bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased Hemoglobin Mass and VO2max With 10 h Nightly Simulated Altitude at 3000 m
Authors: Neya Mitsuo , Enoki Taisuke , Ohiwa Nao , Kawahara Takashi , Gore Christopher J. 
Published: August 2016

Purpose:To quantify the changes of hemoglobin mass (Hbmass) and maximum oxygen consumption (VO2max) after 22 days training at 1300–1800 m combined with nightly exposure to 3000-m simulated altitude. We hypothesized that with simulated 3000-m altitude, an adequate beneficial dose could be as little as 10 h/24 h.Methods:Fourteen male collegiate runners were equally divided into 2 groups: altitude (ALT) and control (CON). Both groups spent 22 days at 1300–1800 m. ALT spent 10 h/night for 21 nights in simulated altitude (3000 m), and CON stayed at 1300 m. VO2max and Hbmass were measured twice before and once after the intervention. Blood was collected for assessment of percent reticulocytes (%retics), serum erythropoietin (EPO), ferritin, and soluble transferrin receptor (sTfR) concentrations.Results:Compared with CON there was an almost certain increase in absolute VO2max (8.6%, 90% confidence interval 4.8–12.6%) and a likely increase in absolute Hbmass (3.5%; 0.9–6.2%) at postintervention. The %retics were at least very likely higher in ALT than in CON throughout the 21 nights, and sTfR was also very likely higher in the ALT group until day 17. EPO of ALT was likely higher than that of CON on days 1 and 5 at altitude, whereas serum ferritin was likely lower in ALT than CON for most of the intervention.Conclusions:Together the combination of the natural and simulated altitude was a sufficient total dose of hypoxia to increase both Hbmass and VO2max.
Planned Intensity Reduction to Maintain Repetitions Within Recommended Hypertrophy Range
Authors: Medeiros Helio S. , Mello Rafael S. , Amorim Mayara Z. , Koch Alexander J. , Machado Marco 
Published: August 2016

Purpose:The authors tested different loading schemes for the number of repetitions completed during multiple sets of resistance exercise.Methods:Twenty-four resistance-trained men (age 24.0 ± 4.5 y, body mass 78.3 ± 10.2 kg, height 177 ± 7 cm) were tested over a 5-wk period. During week 1 a 10-repetition maximum (10RM) in the leg press was determined. During weeks 2–5 subjects completed 4 bouts of leg presses, in a randomized fashion, consisting of 4 sets with 60 s of interset rest. Set 1 of each bout was performed with 10RM, with differing intensity for sets 2–4 as follows: (1) 10RM load for all sets (CON), (2) 5% load reduction after each set (RED 5), (3) 10% load reduction after each set (RED 10), and (4) 15% load reduction after each set (RED 15).Results:Significant (P < .05) decreases in repetitions completed across sets were observed in CON (sets 2, 3, and 4) and RED 5 (sets 3 and 4). Significant increases in repetitions completed across sets (2, 3, and 4) were observed in RED 10 and RED 15 (P < .05). RED 5 (8.3 ± 0.9 repetitions) and RED 10 (12.0 ± 1.1 repetitions) allowed subjects to maintain the majority (>60%) of sets in the range of 8–12 repetitions, whereas both CON and RED 15 resulted in <50% of sets in the range of 8–12 repetitions, with the majority of sets performed <8 repetitions for CON and >12 repetitions for RED 15.Conclusion:Reducing load 5–10% in each set should allow maintenance of 8–12RM loads for most sets of resistance exercise.
Physiological and Performance Responses to a Preseason Altitude-Training Camp in Elite Team-Sport Athletes
Authors: McLean Blake D. , Buttifant David , Gore Christopher J. , White Kevin , Liess Carsten , Kemp Justin 
Published: August 2016

