Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
1.
Int J Exerc Sci ; 17(4): 154-171, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38665852

RESUMO

The purpose of this study was to evaluate the effectiveness of implementing task-specific, post-activation performance enhancement (PAPE) strategies, to acutely improve Army Combat Fitness Test (ACFT) performance. Nineteen ROTC cadets completed two ACFTs, separated by 72 hours. Approximately half (n = 10) completed the traditional "Preparation Drill" as their warm-up prior to the first session and added PAPE warm-up strategies as part of their second session. The other group (n = 9) completed the treatments in the opposite order to facilitate a repeated-measures, crossover design. The participants' composite ACFT score was used as the primary outcome measure of interest to explore mean difference in a two-way (Time x Treatment), repeated measures ANOVA. There was no interaction [F(1,8) = 0.075, p = 0.79] nor main effect of treatment [F(1,8) = 0.084, p = 0.78]. However, there was a main effect of Time [F(1,8) = 58.87, p < 0.001, d = 0.25] (mean ACFT score ± SD: Session 1 = 527 ± 43, Session 2 = 537 ± 39). The results of this study did not support the use of additional PAPE strategies to improve ACFT performance. However, there was a practice effect when the test was completed twice, separated by 72 hours in those with ACFT experience. The effect of Time was present for ACFT cumulative score, as well as event-level differences in three out of six events. Further research should implement familiarization sessions to minimize a practice effect from influencing results.

2.
J Funct Morphol Kinesiol ; 8(3)2023 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-37754962

RESUMO

This study aimed to characterize running-related injuries (RRIs), explore their relationship with run and resistance training (RT) parameters, and identify perceived prevention measures among adult recreational runners. An anonymous online survey was designed and distributed via social media and email. Data were analyzed with chi-square, t-test, or analysis of variance (ANOVA), with significance accepted at p ≤ 0.05. Data from 616 participants (76.8% female, age: 42.3 ± 10.5 y) were analyzed. Most runners (84.4%) had an injury history, with 44.6% experiencing one in the past year. The most common RRI sites included the foot/ankle (30.9%) and knee (22.2%). RRI prevalence was higher in those running >19 miles weekly (48.4%, p = 0.05), but there were no differences based on RT participation status. Among those using RT, relatively more RRIs were observed in runners who trained the hip musculature (50.3%, p = 0.005) and did not include the upper body (61.6%, p < 0.001). A disproportionately high RRI prevalence was found for several of the other risk-reduction strategies. RRIs remain a substantial problem, particularly around the ankle/foot and knee. Higher run volume and performance motives were positively associated with RRIs. Most runners incorporated RRI risk-reduction techniques, with over half using RT. The current study did not determine whether preventative strategies were implemented before or after injury; therefore, prospective studies controlling for previous injuries are required to evaluate the effectiveness of RT in preventing future RRIs.

3.
Int J Exerc Sci ; 16(4): 924-931, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37637241

RESUMO

Physical fitness testing in the military is commonly used to assess whether service members are physically capable of performing the diverse physical tasks that may be required for their job. Body composition can influence an individual's ability to physically perform. This study aimed to analyze the general physical profile of U.S. Air Force (USAF) special warfare candidates by assessing body composition results and physical assessment scores collected over the past four years. Male candidates (n = 1036) were 18.2 years to 39.5 years of age (M = 23.5, SD = 3.9) and weighed 78.8 kg (SD = 8.3) with a BMI of 25.0 (SD = 2.0) at 11.8% body fat (SD = 3.3) as measured using bioelectrical impedance. Body composition and fitness scores were similar to those noted in U.S. Navy special warfare candidates as well as individuals in other elite tactical units. These results highlight the normative body composition profile of individuals assessing for advanced military career fields.

