Suchergebnisse

The aim of this study was to determine strength and oxygen uptake (V[Combining Dot Above]O2max) performances according to different training program intervention design with 8-week duration in prepubescent children through a multiple linear regression models. Two hundred forty-five healthy prepubescent children (aged 10.9 ± 0.5 years) were randomly assigned to a specific training program (strength training only-S; aerobic training only-A; intrasession aerobic and strength training-AS; intrasession strength and aerobic training-SA; or concurrent training performed in different sessions-CT) or a control group (no training regimen-C). It was possible to develop indirect predictive models for each training method, by including each variable pretraining, body fat percentage and body mass index. The models provided explained 82% of variance in the V[Combining Dot Above]O2max, 98% in the 1 kg ball-throw, 96% in the 3 kg ball-throw, 92% in the countermovement jump, 93% in the standing long jump and 98% in the 20 m sprint performances. This novel approach to training evaluation and control aims to provide a tool to allow professionals to calculate changes with a high confidence level (CI 95%), to control gains and to choose the best training methodology to apply according to the defined purposes. The results of this study could be a great support to teachers, coaches, and professionals providing important tools to improve the efficacy and individualization of training. ; This project was supported by the National Funds through FCT – Portuguese Foundation for Science and Technology (UID/DTP/04045/2013) – and the European Fund for Regional Development(FEDER) allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969) – competitiveness and internationalization (POCI).

This project was supported by the National Funds through FCT - Portuguese Foundation for Science and Technology (UID/DTP/04045/2013) - and the European Fund for regional development (FEDER) allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969), and it was supported by the Project NanoSTIMA: Macro-toNano Human Sensing, Towards Integrated Multimodal Health Monitoring and Analytics, NORTE-01-0145-FEDER-000016, co-financed by European Fund for Regional Development (FEDER) - NORTE 2020 ; Research studies agreed that strength and aerobic training either combined or performed separately promote bone density, aerobic capacity, and explosive strength improvements in childhood. Nevertheless, there still is uncertainty regarding to the best training program to be implemented that efficiently improve body fat percentage. The current study aimed to compare different training program's designs on body fat percentage in prepubertal boys.One hundred twenty-three boys (10.93 ± 0.57 years) were randomly assigned into five experimental groups to perform different training protocols for 8 weeks: strength-only (SG), aerobic-only (AG), inter-session concurrent aerobic-strength training (ASG_2), intra-session concurrent aerobic-strength training (ASG), intra-session concurrent strength-aerobic training (SAG), and a control group, no training (CG). SG, AG, ASG and SAG groups performed single sessions two days per week. ASG_2 group performed on different days each week (two and two days per week). The strength training program comprised plyometric exercises (medicine ball throws and jumps) and sprint running. The aerobic training program comprised the 20m shuttle run exercise. Body fat percentage was assessed using a body composition analyzer (Tanita TBF-300A) before and after the 8-weeks of the training program.Body fat percentage showed significant decrements from pre- to the post-training in the ASG_2 (17.6%, p=0.004), SG (16.1%, p=0.000), and SAG (17.7%, p=0.000) groups. There was an impairment in the ASG (4.2%, p=0.492) and control group CG (16.8%, p=0.000). No differences were presented in the AG (p=0.053).The order of intra-session concurrent training influenced body fat percentage changes. Moreover, performing intra-session concurrent strength and aerobic training is more useful than strength or aerobic training only and concurrent training in different sessions to decrease body fat percentage in prepubertal boys. These results have a meaningful interest to optimized school-based fat loss exercise programs in childhood.

Objectives: The aim of this study was to compare the effect of 10 min vs. 20 min passive rest post warm-up on performance in a 100 m freestyle time-trial. Design: Randomized crossover. Methods: Eleven competitive male swimmers performed two experimental trials on different days, consisting of 100 m freestyle time-trials following 10 min or 20 min passive rest after a standard 1200 m warm-up. Performance (time-trial), biomechanical (stroke length, stroke frequency, stroke index, propelling efficiency), physiological (blood lactate concentrations, heart rate, core and tympanic temperature), and psychophysiological (perceived effort) variables were assessed during both trials. Results: Time-trial performance was faster after 10 min as opposed to 20 min passive rest (58.41 ± 1.99 s vs. 59.06 ± 1.86, p < 0.01). This was supported by strong effect sizes (d = 0.99) and the qualitative indication of 'likely' positive effects. Heart rate before the time-trial was also higher after 10 min passive rest (89 ± 12 bpm vs. 82 ± 13 bpm; p < 0.01). Furthermore, net core temperature and oxygen uptake values before the time-trial were substantially lower after 20 min passive rest. Conclusions: These data suggest that the 10 min post warm-up passive rest enhances 100 m freestyle performance when compared to a 20 min period. An improvement that appears to be mediated by the combined effects of a shorter post warm-up period on core temperature, heart rate and oxygen uptake. ; This project was supported by the National Funds through FCT – Portuguese Foundation for Science and Technology (UID/DTP/04045/2013) – and the European Fund for Regional Development (FEDER) allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969) – competitiveness and internationalization (POCI). This work was also supported by a grant from the Science and Technology Foundation (SFRH/BD/74950/2010) and by University of Beira Interior and Santander Totta Bank (UBI/FCSH/Santander/2010).

