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1.
Biol Sport ; 39(3): 537-545, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35959327

RESUMO

This study examined the effect of a 10-week programme of strength training with elastic band (STEB) on fitness components in young female handball players. Twenty-six young female handball players (aged 15.8 ± 0.2 years) from the same club participated in this study. They were randomly assigned between experimental (EG; n = 13) and control (CG; n = 13) groups. The EG performed the STEB, replacing some handball-specific drills in the regular handball training. The CG followed the regular handball training (i.e., mainly technical-tactical drills, small sided and simulated games, and injury prevention drills). Two-way analyses of variance were used to assess: handgrip; back extensor strength; medicine ball throw; 30 m sprint times; Modified Illinois change-of-direction (Illinois-MT); four jump tests: squat jump (SJ), countermovement jump (CMJ), countermovement jump with arm swing (CMJA) and five-jump test (5JT); static (Stork test) and dynamic balance (Y Balance Test); and repeated sprint T-test (RSTT). Results revealed significant gains in handgrip - right (p < 0.001, d = 1.75: large), handgrip - left (p < 0.001, d = 2.52: large), back extensor (p < 0.001, d = 2.01: large), and medicine ball throw (p = 0.002, d = 0.95: large) with EG compared to the CG. The EG also demonstrated greater improvement in sprint performance over 20 m (Δ = 10.6%, p = 0.001, d = 1.07: large) and 30 m (Δ = 7.2%, p < 0.0001, d = 1.56: large) compared to the CG. The EG showed better Illinois-MT (Δ = 5.6%, p = 0.034, d = 0.62: medium) compared to the CG. Further, EG posted significant improvements in the SJ (Δ = 17.3%, p = 0.048, d = 0.58: medium), CMJ (Δ = 17.7%, p = 0.017 d = 0.71: medium), and CMJA (Δ = 16.3%, p = 0.019, d = 0.69: medium) compared to the CG. Similarly, the EG exhibited significant improvement in RSTT best time [p = 0.025, d = 0.66 (medium)], RSTT mean time [p = 0.019, d = 0.69 (medium)] and RSTT total time [p = 0.019, d = 0.69 (medium)] compared to the CG. In conclusion, the 10-week STEB improved the physical abilities in young female handball players.

2.
Front Psychol ; 13: 854208, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35496175

RESUMO

Athletic features distinguishing experts from non-experts in team sports are relevant for performance analyses, talent identification and successful training. In this respect, perceptual-cognitive factors like decision making have been proposed to be important predictor of talent but, however, assessing decision making in team sports remains a challenging endeavor. In particular, it is now known that decisions expressed by verbal reports or micro-movements in the laboratory differ from those actually made in on-field situations in play. To address this point, our study compared elite and amateur players' decision-making behavior in a near-game test environment including sport-specific sensorimotor responses. Team-handball players (N = 44) were asked to respond as quickly as possible to representative, temporally occluded attack sequences in a team-handball specific defense environment on a contact plate system. Specifically, participants had to choose and perform the most appropriate out of four prespecified, defense response actions. The frequency of responses and decision time were used as dependent variables representing decision-making behavior. We found that elite players responded significantly more often with offensive responses (p < 0.05, odds ratios: 2.76-3.00) in left-handed attack sequences. Decision time decreased with increasing visual information, but no expertise effect was found. We suppose that expertise-related knowledge and processing of kinematic information led to distinct decision-making behavior between elite and amateur players, evoked in a domain-specific and near-game test setting. Results also indicate that the quality of a decision might be of higher relevance than the required time to decide. Findings illustrate application opportunities in the context of performance analyses and talent identification processes.

