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1.
Sports Biomech ; 19(1): 1-25, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29781788

RESUMO

The use of isometric strength testing, particularly the isometric mid-thigh pull (IMTP) has increased dramatically over the last decade. The IMTP and isometric squat (ISqT) provide one aspect of performance monitoring with variables such as peak force and rate of force development being derived from the force-time curve. The reliability of some of these variables is conflicting in the literature, and the reporting of the reliability is not standardised across the research. The majority of research only reports intraclass correlation coefficients with very few studies reporting coefficient of variation and 90% confidence intervals. Additionally, methods used to calculate variables from the force-time curve differ across studies. An aim of muscle strength testing is to provide normative values for specific sports, allowing coaches to distinguish between performance levels or evaluate the effects of training on performance. This narrative review aims to evaluate studies that have researched the reliability and/or reported normative data for both tests. Additionally, the testing protocols and the force-time curve analysis techniques utilised are discussed, concluding with practical applications for coaches on the uses and limitations of these tests. Results demonstrate that peak force is the most reliable measure and can be used to determine maximum strength capabilities.


Assuntos
Teste de Esforço/métodos , Força Muscular/fisiologia , Coxa da Perna/fisiologia , Levantamento de Peso , Fenômenos Biomecânicos , Humanos , Contração Isométrica/fisiologia , Valores de Referência , Reprodutibilidade dos Testes , Esportes/fisiologia
2.
Sports Med ; 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31691167

RESUMO

BACKGROUND: There has been a recent increase in research examining training load as a method of mitigating injury risk due to its known detrimental effects on player welfare and team performance. The acute:chronic workload ratio (ACWR) takes into account the current training load (acute) and the training load that an athlete has been prepared for (chronic). The ACWR can be calculated using; (1) the rolling average model (RA) and (2) the exponentially weighted moving average model (EWMA). OBJECTIVE: The primary aim of this systematic review was to investigate the literature examining the association between the occurrence of injury and the ACWR and to investigate if sufficient evidence exists to determine the best method of application of the ACWR in team sports. METHODS: Studies were identified through a comprehensive search of the following databases: EMBASE, Medline, SPORTDiscus, SCOPUS, AMED and CINAHL. Extensive data extraction was performed. The methodological quality of the included studies was assessed according to the Newcastle-Ottawa Scale (NOS) for Cohort Studies. RESULTS: A total of 22 articles met the inclusion criteria. The assessment of article quality had an overall median NOS score of 8 (range 5-9). The findings of this review support the association between the ACWR and non-contact injuries and its use as a valuable tool for monitoring training load as part of a larger scale multifaceted monitoring system that includes other proven methods. There is support for both models, but the EWMA is the more suitable measure, in part due to its greater sensitivity. The most appropriate acute and chronic time periods, and training load variables, may be dependent on the specific sport and its structure. CONCLUSIONS: For practitioners, it is the important to understand the intricacies of the ACWR before deciding the best method of calculation. Future research needs to focus on the more sensitive EWMA model, for both sexes, across a larger range of sports and time frames and also combinations with other injury risk factors.

3.
Phys Ther Sport ; 40: 59-65, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31479981

RESUMO

OBJECTIVES: To investigate factors associated with injury in amateur male and female rugby union players. DESIGN: A prospective cohort study. SETTING: Amateur rugby clubs in Ireland. PARTICIPANTS: Male (n = 113) and female (n = 24) amateur rugby union players from 5 of the top 58 amateur clubs in Ireland. MAIN OUTCOME MEASURES: Pre-season testing included physical tests assessing hamstring flexibility, dorsiflexion range of movement, adductor muscle strength and foot position. Wellness questionnaires assessed sleep quality (PSQI), coping skills (ACSI-28) and support levels (PASS-Q). Players were monitored throughout the season for injury. RESULTS: The time-loss match injury incidence rate was 48.2/1000 player hours for males and 45.2/1000 player hours for females. Two risk profiles emerged involving; 'age + navicular drop + training pitch surface' (53%) and 'age + navicular drop + groin strength' (16%). An inverse relationship between groin strength and groin injury was found for the 'backs' players (-0.307, p < 0.05). Using the PSQI, 61% of players had poor sleep quality, however no relationship between the wellness questionnaires and injury was found. CONCLUSION: Two injury risk profiles emerged, associated with subsequent injury occurrence. Using these risk profiles, individualized prevention strategies may be designed regarding deficits in groin muscle strength and identifying foot alignment.