4.
J Strength Cond Res ; 37(3): 684-687, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36820706

RESUMO

ABSTRACT: Ryan, GA, Bunn, JA, and Eisenman, ML. How accurate are coaches in predicting perceived exertion of their athletes? J Strength Cond Res 37(3): 684-687, 2023-Ratings of perceived exertion (RPE) are used extensively to subjectively evaluate workload in sport. The purpose of this study was to compare season long player to coach perceptions of RPE loads (RPEL) in Division I men's soccer and women's lacrosse programs. Coach and player self-reported RPE were collected during the competitive seasons for both teams within 30 minutes of training sessions. Scores of RPE were multiplied by recorded training time to determine RPEL and averaged to create a daily coach and player RPEL. Accuracy of RPEL prediction between coaches and players was determined via mean bias, mean absolute percent error (MAPE), correlation, and an equivalence test. Soccer coaches underestimated RPEL (1,345 ± 410 arbitrary unit [AU]) compared with players (1,372 ± 435 AU). The coach mean bias was -27.3 ± 151.9 AU, wieth an MAPE of 7.4%, a strong correlation (r = 0.937, p < 0.001), and coach to player equivalence (p = 0.045). Lacrosse coaches overestimated RPELs (876 ± 349 AU) compared with players (829 ± 214 AU). The coach mean bias was 47 ± 189 AU, with an MAPE of 14.7%, a strong correlation (r = 0.883, p < 0.001), and coach to player equivalence (p = 0.010). Analyses indicated that coaches accurately predicted player RPEL within both sports. Variance occurred on days with high RPELs, with overestimations occurring in lacrosse and underestimation in soccer. Coaches can use RPELs to assess subjective training load but should consider objective measures, including microtechnology, to provide a comprehensive assessment.


Assuntos
Condicionamento Físico Humano , Esportes com Raquete , Futebol , Masculino , Humanos , Feminino , Esforço Físico , Atletas
5.
J Strength Cond Res ; 36(4): 1038-1045, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32304515

RESUMO

ABSTRACT: Ryan, GA, Snarr, RL, Eisenman, ML, and Rossi, SJ. Seasonal training load quantification and comparison in college male soccer players. J Strength Cond Res 36(4): 1038-1045, 2022-Monitoring and quantification of training load (TL) throughout a competitive soccer season is important to ensure players are able to perform throughout the season. The intent of this study was to examine the positional demands and patterns of select measures of TL during a 14-week season in collegiate male soccer players. Heart rate (HR), running performance (SZ), and perceived recovery data were collected daily using a bioharness for each subject (n = 21). Data were grouped into 2- to 3-week training blocks (Pre1, Pre2, In1, In2, In3, and In4). Continuous variables were analyzed using a multivariate analysis of variance, with post hoc Least Squared Difference pairwise comparisons. Significant positional differences were observed across the season. During Pre1, center midfielders (CM) spent more time in %HRlow compared to center backs (CB) (p < 0.01), wide midfielders (p < 0.01), and center forwards (p = 0.04). Center midfielders spent greater time in SZlower than CB (p < 0.01) and wide backs (WB) (p = 0.01). Wide backs spent greater time in SZupper compared to other positions (all p < 0.01). During Pre2, WB spent more time in %HRhigh and SZupper compared to other positions (all p < 0.01). Positional differences were more varied throughout in-season comparisons, but generally, WB and CB demonstrated higher intensities in variables compared to other positions. Tracking variations in positional TLs across the season is important for coaching and training staffs to determine player readiness and plan future training sessions, while helping to mitigate overuse injuries during a long competitive season.


Assuntos
Desempenho Atlético , Corrida , Futebol , Desempenho Atlético/fisiologia , Frequência Cardíaca , Humanos , Masculino , Corrida/fisiologia , Estações do Ano , Futebol/fisiologia , Universidades
6.
Int J Exerc Sci ; 14(4): 239-249, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34055166

RESUMO

The American Fitness Industry has seen progressive success with recent increases in facility memberships and annual revenues of fitness centers. The number of fitness trainers and instructors in the United States has persisted this growth and is projected to grow over the next decade. However, only a few known studies have investigated the nutritional education of fitness professionals. This preliminary study explores the education and knowledge among certified fitness professions (CFPs) in the United States. A cross-sectional, descriptive survey design was utilized with a convenience sample of 120 female participants from the United States who were associated with a major fitness newsletter. The average age of the participants was 48.51 years (SD 12), and they had 14.85 years of experience (SD 10.16) and worked an average of 22.04 hours per week (SD 16.78). Most of the participants had some kind of college degree (96.2%) and held a group fitness certification (76.6%) or personal training certification (47.5%). Those with a nutrition certification were found to have significantly higher nutrition knowledge test scores on the 21 question test (18.2 ± 2.0 correct to 17.1 ± 1.9, p=0.04). Additionally, it is revealed that CFPs use the internet as a primary source for nutritional information and was the most frequently used source of nutrition information accessed. This pilot study suggests a more in-depth study would be beneficial to solidify the current results and could allow for more investigation into whether or not completion of nutrition coursework within formal earned degrees by CFPs positively influences their nutritional knowledge.