4.
Int J Sports Physiol Perform ; 17(6): 901-907, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35235906

RESUMO

PURPOSE: In elite team handball, talent identification and selection of the best young players is a fundamental process in several national federations and clubs; however, literature addressing the specific game-based performance in team handball is almost nonexistent. Consequently, the aim of the study was to assess and compare the team-handball-specific game-based performance of elite male team handball players of different ages. METHODS: Twelve under-23, 10 under-19, 10 under-17, and 10 under-15 elite male players performed the team-handball game-based performance test. During testing, oxygen uptake, heart rate, sprinting time in defense, offense, fast breaks, and fast retreats, as well as ball velocity and jump height in the jump shot, were measured. RESULTS: Significant differences (P < .05) between under-23, under-19, under-17, and under-15 players were found for absolute peak oxygen uptake, defense, offense and fast break time, ball velocity, and jump height in the game-based performance test, as well as in body weight and height. CONCLUSION: The results revealed that with increasing age, elite male team handball players are heavier and taller (body weight and height); faster (team-handball offense, defense, and fast break); jump higher and throw faster (in the team-handball jump shot); and perform better aerobically (absolute peak oxygen uptake). The better performance in the under-23 and under-19 players compared with male adult players competing in a lower National Federation league (not on top-elite level) demonstrates that highly specific game-based physical performance determines the potential for developing young male team handball players for competition at the top level.


Assuntos
Desempenho Atlético , Adolescente , Adulto , Desempenho Atlético/fisiologia , Estatura , Peso Corporal , Teste de Esforço/métodos , Humanos , Masculino , Oxigênio
5.
PLoS One ; 16(6): e0253333, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34170964

RESUMO

Despite Dual Careers (sports and education) and mobility of students being priorities in the funding policies of the European Commission, migrating student-athletes report severe challenges and decreased performance or dropouts at sport and academic levels. The objective of this study was to depict and assess the perceptions on challenges, support services, and their effectiveness in consideration of specific characteristics of participants and migrations. Based on a meta-synthesis and previous findings, a 50-items questionnaire was developed and completed by 245 student-athletes in 5 European countries. Participants with Dual Careers migration experience (n = 140) were considered for analyses of qualitative and quantitative (ordinal 5pt-Likert-scaled and metric) data on the Dual Career status, migration characteristics, received services, and outcomes. Chi-square-tests were conducted for differences between countries and genders at a significance level of p < .05. Country-related differences were found for experiences and intentions to migrate (X2(12) = 50.52, p<0.001), duration of the migration (X2(16) = 38.20, p = 0.001), financial support (X2(8) = 29.87, p<0.001), and decreased performances in academics (X2(16) = 56.12, p<0.001) and sports (X2(16) = 31.79, p = 0.01). Gender-related difference emerged in financial support (X2(4) = 10.68, p = 0.03), duration of the migration (X2(4) = 14.56, p = 0.01), and decreased academic performance (X2(4) = 10.57, p = 0.03). Tutoring and counselling support was ranked as the most effective support, especially when received from the academic field (4.0±1.0 pt) and others (4.1±0.8 pt), followed by online services from sport and academic sectors (both: 3.9±0.9 pt). Considering the pervasive globalization of sport and education, Dual Career migration can contribute to the development of a European sport culture. The high ratio of migrating student-athletes underlines the relevance of migrations in the field of Dual Careers. This study contributes to the literature by adding insights on practices, challenges, supports, and outcomes perceived by student-athletes migrating in Europe. Moreover, country- and gender-related differences support the consideration of specific characteristics and reveal critical factors in specific target groups. The findings contribute to identifying requirements and effective support measures in Dual Career migrations and can be used to improve support services.


Assuntos
Atletas , Emigração e Imigração , Esportes , Estudantes , Inquéritos e Questionários , Adulto , Europa (Continente) , Feminino , Humanos , Masculino , Percepção
6.
J Strength Cond Res ; 35(Suppl 12): S70-S75, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32149873

