Bilateral deficit in the countermovement jump and its associations with judo-specific performance.

This study aimed to describe the bilateral deficit (BLD) during the countermovement jump (CMJ) in judo athletes and determine the relationship between the BLD and judo-specific performance. Fourteen male judo athletes participated. Athletes performed three specific judo tests, Maximal Sprint Speed Judo Test, Maximal Aerobic Speed Judo Test and Special Judo Fitness Test (SJFT), and double- and single-leg CMJ. The following CMJ variables were used: jump height (JH), mean (MPO) and peak (PPO) power output, peak force (PF), peak velocity (PV) and impulse (IMP). The Pearson's or Spearman's test were used (p < 0.05). The results show that the BLD is found in all CMJ parameters (20 to 31%). Negative correlations between first set of SJFTTT (total throws) and BLD in PF (r = -0.60; p= 0.022) and between the second set of SJFTTT and BLD in MPO (r= -0.74;p = 0.002), PV (r =-0.59;p = 0.025) and IMP (r =-0.55; p = 0.040) were found. Also, negative correlations between SJFTTT and the BLD in all CMJ parameters (r= -0.53 to -0.85; p < 0.05) were found. Higher values of BLD are related to poor SJFTTT performance.

Usability and effects on gait of an optimized schoolchildren backpack.

BACKGROUND: Backpacks used by children is a global concern, because may cause musculoskeletal discomforts and pain. OBJECTIVE: The purpose of this study was to test the usability and effects on gait kinematics wearing the Trunkpack versus a traditional backpack and no backpack. METHODS: Twenty-four children (9 to 11 years old) from a public school participated in this study. The usability was evaluated after a five-week testing period using a questionnaire. Gait kinematics was evaluated (Vicon) when the children were wearing a standard backpack, an optimized backpack (Trunkpack), and no backpack. Both backpacks were loaded with 10% of body weight. RESULTS: Was observed more trunk, hip and knee flexion when the children carried a standard backpack in comparison using the Trunkpack and not carrying a backpack (p < 0.01). The Trunkpack and no backpack were similar. The Trunkpack was well accepted by the schoolchildren (81% positive responses), 79% liked the head opening, 88% liked the waist straps, and 83% liked the facility to put and take objects in and out of the Trunkpack. CONCLUSION: Trunkpack requires less postural adjustments during gait than a standard backpack. Gait kinematics with the Trunkpack was comparable to the gait without carrying a backpack.

Effect of Vertical Jump and Sprint Training on Power and Speed Performance Transfer.

The aim of this systematic review was to investigate the effect of specific sprint and vertical jump training interventions on transfer of speed-power parameters. The data search was carried out in three electronic databases (PubMed, SCOPUS, and SPORTDiscus), and 28 articles were selected (13 on vertical jump training and 15 on sprint training). We followed the PRISMA criteria for the construction of this systematic review and used the Physiotherapy Evidence Database (PEDro) scale to assess the quality of all studies. It included studies with a male population (athletes and nonathletes, n = 512) from 18 to 30 years old who performed a vertical jump or sprint training intervention. The effect size was calculated from the values of means and SDs pre- and posttraining intervention. The percentage changes and transfer of training effect were calculated for vertical jump training and sprint training through measures of vertical jump and sprint performance. The results indicated that both training interventions (vertical jump training and sprint training) induced improvements in vertical jump and linear sprint performance as well as transfer of training to speed-power performance. However, vertical jump training produced greater specific and training transfer effects on linear sprint than sprint training (untrained skill). It was concluded that vertical jump training and sprint training were effective in increasing specific actions of vertical jump and linear sprint performance, respectively; however, vertical jump training was shown to be a superior alternative due to the higher transfer rate.

Can the history of injury influence shoulder isokinetic torque parameters in volleyball players?

