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1.
Medicina (Kaunas) ; 56(9)2020 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-32824955

RESUMO

Background and Objectives: National Collegiate Athletic Association (NCAA) soccer coaches implement numerous warm-up and flexibility strategies to prepare athletes for training and competition. The Fédération Internationale de Football Association (FIFA) developed the 11+ injury prevention program to reduce non-contact injuries. This study aimed to analyze the level of familiarity with and implementation of the evidence-based FIFA 11+ amongst NCAA Division I (DI) and Division III (DIII) men's and women's soccer coaches. Materials and Methods: NCAA soccer coaches in the United States received an Institutional Review Board-approved survey hyperlink. A total of 240 coaches completed the survey. The respondents represented 47.5% men's and 52.5% women's teams distributed within DI and DIII programs. Descriptive statistics are reported as frequency counts and mean ± standard deviation where applicable. Pearson's chi-square tests were performed to assess potential differences with a significance level set at α < 0.05. Results: The results indicated that approximately 62% of the respondents reported being familiar with the FIFA 11+ program. Of those coaches familiar with the program, 15.0% reported full implementation, 57.5% reported partial implementation, and 27.5% reported no implementation. Chi-square analyses revealed significant differences in FIFA 11+ implementation based upon division level (χ2 = 4.56, p = 0.033) and coaching certification levels (χ2 = 13.11, p = 0.011). Conclusions: This study indicates that there is a gap between FIFA 11+ knowledge and actual implementation. To reduce the risk of non-contact injury, there is a need to educate coaches and athletic trainers on the purpose of the FIFA 11+ program and how to perform the exercises correctly.


Assuntos
Fidelidade a Diretrizes , Guias como Assunto , Tutoria , Exercícios de Alongamento Muscular , Futebol/fisiologia , Exercício de Aquecimento , Traumatismos em Atletas/prevenção & controle , Certificação , Feminino , Humanos , Masculino , Tutoria/normas , Futebol/classificação , Futebol/lesões , Estados Unidos
2.
J Strength Cond Res ; 31(9): 2347-2354, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25734784

RESUMO

Popp, JK, Bellar, DM, Hoover, DL, Craig, BW, Leitzelar, BN, Wanless, EA, and Judge, LW. Pre- and post-activity stretching practices of collegiate athletic trainers in the United States. J Strength Cond Res 31(9): 2347-2354, 2017-The aim of the study was to investigate the knowledge and practices of collegiate-certified athletic trainers (ATs) in the United States. Participants (n = 521) were provided an overview of the study and a hyperlink to a web-based survey. The "pre- and post-activity practices in athletic training questionnaire" consisted of demographic items and elements to measure knowledge and practices related to pre- and post-activity stretching routines. In previous studies, the survey demonstrated construct validity, α = 0.722. Pearson chi-square test was used to evaluate goodness of fit, and kappa was calculated to measure agreement between items. Only 32.2% of ATs recommended dynamic stretching (DS) to be performed pre-activity, whereas a larger percentage (42.2%) recommended a combination of static stretching (SS) and DS. Athletic trainers reported that only 28.0% of athletes are performing DS before activity. Conversely, 60.6% of collegiate ATs recommended SS postexercise, and 61.0% of athletes agree and perform after workout SS (κ = 0.761, p < 0.001). Collegiate ATs seem to underuse the current research evidence, which indicates that DS is more beneficial than SS when used pre-activity, and ATs continue to regularly incorporate SS in their pre-activity routines. However, there is evidence that collegiate ATs in the United States emphasize SS postactivity in a manner consistent with current research.


Assuntos
Atletas , Conhecimentos, Atitudes e Prática em Saúde , Exercícios de Alongamento Muscular/métodos , Universidades , Adulto , Distribuição de Qui-Quadrado , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Fatores Socioeconômicos , Esportes/educação , Estados Unidos
3.
Aging Male ; 19(3): 161-167, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27558186