RESUMO

ABSTRACT: Hajek, F, Keller, M, Taube, W, von Duvillard, SP, Bell, JW, and Wagner, H. Testing-specific skating performance in ice hockey. J Strength Cond Res 35(12S): S70-S75, 2020-Skating performance generally determines overall performance in ice hockey but has not been measured adequately in the past. Consequently, the aim of the study was to develop and validate a specific overall skating performance test for ice hockey (SOSPT) that includes similar movements and intensities as in competition. Ten male elite under-14-year and under-18-year old ice hockey players performed the SOSPT (2 heats only) and a 40-m on-ice sprinting test twice within 8 days. Additionally, 14 under-15, 18 under-17, and 20 under-20 male elite ice hockey players performed only the SOSPT (4 heats). Time was measured from the first subject's movement during a V-start until crossing the line (40-m on-ice sprinting test), first touch of the shoulder on the mat (heat #1 in the SOSPT) or first touch of the puck with the stick (heat #2 in the SOSPT) using a hand stopwatch. We found a high test-retest reliability of the SOSPT and 40-m on-ice sprinting test (interclass correlation coefficient, >0.7; coefficient of variation, <5%) with highly significant differences (p < 0.001) between the under-15, under-17, and under-20 players, a high correlation (r > 0.70) between an expert rating and the SOSPT, and a low correlation between the 40-m on-ice sprinting test and the SOSPT in the under-14 and under-18 players. The results of the study reveal that the SOSPT is a reliable and valid test to determine the specific overall skating performance in ice hockey players and is more suitable compared with straight skating tests of the 40-m on-ice sprinting test.


Assuntos
Hóquei , Patinação , Teste de Esforço , Humanos , Masculino , Movimento , Reprodutibilidade dos Testes
7.
Mol Phylogenet Evol ; 155: 107016, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-33242582

RESUMO

Social parasitism, i.e. the parasitic dependence of a social species on another free-living social species, is one of the most intriguing phenomena in social insects. It has evolved to various levels, the most extreme form being inquiline social parasites which have lost the worker caste, and produce only male and female sexual offspring that are reared by the host worker force. The inquiline syndrome has been reported in 4 species within the ant genus Plagiolepis, in Europe. Whether inquiline social parasitism evolved once or multiple times within the genus remains however unknown. To address this question, we generated data for 5 inquiline social parasites - 3 species previously described and 2 unidentified species - and their free-living hosts from Europe, and we inferred their phylogenetic relationships. We tested Emery's rule, which predicts that inquiline social parasites and their hosts are close relatives. Our results show that inquiline parasitism evolved independently at least 5 times in the genus. Furthermore, we found that all inquilines were associated with one of the descendants of their most related free-living species, suggesting sympatric speciation is the main process leading to the emergence of the parasitic species, consistent with the stricter version of Emery's rule.


Assuntos
Formigas/fisiologia , Evolução Biológica , Interações Hospedeiro-Parasita , Parasitos/fisiologia , Animais , Feminino , Masculino , Modelos Teóricos , Filogenia , Simbiose
8.
Heliyon ; 6(9): e04937, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32984618

RESUMO

Computerized wobble boards (WB) are used to objectively assess balance in healthy and chronic ankle instability individuals. As in field setting health professionals might not own WB, objective evaluations are not always feasible. Therefore, the aim of this tudy was to investigate the contribution of sagittal plane joints angular-displacement and anthropometrics to predict equations to estimate WB performance by portable two-dimensional motion analysis (2D-MA) and cross-validate the developed equations in chronic ankle instability individuals. Thirty-nine healthy and twenty chronic ankle instability individuals stood on a WB in single stance position. The balance test consisted of three 30s trials per limb keeping the platform flat at 0°. Trials were video recorded, and three time-segments joints angular-displacement analyzed with 2D-MA: segment 1 (T1) including 30s data, segment 2 (T2) from second 0 to 10, segment 3 (T3) only the first 5s. Mixed regression for multilevel models was used to estimate WB performance for each time-segment and to examine limb differences for the predicted WB performance in chronic ankle instability sample. The accuracy of the equations to detect injured limbs was calculated via area under the curve for receiver operating characteristic. Ankle and knee angular-displacement parameters, body height and lower limb length were the major predictors of WB performance for the extrapolated models (p < 0.05; R2 = 0.83-0.56). The measured WB performance and T1 model showed significant (p < 0.05) performance differences between the injured and uninjured limbs. Receiver operating characteristic analysis showed an asymptotic significance of 0.03 for T1 equation with area under the curve of 0.70. The proposed models provide different methods to quantify the performance and accurately detect the injured limb in individuals with unilateral chronic ankle instability, when measuring balance via WB might not be feasible. App-makers may use the equations to provide an automatic all-in-one system to monitor the performance status and progress.

