Pre-planned Vs. Executed Real-Time Pacing Strategies during 3-km Race: Role of Rating Perceived Exertion.

Purpose: The aim of the study was to verify the agreement between preplanned and executed pacing during a 3-km race and determine whether adjustments are mediated by the rating of perceived exertion (RPE). Method: Thirteen young runners (eight males and five females, 17.5 ± 2.1 and 17.0 ± 1.6 years old, respectively) with national and international experience participated in the study. Before the simulated competition, the athletes informed of their preplanned pacing for the distance through a dashboard with the most common pacing profiles and were also asked to complete a questionnaire communicating their preplanned RPE for each lap of race. During 3-km, heart rate (HR), executed RPE and lap time were recorded. Results: Our results showed no significant association between preplanned and executed pacing (p = .631). Moreover, no significant difference between preplanned and executed RPE was found, including the analysis by laps and phases. RPE and HR increased over time during the race (p < .001). Conclusions: The athletes changed from their preplanned pacing, however, their RPE were similar in the preplanned and executed during the 3-km race. These findings indicate that the RPE could be responsible for adjustments in the pacing strategy.

Do biological maturity and performance influence the training load of track and field athletes? / A maturação sexual e o desempenho influenciam a carga de treinamento de atletas de atletismo?

Abstract It is necessary to clarify if BM and track and field performance can modulate the perception about RPE-session. The purpose of the present study was to verify if biological maturity and track and field-specific performance can be associated with training load (RPE-session method). Seventy-five young athletes (13-15 years old) of both genders participated in the present study. The experimental protocol lasted seven consecutive days. Performance tests (75-m running, long jump, 250-m running, shot put and 1000-m running) were made on the first day. After 48 hours, five days of track and field training it was prescribed, each day represents a training of each performance test. All training sessions had the same duration (120 min). The value of the training load was obtained multiplying the RPE value with training session duration (in minutes). For girls, the training load of 250-m training was correlated with biological maturity (r = -0.36, p = 0.02, n = 37) and specific performance (r = 0.33, p = 0.04, n = 37). All other analyzes indicate that biological maturity and track and field-specific performance do not influence the training load based on RPE-session method. Training load based on RPE-session is not influenced by biological maturity and track and field-specific performance, therefore can be used to control the training load of young track and field athletes. To girls it is necessary a care to control the training sessions intensity of 250-m running.

Resumo É necessário esclarecer se a maturação biológica e o desempenho no atletismo podem modular a PSE da sessão. O objetivo do presente estudo foi verificar se a maturidade biológica e o desempenho específico no atletismo podem estar associados à carga de treinamento (método de PSE da sessão). Setenta e cinco jovens atletas (13-15 anos) de ambos os sexos participaram do presente estudo. O protocolo experimental durou sete dias consecutivos. Testes de desempenho (75 m de corrida, salto em distância, 250 m de corrida, arremesso de peso e 1000 m de corrida) foram feitos no primeiro dia. Após 48 horas, cinco dias de treinamento de atletismo foram prescritos, cada dia representa um treinamento de cada teste de desempenho. Todas as sessões de treinamento tiveram a mesma duração (120 min). O valor da carga de treinamento foi obtido multiplicando o valor do PSE com a duração da sessão de treinamento (em minutos). Para as meninas, a carga de treinamento de 250 m foi correlacionada com a maturidade biológica (r = -0,36, p = 0,02, n = 37) e desempenho específico (r = 0,33, p = 0,04, n = 37). Todas as outras análises indicam que a maturidade biológica e o desempenho específico no atletismo não influenciam a carga de treinamento com base no método da PSE da sessão. A carga de treinamento com base na PSE da sessão não é influenciada pela maturidade biológica e desempenho específico no atletismo, portanto, pode ser usada para controlar a carga de treinamento de jovens atletas de atletismo. Para as meninas é necessário cuidado para controlar a intensidade das sessões de treino de 250m de corrida.

Effects of Different Conditioning Activities on 100-m Dash Performance in High School Track and Field Athletes.