6.
J Strength Cond Res ; 2019 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-31045754

RESUMO

Sinnott-O'Connor, C, Comyns, TM, and Warrington, GD. Validity of session-RPE to quantify training loads in Paralympic swimmers. J Strength Cond Res XX(X): 000-000, 2019-Multiple measures may be used by coaches to quantify training load (TL). The application of heart rate (HR) has limitations in swimming and in Paralympic swimmers, and it may not always be a suitable measure. Therefore, the aim of this study was to determine the validity and reliability of the session-rate of perceived exertion (sRPE) method for quantifying internal TL in Paralympic swimmers. A further aim was to examine the relationship between athlete and coach perceptions of sRPE TL. Four international Paralympic swimmers selected to compete in Rio 2016 Paralympic Games participated in this study. Heart rate, RPE, and session duration were recorded for 30 training sessions of varied intensities across a 6-week home training period to quantify TL. Significant high to very high positive correlations were observed between sRPE and 3 HR-based measures-Banister's, Edwards, and Lucia's TRIMP (r = 0.68, 0.66, 0.74, p < 0.01, respectively). Moderate correlations were observed between sRPE and distance measures (r = 0.53, p < 0.05) but were lower than those observed with HR-based measures. A 2-way analysis of variance identified significant differences in the sRPE ratings between coaches and athletes (F(2, 108) = 170.4, p < 0.01, η = 0.75). The results of this study suggest that the sRPE method may be an appropriate monitoring tool for quantifying TL during water-based training using a single measure in Paralympic swimmers.

7.
Int J Sports Physiol Perform ; : 1-8, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-30958061

RESUMO

PURPOSE: To examine the relationships between the isometric midthigh pull (IMTP), isometric squat (ISqT), and sprint acceleration performance in track-and-field sprinters and to determine whether there are differences between men and women. METHODS: Fifteen male and 10 female sprinters performed 3 maximal-effort IMTPs, ISqTs, and 3 × 30-m sprints from blocks. RESULTS: Among the men, the results showed significant negative correlations between IMTP and ISqT peak force; relative peak force; force at 100, 150, and 200 ms; rate of force development (0-150 and 0-200 ms); and impulse (0-200 ms) and 0- to 5-m time (r = -.517 to -.714; P < .05). IMTP impulse (B = -0.582, P = .023) and ISqT relative peak force (B = -0.606, P = .017) significantly predicted 0- to 5-m time. Among the women, no IMTP or ISqT variables significantly correlated with any sprint times. Men measured significantly higher than women for all IMTP measures except relative peak force. Men were significantly faster than women at all splits. When comparing measures of the ISqT, there were no significant differences between men and women. CONCLUSIONS: Variables measured during the IMTP and ISqT significantly correlated with 0- to 5-m sprint performance in male athletes. Isometric strength can have a sizable influence on 0- to 5-m time, but in some cases, the maximum effect could be very small.

8.
Int J Sports Physiol Perform ; : 1200-1204, 2019 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-30840515

RESUMO

PURPOSE: To examine the interday reliability and usefulness of a reactive strength index (RSI) derived from a maximal 5-rebound jump test (5max RJT) and a maximal 10-rebound jump test (10/5 RJT). METHODS: Twenty male field-sport athletes (24.5 [3.0] y, 1.78 [0.1] m, 84.9 [5.2] kg) and 15 female participants (21.1 [0.9] y, 1.65 [0.73] m, 62.0 [5.1] kg) performed 2 maximal repetitions of the 5max RJT and the 10/5 RJT on 2 testing days after a specific warm-up. A 1-wk period separated testing days, and these sessions were preceded by a familiarization session. RSI was calculated by dividing jump height (in meters) by contact time (in seconds). The 5max RJT and the 10/5 RJT trial with the highest RSI on each testing day were used for reliability and usefulness analysis. RESULTS: Both tests were deemed reliable for determining RSI for male, female, and pooled male and female cohorts, as the intraclass correlation coefficients were ≥.80 and the coefficient of variation was ≤10%. Only the 5max RJT was rated as "good" at detecting the smallest worthwhile change in performance for female athletes (smallest worthwhile change: 0.10 > typical error: 0.07). The 5max RJT for men and the 10/5 RJT for men and women were rated "good" in detecting a moderate change in performance only. CONCLUSIONS: Both tests are reliable for the determination of RSI, but the usefulness of the tests in detecting the smallest worthwhile change is questionable.