7.
J Strength Cond Res ; 34(9): 2492-2499, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32459737

RESUMO

Cook, J, Ryan, GA, Snarr, RL, and Rossi, S. The relationship between the National Football League scouting Combine and game performance over a 5-year period. J Strength Cond Res 34(8): 2492-2499, 2020-There has been doubt on the ability of the National Football League (NFL) Scouting Combine to predict successful future game performance. This study analyzed data from athletes who participated in the Combine between 2013 and 2017 (n = 1,537) and their subsequent year's performance in the NFL. Data from 6 athletic measures were normalized for each athlete when compared with all other athletes (avgCZ) and athletes of the same position (avgPZ). Correlational analysis was used to ascertain whether the physical performance tests were associated with subsequent year's game performance (avgS). A multiple linear regression was performed to examine whether individual event Combine performance could predict the subsequent year's avgS in the NFL. Of the 35 correlations found when examining relationships, only 2 correlations were found to be moderately strong, avgCZ-avgS2 (r = 0.320), avgPZ-avgS2 (r = 0.332), whereas most were found to be weak (r < 0.3). Furthermore, data analysis suggests that Combine measures can only explain approximately 2.6% of the variance in avgS 1 year after the Combine when using 3 (vertical jump, bench press, and PRO) performance tests as predictors. The primary results of this study suggest that the NFL Combine lacks predictive ability when examining first year game performance. Furthermore, it also lacks correlational strength when examining relationships between performance and subsequent 5-year performance in the NFL. Caution should be used if coaches, general managers, and other front office staff are considering the use of Combine data as a possible selection for the upcoming NFL Draft.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Futebol Americano/fisiologia , Teste de Esforço , Humanos , Masculino , Adulto Jovem
8.
J Strength Cond Res ; 34(1): 183-191, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28796124

RESUMO

Bunn, JA, Ryan, GA, Button, GR, and, and Zhang, S. Evaluation of strength and conditioning measures with game success in Division I collegiate volleyball: A retrospective study. J Strength Cond Res 34(1): 183-191, 2020-The purpose of this study was to retrospectively assess relationships between strength and conditioning (SC) measures and game performance in Division I volleyball. Five years of SC and game data were collected from 1 women's Division I collegiate team, n = 76. Strength and conditioning measures included T-drill, 18.3 m sprint, back squat, hang clean, vertical jump, and broad jump. All game and SC stats were normalized to Z-scores. Analyses included assessing SC differences by position and multiple stepwise regression to assess relationships between game and SC stats. There was a significant difference by position for broad jump (p = 0.002), 18.3 m sprint (p = 0.036), vertical (p ≤ 0.001), and total strength (p = 0.019). Overall, game performance and SC measures were significantly correlated (r = 0.439, p ≤ 0.001). Multiple regression analyses indicated significant relationships (p ≤ 0.05) between SC measures and game success by position as follows: defensive specialist stats with squat and total strength; setters game stats with hang cleans, T-drill, and broad jump; pin hitter game stats with vertical, squat, and total strength; middle blockers game stats with broad jump. These data indicate that SC measures correlate well with game performance and are specific by position. These data could help SC coaches create a more precise training approach to focus on improving specific measures by position, which could then translate to improved game performance. These data could also help coaches with talent identification to determine playing time and rotations to maximize player ability and achieve success.


Assuntos
Desempenho Atlético/estatística & dados numéricos , Treinamento Resistido , Universidades , Voleibol/estatística & dados numéricos , Adolescente , Feminino , Humanos , Força Muscular , Músculo Esquelético/fisiologia , Treinamento Resistido/métodos , Estudos Retrospectivos , Corrida , Adulto Jovem
9.
Appl Physiol Nutr Metab ; 45(3): 336-339, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31730376

RESUMO

This study evaluated the accuracy of bioimpedance analysis (BIA)- and skinfold (SF)-based body fat percentage estimates in collegiate athletes with varying fat-free mass (FFM) hydration levels. Subjects were evaluated as a whole (n = 63) and at FFM hydration levels of 64.00%-68.99% (FFM-HydrationL1; n = 37) and 69.00%-74.00% (FFM-HydrationL2; n = 26). Proportional bias was absent in the SF technique when stratifying FFM hydration levels. Contrarily, proportional bias was observed when using BIA for FFM-HydrationL1, but not in FFM-HydrationL2. Novelty Fat-free mass hydration levels impact BIA-based body fat estimates more than skinfold-based body fat.


