jul;32(4):589-99
Publication Type
Article
Date
Jul-2000
Author
L. Leden
P. Gårder
U. Pulkkinen
Author Affiliation
Luleå University of Technology, Sweden.
Source
Accid Anal Prev. 2000 Jul;32(4):589-99
Date
Jul-2000
Language
English
Publication Type
Article
Keywords
Acceleration
Accidents, Traffic - prevention & control - statistics & numerical data
Bayes Theorem
Bicycling - injuries
Finland
Humans
Monte Carlo Method
Risk assessment
Safety
Sweden
Abstract
This paper presents a risk index model that can be used for assessing the safety effect of countermeasures. The model estimates risk in a multiplicative way, which makes it possible to analyze the impact of different factors separately. Expert judgments are incorporated through a Bayesian error model. The variance of the risk estimate is determined by Monte-Carlo simulation. The model was applied to assess the safety effect of a new design of a bicycle crossing. The intent was to gain safety by raising the crossings to reduce vehicle speeds and by making the crossings more visible by painting them in a bright color. Before the implementations, bicyclists were riding on bicycle crossings of conventional Swedish type, i.e. similar to crosswalks but delineated by white squares rather than solid lines or zebra markings. Automobile speeds were reduced as anticipated. However, it seems as if the positive effect of this was more or less canceled out by increased bicycle speeds. The safety per bicyclist was still improved by approximately 20%. This improvement was primarily caused by an increase in bicycle flow, since the data show that more bicyclists at a given location seem to benefit their safety. The increase in bicycle flow was probably caused by the new layout of the crossings since bicyclists perceived them as safer and causing less delay. Some future development work is suggested. Pros and cons with the used methodology are discussed. The most crucial parameter to be added is probably a model describing the interaction between motorists and bicyclists, for example, how risk is influenced by the lateral position of the bicyclist in relation to the motorist. It is concluded that the interaction seems to be optimal when both groups share the roadway.
PubMed ID
10868762 View in PubMed
Less detail

Are driving and overtaking on right curves more dangerous than on left curves?

https://arctichealth.org/en/permalink/ahliterature272414
Source
Ann Adv Automot Med. 2010;54:253-64
Publication Type
Article
Date
2010
Author
Sarbaz Othman
Robert Thomson
Gunnar Lannér
Source
Ann Adv Automot Med. 2010;54:253-64
Date
2010
Language
English
Publication Type
Article
Keywords
Acceleration
Accidents, Traffic
Automobile Driving
Humans
Safety
Sweden
Abstract
It is well known that crashes on horizontal curves are a cause for concern in all countries due to the frequency and severity of crashes at curves compared to road tangents. A recent study of crashes in western Sweden reported a higher rate of crashes in right curves than left curves. To further understand this result, this paper reports the results of novel analyses of the responses of vehicles and drivers during negotiating and overtaking maneuvers on curves for right hand traffic. The overall objectives of the study were to find road parameters for curves that affect vehicle dynamic responses, to analyze these responses during overtaking maneuvers on curves, and to link the results with driver behavior for different curve directions. The studied road features were speed, super-elevation, radius and friction including their interactions, while the analyzed vehicle dynamic factors were lateral acceleration and yaw angular velocity. A simulation program, PC-Crash, has been used to simulate road parameters and vehicle response interaction in curves. Overtaking maneuvers have been simulated for all road feature combinations in a total of 108 runs. Analysis of variances (ANOVA) was performed, using two sided randomized block design, to find differences in vehicle responses for the curve parameters. To study driver response, a field test using an instrumented vehicle and 32 participants was reviewed as it contained longitudinal speed and acceleration data for analysis. The simulation results showed that road features affect overtaking performance in right and left curves differently. Overtaking on right curves was sensitive to radius and the interaction of radius with road condition; while overtaking on left curves was more sensitive to super-elevation. Comparisons of lateral acceleration and yaw angular velocity during these maneuvers showed different vehicle response configurations depending on curve direction and maneuver path. The field test experiments also showed that drivers behave differently depending on the curve direction where both speed and acceleration were higher on right than left curves. The implication of this study is that curve direction should be taken into consideration to a greater extent when designing and redesigning curves. It appears that the driver and the vehicle are influenced by different infrastructure factors depending on the curve direction. In addition, the results suggest that the vehicle dynamics response alone cannot explain the higher crash risk in right curves. Further studies of the links between driver, vehicle, and highway characteristics are needed, such as naturalistic driving studies, to identify the key safety indicators for highway safety.
Notes
Cites: Ann Adv Automot Med. 2009 Oct;53:155-6520184841
Cites: Accid Anal Prev. 1998 Jul;30(4):455-679666242
PubMed ID
21050608 View in PubMed
Less detail