9.
J Strength Cond Res ; 33(3): 626-632, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30789857

RESUMO

Comyns, TM, Brady, CJ, and Molloy, J. Effect of attentional focus strategies on the biomechanical performance of the drop jump. J Strength Cond Res 33(3): 626-632, 2019-Motor performance can be influenced by focusing an athlete's attention through the use of verbal instructions. There is limited research on the effect of internal, neutral, and external attentional focus strategies on drop jump (DJ) performance aimed at maximizing height jumped (HJ) and minimizing ground contact time (CT). The purpose of this study was to assess the effect of attentional focus strategies on biomechanical variables related to efficient DJ performance, namely HJ, CT, reactive strength index (RSI), leg-spring stiffness, and peak and relative peak ground reaction force (GRF). Seventeen male recreationally trained subjects performed 2 DJs after listening to instructions designed to evoke an internal, external, or neutral attentional focus. In total, 6 DJs were performed in the testing session, and the order of the instructions was randomly assigned. Significance was set at p ≤ 0.05. Results indicated that, compared with the neutral strategy, the external focus resulted in significantly higher RSI (p = 0.046), peak GRF (p = 0.025), relative GRF (p = 0.02), and leg-spring stiffness (p = 0.02). No significant difference was seen in DJ CT and HJ between all 3 conditions (p ≥ 0.05). These results indicate that the use of an external focus of attention may potentially result in a more effective and efficient fast stretch-shortening cycle performance because of the augmentation of RSI and leg stiffness. More research is warranted, however, because of the lack of significant results pertaining to CT and HJ.


Assuntos
Atenção/fisiologia , Movimento/fisiologia , Desempenho Psicomotor , Adulto , Desempenho Atlético , Fenômenos Biomecânicos , Humanos , Masculino , Força Muscular , Distribuição Aleatória , Adulto Jovem
10.
Phys Ther Sport ; 35: 79-88, 2019 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-30472491

RESUMO

OBJECTIVES: To describe the development, implementation and evaluation of a comprehensive injury surveillance system. DESIGN: The four phases; i) A survey of 58 medical professionals working in amateur rugby. ii) The design of a web-based injury surveillance system (IRISweb). iii) Recruitment of 21 of the top 58 amateur clubs to use IRISweb. iv) An evaluation survey of the 21 participating clubs. SETTING: Irish amateur rugby clubs. PARTICIPANTS: Medical professionals working in amateur rugby. MAIN OUTCOME MEASURES: Phase one investigated the injury monitoring practices in operation prior to the IRIS project. Phase four investigated the effectiveness and usefulness of IRISweb. RESULTS: Twenty-one clubs were recruited, however 2 clubs failed to provide a full season of data (10% dropout rate). Eighty-two percent of the remaining 19 clubs rated IRISweb as 'good' or 'very good'. Facilitators of injury surveillance were; increased player adherence (65%) and notifications to update the system (59%), however, poor player adherence (71%) and medical staff availability (24%) were the main barriers. CONCLUSIONS: The IRIS project is the first prospective long-term injury surveillance system in Irish amateur rugby, effectively tracking injuries to guide future evidence-based injury prevention strategies. This study highlights facilitators and barriers to injury surveillance within amateur sport.


Assuntos
Traumatismos em Atletas/epidemiologia , Monitoramento Epidemiológico , Futebol Americano/lesões , Internet , Atletas , Feminino , Humanos , Irlanda , Masculino , Inquéritos e Questionários
11.
Phys Ther Sport ; 33: 27-32, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29982035