RESUMO

The purpose of the study was to examine the effects of acute androstenedione supplementation on hormone levels in older men at rest and during exercise. Men (n = 11) between the ages of 58 and 69 were divided into an experimental (n = 6; 62.33 ± 2.57 y) and control (n = 5; 60.2 ± 1.02 y) groups. Each participant received an oral 300 mg dose of either androstenedione (experimental) or a cellulose placebo (control) for 7 d. Pre- and post-supplementation participants completed two separate, 20-min strength tasks consisting of leg extension and leg curls at different percentages of their 10-RM. Researchers collected blood samples pre-, during, and post-exercise. Blood samples were analyzed for testosterone, androstenedione, and estradiol levels. The researchers found a significant difference between pre- (4.36 ± 56 ng/mL) and post- (5.51 ± 0.35 ng/mL) testosterone levels, as well as pre- (0.88 ± 0.20) and post- (7.46 ± 1.25) androstenedione levels, but no significant differences between pre- and post-estradiol levels for either group. It appears that short-term androstenedione supplementation augmented acute testosterone responses to resistance exercise in older men. However, further study of this supplement is needed to determine any potential it may have in mitigating andropause.


Assuntos
Androstenodiona/uso terapêutico , Suplementos Nutricionais , Testosterona/sangue , Idoso , Androstenodiona/administração & dosagem , Exercício Físico/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Testosterona/deficiência
4.
J Strength Cond Res ; 30(2): 438-45, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26813632

RESUMO

The purpose of this investigation was to determine the acute effects of heavy and light implements on subsequent overhead back (OHB) shot put performance with a competition weight shot put. This investigation was designed to test the efficacy of heavy implements for potentiating subsequent OHB performance. Participants included 41 athletes (20.9 ± 1.18 years.) from 2 National Collegiate Athletic Association Division I schools in the Midwestern United States (n = 23 male and n = 18 female). Mean distance for OHB throw with a competition shot put was examined after treatment (control, light shot put warm-up, and heavy shot put warm-up) through repeated-measures analysis of variance (ANOVA) with post hoc Bonferroni-corrected post hoc analysis. Responses after treatment on the 10-cm visual analog scale (VAS) fatigue were examined through repeated-measures ANOVA and demonstrated a significant main effect for treatment on VAS fatigue (F = 16.463; p = 0.001). The heavy shot put warm-up resulted in the greatest mean performance over the course of the 3 attempts (14.39 ± 1.82 m) followed by the light shot put warm-up (14.18 ± 1.68 m) and the control (14.15 ± 1.70 m). Results of the repeated-measures ANOVA demonstrated a significant main effect for treatment in regard to average distance (F = 6.276; p = 0.003). Post hoc testing suggested that the heavy shot put warm-up resulted in significantly better mean OHB performance than either the light shot put warm-up (t = 2.983; p = 0.0048; ES = 0.472; power = 0.901) or the control shot put warm-up (t = 3.349; p = 0.0018; effect size [ES] = 0.513; power = 0.939). Subsequent analysis examined the relationship between reported fatigue accrued during the overweight shot put warm-up and the change in performance on the OHB throw when compared to the control condition. Analysis revealed that subjects who reported higher levels of VAS fatigue did not perform as well after the overweight treatment (p = 0.0274).


Assuntos
Desempenho Atlético/fisiologia , Músculo Esquelético/fisiologia , Condicionamento Físico Humano/métodos , Adolescente , Adulto , Feminino , Humanos , Masculino , Fadiga Muscular/fisiologia , Escala Visual Analógica , Adulto Jovem
5.
J Strength Cond Res ; 30(9): 2399-405, 2016 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26881803

RESUMO

Judge, LW, Urbina, LJ, Hoover, DL, Craig, BW, Judge, LM, Leitzelar, BM, Pearson, DR, Holtzclaw, KA, and Bellar, DM. The impact of competitive trait anxiety on collegiate powerlifting performance. J Strength Cond Res 30(9): 2399-2405, 2016-The purpose of this study was to determine the relationship between competitive trait anxiety measures and powerlifting (PL) performance. Thirty-six collegiate powerlifters on club teams from 3 universities were recruited during a competition (men = 26, women = 10; age = 19.9 ± 1.5 years; height = 172.5 ± 8.6 cm; weight = 81.4 ± 21.0 kg). The athletes were distributed across weight classes for collegiate PL (47.6 kg: 1; 51.7 kg: 1; 54.9 kg: 1; 59.8 kg: 3; 67.1 kg: 2; 74.8 kg: 7; 82.1 kg: 4; 89.8 kg: 9; 99.8 kg: 5; super heavyweight: 3). A survey containing questions about PL performance history and the 15-item Sport Competition Anxiety Test (SCAT) were administered to the participants before competing. The SCAT total was negatively correlated (r = -0.397; p = 0.02) to the athletes' percentage of best total achieved in the competition (actual performance total/best comp total × 100). Of the individual lifts, the SCAT score was negatively correlated to the personal best for bench press (r = -0.368; p = 0.03) and deadlift (r = -0.317, p = 0.05), but did not significantly correlate for squat (r = -0.182, p = 0.27). These results indicate a negative correlation between the SCAT score and athletes' personal best totals in PL. Increased SCAT scores were associated with decreased personal best PL totals. The results suggest that competitive trait anxiety may have negatively impacted performance and that some PL athletes may benefit from interventions aimed at decreasing anxiety before and during performance.