Are overweight students in Grades 3, 7, and 11 less physically active than their healthy weight counterparts?

https://arctichealth.org/en/permalink/ahliterature152712
Source
Int J Pediatr Obes. 2009;4(1):28-35
Publication Type
Article
Date
2009
Author
Angela M Thompson
Philip D Campagna
Matthew Durant
René J L Murphy
Laurene A Rehman
Laurie A Wadsworth
Author Affiliation
Department of Human Kinetics, St. Francis Xavier University, NS, Canada. amthomps@stfx.ca
Source
Int J Pediatr Obes. 2009;4(1):28-35
Date
2009
Language
English
Publication Type
Article
Keywords
Acceleration
Adolescent
Age Factors
Body mass index
Case-Control Studies
Child
Exercise
Female
Humans
Life Style
Male
Monitoring, Ambulatory - methods
Motor Activity
Nova Scotia
Overweight - physiopathology
Time Factors
Abstract
This study compared the accumulated minutes of objectively measured physical activity in 1,790 boys and girls in Grades 3, 7, and 11 classified as healthy weight, at risk of overweight, and overweight.
Height and weight were measured and body mass index calculated. Minutes of sedentary, light, moderate, hard, and very hard physical activity were obtained from a seven-day measurement of physical activity using an accelerometer (Actigraph, mode 7164; MTI).
In Grade 3, boys (p=0.000) and girls (p=0.012) classified as overweight obtained significantly fewer minutes of very hard physical activity compared with their healthy weight counterparts. Boys in Grade 7 considered overweight obtained significantly fewer minutes of hard (p=0.002) and very hard physical activity (p=0.006) compared with boys who were a healthy weight. There were no significant differences in minutes of sedentary, light, moderate, hard, or very hard intensity physical activity in the boys and girls in Grade 11, who were considered a healthy weight, at risk of overweight, or overweight.
Weak and inconsistent support was provided for the notion that boys and girls classified overweight are less physically active than their healthy weight counterparts.
PubMed ID
19205979 View in PubMed
Less detail

Assessment of Muscular Fitness as a Predictor of Flight Duty Limitation.

