bluuebunny/crossref_metadata_2025 huggingface dataset:
No Effect of Acute and 6-Day Nitrate Supplementation on VO2 and Time-Trial Performance in Highly Trained Cyclists
Authors: Nyakayiru Jean M. , Jonvik Kristin L. , Pinckaers Philippe J.M. , Senden Joan , van Loon Luc J.C. , Verdijk Lex B.
Published: September 2016

While the majority of studies reporting ergogenic effects of dietary nitrate have used a multiday supplementation protocol, some studies suggest that a single dose of dietary nitrate before exercise can also improve subsequent performance. We aimed to compare the impact of acute and 6-day sodium nitrate supplementation on oxygen uptake (V̇O2) and time-trial performance in trained cyclists. Using a randomized, double-blind, cross-over design, 17 male cyclists (25 ± 4 y, V̇O2peak 65 ± 4 ml·kg-1·min-1, Wmax 411 ± 35 W) were subjected to 3 different trials; 5 days placebo and 1 day sodium nitrate supplementation (1-DAY); 6 days sodium nitrate supplementation (6-DAY); 6 days placebo supplementation (PLA). Nitrate was administered as 1097 mg sodium nitrate providing 800 mg (~12.9 mmol) nitrate per day. Three hours after ingestion of the last supplemental bolus, indirect calorimetry was performed while subjects performed 30 min of exercise at 45% Wmax and 30 min at 65% Wmax on a cycle ergometer, followed by a 10 km time-trial. Immediately before exercise, plasma [nitrate] and [nitrite] increased to a similar extent during the 6-DAY and 1-DAY trial, but not with PLA (plasma nitrite: 501 ± 205, 553 ± 278, and 239 ± 74 nM, respectively; p < .001). No differences were observed between interventions in V̇O2 during submaximal exercise, or in time to complete the time-trial (6-DAY: 1004 ± 61, 1-DAY: 1022 ± 72, PLA: 1017 ± 71 s; p = .28). We conclude that both acute and 6-days of sodium nitrate supplementation do not alter V̇O2 during submaximal exercise or improve time-trial performance in highly trained cyclists, despite increasing plasma [nitrate] and [nitrite].
Impact of Fatigue on Positional Movements During Professional Rugby Union Match Play
Authors: Tee Jason C. , Lambert Mike I. , Coopoo Yoga
Published: September 2016

Purpose:

In team sports, fatigue is manifested by a self-regulated decrease in movement distance and intensity. There is currently limited information on the effect of fatigue on movement patterns in rugby union match play, particularly for players in different position groups (backs vs forwards). This study investigated the effect of different match periods on movement patterns of professional rugby union players.

Methods:

Global positioning system (GPS) data were collected from 46 professional match participations to determine temporal effects on movement patterns.

Results:

Total relative distance (m/min) was decreased in the 2nd half for both forwards (–13%, ±8%, ES = very likely large) and backs (–9%, ±7%, ES = very likely large). A larger reduction in high-intensity-running distance in the 2nd half was observed for forwards (–27%, ±16%, ES = very likely medium) than for backs (–10%, ±15%; ES = unclear). Similar patterns were observed for sprint (>6 m/s) frequency (forwards –29%, ±29%, ES = likely small vs backs –13% ±18%, ES = possibly small) and acceleration (>2.75 m/s2) frequency (forwards –27%, ±24%, ES = likely medium vs backs –5%, ±46%, ES = unclear). Analysis of 1st- and 2nd-half quartiles revealed differing pacing strategies for forwards and backs. Forwards display a “slow-positive” pacing strategy, while the pacing strategy of backs is “flat.”

Conclusions:

Forwards suffered progressively greater performance decrements over the course of the match, while backs were able to maintain performance intensity. These findings reflect differing physical demands, notably contact and running loads, of players in different positions.
Cluster Sets: Permitting Greater Mechanical Stress Without Decreasing Relative Velocity
Authors: Tufano James J. , Conlon Jenny A. , Nimphius Sophia , Brown Lee E. , Banyard Harry G. , Williamson Bryce D. , Bishop Leslie G. , Hopper Amanda J. , Haff G. Gregory
Published: September 2016

Purpose:

To determine the effects of intraset rest frequency and training load on muscle time under tension, external work, and external mechanical power output during back-squat protocols with similar changes in velocity.

Methods:

Twelve strength-trained men (26.0 ± 4.2 y, 83.1 ± 8.8 kg, 1.75 ± 0.06 m, 1.88:0.19 one-repetition-maximum [1RM] body mass) performed 3 sets of 12 back squats using 3 different set structures: traditional sets with 60% 1RM (TS), cluster sets of 4 with 75% 1RM (CS4), and cluster sets of 2 with 80% 1RM (CS2). Repeated-measures ANOVAs were used to determine differences in peak force (PF), mean force (MF), peak velocity (PV), mean velocity (MV), peak power (PP), mean power (MP), total work (TW), total time under tension (TUT), percentage mean velocity loss (%MVL), and percentage peak velocity loss (%PVL) between protocols.

Results:

Compared with TS and CS4, CS2 resulted in greater MF, TW, and TUT in addition to less MV, PV, and MP. Similarly, CS4 resulted in greater MF, TW, and TUT in addition to less MV, PV, and MP than TS did. There were no differences between protocols for %MVL, %PVL, PF, or PP.