9.
Obes Surg ; 30(11): 4325-4330, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32666414

RESUMO

BACKGROUND: Laparoscopic conversion of Nissen Fundoplication to Roux-en-Y gastric bypass (RYGB) is a complex procedure due to increased operative time, morbidity, and length of hospital stay (LOS). In this study, a new simplified technique avoiding the total dismantling of the previous Nissen repair to construct the gastric pouch, the so-called hug technique is presented for the conversion of Nissen fundoplication to RYGB. METHODS: The present study is a prospective single-center clinical series reporting on the feasibility and safety of the "hug" technique for the creation of laparoscopic RYGB. The major innovation of this approach is the fact that the posterior part of the fundoplication wrap is left in place without further dissection or manipulation. The anterior part is stapled and remains attached to the excluded stomach. Prospective data on intraoperative and postoperative morbidity and bariatric outcomes were collected. RESULTS: A total of 44 consecutive patients with a mean body mass index (BMI) of 43.7 kg/m2 (SD = 4.0, range = 35.6-52.0) underwent the "hug" procedure between 2004 and 2015. Mean operative time was 72 min (58-105 min). Morbidity was 4.5%, with no mortality. For patients with follow-up at 3 years, the percentage of total body weight loss (%TBWL) was 32.5%; the excess weight loss (EWL) was 64.2%. CONCLUSION: In contrast to current other techniques of bariatric surgery for patients having previously undergone a Nissen fundoplication, the "hug" procedure to create an RYGB is safe and simple to perform. This technique avoids the deconstruction of the previous repair and is still maintaining anti-reflux anatomy. Nevertheless, there is a need for further studies to evaluate the long-term outcomes of the procedure.


Assuntos
Derivação Gástrica , Refluxo Gastroesofágico , Laparoscopia , Obesidade Mórbida , Fundoplicatura , Refluxo Gastroesofágico/cirurgia , Humanos , Obesidade Mórbida/cirurgia , Estudos Prospectivos , Estudos Retrospectivos , Resultado do Tratamento
10.
Int J Sports Physiol Perform ; 15(7): 1019-1025, 2020 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-32534447

RESUMO

PURPOSE: To determine the effect of in-season differential training on volleyball spike-jump technique and performance in elite-level female players. METHODS: During the season, spike jumps of 12 elite female players (Austrian Volleyball League Women) were recorded by 13 Qualisys Oqus cameras (250 Hz) and an AMTI force plate (1000 Hz). First measurement was made at the beginning of the investigation. Two identical measurements were repeated after a first and a second interval. The first interval served as control phase. The second interval was comparable in length and regular program but included differential training (6 wk, 8 sessions of 15-20 min) as a modified warm-up. It addressed specific performance determinants. Analyses of variances were calculated for the 3 measurements and for the development during control and intervention phase. RESULTS: Initial jump height (0.44 [0.09] m) changed by -4.5% during the control phase and +11.9% during the intervention (P < .001, ηp2=.70). All approach variables, arm backswing, and velocity-conversion strategy improved compared with the control phase (Δ%: 6.1-51.2%, P < .05, ηp2=.40-.80). Joint angles, countermovement depth, maximal angular velocities, and torso incline were not affected (Δ%: -2.9-9.1%, P = .066-.969, ηp2=.00-.27). CONCLUSIONS: In-season differential training led to technical adaptations and increased spike-jump height in elite female players. The differential training program allowed players to experience a range of adaptability and to adjust toward an individual optimum in technical components of performance determinants. Coaches are encouraged to apply technical differential training to elite athletes and to target biomechanical performance factors specifically.