https://arctichealth.org/en/permalink/ahliterature300957
Source
Mil Med. 2018 11 01; 183(11-12):e693-e698
Publication Type
Journal Article
Date
11-01-2018
Author
Tuomas Honkanen
Matti Mäntysaari
Janne Avela
Heikki Kyröläinen
Tuomo Leino
Author Affiliation
Aeromedical Centre, Centre for Military Medicine, The Finnish Defense Forces, Helsinki, Finland.
Source
Mil Med. 2018 11 01; 183(11-12):e693-e698
Date
11-01-2018
Language
English
Publication Type
Journal Article
Keywords
Acceleration
Adult
Aerospace Medicine - methods - standards - statistics & numerical data
Anthropometry - methods
Body mass index
Finland
Humans
Male
Military Personnel - statistics & numerical data
Physical Fitness - physiology
Pilots - standards - statistics & numerical data
Return to Work - statistics & numerical data
Abstract
The high acceleration (Gz) exposure among military pilots flying fighter aircraft has been associated with an increased risk for cervical and lumbar disorders. It has been suggested that an adequate level of physical performance could reduce the risk of experiencing these disorders. The Finnish Air Force has for several years used aerobic (bicycle ergometer) and muscular fitness tests (battery of five tests) in the selection process of military pilot candidates in order to evaluate their physical fitness level. The aim of the study was to determine if these selection phase tests and anthropometry measures can predispose those individuals who might be at risk of developing severe spinal disorders leading to permanent flight duty limitations later during their military pilots' career.
The study population consisted of 23 pilots flying with Gz limitation (+2 Gz, +4 Gz or +5 Gz) due to spinal disorders and 50 experienced (+1,000 flight hours) symptomless controls flying actively in operative missions. Data obtained retrospectively for all subjects included anthropometry, physical (aerobic and muscular fitness) test results and self-reported physical activity levels at a pilot selection phase. Aerobic fitness was measured with a maximal ergometer test and muscular endurance was evaluated with a test battery (standing long jump, pull-ups, sit-ups, back extensions, and push-up tests).
Fighter pilots flying without Gz limitation had significantly better mean (±SE) results in pull-up (14.4 ± 4.2 vs. 11.5 ± 2.0, p
PubMed ID
29741654 View in PubMed
Less detail
Source
Accid Anal Prev. 1997 Mar;29(2):153-9
Publication Type
Article
Date
Mar-1997
Author
T. Assum
Author Affiliation
Institute of Transport Economics, Oslo, Norway.
Source
Accid Anal Prev. 1997 Mar;29(2):153-9
Date
Mar-1997
Language
English
Publication Type
Article
Keywords
Acceleration
Accidents, Traffic - prevention & control - psychology
Adolescent
Adult
Aged
Attitude
Automobile Driving - psychology
Female
Humans
Male
Middle Aged
Norway
Risk factors
Safety
Social Responsibility
Abstract
Change of road user attitudes is often advocated as a necessary condition for improvement of road safety. The relation between road user attitudes and accident risk is, however, not well known in road safety research. The objective of this study was to find out whether attitudes are of importance to road safety, i.e. the hypothesis is that drivers having attitudes considered correct according to the traffic code, have lower accident risk than other drivers. The attitudes of a representative sample of Norwegian driver's license holders as well as their accident involvement and driving distance were surveyed by mail questionnaires in two phases. When no other factor is taken into account, accident risk is found to be affected by driver attitudes. When, on the other hand, the age of drivers is taken into account, the relation between attitudes and accident risk disappears. It is concluded that age and annual mileage are more important to accident risk than are attitudes, and more knowledge of the relationship between attitudes and road accident risk is needed.
PubMed ID
9088354 View in PubMed
Less detail

Be aware of neutrons outside short mazes from 10-MV linear accelerators X-rays in radiotherapy facilities.

https://arctichealth.org/en/permalink/ahliterature272304
Source
Radiat Prot Dosimetry. 2015 Jul;165(1-4):464-7
Publication Type
Article
Date
Jul-2015
Author
S. Brockstedt
H. Holstein
L. Jakobsson
A. Tomaszewicz
T. Knöös
Source
Radiat Prot Dosimetry. 2015 Jul;165(1-4):464-7
Date
Jul-2015
Language
English
Publication Type
Article
Keywords
Environmental Exposure
Equipment Design
Hospital Design and Construction
Humans
Neutrons
Occupational Exposure
Particle Accelerators
Radiation Dosage
Radiation Monitoring - methods
Radiation Protection - methods
Radiotherapy - instrumentation - methods
Sweden
X-rays
Abstract
During the radiation survey of a reinstalled 10-MV linear accelerator in an old radiation treatment facility, high dose rates of neutrons were observed. The area outside the maze entrance is used as a waiting room where patients, their relatives and staff other than those involved in the actual treatment can freely pass. High fluence rates of neutrons would cause an unnecessary high effective dose to the staff working in the vicinity of such a system, and it can be several orders higher than the doses received due to X-rays at the same location. However, the common knowledge appears to have been that the effect of neutrons at 10-MV X-ray linear accelerator facilities is negligible and shielding calculations models seldom mention neutrons for this operating energy level. Although data are scarce, reports regarding this phenomenon are now emerging. For the future, it is advocated that contributions from neutrons are considered already during the planning stage of new or modified facilities aimed for 10 MV and that estimated dose levels are verified.
PubMed ID
25802465 View in PubMed
Less detail

The challenge of low physical activity during the school day: at recess, lunch and in physical education.