Assuntos
Atletas , Composição Corporal/fisiologia , Impedância Elétrica , Estado de Hidratação do Organismo/fisiologia , Dobras Cutâneas , Adolescente , Adulto , Humanos , Masculino , Reprodutibilidade dos Testes , Adulto Jovem
10.
Int J Exerc Sci ; 12(5): 1216-1224, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31839855

RESUMO

Increased sedentary behavior and reduced physical activity among children and adults has led to the advent of various active devices to combat these behaviors. Active sitting, consisting of modified chairs or stability balls, allows the body to stay dynamic while seated. While research has evaluated the health benefits of active sitting, minimal research has shown the effects of active sitting on productivity in adult populations. The purpose was to evaluate the effects of various chairs (active versus non-active) on typing and reading task productivity. Twenty adult participants performed typing and reading tasks for 10-minutes while sitting on each of the following: standard chair (SC), stability ball (SB), and active sitting chair (ST). Reading comprehension (RC), words per minute (WPM), accuracy, and errors were measured following each task. Additionally, perceived productivity was measured using a self-reported rating of difficulty scale (1-10). In terms of RC, there was no difference between the chairs (p = 0.16). However, perceived productivity was significantly greater on the SC as compared to SB (p < 0.01) and ST (p < 0.01). For the typing task, no differences were demonstrated for errors (p = 0.87) or accuracy (p = 0.91). However, WPM was significantly greater on SC (38.8 ± 10.5) compared to ST (35.9 ± 9.5) (p = 0.02). For perceived typing productivity, SC and SB demonstrated significantly greater values compared to ST (p < 0.01). Results suggest that various types of active sitting may have a minimal negative effect on workplace performance and perceived productivity.

11.
Ergonomics ; 62(9): 1227-1233, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31204597

RESUMO

Stability balls and active-balance sitting chairs have recently emerged as a way to reduce sedentary behaviours in office settings. The purpose of this study was to determine differences in caloric expenditure and heart rate between a standard chair (SC), stability ball (SB) and active balanced sitting chair (ST) while performing work-related tasks. Participants (n = 20) performed a 10-minute randomised reading and typing task while sitting on the SC, SB and ST. For both the reading and typing tasks, heart rate (HR), caloric expenditure per minute and metabolic equivalents were all significantly greater (i.e. 6-13%; 19-40%; 18-39%, respectively) while using the ST when compared to the SC and SB. No significant differences were observed between the SB and SC for any of the comparisons. The ST produced a greater HR response and caloric expenditure than the SC or SB, indicating that active balanced sitting may be a feasible way to increase energy expenditure in an office setting. Practitioner summary: The purpose of this study was to determine differences in cardiovascular and metabolic responses to various forms of office chairs. The key finding was that active sitting on a balance chair significantly increased heart rate and caloric expenditure as compared to a stability ball and standard chair. Abbreviations: SC: standard chair; SB: stability ball; ST: active balanced chair; HR: heart rate; kcalmin: caloric expenditure per minute; MET: metabolic equivalents.


Assuntos
Frequência Cardíaca , Equivalente Metabólico , Postura Sentada , Análise e Desempenho de Tarefas , Trabalho/fisiologia , Adulto , Estudos Cross-Over , Metabolismo Energético , Feminino , Humanos , Decoração de Interiores e Mobiliário , Masculino
12.
J Strength Cond Res ; 33(12): 3361-3366, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30789577

RESUMO

Nickerson, BS, Snarr, RL, and Ryan, GA. Validity of foot-to-foot bioelectrical impedance for estimating body composition in NCAA Division I male athletes: A 3-compartment model comparison. J Strength Cond Res 33(12): 3361-3366, 2019-The purpose of this study was to validate single-frequency foot-to-foot bioelectrical impedance analysis (FF-BIA) against a 3-compartment (3C) model in NCAA Division I male athletes. Thirty-three athletes (football = 19, baseball = 8, basketball = 3, and cheerleading = 3) had body fat percentages (BF%) and fat-free mass (FFM) estimated using a 3C model and FF-BIA. The criterion 3C model was derived from body mass, body volume (air displacement plethysmography), and total body water (bioimpedance spectroscopy). The mean BF% and FFM values for FF-BIA were not statistically significant when compared with the 3C model (p = 0.14 and 0.28, respectively). The standard error of estimate (2.79% and 2.64 kg), total error (2.95% and 2.64 kg), and 95% limits of agreement (±5.67% and ±5.15 kg) were considered acceptable for BF% and FFM, respectively. However, there was a significant trend in the regression line of the Bland-Altman plot, which indicated proportional bias for BF% (r = -0.50; p < 0.01). No proportional bias was present for FFM (r = 0.26; p > 0.05). Foot-to-foot BIA seems to be valid for estimating group and individual athlete's FFM. Similarly, FF-BIA can be used for estimating group BF%. However, proportional bias indicates that FF-BIA is not valid for individual estimates of BF%.