Assuntos
Ansiedade/psicologia , Desempenho Atlético/psicologia , Levantamento de Peso/psicologia , Adolescente , Adulto , Peso Corporal , Feminino , Humanos , Masculino , Esportes , Inquéritos e Questionários , Universidades , Adulto Jovem
6.
J Strength Cond Res ; 29(7): 2034-40, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25559910

RESUMO

The purpose of this study was to analyze the level of creatine use along with the perceived benefits and barriers of creatine use among collegiate athletes who participate in throwing events within the sport of track and field. A total of 258 throwers from National Collegiate Athletic Association Division I institutions completed an online survey regarding creatine. The results provided baseline levels of creatine use and allowed for the analysis of factors related to athletic conference affiliation. Results indicate that creatine use remains to be a common (32.7%) practice among throwers with significantly higher levels of use among Football Bowl Subdivision (FBS) conference athletes (44.6%) than Football Championship Subdivision (FCS) conference athletes (28.8%), χ² = 5.505, p = 0.019. The most common reasons for using creatine included a desire to improve/increase: strength (83.3%), recovery time (69.0%), and performance (60.7%). The most common perceived obstacles included contamination/quality control (39.5%), cost (33.3%), inconvenience (16.7%), and cramping (14.3%). A desire for additional education and training was noted through an expression of interest (55.6%) with significantly higher levels of interest from FBS athletes (65.6%) than FCS athletes (52.2%), χ² = 6.425, p = 0.039. However, the athletic departments provide nutritional supplement counseling at only 26.6% of the schools. Although the access to full-time nutritionist counsel was available at 57.3% of the schools, there was a significant difference (χ² = 9.096, p = 0.003) between FBS schools (73.7%) and FCS schools (51.7%).


Assuntos
Informação de Saúde ao Consumidor , Creatina , Suplementos Nutricionais , Uso de Medicamentos/estatística & dados numéricos , Substâncias para Melhoria do Desempenho , Atletismo/estatística & dados numéricos , Adolescente , Creatina/efeitos adversos , Suplementos Nutricionais/efeitos adversos , Feminino , Humanos , Masculino , Substâncias para Melhoria do Desempenho/efeitos adversos , Inquéritos e Questionários , Estados Unidos , Universidades , Adulto Jovem
7.
J Strength Cond Res ; 28(8): 2253-61, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24476770

RESUMO

Strength and conditioning training programs are essential components of athletic performance, and the effectiveness of these programs can be linked to the strength and conditioning facilities (SCFs) used by athletes. The primary purpose of this study was to provide a statistical overview of National Collegiate Athletic Association (NCAA) Division I SCFs, equipment and maintenance budget, and the relationship between SCF budget and staffing space, and equipment. The secondary purpose was to note differences in SCFs between those schools with and without football programs. An 84-item online survey instrument, developed with expert input from certified strength professionals, was used to collect data regarding the SCFs in NCAA Division I universities. A total of 110 valid and complete surveys were returned for a response rate of 38.6%. Results of Pearson's χ2 analysis demonstrated that the larger reported annual equipment budgets were associated with larger SCFs (χ2 = 451.4, p ≤ 0.001), greater maximum safe capacity of athletes using the facility (χ2 = 366.9, p ≤ 0.001), increased numbers of full-time coaches (χ2 = 224.2, p ≤ 0.001), and increased number of graduate assistant or intern coaches (χ2 = 102.9, p ≤ 0.001). Based on these data, it can be suggested to athletic administrators and strength and conditioning professionals at the collegiate level that budgets need to be re-evaluated as the number of personnel available to monitor student-athletes and the size and safe capacity of the facility are related to the ability of the strength and conditioning staff to safely and adequately perform their duties.