Conclusions:

These data show that the intraset rest provided in CS4 and CS2 allowed for greater external loads than with TS, increasing TW and TUT while resulting in similar PP and %VL. Therefore, cluster-set structures may function as an alternative method to traditional strength- or hypertrophy-oriented training by increasing training load without increasing %VL or decreasing PP.
The Effect of Maximal- and Explosive-Strength Training on Performance Indicators in Cyclists
Authors: Beattie Kris , Carson Brian P. , Lyons Mark , Kenny Ian C.
Published: September 2016

Cycling economy (CE), power output at maximal oxygen uptake (WV̇O2max), and anaerobic function (ie, sprinting ability) are considered the best physiological performance indicators in elite road cyclists. In addition to cardiovascular function, these physiological indicators are partly dictated by neuromuscular factors. One technique to improve neuromuscular function in athletes is through strength training. The aim of this study was to investigate the effect of a 20-wk maximal- and explosive-strength-training intervention on strength (maximal strength, explosive strength, and bike-specific explosive strength), WV̇O2max, CE, and body composition (body mass, fat and lean mass) in cyclists. Fifteen competitive road cyclists were divided into an intervention group (endurance training and strength training: n = 6; age, 38.0 ± 10.2 y; weight, 69.1 ± 3.6 kg; height, 1.77 ± 0.04 m) and a control group (endurance training only: n = 9; age, 34.8 ± 8.5 y; weight, 72.5 ± 7.2 kg; height, 1.78 ± 0.05 m). The intervention group strength-trained for 20 wk. Each participant completed 3 assessments: physiology (CE, WV̇O2max, power at 2 and 4 mmol/L blood lactate), strength (isometric midthigh pull, squat-jump height, and 6-s bike-sprint peak power), and body composition (body mass, fat mass, overall leanness, and leg leanness). The results showed significant between- and within-group changes in the intervention group for maximal strength, bike-specific explosive strength, absolute WV̇O2max, body mass, overall leanness, and leg leanness at wk 20 (P < .05). The control group showed no significant within-group changes in measures of strength, physiology, or body composition. This study demonstrates that 20 wk of strength training can significantly improve maximal strength, bike-specific explosive strength, and absolute WV̇O2max in competitive road cyclists.
Effects of Velocity Loss During Resistance Training on Performance in Professional Soccer Players
Authors: Pareja-Blanco Fernando , Sánchez-Medina Luis , Suárez-Arrones Luis , González-Badillo Juan José
Published: September 2016

Purpose:

To analyze the effects of 2 resistance-training (RT) programs that used the same relative loading but different repetition volume, using the velocity loss during the set as the independent variable: 15% (VL15) vs 30% (VL30).

Methods:

Sixteen professional soccer players with RT experience (age 23.8 ± 3.5 y, body mass 75.5 ± 8.6 kg) were randomly assigned to 2 groups, VL15 (n = 8) or VL30 (n = 8), that followed a 6-wk (18-session) velocity-based squat-training program. Repetition velocity was monitored in all sessions. Assessments performed before (Pre) and after training (Post) included estimated 1-repetition maximum (1RM) and change in average mean propulsive velocity (AMPV) against absolute loads common to Pre and Post tests, countermovement jump (CMJ), 30-m sprint (T30), and Yo-Yo Intermittent Recovery Test (YIRT). Null-hypothesis significance testing and magnitude-based-inference statistical analyses were performed.

Results:

VL15 obtained greater gains in CMJ height than VL30 (P < .05), with no significant differences between groups for the remaining variables. VL15 showed a likely/possibly positive effect on 1RM (91/9/0%), AMPV (73/25/2%), and CMJ (87/12/1%), whereas VL30 showed possibly/unclear positive effects on 1RM (65/33/2%) and AMPV (46/36/18%) and possibly negative effects on CMJ (4/38/57%). The effects on T30 performance were unclear/unlikely for both groups, whereas both groups showed most likely/likely positive effects on YIRT.

Conclusions:

A velocity-based RT program characterized by a low degree of fatigue (15% velocity loss in each set) is effective to induce improvements in neuromuscular performance in professional soccer players with previous RT experience.
Assessing Muscle-Strength Asymmetry via a Unilateral-Stance Isometric Midthigh Pull
Authors: Dos’Santos Thomas , Thomas Christopher , Jones Paul A. , Comfort Paul
Published: September 2016

Purpose:

To investigate the within-session reliability of bilateral- and unilateral-stance isometric midthigh-pull (IMTP) force–time characteristics including peak force (PF), relative PF, and impulse at time bands (0–100, 0–200, 0–250, and 0–300 milliseconds) and to compare isometric force–time characteristics between right and left and dominant (D) and nondominant (ND) limbs.

Methods:

Professional male rugby league and multisport male college athletes (N = 54; age, 23.4 ± 4.2 y; height, 1.80 ± 0.05 m; mass, 88.9 ± 12.9 kg) performed 3 bilateral IMTP trials and 6 unilateral-stance IMTP trials (3 per leg) on a force plate sampling at 600 Hz.