The aim of the present study was to compare shoulder internal rotator and external rotator isokinetic parameters in concentric and eccentric contractions between volleyball players with and without a history of shoulder injury. Thirty male volleyball players participated of this study, divided into two groups: with a history of injury (WHI) in the dominant shoulder (11 athletes; age: 19.4 ± 3.6 years) and no history of injury (NHI) (19 athletes; age: 18.3 ± 2.9 years). The peak torque (PT) and concentric (Con) and eccentric (Ecc) PT angles in internal (IR) and external rotation (ER) at velocities of 60 and 180°/s were measured. The conventional (Con_ER:Con_IR), functional spiking (Ecc_ER:Con_IR), and cocking ratios (Ecc_IR:Con_ER) were calculated. No significant differences were found between groups for PT and PT angle, or for conventional, functional spiking, and cocking ratios. However, the spiking ratio was considered low (0.87) in the WHI group. Moreover, for the spiking ratio in the WHI group, PT at 60°/s occurred at different angles. We conclude that previous injury in shoulder did not affect the peak torque, as well as conventional, spiking or cocking ratio. However, the PT angles at 60°/s used to calculate the spiking ratio shifted due the prior injury.

Effects of gradual weight loss on strength levels and body composition in wrestlers athletes.

BACKGROUND: Few investigations have evaluated isokinetic torque after a period of weight loss in wrestlers. Thus, the current study sought to investigate the effects of gradual weight loss in the precompetitive period on isokinetic peak torque in the upper and lower limbs and body composition in wrestling athletes. METHODS: Eight elite athletes participated in the study (mean age 20.8±3.1 years). The athletes visited the laboratory on 2 occasions: during the period of weight maintenance (baseline) and during weight loss, in the precompetitive period (post). The variables analyzed were body composition through air displacement plethysmography (BOD POD) and peak torque (PT) of knee flexion and extension movements, and internal and external shoulder rotation in concentric action, at speeds of 60°/s and 180°/s, determined using an isokinetic dynamometer (Biodex Medical Systems; Shirley, NY, USA). RESULTS: A significant decrease was observed in body composition values, except lean mass. No significant differences were observed in the PT of the movements analyzed: Shoulder internal rotation (60°/s P=0.825; 180°/s P=0.245) and external rotation (60°/s P=0.149; 180°/s P=0.163) and knee extension (60°/s P=0.086; 180°/s P=0.630) and flexion (60°/s P=0.310; 180°/s P=0.239). CONCLUSIONS: Gradual weight loss did not affect the production of torque in the wrestlers before a competition. In addition, gradual weight loss contributed to a reduction in body fat, associated with an increase in percentage lean body mass.

Effects of successive judo matches on interlimb asymmetry and bilateral deficit.

OBJECTIVE: To verify the effects of successive judo matches on interlimb asymmetry and bilateral deficit in judo athletes. DESIGN: Repeated measures; SETTING: University Judo center. PARTICIPANTS: Fourteen male judo athletes. OUTCOME MEASURES: Four simulated matches consisting of 4-min. Before the first match and after each match athletes were submitted to single leg tests - Countermovement Jump (SLCMJ) and Standing Long Jump (SLSLJ), and handgrip strength (HGS) in the dominant and non-dominant limbs. Interlimb asymmetry was calculated in both jumps and handgrip strength tests. RESULTS: Most jump-derived variables did not change the magnitude of asymmetry throughout the matches (p > 0.05), with the exception of jump height asymmetry in SLCMJ, that increased after the second match (p = 0.001). The HGS decreased in both hands from the first match (p < 0.001), without asymmetry. The highest bilateral strength deficit was observed in post-match 1 and post-match 2 (close to 10%). CONCLUSION: Four-successive judo matches did not change the magnitude of interlimb asymmetry, with exception of SLCMJ height, which increased after the second match. The handgrip strength decreased throughout the matches, but similarly in both hands. Finally, the direction of asymmetry showed consistency throughout the matches only for SLCMJ height.