Assuntos
Academias de Ginástica , Futebol Americano , Condicionamento Físico Humano , Treinamento Resistido , Equipamentos Esportivos , Universidades , Academias de Ginástica/economia , Academias de Ginástica/estatística & dados numéricos , Futebol Americano/classificação , Futebol Americano/economia , Futebol Americano/estatística & dados numéricos , Humanos , Decoração de Interiores e Mobiliário/economia , Condicionamento Físico Humano/economia , Condicionamento Físico Humano/instrumentação , Treinamento Resistido/instrumentação , Equipamentos Esportivos/economia , Equipamentos Esportivos/estatística & dados numéricos , Estados Unidos , Universidades/classificação , Universidades/economia , Universidades/estatística & dados numéricos , Recursos Humanos
8.
J Strength Cond Res ; 27(9): 2626-33, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22505129

RESUMO

The rapid growth and expanding use of high school strength and conditioning facilities (SCFs) creates a need to research and better understand these vital facilities. This study was designed to examine SCFs at the high school level including facility size, equipment, leadership/staffing, and safety. A 70-item online survey instrument, developed with expert input from certified strength professionals, was used to collect data regarding the SCFs in high schools throughout a midwestern state, and was distributed via email to a total of 390 high school athletic directors. Survey respondents (n = 108) all reported the presence of SCFs with 95.4% indicating a dedicated SCF space. A strong positive correlation (r = 0.610, p ≤ 0.001) was determined between the variables of SCF size in square feet and school size measured by total enrollment. Analysis of variance and χ² analyses revealed significant differences in equipment, facility size, and safety factors based on the categorical variables of school size and the presence of certified strength and conditioning specialist (CSCS) leadership. It appears the CSCS's application of their scientific knowledge goes beyond training athletes for the goal of improving athletic performance to actually influence the SCF itself. Athletic administrators at the high school level need to recognize the impact CSCS program leadership can have on the overall quality of the strength and conditioning program and facility.


Assuntos
Educação Física e Treinamento/normas , Segurança/normas , Instituições Acadêmicas/normas , Certificação , Coleta de Dados , Humanos , Meio-Oeste dos Estados Unidos , Educação Física e Treinamento/estatística & dados numéricos , Treinamento Resistido/instrumentação , Treinamento Resistido/normas , Treinamento Resistido/estatística & dados numéricos , Segurança/estatística & dados numéricos , Instituições Acadêmicas/estatística & dados numéricos , Esportes/educação , Esportes/normas , Esportes/estatística & dados numéricos , Equipamentos Esportivos/normas , Equipamentos Esportivos/estatística & dados numéricos
9.
J Strength Cond Res ; 27(9): 2456-64, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22505134

RESUMO

This study sought to determine the effectiveness of coach certification courses in promoting proper preactivity and postactivity stretching practices in National Collegiate Athletic Association (NCAA) Division I, II, and III crosscountry programs. Distribution of questionnaires to 770 NCAA Division I, Division II, and Division III programs in the U.S.A. resulted in 111 coaches (88 [78.2%] men and 25 [21.8%] women) participating. Chi-square analyses revealed that noncertified coaches reported significantly greater (χ² = 21.582, p = 0.0174) usage of static stretching alone as their preactivity modality (18.9%, n = 9) vs. their certified counterparts (1.8%, n = 1). In addition, certified coaches reported a higher usage of dynamic flexibility only during the preactivity period (47.4%, n = 27) vs. their noncertified peers (32.4%, n = 16). Coaches were also asked if they allowed for static stretching between interval work and events in track and field, and a significantly higher percentage (χ² = 11.948, p = 0.0177) of noncertified coaches (45.5%, n = 23) reported allowing the athletes to perform static stretches between intervals at practice than certified peers (37.9%, n = 22). These significant differences help demonstrate that coaching certification courses are an effective tool for communicating current information about stretching practices. However, the results also revealed that there are still many certified coaches who are not implementing best practices in preactivity routines.