https://arctichealth.org/en/permalink/ahliterature144978
Source
Br J Sports Med. 2011 Aug;45(10):813-9
Publication Type
Article
Date
Aug-2011
Author
L. Nettlefold
H A McKay
D E R Warburton
K A McGuire
S S D Bredin
P J Naylor
Author Affiliation
University of British Columbia, Vancouver, British Columbia, Canada.
Source
Br J Sports Med. 2011 Aug;45(10):813-9
Date
Aug-2011
Language
English
Publication Type
Article
Keywords
Acceleration
Body mass index
British Columbia
Child
Exercise - physiology
Female
Humans
Leisure Activities
Male
Monitoring, Ambulatory - instrumentation
Physical Education and Training - organization & administration
School Health Services - organization & administration
Sedentary lifestyle
Sex Distribution
Time Factors
Abstract
To describe physical activity (PA) intensity across a school day and assess the percentage of girls and boys achieving recommended guidelines.
The authors measured PA via accelerometry in 380 children (8-11 years) and examined data representing (1) the whole school day, (2) regular class time, (3) recess, (4) lunch and (5) scheduled physical education (PE). Activity was categorised as sedentary (SED), light physical activity (LPA) or moderate to vigorous physical activity (MVPA) using age-specific thresholds. They examined sex differences across PA intensities during each time period and compliance with recommended guidelines.
Girls accumulated less MVPA and more SED than boys throughout the school day (MVPA -10.6 min; SED +13.9 min) recess (MVPA -1.6 min; SED +1.7 min) and lunch (MVPA -3.1 min; SED +2.9 min). Girls accumulated less MVPA (-6.2 min), less LPA (-2.5 min) and more SED (+9.4 min) than boys during regular class time. Fewer girls than boys achieved PA guidelines during school (90.9% vs 96.2%), recess (15.7% vs 34.1%) and lunch (16.7% vs 37.4%). During PE, only 1.8% of girls and 2.9% of boys achieved the PA guidelines. Girls and boys accumulated similar amounts of MVPA, LPA and SED.
The MVPA deficit in girls was due to their sedentary behaviour as opposed to LPA. Physical activity strategies that target girls are essential to overcome this deficit. Only a very small percentage of children met physical activity guidelines during PE. There is a great need for additional training and emphasis on PA during PE. In addition schools should complement PE with PA models that increase PA opportunities across the school day.
Notes
Erratum In: Br J Sports Med. 2011 Aug;45(10):819
PubMed ID
20215489 View in PubMed
Less detail

Chosen risk level during car-following in adverse weather conditions.

https://arctichealth.org/en/permalink/ahliterature279598
Source
Accid Anal Prev. 2016 Oct;95(Pt A):227-35
Publication Type
Article
Date
Oct-2016
Author
Odd André Hjelkrem
Eirin Olaussen Ryeng
Source
Accid Anal Prev. 2016 Oct;95(Pt A):227-35
Date
Oct-2016
Language
English
Publication Type
Article
Keywords
Acceleration
Accidents, Traffic - psychology - statistics & numerical data
Automobile Driving - psychology - statistics & numerical data
Automobiles
Humans
Models, Theoretical
Motor Vehicles
Norway
Rain
Risk-Taking
Rural Population
Snow
Visual Perception - physiology
Abstract
This study examines how precipitation, light conditions and surface conditions affect the drivers' risk perception. An indicator CRI (Chosen Risk Index) is defined, which describes the chosen risk level for drivers in a car-following situation. The dataset contains about 70 000 observations of driver behaviour and weather status on a rural road. Based on the theory of risk homeostasis and an assumption that driving behaviour in situations with daylight, dry road and no precipitation reflects drivers' target level of risk, generalised linear models (GLM) were estimated for cars and trucks separately to reveal the effect of adverse weather conditions on risk perception. The analyses show that both car and truck drivers perceive the highest risk when driving on snow covered roads. For car drivers, a snow covered road in combination with moderate rain or light snow are the factors which lowers the CRI the most. For trucks, snow cover and partially covered roads significantly lowers the CRI, while precipitation did not seem to impose any higher risk. Interaction effects were found for car drivers only.
PubMed ID
27454867 View in PubMed
Less detail

110 records – page 1 of 11.