RESUMO

OBJECTIVES: To ascertain current injury surveillance and player education practices in Irish amateur rugby union. DESIGN: Cross-sectional survey. SETTING: Amateur rugby clubs in Ireland. PARTICIPANTS: Medical professionals and rugby coaches of the top 58 amateur rugby clubs in Ireland. MAIN OUTCOME MEASURES: The survey investigated the current injury and training load monitoring practices in operation in Irish amateur rugby. It also explored whether player education sessions regarding injury prevention and concussion recognition and management were conducted in these clubs. RESULTS: Forty-four clubs completed the survey, giving an overall response rate of 76%. Ninety-one percent of the responding clubs monitored injuries. Sixty-four percent of these clubs operated return to play protocols for all injuries, while 36% operated return to play protocols for concussion only. Injury prevention education was conducted by 71% of these clubs and 82% educated players on concussion recognition and management. CONCLUSIONS: Implementing effective injury monitoring strategies in both amateur and professional sport settings may aid in minimizing injury risk. In Ireland, 91% of the responding clubs monitored injuries and 71% educated players on injury prevention. By implementing one centralized injury surveillance system for Irish amateur rugby, injury trends can be effectively monitored and used to guide prevention strategies.


Assuntos
Traumatismos em Atletas/prevenção & controle , Concussão Encefálica/diagnóstico , Concussão Encefálica/terapia , Futebol Americano/lesões , Atletas , Traumatismos em Atletas/diagnóstico , Traumatismos em Atletas/terapia , Estudos Transversais , Humanos , Irlanda , Volta ao Esporte , Inquéritos e Questionários
12.
Sports Med ; 48(4): 837-848, 2018 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-29299876

RESUMO

BACKGROUND: Rugby union is a physically demanding, full-contact team sport that has gained worldwide popularity. The incidence of injury in rugby union has been widely reported in the literature. While comprehensive injury surveillance and prevention programmes have been implemented within the professional game, there is a need for similar strategies in the amateur game. Despite recent increases in the volume of research in rugby, there is little consensus regarding the true incidence rate of match and training injuries in senior amateur male rugby union players. OBJECTIVE: The aim of the current review was to systematically review the available evidence on the epidemiology of time-loss injuries in senior amateur male rugby union players and to subsequently conduct a meta-analysis of the findings. METHODS: A comprehensive search of the PubMed, Scopus, SportDiscus and Google Scholar electronic databases was performed using the following keywords; ('rugby' OR 'rugby union') AND ('amateur' OR 'community') AND ('injur*' OR 'pain*'). Six articles regarding the incidence of injury in senior amateur male rugby union players, in both matches and training, were retrieved and included in the meta-analysis to determine the overall incidence rate of match injury, with descriptive analyses also provided for other reported variables. RESULTS: The overall incidence rate of match injuries within senior amateur rugby union players was 46.8/1000 player hours [95% confidence interval (CI) 34.4-59.2]. Contact events accounted for the majority of injuries, with the tackler more at risk than the player being tackled, and with respective incidence rates of 15.9/1000 player hours (95% CI 12.4-19.5) and 12.2/1000 player hours (95% CI 9.3-15.1). CONCLUSION: This meta-analysis found that the incidence rate of injury in amateur rugby union players was lower than that in professional players, but higher than the incidences reported in adolescent and youth rugby players. By understanding the true incidence and nature of injuries in rugby, injury prevention strategies can best be implemented. Future prevention strategies may best be aimed towards the tackle area, specifically to the tackler, in order to minimize injury risk.


Assuntos
Traumatismos em Atletas/epidemiologia , Futebol Americano/lesões , Adolescente , Adulto , Animais , Austrália/epidemiologia , Humanos , Incidência , Masculino , Adulto Jovem
13.
Int J Sports Physiol Perform ; 13(7): 839-843, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29182422

RESUMO

CONTEXT: Stress responses in athletes can be attributed to training and competition, where increased physiological and psychological stress may negatively affect performance and recovery. PURPOSE: To examine the relationship between training load (TL) and salivary biomarkers immunoglobulin A (IgA), alpha-amylase (AA), and cortisol across a 16-wk preparation phase and 10-d competition phase in Paralympic swimmers. METHODS: Four Paralympic swimmers provided biweekly saliva samples during 3 training phases-(1) normal training, (2) intensified training, and (3) taper-as well as daily saliva samples in the 10-d Paralympic competition (2016 Paralympic Games). TL was measured using session rating of perceived exertion. RESULTS: Multilevel analysis identified a significant increase in salivary immunoglobulin A (sIgA: 94.98 [27.69] µg·mL-1), salivary alpha-amylase (sAA: 45.78 [19.07] µg·mL-1), and salivary cortisol (7.92 [2.17] nM) during intensified training concurrent with a 38.3% increase in TL. During the taper phase, a 49.5% decrease in TL from the intensified training phase resulted in a decrease in sIgA, sAA, and salivary cortisol; however, all 3 remained higher than baseline levels. A further significant increase was observed during competition in sIgA (168.69 [24.19] µg·mL-1), sAA (35.86 [16.67] µg·mL-1), and salivary cortisol (10.49 [1.89] nM) despite a continued decrease (77.8%) in TL from the taper phase. CONCLUSIONS: Results demonstrate that performance in major competition such as Paralympic games, despite a noticeable reduction in TL, induces a stress response in athletes. Because of the elevated stress response observed, modifications to individual postrace recovery protocols may be required to enable athletes to maximize performance across all 10 d of competition.