Physical activity during the COVID-19 pandemic: a survey with adults in Northern Brazil / Atividade física durante a pandemia de COVID-19: uma pesquisa com adultos do norte do Brasil

The aim of this study was to analyze the impact of the social distancing recommendations during COVID-19 pandemic on the physical activity behavior in adults living in the Northern Brazil region. A final sample of 654 adults (386 women) aged 33 ± 10 years old participated in this study. A questionnaire with 45 questions concerning sociodemographic characteristics, self-perception of health and characteristics of physical activity behavior before and after the recommendations of social distancing was applied in an online format. Comparisons between levels of physical activity be-fore and after pandemic were conducted applying a McNemar test. A binary logistic regression was applied to analyze the factors associated to being physically active during the pandemic. Analyzing the percentage levels of physical activity before and during social distancing, we observed an increase of physically inactive behavior (19% vs. 36.7%), as well as a decrease in active (32.6% vs. 18.6%) and very active (16.7% vs. 6.6%) behaviors, respectively. Among participants, 59.2% of them became sedentary during pandemic. Walking and running activities continued to be among the most practiced, although they showed a reduction during social distancing. Social distancing recommendations due to the COVID-19 pandemic caused a decrease in the overall levels of physical activity in adults living in the Amazonas State and specifically in the practice of individuals who were physically active and very physically active before pandemic

O objetivo deste estudo foi analisar o impacto das recomendações de distanciamento social durante a pandemia COVID-19 sobre os níveis de prática de atividade física em adultos residentes na região Norte do Brasil. Uma amostra final de 654 adultos (386 mulheres) com idade de 33 ± 10 anos participou deste estudo. Foi aplicado, em formato online, um questionário com 45 questões sobre características sociodemográficas, autopercepção de saúde e características do comportamento de prática de atividade física antes e após as recomendações de distanciamento social. As comparações entre os níveis de atividade física antes e depois da pandemia foram realizadas aplicando um teste de McNemar. Uma regressão logística binária foi aplicada para analisar os fatores associados à atividade física durante a pandemia. Analisando os níveis percentuais de atividade física antes e durante o distanciamento social, observamos um aumento do comportamento fisicamente inativo (19% vs. 36,7%), bem como uma diminuição dos comportamentos ativo (32,6% vs. 18,6%) e muito ativo (16,7%) vs. 6,6%). Entre os participantes, 59,2% deles se tornaram sedentários durante a pandemia. As atividades de caminhada e corrida continuaram entre as mais praticadas, embora tenham apresentado redução durante o distanciamento social. As recomendações de distanciamento social devido à pandemia COVID-19 causaram diminuição nos níveis gerais de atividade física em adultos residentes no Estado do Amazonas e especificamente na prática de indivíduos que eram fisicamente ativos e muito ativos antes da pandemia

Isokinetic peak torque at the shoulder joint in young volleyball athletes with and without injury history / Pico de torque isocinético de rotadores do ombro de jovens atletas de voleibol com e sem histórico de lesão

ABSTRACT Joint shoulder injuries are quite common in volleyball athletes. Studies suggest that muscle imbalance between the internal and external rotator muscles of the shoulder may be related to such lesions. The objective of this study was to compare the concentric torque peaks (PT) of external and internal rotators of the shoulder in volleyball players with (HL) and without history of injuries in joint shoulder (SH). Participated of present study 21 male volleyball players (age: 17.2 ± 1.96 years, height: 183.6 ± 6.63 cm, weight: 75.1 ± 11.50 kg, fat: 13.4 ± 2, 77%) divided into 2 groups: HL (n = 8); SH (n = 13). Two series of 5 maximal concentric repetitions of internal (RI) and external rotation (RE) of the shoulder were performed at speeds of 60 and 180 °·s for later calculation of the conventional ratio PT concentric for RE at both velocities evaluated (60 and 180 °·s) were significantly higher for the HL group. PT concentric in RI was higher compared to RE in both groups. Only the conventional rate at 60°·s was significantly higher for HL players. It is concluded that athletes with a history of shoulder injury present muscular imbalance, and this factor can be considered an aspect that has led to the appearance of the injury event.