Assuntos
Exercícios de Alongamento Muscular/métodos , Atletismo/fisiologia , Adulto , Coleta de Dados , Feminino , Humanos , Masculino , Exercícios de Alongamento Muscular/normas , Atletismo/educação , Atletismo/normas , Estados Unidos , Universidades
10.
J Strength Cond Res ; 27(10): 2691-9, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23254548

RESUMO

The purpose of this study is to determine the pre- and postactivity stretching practices of Division I, II, and III track and field throws programs. A 33-item survey instrument was developed to collect data regarding the warm-up and flexibility practices at the National Collegiate Athletic Association (NCAA) Division I (n = 320), Division II (n = 175), and Division III (n = 275) universities. A total of 135 surveys were completed for a 17.5% return rate, and although the response rate was generally low, it did mirror the distribution percentages of the 3 divisions. Significant differences were found for the level of United States Track and Field (USATF) certification and the use of static stretching (SS) between throws (χ = 6.333, p = 0.048). Significance was also found for the USATF certification level and athletic trainer (AT) assistance in performing SS (χ = 13.598, p = 0.01). Significant differences were also found for the NCAA division levels and the use of soft tissue mobilization (χ = 5.913, p = 0.026). Although research supports dynamic warm-up/stretching over other forms of preactivity protocols, it seems that some track-and-field throws coaches are reluctant to completely discontinue preactivity SS. The results of this study suggest that it is necessary for track and field throws coaches to reevaluate their own practices, perhaps better aligning them with current research findings.


Assuntos
Braço/fisiologia , Exercícios de Alongamento Muscular/métodos , Atletismo/fisiologia , Coleta de Dados , Humanos , Masculino , Estados Unidos , Universidades , Adulto Jovem
11.
J Hum Kinet ; 79: 111-122, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34400991

RESUMO

Hydration plays an important role in performance, injury prevention, and recovery for athletes engaged in competitive sports. Therefore, it is important that strength and conditioning coaches understand an athlete's hydration needs to prevent illness and enhance performance. The purpose of this study was to identify hydration knowledge, attitudes, and behaviors of collegiate track and field throwers, as well as identify barriers to hydration and sources of nutritional information. The Rehydration and Refueling in Collegiate Track and Field Throwers Survey was sent to 271 track and field thrower coaches with a request to forward the email to current track and field throwers. Pearson correlation coefficients were calculated regarding knowledge, attitude, and behavior scores among the participants in this sample. Differences among response patterns were assessed via Chi-square analysis. Alpha level was set at p = .05. Results demonstrated that 97.3% (n = 287) of respondents knew that dehydration would decrease performance, but 50.5% (n = 149) erroneously believed thirst was the best indicator of dehydration. Chi-square analysis demonstrated a significant difference in reported values between participants who intended to eat a performance-enhancing diet and those who consumed less fluid than recomended values (207 - 295 m)l in the 2-3 hours prior to competition (χ2 = 10.87, p < .05). Pearson correlation coefficients demonstrated a large association between knowledge and behavior (r = .70, p < .05), a medium association between knowledge and attitude (r = .41, p < .05), and a small association between attitude and behavior (r = .21, p < .05). This suggests that strength and conditioning coaches and health staff need to educate and monitor hydration behaviors among collegiate track and field throwers to optimize performance.

12.
Int J Exerc Sci ; 13(6): 260-272, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32148642

RESUMO

Current pre- and post-activity stretching guidelines are designed to optimize performance and reduce injury risk. However, it is unclear whether soccer coaches adhere to these recommendations. The purpose of this study was to determine if collegiate soccer coaches' perceptions and practices align with current scientific recommendations. A total of 781 questionnaires were electronically distributed to soccer coaches from NCAA Division I and III universities. The questionnaire obtained demographic, professional, and educational information, as well as stretching practices. Statistical analysis consisted of computing frequency counts and means where applicable. Pearson's Chi-square tests were performed to assess the potential differences in stretching perceptions and practices among the cohort of soccer coaches. Results suggest that soccer coaches are choosing some forms of stretching more frequently than other coaches (χ2 = 342.7, p < 0.001). Further analysis failed to determine significant associations between stretching type and coaching certification, level, sex, years of experience, and age. Of the 209 respondents, 84.9% believed pre-activity stretching to be of greater than average importance on a seven-point Likert scale. Dynamic stretching (68.7%) or a combination of static and ballistic stretching (18.0%) prior to athletic events was the most typical stretching prescribed. Current post-activity practices demonstrate that most coaches (95.4%) are using some form of a general cool-down following practice or competition. This study is an important assessment of the extent to which collegiate coaches administer appropriate stretching techniques. Most coaches adhere to current recommendations; however, they should continue to evaluate their practices against ongoing research and the practices of their peers.