11.
Mol Biol Evol ; 37(8): 2211-2227, 2020 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-32181804

RESUMO

Understanding how organisms adapt to extreme environments is fundamental and can provide insightful case studies for both evolutionary biology and climate-change biology. Here, we take advantage of the vast diversity of lifestyles in ants to identify genomic signatures of adaptation to extreme habitats such as high altitude. We hypothesized two parallel patterns would occur in a genome adapting to an extreme habitat: 1) strong positive selection on genes related to adaptation and 2) a relaxation of previous purifying selection. We tested this hypothesis by sequencing the high-elevation specialist Tetramorium alpestre and four other phylogenetically related species. In support of our hypothesis, we recorded a strong shift of selective forces in T. alpestre, in particular a stronger magnitude of diversifying and relaxed selection when compared with all other ants. We further disentangled candidate molecular adaptations in both gene expression and protein-coding sequence that were identified by our genome-wide analyses. In particular, we demonstrate that T. alpestre has 1) a higher level of expression for stv and other heat-shock proteins in chill-shock tests and 2) enzymatic enhancement of Hex-T1, a rate-limiting regulatory enzyme that controls the entry of glucose into the glycolytic pathway. Together, our analyses highlight the adaptive molecular changes that support colonization of high-altitude environments.


Assuntos
Aclimatação/genética , Formigas/genética , Evolução Biológica , Genoma de Inseto , Seleção Genética , Animais , Clima Frio , Proteínas de Choque Térmico/genética
12.
J Sci Med Sport ; 23(2): 194-199, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31601458

RESUMO

OBJECTIVES: The multifaceted characteristic and task-specificity of postural control clearly reflects the need of knowing which factors could influence the balance measures in order to provide reliable and unbiased information. Therefore, this study aimed to investigate the effects of selected anthropometric characteristics, sex, lower limb's strength and dominance on the Y balance test (YBT). DESIGN: Descriptive laboratory study. METHODS: Forty-two young adults performed the YBT. The raw and normalized reach distances values were recorded. ANOVA was used to examine differences between sex and limb dominance, whereas multiple linear regression models were built to identify variables associated with better postural control. RESULTS: No significant sex differences were observed, except for the normalized anterior direction (p=0.0324). No significant differences between limbs emerged. Regression models significantly explained between 8-49% of the variance. Trunk length, strength, and the interaction between sex with strength were the major predictors of the raw measures. Unexpectedly, lower limb length explained only 0.08% of the raw anterior direction variance. Strength and its interaction with sex were positively associated with normalized measures. Surprisingly, the relative lower limb length variable was negatively associated with the normalized measures. Each % point increase in relative lower limb length was associated with a decrease in normalized performance ranging from 1.73 to 4.91%. CONCLUSIONS: Anthropometric characteristics, sex and lower limb strength differently influenced the YBT measures, regardless of limb dominance. Consequently, these variables should be controlled to limit the variability for an accurate evaluation of postural balance, especially if different YBT measures are used.


Assuntos
Extremidade Inferior/fisiologia , Força Muscular , Equilíbrio Postural , Adulto , Antropometria , Feminino , Voluntários Saudáveis , Humanos , Masculino , Fatores Sexuais
13.
J Strength Cond Res ; 34(6): 1709-1715, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29481451

RESUMO

Fusco, A, Giancotti, GF, Fuchs, PX, Wagner, H, Varalda, C, Capranica, L, and Cortis, C. Dynamic balance evaluation: reliability and validity of a computerized wobble board. J Strength Cond Res 34(6): 1709-1715, 2020-Computerized wobble boards (WBs) are inexpensive, transportable, and user-friendly devices to objectively quantify the dynamic balance performances out of laboratory settings, although it has not been established if they are reliable and valid tools. Therefore, the purpose of this study was to determine the reliability and validity of a computerized WB. Thirty-nine (18 females and 21 males) young adults (age: 23.3 ± 2.1 years; body mass: 65.9 ± 1.8 kg; height: 168.2 ± 8.8 cm; leg length: 78.8 ± 5.7 cm; and body mass index: 23.2 ± 2.1 kg·m) participated in the study. Subjects were assessed during 3 separate sessions on different days with a 48-hour rest in between. A total number of 2 WB single limb tests and 1 Y Balance Test (YBT) were performed. The WB performance was registered using the proprietary software and represented by the time spent in the target zone, which represented the 0° tilt angle measured by the triaxial accelerometer in the WB. YBT normalized reach distances were recorded for the anterior, posteromedial, and posterolateral directions. Intraclass correlation coefficient, 95% confidence interval, SEM, minimal detectable change, and Bland-Altman plots were used to evaluate intrasession and intersession reliability, whereas Pearson product moment correlation was used to determine concurrent validity. Reliability ranged from fair to excellent, showing acceptable levels of error and low minimal detectable change. However, all correlation coefficients between WB and YBT outcomes were poor. Despite the 2 methods addressing different aspects of balance performance, WB seems to validly serve its purpose and showed good reliability. Therefore, computerized WBs have the potential to become essential devices for dynamic balance assessment.