Results:

Intraclass correlation coefficients (ICCs) and coefficients of variation (CVs) demonstrated high within-session reliability for bilateral and unilateral IMTP PF (ICC = .94, CV = 4.7–5.5%). Lower reliability measures and greater variability were observed for bilateral and unilateral IMTP impulse at time bands (ICC = .81–.88, CV = 7.7–11.8%). Paired-sample t tests and Cohen d effect sizes revealed no significant differences for all isometric force–time characteristics between right and left limbs in male college athletes (P >.05, d ≤ 0.32) and professional rugby league players (P > .05, d ≤ 0.11); however, significant differences were found between D and ND limbs in male college athletes (P < .001, d = 0.43–0.91) and professional rugby league players (P < .001, d = 0.27–0.46).

Conclusion:

This study demonstrated high within-session reliability for unilateral-stance IMTP PF, revealing significant differences in isometric force–time characteristics between D and ND limbs in male athletes.
The Relationship Between Maximal Strength and Reactive Strength
Authors: Beattie Kris , Carson Brian P. , Lyons Mark , Kenny Ian C.
Published: September 2016

Maximum- and reactive-strength qualities both have important roles in athletic movements and sporting performance. Very little research has investigated the relationship between maximum strength and reactive strength. The aim of this study was to investigate the relationship between maximum-strength (isometric midthigh-pull peak force [IMTP PF]) and reactive-strength (drop-jump reactive-strength index [DJ-RSI]) variables at 0.3-m, 0.4-m, 0.5-m, and 0.6-m box heights. A secondary aim was to investigate the between- and within-group differences in reactive-strength characteristics between relatively stronger athletes (n = 11) and weaker athletes (n = 11). Forty-five college athletes across various sports were recruited to participate in the study (age, 23.7 ± 4.0 y; mass, 87.5 ± 16.1 kg; height, 1.80 ± 0.08 m). Pearson correlation results showed that there was a moderate association (r = .302–.431) between maximum-strength variables (absolute, relative, and allometric scaled PF) and RSI at 0.3, 0.4, 0.5 and 0.6 m (P ≤ .05). In addition, 2-tailed independent-samples t tests showed that the RSIs for relatively stronger athletes (49.59 ± 2.57 N/kg) were significantly larger than those of weaker athletes (33.06 ± 2.76 N/kg) at 0.4 m (Cohen d = 1.02), 0.5 m (d = 1.21), and 0.6 m (d = 1.39) (P ≤ .05). Weaker athletes also demonstrated significant decrements in RSI as eccentric stretch loads increased at 0.3-m through 0.6-m box heights, whereas stronger athletes were able to maintain their reactive-strength ability. This research highlights that in specific sporting scenarios, when there are high eccentric stretch loads and fast stretch-shortening-cycle demands, athletes’ reactive-strength ability may be dictated by their relative maximal strength, specifically eccentric strength.
Pacing Strategy During 24-Hour Ultramarathon-Distance Running
Authors: Bossi Arthur H. , Matta Guilherme G. , Millet Guillaume Y. , Lima Pedro , Pertence Leonardo C. , de Lima Jorge P. , Hopker James G.
Published: September 2016

Purpose:

To describe pacing strategy in a 24-h running race and its interaction with sex, age group, athletes’ performance group, and race edition.

Methods:

Data from 398 male and 103 female participants of 5 editions were obtained based on a minimum 19.2-h effective-running cutoff. Mean running speed from each hour was normalized to the 24-h mean speed for analyses.

Results:

Mean overall performance was 135.6 ± 33.0 km with a mean effective-running time of 22.4 ± 1.3 h. Overall data showed a reverse J-shaped pacing strategy, with a significant reduction in speed from the second-to-last to the last hour. Two-way mixed ANOVAs showed significant interactions between racing time and both athlete performance group (F = 7.01, P < .001, ηp2 = .04) and race edition (F = 3.01, P < .001, ηp2 = .02) but not between racing time and either sex (F = 1.57, P = .058, ηp 2 < .01) or age group (F = 1.25, P = .053, ηp2 = .01). Pearson product–moment correlations showed an inverse moderate association between performance and normalized mean running speed in the first 2 h (r = –.58, P < .001) but not in the last 2 h (r = .03, P = .480).

Conclusions:

While the general behavior represents a rough reverse J-shaped pattern, the fastest runners start at lower relative intensities and display a more even pacing strategy than slower runners. The “herd behavior” seems to interfere with pacing strategy across editions, but not sex or age group of runners.
Community-Based Exercise Intervention for Gait and Functional Fitness Improvement in an Older Population: Study Protocol
Authors: Ramalho Fátima , Carnide Filomena , Santos-Rocha Rita , André Helô-Isa , Moniz-Pereira Vera , Machado Maria L. , Veloso António P.
Published: September 2016

Functional fitness (FF) and gait ability in older populations have been associated with increased survival rates, fall prevention, and quality of life. One possible intervention for the improvement of FF is well-structured exercise programs. However, there are inconsistent findings regarding the effects of exercise interventions in the maintenance of gait parameters. The aim of this protocol is to develop a community-based exercise intervention targeting an older population. The intervention aim is the improvement of gait parameters and FF. A control trial with follow-up will be performed. The primary outcome variables will be plantar pressure gait parameters. The secondary outcome variables will be aerobic endurance, lower limb strength, agility, and balance. These variables will be recorded at baseline and after 12, 24, and 36 weeks, in the intervention and control groups. If effective, this protocol can be used by exercise professionals in improving community exercise programs.
Time and Frequency Domain Analysis of Gait Initiation in Younger and Older Adults
Authors: Khanmohammadi Roya , Talebian Saeed , Hadian Mohammad Reza , Olyaei Gholamreza , Bagheri Hossein
Published: September 2016

