Artigos em revistas internacionais - ESDRM
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- Osteogenic index of step exercise depending on choreographic movements, session duration, and stepping ratePublication . Santos-Rocha, Rita; Oliveira, Carla; Veloso, António PrietoStep exercise has been promoted as a low impact physical activity recommended for the improvement of cardiorespiratory and muscular fitness. This recreational activity might also be recommended to improve bone health since mechanical load plays an important role in the normal development of the skeleton.
- Comparative study of plantar pressure during step exercise in different floor conditionsPublication . Santos-Rocha, Rita; Veloso, António PrietoMechanical load has been estimated during step exercise based on ground reaction force (GRF) obtained by force platforms. It is not yet accurately known whether these measures reflect foot contact forces once the latter depend on footwear and are potentially modified by the compliant properties of the step bench. The aim of the study was to compare maximal and mean plantar pressure (PP), and maximal GRF obtained by pressure insoles after performing seven movements both over two metal force platforms and over the step bench. Fifteen step-experienced females performed the movements at the cadences of 130 and 140 beats per minute. PP and GRF (estimated from PP) obtained for each floor condition were compared. Maximal PP ranged from 29.27 +/- 9.94 to 47.07 +/- 12.88 N/cm2 as for metal platforms, and from 28.20 +/- 9.32 to 43.00 +/- 13.80 N/cm2 as for the step bench. Mean PP ranged from 11.09 +/- 1.62 to 14.32 +/- 2.06 N/cm2 (platforms) and from 10.71 +/- 1.54 to 14.22 +/- 1.77 N/cm2 (step bench). GRF (normalized body weight) ranged from 1.43 +/- 0.14 to 2.41 +/- 0.24 BW (platforms) and from 1.38 +/- 0.14 to 2.36 +/- 0.19 BW (step bench). No significant statistical differences were obtained for most of the comparisons between the two conditions tested. The results suggest that metal force platform surfaces are suitable to assess mechanical load during this physical activity. The forces applied to the foot are similar to the softer step bench and the hard force platform surface. This may reflect the ability of the performers to adapt their movement patterns to normalize the impact forces in different floor conditions.
- Comportamento pedagógico dos instrutores de aulas de fitness de localizadaPublication . Franco, Susana; Rodrigues, José; Castañer i Balcells, MartaEste estudo teve como objetivo realizar uma aplicação piloto do novo instrumento desenvolvido, Sistema de Observação do Comportamento dos Instrutores de Fitness – Aulas de Grupo (SOCIF), pretendendo-se identifi car e descrever quais as tendências comportamentais dos instrutores de fi tness nas aulas de grupo, designadamente de localizada. Materiais e Métodos: Foram observadas sessões de localizada, com conteúdo de treino de resistência muscular. Foi efetuado o registro da duração dos comportamentos, através do instrumento SOCIF. Resultados: Foram encontrados valores excelentes de fi delidade intra-observador. Discussão: Verifi cou-se que: quando confrontados os resultados deste estudo com os de outros estudos, independente do contexto, os dois principais comportamentos dos professores, treinadores ou instrutores são a informação e/ou observação, parecendo que os comportamentos restantes apresentam variações em termos de ocorrência; existem alguns comportamentos que os sujeitos nunca manifestaram; os comportamentos positivos predominam em relação aos negativos; as instrutoras utilizam comportamentos que são importantes como estratégias pedagógicas para reter os alunos à prática de exercício, quais sejam, a Afetividade positiva, avaliação positiva, pressão e conversas com alunos. Os comportamentos evidenciam uma variação na sua ocorrência, de sujeito para sujeito. Os comportamentos parecem mudar a sua ocorrência de acordo com as fases da aula. Os comportamentos aparentam ser infl uenciados pela posição de realização dos exercícios. As instrutoras, durante a aula, passam a maioria do seu tempo a realizar exercício físico.Introduction: The aim of this pilot study is to make an application of the new developed instrument Fitness Instructors’ Behaviour Observation System – Group Classes (SOCIF), and to describe which, in Resistance Training classes, the behaviour instructor’s tendencies are. Materials and Methods:There were observed Resistance Training sessions, in group classes, with the content of resistance strength. We registered the behaviours duration through an observation system of the instructors (SOCIF). Results: It was guaranteed excellent values of reliability intra -observer. Discussion: We have concluded that: When we confronted the results of this study with other studies, independently of the context, the two principal behaviours of the teachers, coaches or instructors are Information and/or observation, and the other behaviours present an variable occurrence; there are some behaviours that are never manifested by the instructors; the positive behaviours prevail in relation to the negatives; the instructors use behaviours that are important as pedagogical strategies to retain the participants to the exercise practice, such as positive affectivity, praise, hustle and conversation with participants. The behaviours seem to vary between instructors; the instructors’ behaviour seems to change their occurrence in agreement with the class’ phases. The instructors’ behaviour seems to be influenced by the position of the exercises. The instructors, during the class, spend most of the time in exercise.