Assuntos
Composição Corporal , Impedância Elétrica , Esportes , Absorciometria de Fóton , Adiposidade , Adolescente , Humanos , Masculino , Modelos Biológicos , Pletismografia/métodos , Reprodutibilidade dos Testes , Adulto Jovem
13.
Int J Exerc Sci ; 11(4): 479-492, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29541333

RESUMO

The purpose was to determine if pull-up performance was affected by the use of chalk (100% magnesium carbonate) during open-handed and pinch grip weight-assisted pull-ups (WAPU) in recreationally-trained rock climbers. Furthermore, the reliability of open-handed and pinch grip WAPU was also investigated. Recreationally-active volunteers (n = 9) completed six counterbalanced trials. Participants used chalk during four trials to determine the reliability (test-retest) of the open-handed and pinch grips. While two of the six trials were used to determine if open-handed and pinch grip WAPU performance was affected without using chalk. Three of the six trials included one set of open-handed WAPU, while the remaining trails included one set of pinch grip WAPU. Sets were performed until failure and consisted of either the open-handed or pinch grip pull-ups assisted by a 50% reduction of body weight. Heart rate, ratings of perceived exertion, perceived recovery scale and session-RPE were not significantly different (p > 0.05) among trials. Intraclass correlations (ICC's) for test-retest of the open-handed (R = 0.99) and pinch grip (R = 0.96) WAPU evidenced reliable values. When compared to the non-chalked trials, chalk improved both openhanded (mean = 22.8 ± 4.53 vs. mean no chalk = 19.7 ± 4.39 reps; p = 0.006,) and pinch grip (mean = 14.4 ± 4.47 vs. mean no chalk = 9.1 ± 4.83 reps; p = 0.007) WAPU. ICC's indicated a reliable measurement, while chalk improved performance for both open-handed and pinch grip WAPU when compared to no chalk trials.

14.
J Sci Med Sport ; 21(6): 621-625, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29153867

RESUMO

OBJECTIVES: The purpose of this study was to test the hypothesis that cooling the upper body during a warm-up enhances performance during a subsequent 16.1-km simulated cycling time trial in a hot environment. DESIGN: Counterbalanced, repeated measures design. METHODS: Eight trained, male cyclists (peak oxygen uptake=57.8±5.0mLkg-1min-1) completed two simulated 16.1-km time trials in a hot environment (35.0±0.5°C, 43.8±2.0% relative humidity) each separated by 72h. Treatments were counterbalanced; participants warmed up for 20min while either wearing head and neck ice wraps and an ice vest (COOLING) or no cooling apparatus (CONTROL). RESULTS: Following the warm-up mean skin temperature (T¯sk), mean body temperature (T¯b) and rating of thermal comfort were significantly lower than baseline following the COOLING trial (all P<0.05); however, rectal temperature was unaffected (P=0.35). Because the effects of precooling on T¯sk and T¯b were not sustained during exercise, values for COOLING and CONTROL were not different throughout the time trial (P=0.38). Nonetheless, time to completion was significantly faster following the COOLING intervention when compared to the CONTROL (29.3±3.6min, vs. 30.3±3.1min; P=0.04). CONCLUSIONS: These data suggest that in short distance time trials in hot conditions cyclists may benefit from utilizing a cooling modality during the warm-up.