Assuntos
Modalidades de Fisioterapia , Equilíbrio Postural/fisiologia , Adulto , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes , Adulto Jovem
14.
J Sports Sci ; 37(21): 2411-2419, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31280702

RESUMO

There are well-known biological differences between women and men, especially in technical-coordinative variations that contribute to sex differences in performance of complex movements like the most important offensive action in volleyball, the spike jump. The aim of this study was to investigate sex-dependent performance and biomechanical characteristics in the volleyball spike jump. Thirty female and male sub-elite volleyball players were analysed while striking a stationary ball with maximal spike jump height. Twelve MX13 Vicon cameras with a cluster marker set, two AMTI force plates, surface EMG, and a Full-Body 3D model in Visual3D were used. Main findings include sex differences (P< .05) in jump height (pη2 = .73), approach [speed (pη2 = .61), step length], transition strategy [plant angle, neuromuscular activation (pη2 = .91), horizontal force maxima and impulses], acceleration distances [centre of mass displacement (pη2 = .21), minimal knee and hip angles], use of torso and arms [incline, angular velocity (pη2 = .23)]. Correlations support that the results cannot be explained fully by strength and power differences between sexes but represent the product of technical-coordinative variations. Their relevance is acknowledged for both sexes and numerous performance determinants displayed sex differences. The integration of such attributes into sex-specific training seems promising but its effect requires further investigation.


Assuntos
Desempenho Atlético/fisiologia , Destreza Motora/fisiologia , Voleibol/fisiologia , Aceleração , Fenômenos Biomecânicos , Feminino , Humanos , Extremidade Inferior/fisiologia , Masculino , Músculo Esquelético/fisiologia , Exercício Pliométrico , Fatores Sexuais , Estudos de Tempo e Movimento , Tronco/fisiologia , Extremidade Superior/fisiologia , Adulto Jovem
15.
J Strength Cond Res ; 33(4): 1056-1064, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30707133

RESUMO

Wagner, H, Sperl, B, Bell, JW, and von Duvillard, SP. Testing specific physical performance in male team handball players and the relationship to general tests in team sports. J Strength Cond Res 33(4): 1056-1064, 2019-Team handball is exemplified by frequent changes in intensities and different complex movements during games, whereas physical performance has often been tested predominantly using standardized general tests. The study aimed (a) to determine the relationship between specific and general physical performance as well as between specific aerobic capacity and agility, and (b) to ascertain the relevance of these tests for strength and conditioning professionals. Seventy-two male indoor court players performed a game-based performance test (GBPT) including team handball-specific techniques, upper-body and lower-body strength tests, a 30-m sprint test, a countermovement jump Abalakov (CMJA) test (with arm swing), and an incremental treadmill-running test. To assess the specific physical performance using the general test performance, we used linear regression calculations. In addition, a principal component factor analysis was calculated. Linear regression analyses revealed a low correlation (R < 0.5) between specific and general aerobic performance, 30-m sprinting time and specific agility in the GBPT, jump height in the CMJA test and jump height in the jump shot, as well as isokinetic shoulder rotation torque and ball velocity in the jump shot. However, a moderate correlation (R > 0.5) was found between specific aerobic performance and specific agility in the GBPT. Principal component factor analysis yielded separate components for specific and general physical performance with a cumulative variance of 69%. The results of this study clearly indicated that general and team handball-specific performance are separate components. Recommendations to strength and conditioning professionals and coaches in team handball were presented.