The purpose of study was to demonstrate age-related changes during gait initiation (GI). Therefore, displacement, velocity, total power, mean and median frequency of COP trajectories were measured during phases of GI in anteroposterior (AP) and mediolateral (ML) directions. The older group demonstrated the slower and lesser displacement in comparison with the younger group during anticipatory phase in AP direction and during locomotor phase in AP and ML directions. In addition, the median and mean frequency were greater in the older relative to the younger group during anticipatory phase in AP direction, while these were lesser in older than younger group during locomotor phase in AP and ML directions. Moreover, total power was greater among older than younger adults during the anticipatory phase in ML direction and during all phases in AP direction. This study suggests that COP-related parameters extracted from time and frequency domains have the ability to demonstrate age-related changes.
Physical Activity Intervention Effects on Physical Function Among Community-Dwelling Older Adults: A Systematic Review and Meta-Analysis
Authors: Chase Jo-Ana D. , Phillips Lorraine J. , Brown Marybeth
Published: September 2016

The purpose of this systematic review and meta-analysis was to determine the effects of supervised resistance and/or aerobic training physical activity interventions on performance-based measures of physical functioning among community-dwelling older adults, and to identify factors impacting intervention effectiveness. Diverse search strategies were used to identify eligible studies. Standardized mean difference effect sizes (d, ES) were synthesized using a random effects model. Moderator analyses were conducted using subgroup analyses and meta-regression. Twenty-eight studies were included. Moderator analyses were limited by inconsistent reporting of sample and intervention characteristics. The overall mean ES was 0.45 (k = 38, p ≤ .01), representing a clinically meaningful reduction of 0.92 s in the Timed Up and Go for treatment versus control. More minutes per week (p < .01) and longer intervention session duration (p < .01) were associated with larger effects. Interventions were especially effective among frail participants (d = 1.09). Future research should clearly describe sample and intervention characteristics and incorporate frail populations.
Sedentary Behavior, Physical Activity, and Bone Health in Postmenopausal Women
Authors: Braun Saori I. , Kim Youngdeok , Jetton Amy E. , Kang Minsoo , Morgan Don W.
Published: September 2016

The purpose of this study was to determine if bone health at the femoral neck (FN) and lumbar spine (LS) can be predicted from objectively-measured sedentary behavior and physical activity data in postmenopausal women. Waist-mounted ActiGraph GT1M and GT3X devices were used to quantify levels of sedentary and moderate-to-vigorous intensity behavior during a 7-day period in 44 older females. Bone health (normal and osteopenia/osteoporosis) of FN and LS was derived from T scores generated using dual energy x-ray absorptiometry. Binomial logistic regression analysis indicated that sedentary time and number of breaks in sedentary behavior were significant predictors of osteopenia/osteoporosis at the FN, but not at the LS. Adherence to physical activity guidelines was not a significant predictor of bone health at the FN or LS. Our findings suggest that more frequent interruptions in sedentary behavior are associated with improved bone health in postmenopausal women.
Balance Control and Peripheral Muscle Function in Aging: A Comparison Between Individuals with Acromegaly and Healthy Subjects
Authors: Homem Telassin Silva , Guimarães Fernando Silva , Soares Maurício Santos , Kasuki Leandro , Gadelha Mônica Roberto , Lopes Agnaldo José
Published: September 2016

Advances in the knowledge of acromegaly are leading to an increase in the survival rate of acromegalic subjects. This study was conducted to evaluate balance control, risk of falls, and peripheral muscle function in acromegalic older adults. Seventeen older subjects with acromegaly (67 [63–73] years) and 20 paired control subjects were evaluated with balance scales, force platform, and knee isokinetic dynamometry tests. There were significant differences between the groups on several balance and gait scales, with a worse performance and greater risk of falls in the acromegalic older adults. Acromegalic older adults had lower values for peak torque, maximum repetition of the total work, and total work during extension at 240°/s. The acromegalic older adults had higher values in the medial-lateral range. Acromegaly subjects had lateral instability that compromises their body balance and increases the risk of falls. Moreover, there was a propensity for muscle fatigue in these individuals.
Increased Thermoregulatory Strain When Wearing an Upper Body Compression Garment During Moderate Exercise in Trained Older Adults
Authors: Leoz-Abaurrea Iker , Izquierdo Mikel , Gonzalez-Izal Miriam , Aguado-Jiménez Roberto
Published: September 2016

The efficacy of the use of an upper body compression garment (UBCG) as an ergogenic aid to reduce thermoregulatory strain in older adults remains unknown. The aim of this study was to evaluate the effects of UBCG on thermoregulatory, cardiorespiratory, and perceptual responses during cycling in a temperate environment (~25 °C, 66% rh) in trained older adults. Twelve cyclists aged 66 ± 2 years performed an intermittent 1-hr cycling trial at 50% of the peak power output followed by 10 min of passive recovery. Participants were provided with either commercially available UBCG or a control garment in a randomized order. UBCG increased thermoregulatory strain during exercise, as indicated by a significantly higher core temperature (38.1 ± 0.3 °C vs. 37.9 ± 0.3 °C; p = .04), body temperature (36.9 ± 0.2 °C vs. 36.7 ± 0.2 °C; p = .01), and thermal sensation (8.0 ± 0.4 vs. 7.5 ± 1.0; p = .02). These results suggest that the use of UBCG in trained older adults does not reduce the thermoregulatory strain during moderate exercise.
How Much Walking Should be Advocated for Good Health in Adolescent Girls?
Authors: MacDonald Mhairi , Fawkner Samantha G. , Niven Ailsa
Published: September 2016

Background:

It is currently not known how much walking should be advocated for good health in adolescent girls. The aim of this study was therefore to recommend health referenced standards for step defined physical activity relating to appropriate health criterion/indicators in a group of adolescent girls.