Purpose:Little research has been done on the physiological and performance effects of altitude training on team-sport athletes. Therefore, this study examined changes in 2000-m time-trial running performance (TT), hemoglobin mass (Hbmass), and intramuscular carnosine content of elite Australian Football (AF) players after a preseason altitude camp.Methods:Thirty elite AF players completed 19 days of living and training at either moderate altitude (~2130 m; ALT, n = 21) or sea level (CON, n = 9). TT performance and Hbmass were assessed preintervention (PRE) and postintervention (POST1) in both groups and at 4 wk after returning to sea level (POST2) in ALT only.Results:Improvement in TT performance after altitude was likely 1.5% (± 4.8–90%CL) greater in ALT than in CON, with an individual responsiveness of 0.8%. Improvements in TT were maintained at POST2 in ALT. Hbmass after altitude was very likely increased in ALT compared with CON (2.8% ± 3.5%), with an individual responsiveness of 1.3%. Hbmass returned to baseline at POST2. Intramuscular carnosine did not change in either gastrocnemius or soleus from PRE to POST1.Conclusions:A preseason altitude camp improved TT performance and Hbmass in elite AF players to a magnitude similar to that demonstrated by elite endurance athletes undertaking altitude training. The individual responsiveness of both TT and Hbmass was approximately half the group mean effect, indicating that most players gained benefit. The maintenance of running performance for 4 wk, despite Hbmass returning to baseline, suggests that altitude training is a valuable preparation for AF players leading into the competitive season.
The Effect of Overnight Sleep Deprivation After Competitive Rugby League Matches on Postmatch Physiological and Perceptual Recovery
Authors: Skein Melissa , Duffield Rob , Minett Geoffrey M. , Snape Alanna , Murphy Alistair 
Published: August 2016

Purpose:This study examined the effects of overnight sleep deprivation on recovery after competitive rugby league matches.Methods:Eleven male amateur rugby league players played 2 competitive matches, followed by either a normal night’s sleep (~8 h; CONT) or a sleep-deprived night (~0 h; SDEP) in a randomized fashion. Testing was conducted the morning of the match, immediately postmatch, 2 h postmatch, and the next morning (16 h postmatch). Measures included countermovement-jump (CMJ) distance, knee-extensor maximal voluntary contraction (MVC) and voluntary activation (VA), venous-blood creatine kinase (CK) and C-reactive protein (CRP), perceived muscle soreness, and a word–color recognition cognitive-function test. Percent change between postmatch and 16-h postmatch was reported to determine the effect of the intervention the next morning.Results:Large effects indicated a greater postmatch to 16-h-postmatch percentage decline in CMJ distance after SDEP than in CONT (P = .10–.16, d = 0.95–1.05). Similarly, the percentage decline in incongruent word–color reaction times was increased in SDEP trials (P = .007, d = 1.75). Measures of MVC did not differ between conditions (P = .40–.75, d = 0.13–0.33), although trends for larger percentage decline in VA were detected in SDEP (P = .19, d = 0.84). Furthermore, large effects indicated higher CK and CRP responses 16 h postmatch in SDEP than in CONT (P = .11–.87, d = 0.80–0.88).Conclusions:Sleep deprivation negatively affected recovery after a rugby league match, specifically impairing CMJ distance and cognitive function. Practitioners should promote adequate postmatch sleep patterns or adjust training demands the next day to accommodate the altered physical and cognitive state after sleep deprivation.
Natural Bodybuilding Competition Preparation and Recovery: A 12-Month Case Study
Authors: Rossow Lindy M. , Fukuda David H. , Fahs Christopher A. , Loenneke Jeremy P. , Stout Jeffrey R. 
Published: August 2016

Bodybuilding is a sport in which competitors are judged on muscular appearance. This case study tracked a drug-free male bodybuilder (age 26–27 y) for the 6 mo before and after a competition.Purpose:The aim of this study was to provide the most comprehensive physiological profile of bodybuilding competition preparation and recovery ever compiled.Methods:Cardiovascular parameters, body composition, strength, aerobic capacity, critical power, mood state, resting energy expenditure, and hormonal and other blood parameters were evaluated.Results:Heart rate decreased from 53 to 27 beats/min during preparation and increased to 46 beats/min within 1 mo after competition. Brachial blood pressure dropped from 132/69 to 104/56 mmHg during preparation and returned to 116/64 mmHg at 6 mo after competition. Percent body fat declined from 14.8% to 4.5% during preparation and returned to 14.6% during recovery. Strength decreased during preparation and did not fully recover during 6 months of recovery. Testosterone declined from 9.22 to 2.27 ng/mL during preparation and returned back to the baseline level, 9.91 ng/mL, after competition. Total mood disturbance increased from 6 to 43 units during preparation and recovered to 4 units 6 mo after competition.Conclusions:This case study provides a thorough documentation of the physiological changes that occurred during natural bodybuilding competition and recovery.
Activity Profiles and Demands of Seasonal and Tournament Basketball Competition
Authors: Klusemann Markus J. , Pyne David B. , Hopkins Will G. , Drinkwater Eric J. 
Published: August 2016