Assuntos
Comportamento Competitivo/fisiologia , Pessoas com Deficiência/psicologia , Condicionamento Físico Humano , Saliva/química , Estresse Psicológico , Natação/fisiologia , Natação/psicologia , Adolescente , Biomarcadores/análise , Feminino , Humanos , Hidrocortisona/análise , Imunoglobulina A/análise , Masculino , Estresse Psicológico/fisiopatologia , Adulto Jovem , alfa-Amilases/análise
14.
Int J Sports Physiol Perform ; 13(7): 844-852, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29182457

RESUMO

PURPOSE: To examine the reliability and usefulness of the isometric midthigh pull (IMTP) and isometric squat (ISqT) performed at the same knee and hip angles. The scores produced in each test were compared to determine the magnitude of differences between tests. METHODS: Twenty-six male and female athletes (age, 23.6 [4.3] y; height, 1.75 [0.07] m; and body mass, 68.8 [9.7] kg) performed 2 maximal repetitions of the IMTP and ISqT following a specific warm-up. RESULTS: Maximum force, absolute peak force (PF), relative PF, allometrically scaled PF, rate of force development (0-200 and 0-250 ms), and impulse (0-300 ms) were deemed reliable (intraclass correlation coefficient [ICC] ≥.86 and coefficient of variation [CV] ≤9.4%) in the IMTP and ISqT based on predetermined criteria (ICC ≥.8 and CV ≤10%). Impulse (0-200 and 0-250 ms) was reliable in the ISqT (ICC ≥.92 and CV ≤9.9%). Participants produced significantly (P < .05) greater PF and impulse (0-300 ms) during the ISqT compared with the IMTP. When split by sex, female participants produced significantly greater PF (P = .042) during the ISqT, with no significant differences among male participants (P = .245). Both tests are capable of detecting changes in performance in maximum force and absolute PF. CONCLUSIONS: Both tests are reliable for non-time-dependent maximal strength measures when measured at the same knee and hip angles. The ISqT may be preferred when coaches want to test an athlete's true maximum lower-limb strength, especially female athletes.


Assuntos
Teste de Esforço/métodos , Adulto , Estudos Transversais , Feminino , Quadril/fisiologia , Humanos , Contração Isométrica , Joelho/fisiologia , Masculino , Força Muscular/fisiologia , Reprodutibilidade dos Testes , Fatores Sexuais , Coxa da Perna/fisiologia , Adulto Jovem
15.
J Sports Med Phys Fitness ; 58(12): 1728-1734, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29199780

RESUMO

BACKGROUND: The purpose of this study was to investigate the effects of increased training volume during a 10-day training camp on competitive performance and internal training load (ITL). In addition, coach and swimmer rating of perceived exertion (RPE) for each session was compared. METHODS: Ten national level swimmers (gender: 4 males and 6 females; age: 15±1 years; height: 170.5±6.4 cm; body mass: 61.4±7.4 kg) participated in the training camp which involved a 36% increase in swimming volume. Competitive performance, as assessed using the FPS (FINA points system), was recorded pre and post-camp. ITL was recorded using the Session-RPE method and RESTQ-52 Sport questionnaire for each session and for day 1, 5 and 10 of the camp, respectively. Coach RPE was recorded after each training session for coach-swimmer RPE comparisons. RESULTS: Competitive performance increased by 7.1% from pre-camp to post-camp (P=0.001, dz=1.6). Session-RPE increased between day 1 and all other days of the training camp (P<0.05), except day 6 (P=0.221). The injury scale of the RESTQ questionnaire increased from day 1 to day 5 (P=0.022). Across 16 swimming sessions, there was a strong correlation between coach and swimmer RPE (rs=0.76) however RPE was found to be higher for the swimmers than the coach (P≤0.0005) during moderate training sessions. CONCLUSIONS: These findings suggest that a 36% increase in swimming volume during a 10 day training camp resulted in significant changes to competitive performance and ITL. However, coach and swimmer RPE should be monitored closely during future camps.