Method:

Two hundred and thirty adolescent girls aged between 12 to 15 years volunteered to take part in the study. Each participant undertook measurements (BMI, waist circumference, % body fat, and blood pressure) to define health status. Activity data were collected by pedometer and used to assess daily step counts and accumulated daily activity time over 7 consecutive days.

Results:

Individuals classified as ‘healthy’ did not take significantly more steps·day–1 nor spend more time in moderate intensity activity than individuals classified as at health risk or with poor health profiles.

Conclusion:

‘Healthy’ adolescent girls do not walk significantly more in term of steps·day–1 or time spent in activity than girls classified as ‘unhealthy.’ This could suggest that adolescent girls may not walk enough to stratify health and health related outcomes and as a result the data could not be used to inform an appropriate step guideline for this population.
Associations of Perceived and Objectively Measured Neighborhood Environmental Attributes With Leisure-Time Sitting for Transport
Authors: Liao Yung , Sugiyama Takemi , Shibata Ai , Ishii Kaori , Inoue Shigeru , Koohsari Mohammad Javad , Owen Neville , Oka Koichiro
Published: September 2016

Background:

This study examined associations of perceived and objectively measured neighborhood environmental attributes with leisure-time sitting for transport among middle-to-older aged Japanese adults.

Method:

Data were collected using a postal survey of 998 adults aged 40 to 69 years. Generalized linear modeling with a gamma distribution and a log link was used to examine associations of perceived (International Physical Activity Questionnaire-Environmental module) and Geographic Information Systems (GIS)-derived built environment attributes with self-reported leisure-time sitting for transport.

Results:

Mean leisure-time sitting time for transport was 20.4 min/day. After adjusting for potential confounders, perceived higher residential density, GIS-measured higher population density, better access to destinations, better access to public transport, longer sidewalk length, and higher street connectivity, were associated significantly with lower sitting time for transport.

Conclusion:

Residents living in neighborhoods with attributes previously found to be associated with more walking tended to spend less time sitting for transport during leisure-time. The health benefits of walkability-related attributes may accrue not only through increased physical activity, but also through less sedentary time.
Incident Type 2 Diabetes in a Large Australian Cohort Study: Does Physical Activity or Sitting Time Alter the Risk Associated With Body Mass Index?
Authors: Nguyen Binh , Bauman Adrian , Ding Ding
Published: September 2016

Purpose:

To examine the combined effects of body mass index (BMI), physical activity (PA) and sitting on incident type 2 diabetes mellitus (T2DM) among Australian adults.

Methods:

A sample of 29,572 adults aged ≥45 years from New South Wales, Australia, completed baseline (2006–2008) and follow-up (2010) questionnaires. Incident T2DM was defined as self-reported, physician-diagnosed diabetes at follow-up. BMI was categorized as normal/overweight/obese. PA was tertiled into low/medium/ high. Sitting was dichotomized as higher/lower sitting (≥ 8 hours/day or < 8 hours/day). Odds ratios (OR) were estimated for developing T2DM using logistics regression for individual and combined risk factors, and data stratified by BMI categories.

Results:

During a mean 2.7 (SD: 0.9) years of follow-up, 611 (2.1%) participants developed T2DM. In fully adjusted models, BMI was the only independent risk factor for incident T2DM. In stratified analyses, the association between BMI and T2DM did not differ significantly across sitting or PA categories. Overweight/obese individuals with high PA and lower sitting had higher odds of incident T2DM than normal counterparts with low PA and higher sitting.

Conclusions:

High PA/low sitting did not attenuate the risk of T2DM associated with overweight/obesity. Maintaining a healthy weight, by adopting healthy lifestyle behaviors, is critical for T2DM prevention.
Achilles Tendon Adaptation During Transition to a Minimalist Running Style
Authors: Joseph Michael F. , Histen Katherine , Arntsen Julia , L’Hereux Lauren , Defeo Carmine , Lockwood Derek , Scheer Todd , Denegar Craig R.
Published: September 2016

Context:

Achilles tendons (ATs) adapt to increased loading generated by long-term adoption of a minimalist shoe running style. There may be difference in the chronology and extent of adaptation between the sexes.

Objective:

To learn the chronology of AT adaptations in female and male runners who transitioned to a minimalist running style through a planned, progressive 12-wk transition program.

Design:

Prospective cohort study of well-trained, traditionally shod runners who transitioned to minimalist shoe running.

Setting:

Repeated laboratory assessment at baseline and 3, 12, and 24 wk after initiating transition program.

Participants:

Fifteen women and 7 men (of 29 enrolled) completed the study.

Main Outcome Measures:

The authors used diagnostic ultrasound and isokinetic dynamometry to generate a force elongation curve and its derivatives at each time point.