Assuntos
Limiar Anaeróbio , Teste de Esforço/métodos , Movimento/fisiologia , Desempenho Físico Funcional , Esportes/fisiologia , Adolescente , Adulto , Humanos , Masculino , Força Muscular , Análise de Componente Principal , Corrida/fisiologia , Adulto Jovem
16.
J Sci Med Sport ; 22(7): 833-837, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30630741

RESUMO

OBJECTIVES: Performance factors in the volleyball spike jump are well known for male players; however, technical-coordinative differences for female players are known only marginally. The objective of this study was to investigate the relationship between movement characteristics and female' spike jump performance and to identify the most relevant aspects of jump height and ball velocity. DESIGN: Single group correlation and regression. METHODS: Fifteen elite female volleyball players performed spike jumps by striking a stationary ball at maximal jump height. Data were collected via twelve MX13 Vicon cameras (250Hz), two AMTI force plates (2000Hz), and controlled via Visual3D software. RESULTS: Ten out of 42 characteristics correlated with jump height and none of 22 correlated with ball velocity. A stepwise regression model (adjusted R2=0.82, p<0.001) predicted jump height based on orientation step length and maximal angular velocity of dominant knee extension. For ball velocity, stepwise regression analysis was not feasible; however, an alternative model yielded adjusted R2=0.55, p<0.01. CONCLUSIONS: Key aspects for jump height were (1) optimised approach and energy conversion, (2) wide dynamic arm swing allowing for a forceful countermovement and, thus, increased range of motion in lower limbs, and (3) large angular velocities in ankles and knees, especially on the dominant side. These aspects strongly determined jump height in females and should be included in technical and strength-related training. For ball velocity, upper body anthropometrics and angular joint velocities emerged as the most important criteria. The importance of specific joints may depend on variations in striking technique.


Assuntos
Desempenho Atlético/fisiologia , Movimento/fisiologia , Amplitude de Movimento Articular/fisiologia , Voleibol/fisiologia , Adolescente , Antropometria , Feminino , Humanos , Imageamento Tridimensional , Análise e Desempenho de Tarefas , Gravação em Vídeo , Adulto Jovem
17.
Sportverletz Sportschaden ; 33(2): 96-103, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29444539

RESUMO

BACKGROUND: The purpose of this study was to examine relationships between lower body muscular strength, anthropometric characteristics and several measures of explosive performance in elite team-handball players. METHODS: 22 male elite team-handball players (age: 19.1 ±â€Š1.7 years) were studied during the competitive season. Standard anthropometric and body composition measures included body mass index, lower limb and thigh muscle volume, and body fat percentage. Maximal leg strength was determined by a one-repetition maximum (1-RM) half back-squat. Vertical jump performance was assessed using a squat jump (SJ) and a counter movement jump (CMJ). Repeated shuttle-sprint ability (RSA) was tested by 6 (2 × 15 m) shuttle sprints with 20 s of active recovery intervals. The best time in a single shuttle sprint (30m; RSAbest), fastest total time (RSATT) and RSA test performance decrement (RSAdec) were recorded. Agility was measured using a modified T-half test (MAT). Throwing velocities of jump shooting and 3-step throwing were recorded by digital video camera. RESULTS: The explained variance of 1-RM half-back-squats ranged from 0.2 % (RSA% Fatigue Index) to 70.1 % (CMJ). Four out of 8 variables (RSA Best Time, CMJ, SJ, throwing velocity of jump shoot) demonstrated an r2 > 0.5. Jump performances seemed closely related to 1-RM half-back-squats. Furthermore, 1-RM half-back-squats were positively correlated with leg and thigh muscle volumes (r = 0.652, r = 0.768). CONCLUSION: The anthropometric characteristics and some physical performance tests are closely related to the maximal strength performance of handball players. Coaches should focus on maximal strength training programs for the lower limbs when seeking improvements in the throwing velocity and jump performance of handball players.