RESUMO Lesões articulares no ombro são bastante comuns em atletas de voleibol. Estudos sugerem que o desequilíbrio muscular entre os músculos rotadores internos e externos do ombro podem estar relacionados a tais lesões. O objetivo deste estudo foi comparar os picos de torque (PT) concêntricos de rotadores externos e internos do ombro em jogadores de voleibol com (HL) e sem histórico (SH). Participaram 21 jogadores de voleibol do sexo masculino (idade: 17,2±1,96 anos; estatura: 183,6±6,63 cm; peso: 75,1±11,50 kg; gordura: 13,4±2,77%) divididos em 2 grupos: HL (n=8); SH (n=13). Foram realizadas duas séries de 5 repetições concêntricas de rotação interna (RI) e externa (RE) do ombro nas velocidades de 60 e 180°·s para posterior cálculo das razões convencionais. O PT concêntrico para RE em ambas velocidades avaliadas (60 e 180°·s) foram significativamente superiores para o grupo HL. O PT concêntrico na RI foi maior comparado a RE em ambos os grupos. Apenas a razão convencional à 60º/s, foi significativamente maior para jogadores HL. Conclui-se que os atletas com histórico de lesão de ombro apresentam desequilíbrio muscular, podendo este fator ser considerado um aspecto que tenha levado ao aparecimento do evento lesivo.

Rebound boots change lower limb muscle activation and kinematics during different fitness exercises.

The purpose of this study was to evaluate electromyography and kinematic parameters of the lower limbs using rebound boots (RB) and barefoot during a gym workout. This information can be helpful to practitioners to schedule rehabilitation and training programs. Ten women (25 ± 9 years) volunteered for the study; inclusion criteria were as follows: subjects must have experienced the use of RB and the analyzed exercises for at least 6 months, and have no previous injuries in the lower limbs. Seven exercises were performed for 30 s with the RB and subsequently barefoot. Data from muscle activation of vastus lateralis (VL), biceps femoris (BF), lateral gastrocnemius (LG) and 2D kinematics were collected. The use of RB triggered postural changes, characterized by greater hip extension (in 4 of the exercises) and knee extension (in 6 of the exercises) for the landing. RB reduced activation mainly in LG (in 6 of the exercise) while no changes were observed for VL (except in exercise 1) and BF. RB change kinematics and muscle activation suggesting changes in the way the legs absorb and transmit force during jumps. LG was the main muscle affected by the use of RB.

Power Output Prediction From Jump Height and Body Mass Does Not Appropriately Categorize or Rank Athletes.

The purposes of this study were (a) to verify the agreement of categorization and ranks based on the actual power output measured by a force plate (PPact) and the estimated power output (PPest) from jump height and body mass (BM), and (b) to verify whether the ratio standard is adequate to scale the PPact for BM. The countermovement jumps of 309 male athletes were analyzed. The athletes were first categorized into tertiles (superior, intermediate, and inferior) according to PPact and PPest. After that the athletes were ranked (highest to lowest power output) according to PPact and PPest. The PPest equation explained 81% of PPact variance (standard error of estimate = 277.4 W). The PPest (3,757.1 ± 579.8 W) displayed similar mean values compared with PPact (3,757.1 ± 642.3 W). However, the agreement between the categories generated by PPact and PPest was only moderate (k = 0.6; p < 0.01), and in the intermediate tertile, the categorization differs 38.8%. The agreement between the ranks analyzed from a Bland-Altman plot shows bias zero, but a wide limits of agreement (81 ranks; 26.2%). For the PPact scaling, the ratio standard may be considered as an adequate method for removing the BM effect, considering the lack of correlation between the scaled PPact (PPact/BM) and BM, and also the confirmation of Tanner's special circumstance. In conclusion, our findings indicate that the athlete's power output was not appropriately categorized or ranked when using PPest. Furthermore, the use of the scaled PPact is recommended to fairly compare athletes with different BMs.

Effect of different knee starting angles on intersegmental coordination and performance in vertical jumps.