This study compared the effects of different conditioning activities on the 100-m dash performance of 11 male, high school track and field athletes (mean age = 16.3; SD = 1.2 years). Participants performed a 100-m dash seven minutes after each of four randomized conditioning protocols, with each condition and 100-m dash separated by 3-10 days. The conditioning protocols were (a) control, no conditioning activity; (b) weighted plyometric, three sets of 10 repetitions of alternate leg bounding with additional load of 10% of the body mass; (c) free sprint, two 20-m sprints; and (d) resisted sprint (RS), two 20-m resisted sprints using an elastic tubing tool. We obtained session ratings of perceived exertion (SRPE) immediately after each conditioning protocol. There were no significant differences between any of the three experimental conditioning activities on 100-m sprint time, but the RS protocol improved 100-m sprint time compared with the control (no conditioning) protocol ( p < .001). The RS also led to greater sprint velocity and higher SRPE compared with the control condition ( p < .01). There was no significant association between SRPE and 100-m performance ( p = .77, r = .05). These results suggest a benefit for young male track and field athletes to the elastic tubing warm-up activities prior to the 100-m dash.

Energy Expenditure and Intensity of Active Video Games in Children and Adolescents.

PURPOSE: This study aimed to compare the energy expenditure and intensity of active video games to that of treadmill walking in children and adolescents. METHOD: Seventy-two boys and girls (aged 8-13 years) were recruited from local public schools. Energy expenditure and heart rate were measured during rest, during 3-km/hr, 4-km/hr, and 5-km/hr walks, and during active games (Adventure, Boxing I, Boxing II, and Dance). During walking and active games, we also assessed physical activity using an accelerometer. RESULTS: The energy expenditure of the active games Adventure, Boxing I, Boxing II, and Dance was similar to that of treadmill walking at 5 km/hr in boys and girls. Heart rate was significantly higher for the game Adventure compared with walking at 3 km/hr, 4 km/hr, and 5 km/hr and the game Dance in both genders. The heart rate of girls during the games Adventure and Dance was significantly higher compared with boys. There was a statistically significant difference (p < .05, with an effect size ranging from 0.40 to 3.54) in the counts·min-1, measured through accelerometry, between activities. CONCLUSION: XBOX 360 Kinect games provide energy expenditure and physical activity of moderate intensity for both genders. The use of active video games can be an interesting alternative to increase physical activity levels.

Immediate and 24-h blood pressure-lowering effects of arm crank exercise in patients with traumatic lower-limb amputation: a randomized cross-over study.

AIM: This study aimed to investigate the clinic and 24-h postexercise hypotension (PEH) after a moderate-intensity arm crank exercise session in individuals with traumatic lower-limb amputation. PARTICIPANTS AND METHODS: Nine men (46±17 years) with unilateral traumatic lower-limb amputation participated in two experimental sessions conducted randomly: an aerobic exercise (EXE: arm crank ergometer, 30 min) or a control session (CON: participants remained seated on the cycle ergometer, 30 min). Clinic and 24-h systolic, diastolic, and mean blood pressure (BP) response were measured after both sessions. The clinical measurements of blood flow and forearm vascular resistance (FVR) were also performed. RESULTS: Compared with the preintervention period, the BP levels did not change in the CON session. However, EXE resulted in a significant hypotensive effect in systolic (-10±0.9 mmHg, P≤0.05), diastolic (-11±1.5 mmHg, P≤0.05), and mean BP (-11±1.2 mmHg, P≤0.05) during the entire postexercise period. The PEH was accompanied by a decreased FVR over the entire postintervention period (P≤0.05). Significant reductions were found for 24-h average systolic, diastolic, and mean BP levels (P=0.03, 0.01, and 0.02, respectively) following EXE compared with the CON session. CONCLUSION: These results showed, for the first time, that individuals with traumatic lower-limb amputation presented immediate and 24-h PEH after a single bout of arm crank exercise testing. The PEH at the clinic condition was justified, at least in part, by the reduction in peripheral FVR.