Competition-specific conditioning for tournament basketball games is challenging, as the demands of tournament formats are not well characterized.Purpose:To compare the physical, physiological, and tactical demands of seasonal and tournament basketball competition and determine the pattern of changes within an international tournament.Methods:Eight elite junior male basketball players (age 17.8 ± 0.2 y, height 1.93 ± 0.07 m, mass 85 ± 3 kg; mean ± SD) were monitored in 6 seasonal games played over 4 mo in an Australian second-division national league and in 7 games of an international under-18 tournament played over 8 days. Movement patterns and tactical elements were coded from video and heart rates recorded by telemetry.Results:The frequency of running, sprinting, and shuffling movements in seasonal games was higher than in tournament games by 8–15% (99% confidence limits ± ~8%). Within the tournament, jogging and low- to medium-intensity shuffling decreased by 15–20% (± ~14%) over the 7 games, while running, sprinting, and high-intensity shuffling increased 11–81% (± ~25%). There were unclear differences in mean and peak heart rates. The total number of possessions was higher in seasonal than in tournament games by 8% (± 10%).Conclusions:Coaches should consider a stronger emphasis on strength and power training in their conditioning programs to account for the higher activity of seasonal games. For tournament competition, strategies that build a sufficient aerobic capacity and neuromuscular resilience to maintain high-intensity movements need to be employed. A focus on half-court tactics accounts for the lower number of possessions in tournaments.
Adherence Within and Between Lifestyle Physical Activity Groups in Project PRIME
Authors: Heesch Kristiann , Mâsse Louise C. , Frankowski Ralph F. , Dunn Andrea L. 
Published: August 2016

Background:Interventions that teach strategies for integrating physical activity into a person’s daily routine are becoming more common. These interventions have been found to increase physical activity behavior, although the increases have not been large. The small to moderate changes in physical activity can result from participants having insufficient adherence to the intervention protocol to produce an intervention effect. Given that adherence is likely to affect the power to find a treatment effect, it should be tracked. This study examined changes in adherence over 6 months for a lifestyle physical activity intervention.Methods:Participants were 244 sedentary adults who took part in the Project PRIME lifestyle physical activity intervention. Adherence was assessed separately for a group-based intervention (PRIME G) and a telephone- and mail-based intervention (PRIME C). Markers of adherence were completion of homework, self-monitoring of physical activity, attendance at class (PRIME G only), and completion of monthly telephone calls (PRIME C only). Changes over time in adherence markers and differences between intervention groups for homework completion and adherence to self-monitoring were modeled with generalized estimating equations (GEE).Results:The probability of attending class, completing the telephone calls, and completing the homework decreased significantly over 6 months. Participants only self-monitored an average of 5 to 6 days each calendar month. Participants in the group-based intervention were more likely than those in the telephone- and mail-delivered intervention to complete the homework throughout the study.Conclusions:The findings suggest that individuals are willing to adhere with a telephone call protocol over 6 months. They are less willing to complete homework and attend class over this same time period. Most are not willing to self-monitor their lifestyle physical activities more than a few days a month.
Leisure-Time Physical Activity Levels Among Canadian Adolescents, 1981–1998
Authors: Eisenmann Joey C. , Katzmarzyk P.T. , Tremblay Mark S. 
Published: August 2016