This study aimed to analyze the effect of different knee starting angles on jump performance, kinetic parameters, and intersegmental coupling coordination during a squat jump (SJ) and a countermovement jump (CMJ). Twenty male volleyball and basketball players volunteered to participate in this study. The CMJ was performed with knee flexion at the end of the countermovement phase smaller than 90° (CMJ(<90)), greater than 90° (CMJ(>90)), and in a preferred position (CMJ(PREF)), while the SJ was performed from a knee angle of 70° (SJ(70)), 90° (SJ(90)), 110° (SJ(110)), and in a preferred position (SJ(PREF)). The best jump performance was observed in jumps that started from a higher squat depth (CMJ(<90)-SJ(70)) and in the preferred positions (CMJ and SJ), while peak power was observed in the SJ(110) and CMJ(>90). Analysis of continuous relative phase showed that thigh-trunk coupling was more in-phase in the jumps (CMJ and SJ) performed with a higher squat depth, while the leg-thigh coupling was more in-phase in the CMJ(>90) and SJ(PREF). Jumping from a position with knees more flexed seems to be the best strategy to achieve the best performance. Intersegmental coordination and jump performance (CMJ and SJ) were affected by different knee starting angles.

Effect of squat depth on performance and biomechanical parameters of countermovement vertical jump / A influência da profundidade de agachamento no desempenho e em parâmetros biomecânicos do salto com contra movimento

The aim of this study was to analyze the effect of different squat depths in the performance and biomechanical parameters at counter movement jump (CMJ). Twenty-two male volleyball or basketball players volunteered to participate in this study and all were currently competing at the college level. The CMJ was performed in three different conditions: 1) with relative knee flexion at the end of counter movement phase smaller than 90° (<90°); 2) greater than 90° (>90°), and; 3) preferred position (PREF). During the CMJ, kinematic, kinetic, and electromyography parameters were assessed. ANOVA for repeated measures with post-hoc Bonferroni´s test was used for variables comparison, with a significance level set at p≤0.05. The higher performance was on PREF and <90° situations compared with CMJ>90°. Average and peak power, as well as absolute and normalized peak forces, were higher ​​in >90° CMJ. The peak velocity of CG and angular velocities of hip and knee were higher in the <90° condition. EMG activity of the vastus lateralis (VL) during the descending and ascending phases were higher in position >90°. Recuts femoris and biceps femoris did not show difference in any jump phases. In conclusion, the knee flexion interferes the performance and the biomechanical variables at the CMJ. The highest jumps were got at a deeper squat, so this technique could be used for athletes in order to optimize the vertical jump performance in the training and competitions.

O objetivo do presente estudo foi analisar a influência de diferentes profundidades de agachamento no desempenho e em parâmetros biomecânicos no salto com contra movimento (CMJ). Participaram do estudo 22 atletas de voleibol ou basquetebol do sexo masculino, participantes de competições em nível regional e universitário. Os CMJ foram realizados em três condições: 1) com flexão relativa do joelho ao final da fase de contra movimento menor que 90° (CMJ<90°); 2) maior que 90° (CMJ>90°) e; 3) posição preferida (CMJPREF). Durante os CMJ foram mensurados: altura do salto, variáveis cinemáticas, cinéticas e eletromiográficas. ANOVA para medidas repetidas com post-hoc de Bonferroni foi utilizado na comparação das variáveis, adotando-se nível de significância de p≤0,05. O desempenho foi maior na situação PREF e <90° comparado ao CMJ >90°. A potência média e pico, a força máxima normalizada e absoluta, apresentaram os maiores valores na posição >90°. O pico de velocidade e as velocidades angulares de quadril e joelho apresentaram os maiores valores na posição <90°. A EMG do vasto lateral, durante as fases descendente e ascendente, foi maior na posição >90°. Os músculos reto femoral e bíceps braquial não apresentaram diferença entre as condições. Conclui-se que o desempenho e as variáveis biomecânicas analisadas no CMJ são influenciados pelo nível de flexão do joelho. As maiores alturas foram obtidas nos saltos realizados a partir de uma maior profundidade de agachamento, assim, tal estratégia técnica poderia ser utilizada por atletas a fim de otimizar a altura do salto vertical nos treinamentos e competições.

