Injury Frequency in Handball Players: A Descriptive Study of Injury Pattern in São Paulo State Regional Teams

Abstract Aim: To assess the frequency of injuries among male and female handball athletes, identifying injured anatomic parts, injury diagnostics, their severity and type. Methods: The participants were composed of 122 handball players from São Paulo state teams, being 63 male (21.2±5.3 years) and 59 female (19.9±5.3 years) athletes who were interviewed using the "Champion Profile" questionnaire. The injuries were sorted by type: acute or overuse; and severity (major, moderate, slight, minor), given by the period of absence from team activities (training sessions and matches), and our results are presented as descriptive statistics. Results: The majority of injuries was found in the lower limbs, both in female (69.6%) and male (47.4%) players, as well as the knee was the most commonly injured anatomic part, representing 33.7% and 20.8% of the total number of injuries for the respective genders. We found a higher number of major injuries in female (35.8%) and male (20.8%) players when compared to the other severity categories. The acute injuries were more common among the total sample (48%) when compared to overuse injuries (22.7%), while a sprain was the most commonly diagnosed injury. Conclusion: It was observed that Brazilian handball players demonstrated an important number of major and acute injuries, forcing them to abstain from training sessions and matches, which can lead to both team and athlete performance losses. Furthermore, we suggest the inclusion of preventive training to reduce the frequency of injuries in handball athletes.

Efeito da velocidade de corrida em variáveis eletromiográficas e metabólicas / Effect of running velocity on electromyographic and metabolic variables

O objetivo deste estudo foi analisar o sinal eletromiográfico dos músculos reto femoral (RF), vasto lateral (VL), bíceps femoral (BF), tibial anterior (TA) e gastrocnêmio lateral (GL) de sete voluntários do sexo masculino, entre diferentes velocidades de corrida, e determinar e comparar os índices LF EMG (limiar de fadiga eletromiográfico), LL (limiar de lactato) e LAn (limiar anaeróbio). O protocolo de corrida iniciou em 10 km.h-1, com incrementos de 1 km.h-1 a cada três minutos até a exaustão, com 30 segundos de intervalo para coleta de 25μl de sangue. Foi verificado aumento do valor RMS no RF da velocidade de 12 km.h-1 para 14 km.h-1. O LFEMG apresentou-se semelhante entre os músculos, e entre os índices houve as seguintes diferenças significativas: LAn > LL; LFEMG RF e LFEMG VL < LAn e LFEMG VL e LFEMG BF > LL. Os dados confirmam a viabilidade da utilização do LFEMG como possível indicador para análise da fadiga muscular.

The aim of this study was to analyze the electromyographic signal of the rectus femuris (RF), vastus lateralis (VL), biceps femuris (BF), tibialis anterior (TA), and gastrocnemius lateralis (GL) muscles of seven male volunteers, during different running velocities; and determine and compare the EMG FT (electromyographic fatigue threshold), LT (lactate threshold) and AT (anaerobic threshold). The running protocol started with a velocity of 10 km.h-1 and each three minutes elapsed occurred an increments of 1 km.h-1 until the exhaustion, with an 30 second interval between each velocity increment to collect 25 μl of blood. The increase of RMS values was verified in the RF in the velocities of 12 km.h-1 to 14 km.h-1. The EMGFT showed similarity between the muscles and in the indexes were found the following significant differences: AT > LT; EMGFT RF and EMGFT VL < AT and EMGFT VL and EMGFT BF > LT. These data confirmed the viability of using the EMGFT as a possible indicator to analyze the muscle fatigue.

Efeito da fadiga muscular na biomecânica da corrida: uma revisão / Muscular fatigue effects on running biomechanics: a review

A corrida é uma atividade física amplamente realizada para manutenção da saúde, prescrição do treinamento, lazer e para realização de testes de aptidão física. A avaliação biomecânica constitui-se de uma importante ferramenta para melhora de seu desempenho. Para tanto, esteiras de corrida são geralmente utilizadas, pois possibilitam condições controladas para aquisição de dados biomecânicos, viabilizando a análise dos fatores envolvidos no desenvolvimento da fadiga muscular. A corrida prolongada ou de alta intensidade induz a modificações nos parâmetros eletromiográficos e cinemáticos, decorrentes de um processo de fadiga. Além disso, a literatura demonstra que atividades precedentes – como o ciclismo - modificam o padrão subseqüente de corrida.

Running is one of the most popular physical activities performed for health maintenance, training prescription, leisure and physical tests. The biomechanics evaluation is an important tool for running performance improvement. Treadmill running is often used for biomechanics evaluation because allow controlled conditions for biomechanics data acquisition, making possible the analysis of the factors involved in the muscular fatigue development. Prolonged run or run performed in a high intensity induces changes in the electromyographic and kinematic parameters, resulting from a fatigue process. Moreover, the literature shows that previous activities - such as cycling - modify the subsequent running pattern.

Análise de variáveis eletromiográficas durante contração isométrica fadigante / Electromyographic variables analysis during fatiguing isometric contraction

O objetivo do presente estudo foi analisar o comportamento das variáveis Root Mean Square (RMS) e Freqüência Mediana (FM) do sinal eletromiográfico dos músculos Reto Femoral (RF), Vasto Medial (VM) e Vasto Lateral (VL) de 10 voluntários, durante o tempo de execução do exercício de extensão isométrica do joelho realizado com cargas de 20%, 30%, 40% e 50% da Contração Voluntária Máxima (CVM). Para realização do exercício utilizou-se cadeira específica, célula de carga, e indicador digital. Os sinais eletromiográficos foram obtidos por meio de eletrodos de superfície, módulo de aquisição de sinais biológicos, placa A/D e software específico (freqüência de amostragem: 1000 Hz, ganho: 1000 vezes, filtro de passa alta: 20Hz, filtro de passa baixa: 500Hz). Os valores de RMS e FM foram calculados a cada 5% do tempo total de execução do exercício em cada carga, e foram normalizados pela CVM. Os valores normalizados foram analisados entre o tempo inicial em relação as demais porcentagens de tempo, assim como foram correlacionados em função do tempo total. Os resultados da análise dos valores de RMS dos músculos VM e VL demonstraram comportamento característico da fadiga muscular, com o aumento do RMS em função do tempo, o que ocorreu predominantemente a partir de 60% do tempo total. A FM somente demonstrou diminuição em função do tempo total para o músculo RF. Diante deste comportamento, conclui-se que os músculos estudados apresentam diferentes capacidades de resistência, o que permite um melhor direcionamento das condutas de reabilitação e treinamento.

The purpose of this study was to analyze the behavior of root mean square (RMS) and median frequency (MF) electromyographic variables from rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL) muscles of 10 volunteers during the execution time of isometric knee extension exercise performed with 20%, 30%, 40% and 50% of maximal voluntary contraction (MVC). A specific chair, load cell and digital display were used to perform the exercise. The electromyographic signals were obtained by surface electrodes, acquisition module of biological signals, A/D board, specific software calibrated with frequency rate: 1000Hz, gain: 1000 times, high pass filter: 20Hz and low pass filter: 500Hz. The RMS and MF values were calculate in each 5% of total exercise execution time in each load, and were normalized by MVC. The normalized values were analyzed between the initial time with others percentages of time and all values were correlated in relation to the total time. The results showed that the RMS obtained from VM and VL muscles presented the characteristic behavior of muscular fatigue by the increasing of RMS with time, which predominantly happen after 60% of total time. The MF decreases with total time only to RF muscle. With these behaviors, we concluded that the muscles analyzed here present different endurance capacity, which may accomplish rehabilitation and training programs.