Background:In recent years, it has been noted that children and youth are physically inactive, and physical activity levels have declined over the past decades. However, few empirical studies have been conducted to test this assumption. Therefore, the purpose of this study was to examine leisure-time physical activity levels among Canadian adolescents 12–19 years of age.Methods:Age, sex, geographic, and temporal trends in leisure-time physical activity energy expenditure (AEE) were examined using data from 5 national surveys conducted between 1981 and 1998. AEE was calculated from participants’ questionnaire responses on physical activity participation. General linear models were used to examine the differences in AEE across survey years, geographic regions, sexes, and age groups.Results:Males and 12–14-year-olds displayed greater AEE than females and 15–19-year-olds, respectively, and AEE was lowest in Quebec and highest in the West. AEE increased between the 1981 and 1988 surveys and has since remained relatively stable. The prevalence of subjects meeting the 12.6 kJ · kg−1 · d−1 (3 kcal · kg−1 · d−1) recommendation increased from 1981 to 1988. Since 1988, the prevalence of those meeting the 12.6 kJ · kg−1 · d−1 recommendation has decreased in 12–14 year old boys and remained relatively stable in the other groups. In 1998, about 45% of males and 35% of females met the 12.6 kJ · kg−1 · d−1 recommendation. In 1998, about 20% of 12–19-year-old males and 12–14-year-old females met the 25.1 kJ · kg−1 · d−1 (6 kcal · kg−1 · d−1) recommendation, while about 10% of 15–19-year-old females met this recommendation. In females, the prevalence of those meeting the 25.1 kJ · kg−1 · d−1 recommendation has remained relatively stable (about 10%) since 1981 except for an increase between 1996 and 1998 in 12–14-year-old girls. In males, a similar pattern, but not as dramatic, of that observed for the prevalence of those meeting the 12.6 kJ · kg−1 · d−1 emerged—that is, an increase between 1981 and 1988 and then a decrease in 12–14-year-old boys and a stable pattern in 15–19-year-old boys.Conclusion:Although self-reported leisure-time physical activity appears to have increased since 1981, a majority of Canadian adolescents do not meet current recommendations for physical activity.
The Independent Influence of Physical Inactivity and Obesity on Health Complaints in 6th to 10th Grade Canadian Youth
Authors: Janssen Ian , Katzmarzyk Peter T. , Boyce William F. , Pickett William 
Published: August 2016

Background:The purpose of this study was to examine the independent influence of physical inactivity and obesity on health complaints in school-aged youth.Methods:The findings are based on Canadian records from the 2001-2002 Health Behaviour in School-Aged Children Survey. The study cohort consisted of 5673 youth in grades 6 to 10. Body weight and height (used to calculate body mass index and adiposity level), physical activity, and somatic (physical) and psychological health complaints were measured by questionnaire. General linear models were used to characterize the associations between physical activity and adiposity with somatic and psychological health complaints.Results:In boys and girls, adiposity level alone was independently associated with somatic health complaints, whereas both physical activity level and adiposity level were independently associated with psychological health complaints.Conclusion:The findings suggest that the prevention and treatment of both physical inactivity and obesity are important in school-aged youth.
Reliability and Validity of the VmaxST Portable Metabolic Analyzer
Authors: Perkins Candace D. , Pivarnik James M. , Green Matthew R. 
Published: August 2016

Background:The reliability and validity of the SensorMedics VmaxST was tested.Methods:Thirty subjects (age = 24.5 ± 4.0 years, height = 174.8 ± 9.8 cm, weight = 70.3 ± 12.6 kg) performed treadmill exercise on three occasions, twice using the VmaxST and once using the SensorMedics 2900 system. Oxygen consumption (VO2; L/min) and heart rate (HR; beats/min) were measured continuously during three, 6- minute stages: 80 m/min, 0% grade; 94 m/min, 5% grade; and 160 m/min, 0% grade, and VO2max.Results:Reliability was high, and measurement error was low for VO2 (Rxx range = 0.97 - 0.99, CI = 0.94 - 1.00, SEM = 0.03 - 0.08 L/min) and HR (Rxx = 0.94 - 0.99, CI = 0.88 - 1.00, SEM = 1.8 - 3.2 beats/min). Validity was high for VO2 (Rxy range = 0.92 - 0.98, CI = 0.84 - 0.99, SEE = 0.08 - 0.21 L/min) and HR (Rxy = 0.97 - 0.99, CI = 0.94 - 1.00, SEE = 0.9 - 1.8 beats/min). Mean differences in VO2 between VmaxST and 2900 were small yet significant (P < 0.001).Conclusions:The VmaxST demonstrated excellent reliability and validity for measuring VO2 and HR over several exercise intensities. Small overestimates in VO2 by the VmaxST are countered by low measurement error.
Sedentary Behaviors and Obesity in a Low-Income, Ethnic-Minority Population
Authors: Shuval Kerem , Leonard Tammy , Murdoch James , Caughy Margaret O. , Kohl Harold W. , Skinner Celette Sugg 
Published: August 2016