Assuntos
Desempenho Atlético/fisiologia , Comportamento Competitivo , Condicionamento Físico Humano/métodos , Natação/fisiologia , Adolescente , Atletas , Feminino , Humanos , Masculino , Esforço Físico , Inquéritos e Questionários
16.
J Hum Kinet ; 57: 147-158, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28713467

RESUMO

The debate over low-volume, high-intensity training versus high-volume, low-intensity training, commonly known as Quality versus Quantity, respectively, is a frequent topic of discussion among swimming coaches and academics. The aim of this study was to explore expert coaches' perceptions of quality and quantity coaching philosophies in competitive swimming and to investigate their current training practices. A purposeful sample of 11 expert swimming coaches was recruited for this study. The study was a mixed methods design and involved each coach participating in 1 semi-structured interview and completing 1 closed-ended questionnaire. The main findings of this study were that coaches felt quality training programmes would lead to short term results for youth swimmers, but were in many cases more appropriate for senior swimmers. The coaches suggested that quantity training programmes built an aerobic base for youth swimmers, promoted technical development through a focus on slower swimming and helped to enhance recovery from training or competition. However, the coaches continuously suggested that quantity training programmes must be performed with good technique and they felt this was a misunderstood element. This study was a critical step towards gaining a richer and broader understanding on the debate over Quality versus Quantity training from an expert swimming coaches' perspective which was not currently available in the research literature.

17.
J Strength Cond Res ; 31(3): 837-847, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27465628

RESUMO

Nugent, FJ, Comyns, TM, Burrows, E, and Warrington, GD. Effects of low-volume, high-intensity training on performance in competitive swimmers: a systematic review. J Strength Cond Res 31(3): 837-847, 2017-The purpose of this systematic review was to examine the extent and quality of the current research literature to determine the effects of low-volume, high-intensity training (HIT) on physiological performance and swimming performance in competitive swimmers. The methodology followed the preferred reporting items for systematic review and meta-analysis protocol. A search of relevant databases and conference proceedings was performed until December 2015. The inclusion criteria were (a) competitive swimmers, (b) ≥4 weeks HIT intervention, (c) comparison group had to involve a higher training volume, (d) outcome measures of physiological and swimming performance, and (e) all experimental study designs. Quality assessment was performed using the Quality Index checklist. Results indicate that of the 538 studies retrieved, 7 studies met the inclusion criteria. Six of the 7 studies found that an HIT intervention resulted in significant improvements in physiological performance. Four of the 7 studies found that HIT resulted in significant improvements in swimming performance, whereas none of the 7 studies resulted in a reduction in physiological or swimming performance. Despite the positive findings of this review, the short study duration is a limitation to a number of studies. The current evidence on the effects of HIT on performance is promising; however, it is difficult to draw accurate conclusions until further research has been conducted.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Exercício/fisiologia , Natação/fisiologia , Humanos , Projetos de Pesquisa , Fatores de Tempo
18.
J Strength Cond Res ; 26(6): 1601-8, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21921816

RESUMO

The purpose of this investigation was to determine the concurrent validity of a commonly used electronic switch mat (ESM), or jump mat, compared with force plate (FP) data. The efficiency of collection and accuracy of data are paramount to athlete and player field testing for the strength and conditioning coach who often has access only to a jump mat. Ten subjects from 5 different sporting backgrounds completed 3 squat jumps (SJs), 3 countermovement jumps (CMJs), and 3 drop jumps (DJs). The jumps were performed on an AMTI FP operating at 1,000 Hz with an ESM positioned on top of the platform. All the subjects were experienced with the protocols involved with jump testing. The resulting absolute errors between FP and ESM data were 0.01, 0.02, and 0.01 m for CMJ, SJ, and DJ heights, respectively. However, the coefficient of variation for the DJ contact time (CT) was 57.25%, CMJ (r = 0.996), and SJ (r = 0.958) heights correlated very strongly with force platform data, and DJ data were not as strong (r = 0.683). Confidence interval tests revealed bias toward CMJ and SJ (p < 0.05). The jump mat can accurately calculate the CMJ height, SJ height, and reactive strength index for all the 3 jump protocols. However, the faster CTs and rapid movements involved in a DJ may limit its reliability when giving measures of CT, flight time, and height jumped for DJs. Strength and conditioning coaches can use such a jump mat device with the confidence that it is accurately producing valid measurements of their athlete's performance for CMJ and SJ slow SSC protocols.