Reliability and validity of the 30-s continuous jump test for anaerobic fitness evaluation.

OBJECTIVES: To determine the test-retest reliability and concurrent validity of the 30-s continuous jump (CJ30) test using the Wingate test as a reference. DESIGN: Descriptive validity study. METHODS: Twenty-one male volleyball players (23.8 ± 3.8 years; 82.5 ± 9.1 kg; 185 ± 4.7 cm) were tested in three separate sessions. The first and second sessions were used to assess the reliability of the CJ30 while in the third session the Wingate test was performed. In the continuous jump test, consisting of maximal continuous jumps performed for 30s, jump height was determined by video kinematic analysis. Blood samples were collected after each test to determine lactate concentration. RESULTS: The CJ30 showed excellent test-retest reliability for the maximal jump height (ICC = 0.94), mean vertical jump height (ICC = 0.98) and fatigue index (ICC = 0.87). Peak lactate showed moderate reliability (ICC = 0.45). Large correlations were found between the mean height of the first four jumps of CJ30 and the peak power of the Wingate (r = 0.57), between the mean vertical jump height of CJ30 and the mean power of the Wingate (r = 0.70) and between the lactate peak of CJ30 and Wingate (r = 0.51). A moderate correlation of fatigue index between CJ30 and the Wingate was found (r = 0.43). CONCLUSIONS: The continuous jump is a reliable test and measures some of the same anaerobic properties as WAnT. The correlations observed in terms of anaerobic indices between the tests provide evidence that the CJ30 may adequately assess anaerobic performance level.

Comparison of body composition and aerobic and anaerobic performance between competitive cyclists and triathletes / Comparação da composição corporal, desempenho aeróbio e anaeróbio entre ciclistas e triatletas competitivos

The aim of this study was to compare anthropometric characteristics and aerobic and anaerobic fitness between competitive cyclists and triathletes. The sample consisted of 11 cyclists and 12 triathletes with experience in competitions. The tests were performed on two different days, with an interval of 48 h between sessions. On the first day, the athletes were submitted to anthropometric assessment (body mass, height, and skinfold thickness) and a maximal incremental test to determine maximal oxygen uptake, maximum power, maximum heart rate, maximum lactate, and the first (LL1) and second lactate threshold (LL2). The Wingate test was conducted on the second day to determine peak power, average power, and fatigue index. There were significant difference (p < 0.05), with medium effect size (0.80 - 1.5), in mid-thigh skinfold thickness (15.2 ± 6.3 and 10.5 ± 4.8 mm), power at LL1 (195.0 ± 30.9 and 162.7 ± 28.3 W), power at LL2 (247.6 ± 25.0 and 219.7 ± 37.9 W), and fatigue index (47.2 ± 13.0 and 60.1 ± 16.4%) between cyclists and triathletes, respectively. The other variables did not differ between groups. Anthropometric characteristics are similar in triathletes and cyclists. However, cyclists present higher power outputs at the lactate thresholds (LL1 and LL2) and lower fatigue indexes.