Background:Numerous studies have documented adverse health effects from prolonged sitting and TV viewing. These sedentary pastimes are linked to increased risk for obesity and other cardiometabolic risk factors. No studies, however, have examined these associations specifically in low-income, minority communities in the US.Methods:This cross-sectional, community-based study was conducted in South Dallas, TX. Multivariable ordered logistic regression models were used to examine the association between sedentary behaviors (self-report) and measures of objectively assessed obesity (BMI, waist circumference).Results:Among a low-income, ethnic-minority population, there were independent and significant associations between higher levels of sitting time, computer use, and transit time with elevated BMI (P < .05). Elevated waist circumference was also linked to increased sitting time, computer use, and transit time, yet without statistical significance.Conclusions:Increased time spent in passive-leisure activities is a risk marker for obesity in this population.
Selling New Neighborhoods as Good for Walking: Issues for Measuring Self-Selection
Authors: Nathan Andrea , Wood Lisa , Giles-Corti Billie 
Published: August 2016

Background:Self-selection—whether individuals inclined to walk more seek to live in walkable environments—must be accounted for when studying built environment influences on walking. The way neighborhoods are marketed to future residents has the potential to sway residential location choice, and may consequently affect measures of self-selection related to location preferences. We assessed how walking opportunities are promoted to potential buyers, by examining walkability attributes in marketing materials for housing developments.Methods:A content analysis of marketing materials for 32 new housing developments in Perth, Australia was undertaken, to assess how walking was promoted in the text and pictures. Housing developments designed to be pedestrian-friendly (LDs) were compared with conventional developments (CDs).Results:Compared with CDs, LD marketing materials had significantly more references to ‘public transport,’ ‘small home sites,’ ‘walkable parks/open space,’ ‘ease of cycling,’ ‘safe environment,’ and ‘boardwalks.’ Other walk-ability attributes approached significance.Conclusion:Findings suggest the way neighborhoods are marketed may contribute to self-reported reasons for choosing particular neighborhoods, especially when attributes are not present at the time of purchase. The marketing of housing developments may be an important factor to consider when measuring self-selection, and its influence on the built environment and walking relationship.
Epidemiology of 10,000 High School Football Injuries: Patterns of Injury by Position Played
Authors: Badgeley Marcus A. , McIlvain Natalie M. , Yard Ellen E. , Fields Sarah K. , Comstock R. Dawn 
Published: August 2016

Background:With more than 1.1 million high school athletes playing annually during the 2005−06 to 2009−10 academic years, football is the most popular boys’ sport in the United States.Methods:Using an internet-based data collection tool, RIO, certified athletic trainers (ATs) from 100 nationally representative US high schools reported athletic exposure and football injury data during the 2005−06 to 2009−10 academic years.Results:Participating ATs reported 10,100 football injuries corresponding to an estimated 2,739,187 football-related injuries nationally. The injury rate was 4.08 per 1000 athlete-exposures (AEs) overall. Offensive lineman collectively (center, offensive guard, offensive tackle) sustained 18.3% of all injuries. Running backs (16.3%) sustained more injuries than any other position followed by linebackers (14.9%) and wide receivers (11.9%). The leading mechanism of injury was player-player contact (64.0%) followed by player-surface contact (13.4%). More specifically, injury occurred most commonly when players were being tackled (24.4%) and tackling (21.8%).Conclusions:Patterns of football injuries vary by position. Identifying such differences is important to drive development of evidence-based, targeted injury prevention efforts.
Are Older Adults Who Volunteer to Participate in an Exercise Study Fitter and Healthier Than Nonvolunteers? The Participation Bias of the Study Population
Authors: Barreto Philipe de Souto , Ferrandez Anne-Marie , Saliba-Serre Bérengère 
Published: August 2016

Background:Participation bias in exercise studies is poorly understood among older adults. This study was aimed at looking into whether older persons who volunteer to participate in an exercise study differ from nonvolunteers.Methods:A self-reported questionnaire on physical activity and general health was mailed out to 1000 persons, aged 60 or over, who were covered by the medical insurance of the French National Education System. Among them, 535 answered it and sent it back. Two hundred and thirty-three persons (age 69.7 ±7.6, 65.7% women) said they would volunteer to participate in an exercise study and 270 (age 71.7 ±8.8, 62.2% women) did not.Results:Volunteers were younger and more educated than nonvolunteers, but they did not differ in sex. They had less physical function decline and higher volumes of physical activity than nonvolunteers. Compared with volunteers, nonvolunteers had a worse self-reported health and suffered more frequently from chronic pain. Multiple logistic regressions showed that good self-reported health, absence of chronic pain, and lower levels of physical function decline were associated with volunteering to participate in an exercise study.Conclusions:Volunteers were fitter and healthier than nonvolunteers. Therefore, caution must be taken when generalizing the results of exercise intervention studies.