- Angiotensin-converting enzyme genotype affects skeletal muscle strength in elite athletesPublication . Costa, Aldo; Silva, António; Garrido, Nuno; Louro, Hugo; Marinho, Daniel; Marques, Mário; Breitenfeld, LuisaPrevious studies have associated angiotensin-converting enzyme (ACE) D allele with variability in the skeletal muscle baseline strength, though conclusions have been inconsistent across investigations. The purpose of this study was to examine the possible association between ACE genotype and skeletal muscle baseline strength in elite male and female athletes involved in different event expertise. A group of 58 elite athletes, designated as Olympic candidates, were studied: 35 swimmers (19 males and 16 females, 18.8 ± 3.2 years) and 23 triathletes (15 males and 8 females, 18.7 ± 3.0 years). The athletes were classified as: short (≤ 200m) and middle (400m to 1500m) distance athletes, respectively. For each subject the grip strength in both hands was measure using an adjustable mechanical hand dynamometer. The maximum height in both squat jump (SJ) and counter movement jump (CMJ) were also assessed, using a trigonometric carpet (Ergojump Digitime 1000; Digitest, Jyvaskyla, Finland). DNA extraction was obtained with Chelex 100® and genotype determination by PCR-RFLP methods. Both males and females showed significantly higher right grip strength in D allele carriers compared to II homozygote’s. We found that allelic frequency differs significantly by event distance specialization in both genders (p < 0.05). In fact, sprinter D allele carriers showed the superior scores in nearly all strength measurements (p < 0.05), in both genders. Among endurance athletes, the results also demonstrated that female D allele carriers exhibited the higher performance right grip and CMJ scores (p < 0.05). In conclusion, the ACE D allele seems associated with skeletal muscle baseline strength in elite athletes, being easily identified in females.
- Stability of patterns of behavior in the butterfly swimmers.Publication . Louro, Hugo; Silva, António José; Anguera, T.; Camerino, O.; Oliveira, C.; Conceição, A.; Campaniço, J.OBJECTIVE: The purpose of this study was to find patterns in the swimming technique of butterfly, with an adaptation of the Behavioral Observation System Tech. This, as a instrument for ad-hoc qualitative analysis enables the study of the stability of the technical implementation, an applicant in optimization sport. When used in the training of swimmers, can turn, reduce the variability in behavioral tuning technique of swimming. Through the analysis of temporal patterns (T-pattern) and a sequence of five cycles run at maximum speed hand, studied the behavior of four technical elite swimmers in Portuguese, with a record 259 alphanumeric codes and a total 160 configurations. The structure of the original instrument based on a mixed system of categories and formats Field, which can record technical features observed during the execution of hand cycles. The validity was ensured through the index of intra-observer reliability (95%) and inter-observer accuracy (96%). To detect patterns exist, each swimmer, using the Theme 5.0 software, which allowed to identify the stable structures of technical performance within a critical interval of time (P<0,05) t-patterns. RESULTS: The patterns were different, adjusting to the characteristics of technical implementation of the swimmers. Found that the swimmer can make settings with different levels of complexity of structure, depending on the implementation of changes within the hand cycle. Variations of codes in each configuration obtained using the SOCTM, determine the differences between swimmers. DISCUSSION & CONCLUSION However, the records show a clear behavioral similarity compared the result with a general pattern of the butterfly technique. Conclusion: As we can see that the potential quality of this instrument is evident by the patterns obtained from a temporal sequence.