O objetivo do presente estudo foi comparar as características antropométricas e aptidão aeróbia e anaeróbia entre ciclistas e triatletas competitivos. Participaram do estudo 11 ciclistas e 12 triatletas com experiência em competições esportivas. As avaliações foram realizadas em dois dias distintos, com intervalo de 48 h entre as sessões. No primeiro dia, foram realizados a avaliação antropométrica (massa corporal, estatura e dobras cutâneas) e um teste incremental máximo para determinação do consumo máximo de oxigênio, potência máxima, frequência cardíaca máxima, lactato máximo, primeiro limiar de lactato (LL1) e segundo limiar de lactato (LL2). No segundo dia, foi realizado um teste de Wingate para obter a potência pico, potência média e índice de fadiga. Houve diferença significativa (p < 0,05) e com tamanho de efeito moderado (0,80 - 1,5) para a dobra cutânea da coxa média (15,2 ± 6,3 e 10,5 ± 4,8 mm), potência no LL1 (195,0 ± 30,9 e 162,7 ± 28,3 W), potência no LL2 (247,6 ± 25 e 219,7 ± 37,9 W) e índice de fadiga (47,2 ± 13,0 e 60,1 ± 16,4 %) entre ciclistas e triatletas, respectivamente. As demais variáveis analisadas não diferiram estatisticamente entre os grupos. Os triatletas e ciclistas são semelhantes em relação às características antropométricas. No entanto, ciclistas apresentam maiores valores de potência nos limiares (LL1 e LL2) e menores valores do índice de fadiga.

Stiffness, intralimb coordination, and joint modulation during a continuous vertical jump test.

This study analysed the modulation of jump performance, vertical stiffness as well as joint and intralimb coordination throughout a 30-s vertical jump test. Twenty male athletes performed the test on a force plate while undergoing kinematic analysis. Jump height, power output, ground contact time, vertical stiffness, maximum knee and hip flexion angles, and coordination by continuous relative phase (CRP) were analysed. Analysis of variance was used to compare variables within deciles, and t-tests were used to compare CRP data between the initial and final jumps. Results showed reduction in jump height, power output, and vertical stiffness, with an increase in contact time found during the test. Maximum knee and hip flexion angles declined, but hip angle decreased earlier (10-20% of the test) than knee angle (90-100%). No changes were observed in CRP for thigh-leg coupling when comparing initial and final jumps, but the trunk-thigh coupling was more in-phase near the end of the test. We conclude that fatigue causes reduction in jump performance, as well as changes in stiffness and joint angles. Furthermore, changes in intralimb coordination appear at the last 10% of the test, suggesting a neuromotor mechanism to counterbalance the loss of muscle strength.

Aclimatação em altitude simulada: efeitos sobre a frequência cardíaca e saturação de oxigênio da hemoglobina em jogadores de futebol / Acclimatization at simulated altitude: effects on the heart rate and hemoglobin oxygen saturation in soccer players

A exposição aguda à altitude sem aclimatação prévia pode provocar mal-estar e diminuir o desempenho físico e esportivo. O objetivo deste estudo foi verificar o efeito de sessões de hipoxia normobárica, em repouso, na Frequência Cardíaca (FC) e Saturação de Oxigênio da Hemoglobina (SpO2) em atletas de futebol profissional. Participaram do estudo 13 atletas, os quais foram submetidos a 15 sessões de hipoxia, 5-6 vezes por semana. A duração das sessões foi de 60 min, com fração inspirada de oxigênio entre 14% e 12 %. A SpO2 e FC foram registrados segundo a segundo durante a primeira e última sessão. Para comparar, a SpO2 e FC da primeira sessão, última sessão e normoxia foi utilizado Anova para medidas repetidas. Houve aumento da SpO2 (p<0,05) e redução da FC (p<0,05) na última sessão, quando comparado à primeira. Concluímos que o protocolo de treinamento utilizado no estudo melhora a resposta do organismo em hipoxia.

The acute exposure at altitude without previous acclimatization may cause sickness and decrease the sport and physical performance. This research aimed at verifying the effect of normobaric hypoxia sessions, at rest, on the Hemoglobin Oxygen Saturation (SpO2) and the Heart Rate (HR) of professional soccer athletes. Thirteen athletes performed 15 sessions of hypoxia, 5-6 times a week, with 60 min of duration and with the fraction of inspired oxygen between 14 and 12%. The SpO2 and HR were recorded every second during the first and the last session. In order to compare the SpO2 and HR from the first session, last session and normoxia it was used the ANOVA with repeated measures. There was an increase in the SpO2 (p<0.05) and a decreased HR (p<0.05) for the last session when compared to the first session. We conclude that the training protocol used in the acclimatization study improves the organism response to hypoxia.