Monitoring the training intensity and recovery with a psychometrics approach: a gender comparison with young athletes

AIMS: The purpose of present study was verify if the RPE-training session differs between females and males during the track and field training and if biological maturity (BM) has interference on this response. METHODS: Seventy-five athletes (13-15 years old) have participated of study, with 38 male 37 female. Five training sessions of track and field were prescribe and monitoring by RPE-training session (intensity) and Total Quality Recovery (TQR) (recovery). RESULTS: There was no statistical difference between males and females on 75-meters run, long jump and shot put. Otherwise, for training of 250 and 1000-meters females related higher RPE-values than males 3.68 ± 0.79, 3.26 ± 0.56, p < 0.01 and 4.14 ± 0.94, 3.72 ± 0.89, p < 0.05; respectively. Even when controlling the effect of biological maturity the same results were observed to 250-meters F1,73 = 2.060; p = 0.002 and 1000-meters F1,73 = 0.997; p = 0.036. There was no difference for TQR between genders. CONCLUSION: The comparison the RPE-training session of females and males indicated there were difference to 250 and 1000-m training sessions, females have more RPE-training sessions than males. Additionally, there were no differences between genders for recovery parameters, even controlling BM.(AU)

Increased peripheral vascular resistance in male patients with traumatic lower limb amputation: one piece of the cardiovascular risk puzzle.

AIM: The increased morbidity and mortality in traumatic lower limb amputees can be explained by the development of risk factors, among which high blood pressure plays an important role. However, the possible mechanisms underlying increased blood pressure levels observed in this population remain unclear. Thus, we aimed to test the hypothesis that peripheral vascular resistance is increased at rest in patients with traumatic lower limb amputation. PATIENTS AND METHODS: In a cross-sectional study, eight patients with traumatic unilateral lower limb amputation (amputee group) and eight healthy individuals without amputation (control group) were included. Resting blood pressure, heart rate, and forearm blood flow were recorded simultaneously and thus, forearm vascular resistance was calculated. RESULTS: The amputee group showed higher systolic (126±2 vs. 118±5 mmHg, P<0.01), diastolic (78±2 vs. 63±3 mmHg, P<0.01), mean blood pressure (94±2 vs. 81±3 mmHg, P<0.01), and heart rate (74±5 vs. 65±8 bpm, P=0.02) compared with the control group. Despite the similar forearm blood flow response between groups, patients with traumatic lower limb amputation presented increased peripheral vascular resistance at rest compared with the control group (31.3±3.8 vs. 25.7±6.5 U, P=0.05). CONCLUSION: Patients with traumatic amputation present increased peripheral vascular resistance. Our findings clarify one possible mechanism underlying the higher blood pressure levels observed in this population.

Effects of load and type of physical training on resting and postexercise cardiac autonomic control.

The aim of the study was to investigate the influence of training load and exercise mode on heart rate variability and heart rate recovery (HRR) in healthy individuals. The subjects were divided into three groups: sedentary (SED), resistance trained (RT) and aerobically trained (RT). Resting and postmaximal exercise RR intervals were recorded on supine and seated position, respectively. The HRV indices calculated in the resting position were RMSSD and LF and HF power densities. The following HRR indices were calculated throughout the 5-minute postmaximal recovery period: semi-logarithmic regression analysis of the first 30 s (T30); absolute difference between the peak and 60 s HR (HRR(60s)); and mono-exponential time constant of HRR (HRRτ). The RMSSD on subsequent 30-s segments (RMSSD(30s)) on recovery period was also calculated. Both RT and AT groups presented faster HRR than SED (P<0·05). The aerobic trained group was the only group that presented vagal reactivation, when analysing the RMSSD(30s). There were no correlations between the Baecke sport score and the HRV vagal-related indices. However, it was significantly correlated with HRR. It was concluded that that the training load positively influences the HRR, but has no effect on the HRV at rest and that the type of exercise, showed a marked influence on HRV recovery.