- Kinematical constrictions during Breaststroke swimming with a portable gas analyzer snorkelPublication . Reis, V.; Silva, A.; Barbosa, T.; Brito, J.; Reis, A.; Louro, Hugo; Conceição, A.OBJECTIVE: To determine the kinematical constrictions in maximal breaststroke swimming bouts with the AquaTrainer snorkel (Cosmed, Rome, Italy). METHODS: Seven national level breaststrokers performed two maximal bouts of 100-m swims (separated by 48 hours): (i) one bout connected to the AquaTrainer snorkel (constricted swim); (ii) one bout without the snorkel (free swim). The swims were videotaped in sagittal plane with a pair of cameras providing a dual projection from both above and underwater. The study comprised kinematical analysis of stroke cycles using APAS and a VCR (f = 50 Hz). To create a single dual projection image, the independent digitalization from both cameras was reconstructed with the help of a calibration volume and a 0.01). The 2D-DLT algorithm. Digitalization reliability was high (ICC=0.97 following measures were assessed: (i) swimming performance (T100); (ii) stroke parameters (stroke cycle period, stroke rate, stroke length and mean swimming velocity); (iii) estimated swimming efficiency by the swimming index; (iv) speed fluctuation (dv) and the mathematical characterization of dv. Mean dv curves normalized to time were computed with MATLAB. The polynomial regression (7th power) between dv and normalized duration of the full stroke cycle was calculated. Wilcoxon tests were performed to compare significant differences in the dependent variables (performance, stroke mechanics and efficiency variables) according to the independent variable (free versus constricted swim) (P 0.05). RESULTS: T100 was significantly higher for constricted swimming than in free condition (6.26%; Z=-2.366; P=0.02). The remaining variables showed no significant differences between the two swimming conditions. In both exercise conditions, dv was characterized by a bi-modal profile. The determination coefficients for the dv mathematical model were significant (P<0,01) and 0,47. DISCUSSION & CONCLUSION: None of the stroke mechanics and efficiency variables evaluated presented significant differences between both swimming conditions. The AquaTrainer constrictions might be related mainly to the start and turn phases. (Supported by FCT grant: POCI/DES/58362/2004)
- Tethered swimming in crawl: Arm stroke propulsive force at different 5 swim ratesPublication . Leitão, L.; Karsai, I.; Louro, Hugo; Garrido, N.; Conceição, A.; Conceição, AnaOBJECTIVE: A swimmers performance results from the interaction of propulsive and resistive forces, which can only increase by reducing the resistive forces, or increase the propulsives forces (Toussaint, 2006). Researchers have developed many methods for this type of evaluation, tethered swim (Dopsaj et al., 2003, Taylor et al., 2001) and Mad System (Toussaint, 2006). METHODS: Six males’ swimmers of the portuguese national team (21.8+.9yrs,73.64+6.9 bm,182.26+6.1bh) performed only the arm crawl swimming task, on an ergometer without breathing, with tied and supported legs, and with the head placed in a helmet containing a sensor of force, connected to a computer. The frequency increment was set at 5 cycle/min(C/M) from 35C/M to 55C/M. Four underwater cameras were used to kinematical analysis with APAS. Descriptive statistics were used, and Pearson correlation to identify the correlation between the increase of the propulsive force and swim rate, with a level of significance of p. DISCUSSION & CONCLUSION: The most effective swim rate is the 45C\\M which the swimmer can develop greater propulsive force (128.01 N) whether or not the fastest swim rate analyzed, and the insweep action is the most propulsive on all stroke phases.