13.
Yonsei Med J ; 49(6): 1008-16, 2008 Dec 31.
Artigo em Inglês | MEDLINE | ID: mdl-19108026

RESUMO

PURPOSE: Effect of recombinant human growth hormone (rhGH) administration on lipid storage, and its subsequent effect on insulin sensitivity have not yet been adequately examined. Thus, we investigated the effects of rhGH treatment on muscle triglyceride (TG) and ceramide content, and insulin sensitivity after 4 weeks of rhGH administration in rats. MATERIALS AND METHODS: Fourteen rats were randomly assigned to two groups: rhGH injection group (GH, n = 7) and saline injection group (CON, n = 7). GH received rhGH by subcutaneous injections (130 microg.kg(-1).day(-1), 6 days.week(-1)) for 4 weeks, while CON received saline injections that were equivalent in volume to GH group. Intramuscular TG and ceramide content and hepatic TG content were measured. To determine insulin sensitivity, oral glucose tolerance test (OGTT) and muscle incubation for glucose transport rate were performed in rats, and used as indicators of insulin sensitivity. We also examined plasma lipid profiles. RESULTS: After 4 weeks of rhGH treatment, the GH group had higher muscle and liver TG contents than the CON (p < 0.05). Ceramide content in GH was significantly greater than that in CON (p < 0.05). GH also had higher plasma levels of FFA (p < 0.05), glucose and insulin responses during OGTT (p < 0.05), and lower glucose transport rates in submaximal insulin concentration (p < 0.05) as compared with CON. Results indicate that rhGH treatment is associated with insulin resistance in rats. CONCLUSION: rhGH treatment elevated muscle TG and ceramide content, and hepatic TG content. Thus, elevation of these compounded by rhGH treatment could contribute to the development of insulin resistance in rats.


Assuntos
Hormônio do Crescimento Humano/administração & dosagem , Resistência à Insulina , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Animais , Ceramidas/metabolismo , Glucose/metabolismo , Transportador de Glucose Tipo 4/metabolismo , Humanos , Masculino , Ratos , Ratos Sprague-Dawley , Proteínas Recombinantes/administração & dosagem , Triglicerídeos/metabolismo
14.
J Strength Cond Res ; 20(4): 971-7, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17194256

RESUMO

The purposes of this study were (a) to determine whether a significant strength imbalance existed between the left and right or dominant (D) and nondominant (ND) legs and (b) to investigate possible correlations among various unilateral and bilateral closed kinetic chain tests, including a field test, and traditional isokinetic dynamometry used to determine strength imbalance. Fourteen Division I collegiate women softball players (20.2 +/- 1.4 years) volunteered to undergo measures of average peak torque for isokinetic flexion and extension at 60 degrees .s(-1) and 240 degrees .s(-1); in addition, measures of peak and average force of each leg during parallel back squat, 2-legged vertical jump, and single-leg vertical jump and performance in a 5-hop test were examined. Significant differences of between 4.2% and 16.0% were evident for all measures except for average force during single-leg vertical jump between the D and ND limbs, thus revealing a significant strength imbalance. The 5-hop test revealed a significant difference between D and ND limbs and showed a moderate correlation with more sophisticated laboratory tests, suggesting a potential use as a field test for the identification of strength imbalance. The results of this study indicate that a significant strength imbalance can exist even in collegiate level athletes, and future research should be conducted to determine how detrimental these imbalances could be in terms of peak performance for athletes, as well as the implications for injury risk.


Assuntos
Beisebol/fisiologia , Extremidade Inferior/fisiologia , Força Muscular/fisiologia , Adulto , Análise de Variância , Traumatismos em Atletas/prevenção & controle , Beisebol/lesões , Fenômenos Biomecânicos , Feminino , Humanos , Torque
15.
J Strength Cond Res ; 17(4): 792-800, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-14666945