Results:

Greater adaptations were observed in men than in women, with men generating more force and having greater increases in CSA, stiffness, and Young’s modulus and less elongation after 12 wk of training.

Conclusion:

Men demonstrated changes in AT properties that were consistent with increased loading of the triceps surae during exercise. The women demonstrated far smaller changes. Further investigation is warranted to understand when adaptations may occur in women and the implications of altered AT mechanical properties for performance and injury risk.
Old Story with a New Twist: Applying Decision Theory to Advance Understanding of the Negative Socialization Cycle of Physical Education Teachers
Authors: Wyant James D. , Wyant Kristi N.
Published: September 2016

In recent years, the physical education (PE) profession has been forced to confront a plethora of issues, from the demise of teacher education programs to the loss of programming in the K–12 context. Calls for change and a time of introspection have been prompted by this climate. The impetus for change has long been a staple of PE discourse. Occupational socialization theory, which describes the forces that shape the decisions and behaviors of physical education teachers, offers insight on the change narrative. Emerging from the results of occupational socialization research are myriad negative issues that highlight a perplexing problem—some PE teachers have the propensity to make irrational decisions. The purpose of this article is to apply decision theory as a means to critically examine issues that have emerged from the negative socialization cycle of PE teachers. Beyond connecting theories, suggestions will be provided to improve the decision-making of PE professionals.
Activity Profiles and the Associations With Weight Status in Population Studies of Young Children: Are There Gender Differences?
Authors: O’Neill Aoife , Dowd Kieran , O’Gorman Clodagh , Hannigan Ailish , Walsh Cathal , Purtill Helen
Published: September 2016

Purpose:

Profiling activity behaviors in young children is important to understand changes in weight status over time. The purpose of this study is to identify activity profiles from self- and parental-reported Physical Activity (PA) and Sedentary Behavior (SB) variables by gender, and determine if the identified profiles are predictive of weight change from age 9–13 years.

Methods:

Cluster analysis was used to generate activity profiles for the National Longitudinal Study of 8570 9-year-old children (Growing Up in Ireland).

Results:

5.4% of boys were found to be obese. Four cohesive activity profiles were identified for boys, with 7.3% of boys in the least active group identified as obese compared with 4.1% in the most active group. The odds of a normal weight 9-year-old boy in the least active profile becoming overweight or obese at age 13 were over twice those in most active profile (OR = 2.5, 95% CI: 1.9, 3.5). No coherent activity profiles were identified for girls.

Conclusions:

This study suggests that self- and parental-reported data can identify meaningful activity profiles for boys, which are predictive of weight changes over time. Future research should consider potential gender differences in self- and parental-reported PA and SB variables.
Contrast Loading Increases Upper Body Power Output in Junior Volleyball Athletes
Authors: Smilios Ilias , Sotiropoulos Konstantinos , Barzouka Karolina , Christou Marios , Tokmakidis Savvas P.
Published: September 2016

Purpose:

This study examined the acute effects of contrast loading on mechanical power output during bench-press throws in junior volleyball players.

Method:

Eleven males (age: 16.5 ± 0.5 years) performed a contrast loading and a control protocol. The contrast protocol included the execution of 3 bench-throws with a 30% load of 1RM, after 3 min a conditioning set of 5 bench-throws with a 60% load of 1RM and after 3 and 5 min two more sets of 3 bench-throws with a 30% load of 1RM. The control protocol included the execution of 3 sets of 3 bench-throws with a 30% load of 1RM at the same time points as in the contrast protocol without the execution of the conditioning set.

Results:

Mechanical power with a 30% load was higher (p < .05) 3 and 5 min following the conditioning set at the contrast protocol compared with the control protocol (8.7 ± 7.5 and 10.4 ± 3.4%, respectively). High correlations (p < .05) were obtained between participant’s relative maximal strength (r = .87) and power (r = .82) and the increases in power output.

Conclusion:

Contrast loading increases upper body power output produced with a light load by junior athletes. The potential for increased upper body performance is more evident in stronger or more powerful individuals.
A Review of Childhood Physical Activity, Brain, and Cognition: Perspectives on the Future
Authors: Hillman Charles H. , Biggan John R.
Published: September 2016

This manuscript, which arose from the inaugural Tom Rowland Lecture Series at the 2016 North American Society for Pediatric Exercise Medicine conference, provides a brief descriptive review of what is known (i.e., the state of the science) regarding the relation of childhood physical activity (PA) and cardiorespiratory fitness (CRF) to brain health, cognition, and academic outcomes. Gaps in the knowledgebase are identified, including characteristics of the PA stimulus that promotes changes in brain and cognition, whether critical periods in development exist in which PA/CRF may have a disproportionately large influence, the understanding of individual difference factors, and the influence upon learning. Lastly, several possible directions for future research are proposed. Although the field of childhood PA, CRF, brain, and cognition is rapidly expanding, there is considerable room for future growth. This manuscript may be helpful in shaping that future growth, with the goal of improving lifelong health and effective functioning.
Skateboarding in Dude Space: The Roles of Space and Sport in Constructing Gender Among Adult Skateboarders
Authors: Carr John N.
Published: September 2016

This study aims to address how, to what extent, and under what conditions may those who are not cisgendered as male do the work of negotiating access to male sporting space. In doing so, it brings together critical geographies of masculinity and the critical literature on skateboarding to address the role of particular kinds of skateboarding spaces in either reproducing or potentially disrupting gender segregated, patriarchal skateboarding cultures. This project is offered not only to challenge patriarchal practices and values, but also to step beyond theory and actually examine how sport environments might be designed and sited so as to enable a wider range of gender performances and more inclusive spaces. Specifically, my research suggests that certain types of skate environments can somewhat lower women’s barriers to entering the gender charged realm of skateboarding if and when those responsible for those spaces take patriarchy and the needs of noncisgendered male skateboarders seriously.