Pre-game hydration status, sweat loss, and fluid intake in elite Brazilian young male soccer players during competition.

In this study, we assessed the pre-game hydration status and fluid balance of elite young soccer players competing in a match played in the heat (temperature 31.0 ± 2.0 ° C, relative humidity 48.0 ± 5.0%) for an official Brazilian soccer competition. Fluid intake was measured during the match, as were urine specific gravity and body mass before and after the game to estimate hydration status. Data were obtained from 15 male players (age 17.0 ± 0.6 years, height 1.78 ± 0.06 m, mass 65.3 ± 3.8 kg); however, data are only analysed for 10 players who completed the full game. The mean (± s) sweat loss of players amounted to 2.24 ± 0.63 L, and mean fluid intake was 1.12 ± 0.39 L. Pre-game urine specific gravity was 1.021 ± 0.004, ranging from 1.010 to 1.025. There was no significant correlation between sweat loss and fluid intake (r = 0.504, P = 0.137) or between urine specific gravity and fluid intake (r = -0.276, P = 0.440). We conclude that young, native tropical soccer players started the match hypohydrated and replaced about 50% of the sweat lost. Thus, effective strategies to improve fluid replacement are needed for players competing in the heat.

Heart rate monitoring in soccer: interest and limits during competitive match play and training, practical application.

The identification of physiological loads imposed by soccer training or match play reveals essential information, which may help improve training and recovery strategies. Until today, the use of heart rate (HR) monitoring is not standardized in soccer. Thus, the aim of this review was to analyze, determine and compare the exercise intensity (EI) monitored by HR in professional, youth, and recreational soccer players during matches and training sessions using a meta-analysis. Heart rate is one of the most common physiological variables used to determine exercise internal training load. The mean EI recorded during competitive matches was described as 70-80% of VO2max or 80-90% of maximal heart rate (HRmax), independent of the playing level. With respect to HR training zones, approximately 65% of the total match duration is spent at intensity of 70-90% HRmax and rarely below 65% HRmax. However, although HRmax is mostly employed in the literature, monitoring EI should be expressed in relation to reserve heart rate, as it was described as a more reliable indicator of HR, allowing interindividual comparisons. The HR response according to the playing position indicates that midfielders are characterized by the highest EI, followed by forwards and fullbacks. Moreover, in the second half of the match, the EI is lower than that observed during the first half; this reduction could be correlated with the level of the player's physical conditioning. Consequently, coaches may favor the use of interval training or small-sided training games because these are shown to improve both aerobic capacity and the ability to repeat high-intensity actions. Small-sided games allow reaching similar HR responses to those found during interval training and match play but with greater heterogeneity values. Future investigations should include a larger sample of players with special reference to playing position and the expression of EI in percentage of the reserve heart rate, analyzing the possible intergender differences in HR response.

Influência do nível de atividades físicas laborais, de lazer e locomoção na modulação autonômica cardíaca de repouso e na frequência cardíaca de recuperação / Influence of labor, leisure and locomotion physical activity level on resting cardiac autonomic modulation and in heart rate recovery

O objetivo deste estudo foi verificar a influência do nível das atividades laborais, de lazer e locomoção na modulação autonômica cardíaca de repouso e na freqüência cardíaca de recuperação. Métodos: Vinte jovens, saudáveis, do sexo masculino, que não praticavam exercício físico regular, foram divididos em dois grupos de acordo com o nível de atividade física habitual, obtido a partir do cálculo do escore total (ET), do questionário de Baecke: ‘menos ativos’ (n=10; 22,8±1,9 anos) e ‘mais ativos’ (n=10; 22,3±2,2 anos). Os registros dos intervalos R-R dos voluntários foram feitos em repouso, na posição supina por 15 minutos; durante o teste cardiopulmonar máximo e; por 5 minutos do período de recuperação. A variabilidade da freqüência cardíaca (VFC) foi analisada no domínio do tempo e da freqüência durante os últimos 5 minutos da coleta de repouso. Analisaram-se também índices de recuperação da freqüência cardíaca (FCrec). Resultados: Não houve diferença significativa entre os dois grupos em nenhum dos índices da VFC, assim como nos índices da FCrec. Conclusão: sugere-se que apenas atividades laborais, de lazer e te locomoção parecem não promover efeitos significativos na modulação autonômica cardíaca de repouso e na freqüência cardíaca de recuperação em jovens saudáveis. Nesse sentido, reforça-se a necessidade de atividades físicas sistematizadas e/ou aumento na intensidade das atividades laborais, de lazer e locomoção para promover adaptações autonômicas cardíacas.