Assuntos
Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Regulação da Temperatura Corporal , Temperatura Corporal , Temperatura Cutânea , Exercício de Aquecimento , Adulto , Temperatura Baixa , Temperatura Alta , Humanos , Masculino , Adulto Jovem
15.
J Strength Cond Res ; 31(8): 2060-2065, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28323792

RESUMO

Bishop, SH, Szymanski, DJ, Ryan, GA, Herron, RL, and Bishop, PA. The effect of intermittent vest cooling on thermoregulation and cardiovascular strain in baseball catchers. J Strength Cond Res 31(8): 2060-2065, 2017-Baseball catchers are exposed to multiple physiological challenges while playing outside during the spring and summer months, many of which deal with recovery and thermoregulation. The purpose of this study was to investigate the effect of intermittent cooling on core temperature, cardiovascular strain, exertion, and recovery during a simulated catching performance in the heat. Six trained college-aged baseball catchers performed in a controlled, hot (35° C), and humid (25% relative humidity) environment in a counter-balanced, cross-over design. Ice vest cooling (VC) was used as a cooling modality and was compared with a control of no cooling (NC). Rectal temperature (Tre), heart rate (HR), rating of perceived exertion (RPE), and perceived recovery scale (PRS) were recorded before and after each simulated inning. All activities took place in a heat chamber, and each inning consisted of catchers receiving 12 pitches in their position followed by 6 minutes of recovery. Nine total innings were performed, and 27 total innings were performed with each of the 2 treatments. A significantly smaller mean Tre change was seen in VC when compared with NC (0.58 ± 0.2° C, 0.98 ± 0.2° C, p ≤ 0.01, respectively). Rating of perceived exertion was significantly lower and PRS was significantly improved for VC compared with NC (both p ≤ 0.05). Mean recovery HR during VC was significantly lower than NC in the fifth (VC = 84 ± 8 b·min, NC = 90 ± 9 b·min, p = 0.04), seventh (VC = 84 ± 3 b·min, NC = 92 ± 7 b·min, p = 0.02), and ninth (VC = 85 ± 7 b·min, NC = 93 ± 5 b·min, p = 0.01) innings. Heart rate during catching was significantly lower at the end of the VC trials when compared with NC (108 ± 16 b·min vs. 120 ± 19 b·min, p = 0.02, respectively). Vest cooling decreased heat strain, cardiovascular strain, and RPE while it improved perceived recovery in catchers over a simulated 3-game series performed in hot conditions.


Assuntos
Beisebol/fisiologia , Regulação da Temperatura Corporal/fisiologia , Temperatura Corporal/fisiologia , Fenômenos Fisiológicos Cardiovasculares , Temperatura Baixa , Estudos Cross-Over , Frequência Cardíaca/fisiologia , Temperatura Alta , Humanos , Masculino , Percepção , Esforço Físico/fisiologia , Adulto Jovem
16.
J Occup Environ Hyg ; 12(4): 222-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25437276

RESUMO

Previous research has studied the impact of Level II concealed soft body armor (SBA) on the augmentation of heat storage in a hot environment simulating a typical summer day in the southeastern United States (wet bulb globe temperature [WBGT] = 30°C) and noted a significant difference between macro- and micro-WBGTs. The purpose of this study was to characterize the microclimate (micro-WBGT) under a concealed Level II SBA during 60 min of moderately intense work at two separate macro-WBGTs (26°C and 30°C), and to establish WBGT corrections to allow prediction of heat strain in an individual wearing a concealed Level II SBA. A single trial was performed with nine volunteers (27 ± 4 years) outfitted with a simulated standard law enforcement uniform and a traditional concealed Level II SBA, in a moderately warm environment (WBGT = 26°C). Each participant performed cycles of 12 min of walking (1.25 L · min(-1)) and 3 min of arm curls (14.3 kg, 0.6 L · min(-1)) with a 5 min rest after every other cycle, for a total of 60 minutes. This trial was compared to an identical previously completed 60-min work bout at 30°C. A two-way repeated measures ANOVA with Post hoc Bonferroni and paired samples t-test analysis was conducted. A greater difference between macro- micro-WBGTs existed at 26°C compared to the 30°C macro-WBGT. Under these conditions, a moderate work in Level II SBA requires a WBGT correction of 8.9°C and 6.2°C at macro-WBGTs of 26°C and 30°C, respectively. A modified simple linear regression prediction model was established for mean Micro-WBGT for each macro-WBGTs after the plateau point at the 30 min mark. The derivation regressions at 26°C (R(2) = 0.99), and 30°C (R(2) = 0.99) indicate that micro-WBGT could be predicted for each 15 minutes time at both macro-WBGTs tested for individuals doing moderate intensity (300 Kcals · hr(-1)) work wearing concealed Level II SBA.