RESUMO

Seven trained male cyclists (ate 22.3 +/- 2 years) participated in 4 separate supplementation phases. They ingested 2 capsules per day containing the following treatments: placebo (placebo plus placebo); vitamin C (1 g per day vitamin C plus placebo); vitamin C and E (1 g per day vitamin C plus 200 IU per kg vitamin E); and vitamin E (400 IU per kg vitamin E plus placebo). The treatment order (placebo, vitamin C, vitamin C and E, and vitamin E) was the same for all subjects. Performance trials consisting of a 60-minute steady state ride (SSR) and a 30-minute performance ride (PR) on Cybex 100 Metabolic cycles were performed after each trial. Workloads of 70% of the VO2max were set for the SSR and PR rides, with pedal rate maintained at 90 rpm (SSR) or self determined (PR). Blood samples (5 ml) were drawn pre- and postexercise and analyzed for malonaldehyde (MDA) and lactic acid. The results indicate that vitamin E treatment was more effective than vitamin C alone or vitamin C and E. Pre-exercise plasma levels of MDA in the vitamin E trial was 39% below the pre-exercise MDA levels of the placebo: 2.94 +/- 0.54 and 4.81 +/- 0.65 micromol per ml, respectively. Plasma MDA following exercise in the vitamin E group was also lower than teh placebo: 4.32 +/- 0.37 vs 7.89 +/- 1.0 micromol per ml, respectively. Vitamin C supplementation, on the other hand, elevated both the resting and exercise plasma levels of MDA. None of th supplemental phases had any significant effect on performance. In conclusion, the results indicate that 400 IU/day of vitamin E reduces membrane damage more effectively than vitamin C but does not enhance performance. Athletes are encouraged to include antioxidants, such as vitamin E and C, in their diet to counteract these detrimental effects of exercise. The data presented here suggests that 400 IU/day of vitamin E will provide adequate protection but supplementing the diet with 1 g per day of vitamin C may promote cellular damage. However neither of these vitamins, either alone or in combination, will enhance exercise performance.


Assuntos
Antioxidantes/uso terapêutico , Ácido Ascórbico/uso terapêutico , Ciclismo/fisiologia , Peroxidação de Lipídeos/efeitos dos fármacos , Vitamina E/uso terapêutico , Adulto , Análise de Variância , Suplementos Nutricionais , Humanos , Masculino , Malondialdeído/sangue , Análise de Regressão , Método Simples-Cego
16.
J Strength Cond Res ; 17(3): 455-62, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12930169

RESUMO

The purpose of this investigation was to examine the influence of L-carnitine L-tartrate (LCLT) supplementation using a balanced, cross-over, placebo-controlled research design on the anabolic hormone response (i.e., testosterone [T], insulin-like growth factor-I, insulin-like growth factor-binding protein-3 [IGFBP-3], and immunofunctional and immunoreactive growth hormone [GHif and GHir]) to acute resistance exercise. Ten healthy, recreationally weight-trained men (mean +/- SD age 23.7 +/- 2.3 years, weight 78.7 +/- 8.5 kg, and height 179.2 +/- 4.6 cm) volunteered and were matched, and after 3 weeks of supplementation (2 g LCLT per day), fasting morning blood samples were obtained on six consecutive days (D1-D6). Subjects performed a squat protocol (5 sets of 15-20 repetitions) on D2. During the squat protocol, blood samples were obtained before exercise and 0, 15, 30, 120, and 180 minutes postexercise. After a 1-week washout period, subjects consumed the other supplement for a 3-week period, and the same experimental protocol was repeated using the exact same procedures. Expected exercise-induced increases in all of the hormones were observed for GHir, GHif, IGFBP-3, and T. Over the recovery period, LCLT reduced the amount of exercise-induced muscle tissue damage, which was assessed via magnetic resonance imaging scans of the thigh. LCLT supplementation significantly (p < 0.05) increased IGFBP-3 concentrations prior to and at 30, 120, and 180 minutes after acute exercise. No other direct effects of LCLT supplementation were observed on the absolute concentrations of the hormones examined, but with more undamaged tissue, a greater number of intact receptors would be available for hormonal interactions. These data support the use of LCLT as a recovery supplement for hypoxic exercise and lend further insights into the hormonal mechanisms that may help to mediate quicker recovery.


Assuntos
Carnitina/administração & dosagem , Suplementos Nutricionais , Exercício Físico/fisiologia , Hormônio do Crescimento/sangue , Proteína 3 de Ligação a Fator de Crescimento Semelhante à Insulina/sangue , Fator de Crescimento Insulin-Like I/metabolismo , Tartaratos/administração & dosagem , Testosterona/sangue , Administração Oral , Adulto , Análise de Variância , Carnitina/farmacologia , Distribuição de Qui-Quadrado , Estudos Cross-Over , Humanos , Imageamento por Ressonância Magnética , Masculino , Músculo Esquelético/fisiologia , Tartaratos/farmacologia
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