Cette étude a pour but de savoir comment, dans quelle mesure et dans quelles conditions, les personnes n’étant pas des hommes cisgenres négocient leur accès dans l’univers sportif masculin. Pour ce faire, elle réunit les géographies critiques de la masculinité et la littérature critique sur le skateboard pour examiner le rôle de certains univers particuliers de cette pratique dans la reproduction, ou dans l’éventuelle rupture avec la ségrégation genrée, des cultures patriarcales du skateboard. Le but de ce projet n’est pas seulement de contester les pratiques et les valeurs patriarcales, mais aussi de dépasser la théorie et d’examiner vraiment comment les environnements sportifs pourrait être conçus et localisés de manière à permettre une plus grande variété de performances en fonction du genre et de devenir des espaces plus inclusifs. Plus spécifiquement, ma recherche suggère que certains types d’environnements dédiés à la glisse pourraient contribuer à réduire les barrières que rencontrent les femmes pour entrer dans la sphère fortement genrée du skateboard si et quand les responsables de ces espaces prendront sérieusement en compte le patriarcat et les besoins des skatebordeurs qui ne sont pas cisgenres.
Liver transplantation for acute liver failure accompanied by severe acute pancreatitis
Authors: Kirino Izumi , Fujimoto Yasuhiro , Hata Koichiro , Uemoto Shinji
Published: September 2016

The role of liver transplantation (LT) in acute liver failure (ALF) complicated by severe acute pancreatitis is still unclear. We here report a case of deceased-donor LT for idiopathic ALF accompanied by severe acute pancreatitis. A 58-year-old man with no history of liver disease presented with idiopathic ALF and acute pancreatitis. After careful consideration, he received a liver from a deceased donor. Following surgery, the patient's liver function rapidly reverted to normal level and the acute pancreatitis simultaneously subsided. The patient later developed a pancreatic pseudocyst, which was treated successfully with combination interventional radiology. LT can be considered for ALF associated with severe acute pancreatitis if there is no clinical evidence of an absolute contraindication for organ transplantation, such as systemic or local infection. Moreover, we recommend a close follow-up by ultrasonography to allow early detection and treatment of pancreatic pseudocysts following surgery.
Anisakidosis: a fortuitous mimicker of gastrointestinal malignancy
Authors: Khan Mohammad Qasim , Williams Jonathan
Published: September 2016

A 51-year-old woman presented with epigastric pain, vomiting and diarrhoea. Her sister was recently diagnosed with duodenal adenocarcinoma, manifesting similar symptoms. Imaging revealed thickened gastric antrum with enlarged local lymph nodes. Endoscopy illustrated 3 worms embedded in the antral wall, identified asAnisakis simplexlarvae. Larvae removal and a 2-week albendazole regimen treated the symptoms. With globalisation of cultural culinary practices, physicians must be vigilant of anisakidosis. Its ability to mimic peptic ulcer disease, chronic gastritis and malignancy necessitates broader differential diagnoses and lower thresholds for endoscopy.
Traumatic injuries and persistent opioid use in the USA: findings from a nationally representative survey
Authors: Alghnam Suliman , Castillo Renan
Published: September 2016

Background

Although opioid abuse is a rising epidemic in the USA, there are no studies to date on the incidence of persistent opioid use following injuries. Therefore, the aims of this study are: (1) to examine the incidence of persistent opioid use among a nationally representative sample of injured and non-injured populations; (2) to evaluate whether an injury is an independent predictor of persistent opioid use.

Method

Data from the Medical Expenditure Panel Survey were pooled (years 2009–2012). Adults were followed for about 2 years, during which they were surveyed about injury status and opioid use every 4–5 months. To determine whether injuries are associated with persistent opioid use, weighted multiple logistic regressions were constructed.

Results

While 2.3 million injured individuals received any opioid during the follow-up, 371 170 (15.6%) individuals became persistent opioid users (defined as opioid use across multiple time points). In a multiple logistic regression analysis adjusting for sociodemographic characteristics and self-reported health, those who sustained injuries were 1.4 times (95% CI 1.1 to 1.9) more likely to report persistent opioid use than those without injuries.

Conclusions

We found injuries to be significantly associated with persistent opioid use in a nationally representative sample. Further investment in injury prevention may facilitate reduction of persistent opioid use and, thus, improve population health and reduce health expenditures.
Pediatric neurointervention: collimation on radiation exposure-associated lifetime excess tumor risk
Authors: Chen Karen , Paramasivam Srinivasan , Berenstein Alejandro
Published: September 2016

Background

Intracranial vascular malformations in children are being addressed through a variety of treatment modalities including open surgery, external beam radiation, and image-guided neuroendovascular procedures. These patients often receive multiple treatments and incur serial exposures to ionizing radiation which has been linked to tumor development in population-based data.