Assuntos
Exercício/fisiologia , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Exercício Pliométrico/instrumentação , Esportes/fisiologia , Desempenho Atlético , Fenômenos Biomecânicos , Humanos , Aptidão Física , Reprodutibilidade dos Testes , Análise e Desempenho de Tarefas , Adulto Jovem
19.
J Strength Cond Res ; 25(8): 2177-84, 2011 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-21572355

RESUMO

The aim of this study was to investigate the recovery process of a maximal stretch-shortening cycle (SSC) fatigue workout on the biomechanical performance of drop jump (DJ) and rebound jump (RBJ) on a force sledge apparatus. Thirteen elite level rugby players performed sledge DJs and RBJs before and 15, 45, 120, and 300 seconds after a maximum SSC fatigue workout. Flight time, ground contact time (CT), peak force, reactive strength index (RSI), and leg-spring stiffness were the dependent variables. The DJ results showed that after 15 seconds recovery, there was a significant reduction in flight time (FT) (p < 0.01), RSI (p < 0.001), peak force (p < 0.01), and leg stiffness (p < 0.001). Similarly, the results for the RBJ indicated that the fatigue workout significantly reduced FT (p < 0.001), peak force (p < 0.01), RSI (p < 0.01), and significantly increased CT (p < 0.05) at the 15-second interval. The results also indicated a potentiation effect at the 300-second interval because of significant increases in RSI, peak force, and leg stiffness (p < 0.05) for the RBJ and significant increases in RSI (p < 0.05), peak force, and leg stiffness (p < 0.01) and a significant decrease in ground CT (p < 0.05) for the DJ. A maximal SSC fatigue workout had both an inhibiting and potentiating effect on DJ and RBJ performance depending on the recovery interval. The efficiency of the SSC function was reduced immediately after the cessation of the fatigue workout. A potentiation effect was evident for both jumps 300 seconds postfatigue.


Assuntos
Futebol Americano/fisiologia , Fadiga Muscular/fisiologia , Recuperação de Função Fisiológica , Atletas , Humanos , Perna (Membro)/fisiologia , Masculino , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Adulto Jovem
20.
J Strength Cond Res ; 24(3): 610-8, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20145557

RESUMO

This study was undertaken to examine the effect of a heavy weight training exercise on sprinting performance and on the effect of repeated exposure to a complex training protocol. Eleven male rugby union players (age 20.9 +/- 3.1 years) participated in the study, which involved 5 separate testing sessions. Back squat 3 repetition maximum (3RM) was established in session 1. Sessions 2-5 were identical and involved the subjects completing a 30-m sprint before and after a 3RM back squat protocol. Four minutes of rest was given between the back squatting and the posttest 30-m sprint. All sprint trials were measured with a laser measurement device (LAVEG, Jenoptik, Jena, Germany). Sprint time and instantaneous, average, and maximum velocity were the dependent variables. The criterion for significance was set at an alpha level of p > or = 0.05. No significant improvement was evident for any of the testing sessions (p > or = 0.05). In session 1, there was a significant increase in 30-m time and a significant reduction in average 30-m velocity and maximum velocity (p < 0.05). The expected benefits in sprinting may not have been realized because of intra and intersubject variations in sprint technique. The session x phase interaction revealed a significant improvement in the pre to posttest changes in instantaneous velocity at 20 m (p = 0.035) and 30 m (p = 0.036) from session 1 to session 4. This indicates that the rugby players may be able to learn to apply the potentiation effects of complex training. From a practical perspective, players may need repeated exposure to this training modality to gain benefit from it, and this should be reflected in program planning.


Assuntos
Futebol Americano/fisiologia , Treinamento de Resistência , Corrida/fisiologia , Desempenho Atlético/fisiologia , Humanos , Masculino , Resistência Física/fisiologia , Fatores de Tempo , Adulto Jovem
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