Assuntos
Desempenho Atlético/fisiologia , Força Muscular , Adolescente , Antropometria , Teste de Esforço , Humanos , Extremidade Inferior , Masculino , Esportes , Adulto Jovem
18.
Int J Sports Physiol Perform ; 14(1): 60-67, 2019 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29893597

RESUMO

PURPOSE: Biological differences between men and women are well known; however, literature addressing knowledge about the influence of sex on specific and general performance in team handball is almost nonexistent. Consequently, the aim of the study was to assess and compare specific and general physical performance in male and female elite team-handball players, to determine if the differences are consequential for general compared with specific physical performance characteristics and the relationship between general and specific physical performance. METHODS: Twelve male and 10 female elite team-handball players performed a game-based performance test, upper- and lower-body strength and power tests, a sprinting test, and an incremental treadmill running test. RESULTS: Significant differences (P < .05) between male and female players were found for peak oxygen uptake and total running time during the treadmill test, 30-m sprinting time, leg-extension strength, trunk- and shoulder-rotation torque, and countermovement-jump height, as well as offense and defense time, ball velocity, and jump height in the game-based performance test. An interaction (sex × test) was found for time and oxygen uptake, and except shoulder-rotation torque and ball velocity in women, the authors found only a low relationship between specific and general physical performance. CONCLUSION: The results of the study revealed that male players are heavier, taller, faster, and stronger; jump higher; and have better aerobic performance. However, female players performed relatively better in the team-handball-specific tests than in the general tests. The findings also suggest that female players should focus more on strength training.

19.
Gait Posture ; 68: 352-356, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30579039

RESUMO

BACKGROUND: Wobble boards (WBs), commonly used to train postural control, have been recently equipped with accelerometers connected to a computer displaying real-time balance performances. However, little is known about their ability to detect balance deficits in subjects with unilateral chronic ankle instability (CAI). OBJECTIVE: To determine if computerized WBs can detect balance deficits in subjects with unilateral CAI. METHODS: Fifteen subjects with unilateral CAI and fifteen uninjured subjects performed one WB test and one Y Balance Test (YBT) during two separate randomized sessions. WB performance was assessed as the time (s) spent on the platform by keeping it flat at 0° during three 30-s trials for each limb. Normalized (%) reach distances values for anterior, posteromedial, posterolateral directions and composite were recorded for YBT. RESULTS: WB has been shown to be a reliable and accurate device for detecting balance deficits between and within subjects with unilateral CAI. The area under the curve for receiver operating characteristic was 0.80 (asymptotic significance 0.001), suggesting that WBs have the capability to accurately discriminate between injured and uninjured limbs. SIGNIFICANCE: Computerized WBs can fill the gap caused by limitations between subjective-based clinical assessment and laboratory-based testing, especially in field-based settings, where specificity, transportability and time constraints are crucial. The results of the present study suggest that WBs may facilitate the detection of balance impairments in subjects with unilateral CAI, without complexity in its use or data interpretation.


Assuntos
Acelerometria/métodos , Articulação do Tornozelo/fisiopatologia , Instabilidade Articular/fisiopatologia , Equilíbrio Postural/fisiologia , Acelerometria/instrumentação , Adulto , Área Sob a Curva , Doença Crônica , Feminino , Humanos , Masculino , Reprodutibilidade dos Testes
20.
Sci Rep ; 8(1): 12547, 2018 08 22.
Artigo em Inglês | MEDLINE | ID: mdl-30135509

RESUMO

Cryptic species are morphologically very similar to each other. To what extent stasis or convergence causes crypsis and whether ecology influences the evolution of crypsis has remained unclear. The Tetramorium caespitum complex is one of the most intricate examples of cryptic species in ants. Here, we test three hypotheses concerning the evolution of its crypsis: H1: The complex is monophyletic. H2: Morphology resulted from evolutionary stasis. H3: Ecology and morphology evolved concertedly. We confirmed (H1) monophyly of the complex; (H2) a positive relation between morphological and phylogenetic distances, which indicates a very slow loss of similarity over time and thus stasis; and (H3) a positive relation between only one morphological character and a proxy of the ecological niche, which indicates concerted evolution of these two characters, as well as a negative relation between p-values of correct species identification and altitude, which suggests that species occurring in higher altitudes are more cryptic. Our data suggest that species-specific morphological adaptations to the ecological niche are exceptions in the complex, and we consider the worker morphology in this complex as an adaptive solution for various environments.


Assuntos
Formigas/fisiologia , Evolução Biológica , Animais , Formigas/genética , Ecossistema , Filogenia
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