Objective

This study quantifies the effect of collimation on exposures from single procedures and over patient lifetimes to estimate excess risk of lifetime tumor development.

Methods

215 patients aged 0–21 years from a single center took part in the study. Radiation exposure from neuroendovascular procedures was tabulated and converted to brain doses using modeled data and extrapolated to risk ratios using results of population-based estimates found in the literature.

Results

Lifetime and per procedure risk was highest in patients with brain arteriovenous malformations, brain arteriovenous fistulas, and vein of Galen malformations, a reflection of our institutional referral patterns. Across all pathologies the per procedure excess relative risk decreased from 13.4 to 2.3 when full collimation was employed. Lifetime excess relative risk decreased from 49.0 to 7.7 for full collimation.

Conclusions

This is the first study to quantify the effect of collimation on lifetime and per procedure risk of tumor development in a pediatric population. In addition to collimation, technical and operator-based aspects of the neurointerventional suite are discussed to further reduce patient exposure without sacrificing image quality.
Model uncertainty in uplift resistance calculations for sandy backfills
Authors: Stuyts Bruno , Cathie David , Powell Toby
Published: September 2016

Trenching and backfilling is one of the most practical and cost-effective methods for protection and stabilization of offshore pipelines. Defining the geotechnical properties of backfill material resulting from mechanical backfilling or jet trenching is an area of substantial uncertainty and the resistance against pipeline uplift provided by these backfills needs to be characterized accounting for these uncertainties. This paper compares the properties of sandy backfill material and the available calculation models for uplift resistance against a database of more than 300 controlled pipeline uplift tests. The model uncertainty for uplift resistance calculations is derived from a back-analysis of the uplift tests. The uncertainties on uplift resistance and mobilization distance are correlated and characterized using a joint probability distribution. The selected distributions are applied to an example uplift resistance problem. When compared against this probabilistic formulation, the factors applied to uplift resistance in pipeline analysis can be refined to lead to a more cost-effective solution.
Spatial and temporal dynamics of the soil charcoal pool in relation to fire history in a boreal forest landscape
Authors: Kasin Isabella , Ellingsen Vanessa Marie , Asplund Johan , Ohlson Mikael
Published: September 2016

Charcoal pools in boreal forest soils constitute considerable amounts of slow cycling organic matter that is important in the global carbon cycle. However, these pools are characterized by spatiotemporal variations that are not well understood. Here, we have analyzed the charcoal pool in 100 soil samples to determine charcoal stock species origin and how the size and age of this pool varies across different spatial scales in a Norwegian boreal forest landscape including forests that differ in terms of tree-species composition, tree density, and recent fire histories. The size of the charcoal pool was site-specific and highly variable, ranging from 0 to 2108 g·m–2. Geostatistical analyses showed that the charcoal pool was only weakly spatially structured at fine spatial scales (metres) and broader between-site scales (100s of metres). Unexpectedly, there was no significant relationship between the amount of charcoal and contemporary forest composition and density, although there was proportionally more charcoal from broadleaved trees in today’s Scots pine forests than in the Norway spruce forests. When relating this information to the fire history, the results indicate that charcoal is lost at a millennial time scale.
Fluctuation sound absorption in quark matter
Authors: Kerbikov B. O. , Lukashov M. S.
Published: September 2016

We investigate the sound absorption in quark matter due to the interaction of the sound wave with the precritical fluctuations of the diquark-pair field above [Formula: see text]. The soft collective mode of the pair field is derived using the time-dependent Ginzburg–Landau functional with random Langevin forces. The strong absorption near the phase transition line may be viewed as a manifestation of Mandelshtam–Leontovich slow relaxation time theory.
PRICING COVARIANCE SWAPS FOR BARNDORFF–NIELSEN AND SHEPHARD PROCESS DRIVEN FINANCIAL MARKETS
Authors: HABTEMICAEL SEMERE , SENGUPTA INDRANIL
Published: September 2016

The objective of this paper is to study the arbitrage free pricing of the covariance swap for Barndorff–Nielsen and Shephard (BN–S) type Lévy process driven financial markets. One of the major challenges in arbitrage free pricing of swap is to obtain an accurate pricing expression which can be used with good computational accuracy. In this paper, we obtain analytic expressions for the pricing of the covariance swap. We show that with the analytic expressions obtained from the BN–S model, the error estimation in fitting the delivery price is much less than the existing models with comparable parameters. The models and pricing formulas proposed in this paper are computable in real time and hence can be efficiently used in practical applications.
ENDOGENIZING CONSUMPTION DECISION IN THE FRENKEL–JOVANOVIC STOCHASTIC MODEL OF MONEY HOLDING
Authors: AHALYA R. , RAMANATHAN R.
Published: September 2016

It is shown that the stochastic model of transaction and precautionary demand for money developed by Frenkel and Jovanovic can be made general even within the purview of their restricted treatment of the problem of estimation of optimal money holdings. While all the predecessor models on optimal money holdings assume the consumption decision to be an exogenous factor outside the realm of the model, the present treatment endogenizes the consumption decision by including an additional decision-dependent parameter in the very structure of the generalized model. In our model, it has been found that contrary to the Baumol–Tobin and Frenkel–Jovanovic models, the interest elasticity is positive when the consumption decisions are endogenous.