Assuntos
Exposição Ocupacional , Roupa de Proteção , Adulto , Temperatura Corporal/fisiologia , Frequência Cardíaca/fisiologia , Humanos , Masculino , Esforço Físico/fisiologia , Polícia , Sudeste dos Estados Unidos , Temperatura
17.
J Occup Environ Hyg ; 11(2): 93-100, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24369931

RESUMO

Concealed soft body armor inhibits convective and evaporative heat loss and increases heat storage, especially in hot environments. One option to potentially mitigate heat storage is to promote airflow under the soft body armor. The purpose of this study was to evaluate the effect of ambient air induction (∼100 liters per minute) on heat strain while wearing concealed soft body armor in a hot environment (wet bulb globe temperature = 30°C). A counter-balanced, repeated measures protocol was performed with nine healthy male volunteers. Participants were fitted with either a traditional or modified Level II concealed soft body armor. Participants performed cycles of 12 min of walking (1.25 liters per minute) and 3 min of arm curls (0.6 liters per minute) for a total of 60 min. Two-way repeated measures ANOVA was used to assess the mean differences in physiological measures (rectal temperature, heart rate, micro-environment [temperature and relative humidity]). Post hoc Bonferroni analysis and paired samples t-tests (alpha = 0.01) were conducted on omnibus significant findings. Perceptual measures (perceived exertion, thermal comfort) were analyzed using Wilcoxon Signed Ranks Tests. Modification led to an improvement in perceived exertion at 45 min (MOD: 10 ± 1; CON: 11 ± 2; p ≤ 0.001) and 60 min (MOD: 10 ± 2; CON: 12 ± 2; p ≤ 0.001) and a reduction in micro-environment temperature in MOD (1.0 ± 0.2°C, p = 0.03) compared to CON. Modification did not attenuate change in rectal temperature or heart rate (p < 0.01) during 60-min work bout. Change in rectal temperature approached significance between MOD and CON at the end of the work bout (MOD: 0.4 ± 0.2°C; CON: 0.7 ± 0.3°C; p = 0.048). The slope of rectal temperature was significantly greater (p = 0.04) under CON compared to MOD. These data suggest that air induction may provide small benefits while wearing concealed soft body armor, though improvements are needed to lessen physiological strain.


Assuntos
Temperatura Corporal , Roupa de Proteção , Adulto , Regulação da Temperatura Corporal , Metabolismo Energético , Frequência Cardíaca , Humanos , Masculino , Exposição Ocupacional , Polícia
18.
J Strength Cond Res ; 26(5): 1348-52, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22516908

RESUMO

The purpose of this study was to examine 2 recovery modalities (with and without an ice bag treatment) on closed-handed and open-handed weight-assisted pull-ups in recreationally-trained rock climbers. Healthy and recreationally active volunteers (n = 9) completed 4 counterbalanced trials separated by 72 hours. Trials included 3 sets of closed-handed and open-handed weight-assisted pull-ups supported by 50% of body weight, until failure. Between each set, participants sat quietly in a chair and engaged in approximately 20 minutes of either passive or ice bag treatment. Ice bags were placed on the participants' arms and shoulders. Heart rate (HR), ratings of perceived exertion (RPE), session-RPE (S-RPE), and perceived recovery were also assessed. Hand-grip strength pretrial and posttrial was not different between ice bag conditions. Also, there were no differences between treatments for HR, RPE, perceived recovery, S-RPE, or comfort ratings. The overall number of open-handed pull-ups (mean ± SD = 19 ± 5) was lower than closed-handed pull-ups (34 ± 14; p < 0.001). Ice bag recovery attenuated the decrease in open-handed pull-up performance for sets 2 (22 ± 5; p = 0.004) and 3 (22 ± 5; p = 0.003) relative to set 3 using passive recovery only (i.e., no ice bag; 17 ± 6). There were no differences (p = 0.31) between treatments for closed-handed pull-ups. The findings support the recommendations to use ice bags for recovery between bouts of rock climbing that involve a predominantly open-handed grip to maintain performance.


Assuntos
Crioterapia , Força da Mão/fisiologia , Montanhismo/fisiologia , Recuperação de Função Fisiológica , Treinamento Resistido , Descanso/fisiologia , Adulto , Análise de Variância , Terapia Combinada , Frequência Cardíaca , Humanos , Masculino , Esforço Físico , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...