Objective: The aim of this study was to investigate the labour, leisure and locomotion physical activities level on resting cardiac autonomic modulation and in heart rate recovery (HRR). Methods: 20 young healthy men, that didn’t practice physical exercise regularly, were divided into twogroups, according to their habitual physical activity level, obtained by the calculation of the total score, from Baecke’s questionnaire: ‘less actives’ (n=10; 22,8±1,9 years) and ‘more actives’ (n=10; 22,3±2,2years). The subjects’ R-R interval register was done by the supine resting position for 15 minutes; during the maximal effort text and; for 5 minutes from the recovery period. The heart rate variability (HRV) was analyzed in time and frequency domains, during the last 5 minutes of the resting register. It was alsoanalyzed HRR indexes. Results: There aren’t significant differences between the two groups in none of the HRV nor in the HRR indexes. Conclusion: In summary, it is suggested that only labour, leisure and locomotion activities seem not to provide significant effects on the resting cardiac autonomic modulation likewise in the HRR in healhy young men. Therefore, systematized physical activity or the rising of the intensity of labour, leisure and locomotionis are reinforced to provide positive cardiac autonomic adaptations.

Exercise intensity and technical demands of small-sided games in young Brazilian soccer players: effect of number of players, maturation, and reliability.

The aims of this study were to examine in young soccer players (a) the effect of varying the number of players on exercise intensity (EI) and technical actions during small-sided games (SSGs), (b) the reliability of EI and technical actions, and (c) the influence of the players' maturation on EI and involvements with the ball (IWBs). Sixteen male soccer players (mean ± SD; age 13.5 ± 0.7 years, height 164 ± 7 cm, and weight 51.8 ± 8 kg) completed 2 bouts of 3 vs. 3 (SSG3), 4 vs. 4 (SSG4), and 5 vs. 5 (SSG5) training. Exercise intensity was measured using heart rate and expressed as a percentage of maximal heart rate (%MHR). Technical actions were quantified from video recordings. Maturation stage was determined with the Tanner scale. Exercise intensity in SSG3 (89.8 ± 2%MHR) was higher (p < 0.003) than that in SSG5 (86.9 ± 3%MHR). The EI in the first set (86.8 ± 4%MHR) was lower (p < 0.001) than that in the second (89.1 ± 3%MHR) and in the third set (89.4 ± 3%MRH). No effects of number of players were found in IWB, passes, target passes, tackles, and headers. Significantly more crosses, dribbling, and shots on goal were observed during SSG3 compared to during SSG4 or SSG5 (p < 0.05). The typical error for EI, expressed as coefficient of variation, ranged from 2.2 to 3.4%. The reliability for the most frequent technical actions ranged from 6.8 to 19.3%. The level of maturation was not correlated with either EI or IWB. These results extend previous findings with adult players suggesting that SSGs can provide an adequate training stimulus for young players and are feasible for groups with heterogeneous maturation levels.

Fluid balance of elite Brazilian youth soccer players during consecutive days of training.