- Characterization of temporal patterns of behavior of the crawl techniquePublication . Louro, Hugo; Conceição, A.; Matos, T.; Nilton, J.; Franco, R.; Camerino, O.; Campaniço, J.OBJECTIVE: With this work we want to check the standards of the crawl technique from an observational methodology appropriated.The instrument of observation (Nilton, 2008) was developed Ad Hoc, using the references of biomechanical models, based on a mixed system of categories and formats of fields, with particular reference to four criteria that add in the form of alpha-numeric codes. The results of the quality of the instrument revealed indices of reliability and high precision. METHODS: We use a sample of six swimmers from Portuguese and international level as part of the Portuguese national team in swimming. Each element was subject to the overall swimming crawl technique at a distance of 25m to achieve maximum speed without a breath. The units of observation are natural (events and behaviors) and analytical (of behavior). The detection of temporal patterns by binomial analysis (Magnusson, 2000) was made by the software 5.0 Theme created by Magnusson (1996, 2000). The instrument is intended to identify patterns which are within the critical intervals, allowing examination of the inter-relationship of temporal events (movement), using the record of occurrences in the collection of patterns found in data. RESULTS: The patterns found in each swimmer is different and each pattern is adjusted to the particular individual techniques. DISCUSSION & CONCLUSION: The same swimmer can present similar structures for implementation, representing a behavior pattern. In all the swimmers were identified more than one standard. However, it is noteworthy that no swimmer of the sample made the same overall behavior at any stage observed in the five cycles analyzed.
- Observation of the stability of a technical implementation of evidence in 200m butterflyPublication . Louro, Hugo; Silva, A.; Costa, A.; Rodrigues, J.; Conceição, Ana; Campaniço, J.OBJECTIVE: The aim of this study was find patterns in the swimming butterfly technique at a distance of 200 meters using the system Behavioural Observation System of the Technical Butterfly, qualitative analysis allows the observation and study of the stability of the technical implementation. METHODS: Instrument for ad-hoc, with the structure of the instrument based on a mixed system Categories and Field Formats which we can record specific techniques observed during the gestual cycles. We performed the analysis of temporal patterns (T-pattern), a sequence of five gestual cycles of the butterfly style in each part of 50 meters. To study the sequence of codes and their interaction representative of the technician in two swimmers at the national level. Swimmers performed the tasks with speed competition, with the same control by the GBK PACER. To detect the emporal patterns of each swimmer, using the Theme 5.0 software, which allows to identify the structures of the technical standard within a range of critical time (p<0,05) – T-patterns. RESULTS: In the results the patterns found settings are different and different levels of complexity depending on the adjustments made by the swimmers in gestual cycles. Variations of codes in each time producing different settings, to determine the differences between cycles of the swimmer. DISCUSSION & CONCLUSION Comparing patterns found distinct differences between swimmers, the records demonstrated a clear behavioral similarity when compared the result with the biomechanical model of the general butterfly technique. Technique is objective for the purpose it was created and is a valuable instrument for qualitative analysis.
- Can the curriculum be used to estimate critical velocity in young competitive swimmers?Publication . Costa, Aldo; Silva, António; Louro, Hugo; Reis, Victor; Garrido, Nuno; Marques, Mário; Marinho, DanielThe aims of the present study were to assess critical velocity using the swimmer curriculum in front crawl events and to compare critical velocity to the velocity corresponding to a 4 mmol·l-1 of blood lactate concentration and to the velocity of a 30 min test. The sample included 24 high level male swimmers ranged between 14 and 16 years old. For each subject the critical velocity, the velocity corresponding to a 4 mmol·l-1 of blood lactate concentration and the mean velocity of a 30 min test were determined. The critical velocity was also estimated by considering the best performance of a swimmer over several distances based on the swimmer curriculum. Critical velocity including 100, 200 and 400 m events was not different from the velocity of 4 mmol·l-1 of blood lactate concentration. Critical velocity including all the swimmer events was not different from the velocity of a 30 min test. The assessment of critical velocity based upon the swimmer curriculum would therefore seem to be a good approach to determine the aerobic ability of a swimmer. The selection of the events to be included in critical velocity assessment must be a main concern in the evaluation of the swimmer.