In this study we investigated pre-training hydration status, fluid intake, and sweat loss in 20 elite male Brazilian adolescent soccer players (mean ± s: age 17.2 ± 0.5 years; height 1.76 ± 0.05 m; body mass 69.9 ± 6.0 kg) on three consecutive days of typical training during the qualifying phase of the national soccer league. Urine specific gravity (USG) and body mass changes were evaluated before and after training sessions to estimate hydration status. Players began the days of training mildly hypohydrated (USG > 1.020) and fluid intake did not match fluid losses. It was warmer on Day 1 (33.1 ± 2.4°C and43.4 ± 3.2% relative humidity; P < 0.05) and total estimated sweat losses (2822 ± 530 mL) and fluid intake (1607 ± 460 mL) were significantly higher (P < 0.001) compared with Days 2 and 3. Data also indicate a significant correlation between the extent of sweat loss and the volume of fluid consumed (Day 1: r = 0.560, P = 0.010; Day 2: r = 0.445, P = 0.049; Day 3: r = 0.743, P = 0.0001). We conclude that young, native tropical soccer players arrive hypohydrated to training and that they exhibit voluntary dehydration; therefore, enhancing athletes' self-knowledge of sweat loss during training might help them to consume sufficient fluid to match the sweat losses.

[Effects of sexual maturation on body composition, dermatoglyphics, somatotype and basic physical qualities of adolescents]. / Efeitos da maturação sexual na composição corporal, nos dermatóglifos, no somatótipo e nas qualidades físicas básicas de adolescentes.

OBJECTIVES: Describe the characteristics of body composition, somatotype, basic physical qualities, dermatoglyphics and bone age regarding sexual maturation stages of boys. METHODS: A transversal study was carried out in 136 boys, between 10 and 14 years of age. Clinical assessment, physical examination and radiography of wrists and hands to calculate bone age were performed. RESULTS: A tendency of increasing total body mass, stature, body mass index, body bone diameters and muscle circumferences and basic physical qualities was found with the advancing of puberty. No differences were found in dermatoglyphics and somatotype between different stages of puberty maturation. CONCLUSIONS: Due to the changes in important parameters of physical training that occur during puberty, it can be concluded that the selection of children and adolescents for sport training and competitions should be based not only on chronological age but also, and mainly on sexual maturation, for better physical assessment and appropriate training for this population.

Efeitos da maturação sexual na composição corporal, nos dermatóglifos, no somatótipo e nas qualidades físicas básicas de adolescentes / Effects of sexual maturation on body composition, dermatoglyphics, somatotype and basic physical qualities of adolescents

OBJETIVOS: Descrever como se comportam a composição corporal, o somatótipo, as qualidades físicas básicas, os dermatóglifos e a idade óssea, nos diversos estágios de maturação sexual. MÉTODOS: Foi realizado estudo transversal envolvendo 136 meninos, na faixa etária de 10 a 14 anos, e realizados exame clínico, avaliação física e radiografias de mãos e punhos para avaliação de idade óssea. RESULTADOS: Encontraram-se tendência de aumento de estatura, massa corporal total, índice de massa corporal, idade óssea, diâmetros ósseos, circunferências musculares e qualidades físicas básicas, com o avançar da puberdade. Não se observaram diferenças nos dermatóglifos e no somatótipo, entre os estágios puberais. CONCLUSÕES: Por causa das mudanças em importantes parâmetros para o treinamento físico, durante a puberdade, a seleção de crianças e adolescentes para a atividade desportiva não deve se fundamentar apenas na idade cronológica, mas, sobretudo, na maturação sexual, visando a melhor avaliação física e o treinamento apropriado para essa população.

OBJECTIVES: Describe the characteristics of body composition, somatotype, basic physical qualities, dermatoglyphics and bone age regarding sexual maturation stages of boys. METHODS: A transversal study was carried out in 136 boys, between 10 and 14 years of age. Clinical assessment, physical examination and radiography of wrists and hands to calculate bone age were performed. RESULTS: A tendency of increasing total body mass, stature, body mass index, body bone diameters and muscle circumferences and basic physical qualities was found with the advancing of puberty. No differences were found in dermatoglypics and somatotype between different stages of puberty maturation. CONCLUSIONS: Due to the changes in important parameters of physical training that occur during puberty, it can be concluded that the selection of children and adolescents for sportive training and competitions should be based not only on chronological age but also, and mainly on sexual maturation, for better physical assessment and appropriate training for this population.