The aim of this study was to verify the effects of different aerobic intensities combined with the same resistance training on strength and aerobic performances. Thirty-nine men were randomly assigned to a low-intensity group (LIG), moderate-intensity group (MIG), high-intensity group (HIG), and a control group. The training program consisted of full squat, jumps, sprints, and running at 80% (LIG), 90% (MIG), or 100% (HIG) of the maximal aerobic speed for 16-20 minutes. The training period lasted for 8 weeks, followed by 4 weeks of detraining. Evaluations included 20-m sprints (0-10 m: T10; 0-20 m: T20), shuttle run, countermovement jump (CMJ), and strength (1RM(est)) in full squat. There were significant improvements from pre-training to post-training in T10 (LIG: 4%; MIG: 5%; HIG: 2%), T20 (3%; 4%; 2%), CMJ (9%; 10%; 7%), 1RM(est) (13%; 7%; 8%), and oxygen uptake (V?o(2)max; 10%; 11%; 10%). Comparing the changes between the experimental groups, 1RM(est)gains were significantly higher in the LIG than HIG (5%) or MIG (6%). Furthermore, there was a tendency for higher gains in LIG and MIG compared with HIG, with 'possibly' or 'likely' positive effects in T10, T20, and CMJ. Detraining resulted in performance decrements, but minimal losses were found for V?o(2)max in LIG (-1%). Concurrent training seems to be beneficial for strength and aerobic development regardless of the aerobic training intensity. However, choosing lower intensities can lead to increased strength and is recommended when the cardiorespiratory gains should be maintained for longer. ; This project was supported by the National Funds through FCT-Portuguese Foundation for Science and Technology (UID/DTP/04045/2013)-and the European Fund for Regional Development (FEDER) allocated by European Union through the COMPETE 2020 Program (POCI-01-0145-FEDER-006969)-competitiveness and internationalization (POCI).

This study analyzed the acute effects of heavy strength training on mechanical, hemodynamic, metabolic, and psychophysiological responses in adult males. Thirteen recreational level males (23.3 ± 1.5 years) randomly performed two heavy strength training sessions (3 sets of 8 repetitions at 80% of one repetition maximum [1RM]) using the bench press (HST-BP) or full squat (HST-FS)). The repetition velocity was recorded in both sessions. Moreover, before and after the sessions, the velocity attained against the ~1.00 m·s−1 load (V1Load) in the HST-BP, countermovement jump (CMJ) height in the HST-FS, blood pressure, heart rate, blood lactate, and psychophysiological responses (OMNI Perceived Exertion Scale for Resistance Exercise) were measured. There were differences between exercises in the number of repetitions performed in the first and third sets (both <8 repetitions). The velocity loss was higher in the HST-BP than in the HST-FS (50.8 ± 10.0% vs. 30.7 ± 9.5%; p < 0.001). However, the mechanical fatigue (V1Load vs. CMJ height) and the psychophysiological response did not differ between sessions (p > 0.05). The HST-FS caused higher blood pressure and heart rate responses than the HST-BP (p < 0.001 and p = 0.02, respectively) and greater blood lactate changes from pre-training to post-set 1 (p < 0.05). These results showed that the number of maximal repetitions performed in both sessions was lower than the target number and decreased across sets. Moreover, the HST-BP caused a higher velocity loss than the HST-FS. Finally, the HST-FS elicited higher hemodynamic and metabolic demand than the HST-BP.

Backpacks for transporting school loads are heavily utilized by children, and their mechanical advantages have been allowing children to transport heavy loads. These heavy loads may increase ground reaction forces (GRFs), which can have a negative effect on joints and bone health. The aim of this study was to investigate the effect of backpacks on the GRFs generated by children during walking, running, and jumping. Twenty-one children from the fifth (G-5, n = 9) and ninth (G-9, n = 12) grades walked, ran, and jumped over a force plate. When walking, the G-5 had GRF increments in the first (17.3%; p 0.05), unlike the G-5 (p = 0.001). When running, total stance time increased 15% (p < 0.001) and 8.5% (p < 0.001) proportionally to the relative load carried, in the G-5 and G-9, respectively. Peak GRF did not increase in any group when running or landing from a jump over an obstacle. It was found that GRF was affected by the backpack load when walking and running. However, when landing from a jump with the backpack, schoolchildren smoothed the landing by prolonging the reception time and thus avoiding GRF peak magnitudes. ; This work is supported by national funding through the Portuguese Foundation for Science and Technology, I.P., under the project UID/DTP/04045/2019 and the European Fund for Regional Development (FEDER) allocated by European Union through the COMPETE 2020 Programme (POCI-01-0145-FEDER-006969)—competitiveness and internationalization (POCI).

This work is supported by national funding through the Portuguese Foun- dation for Science and Technology, I.P., under project UID/DTP/04045/2019 and the European Fund for Regional Development (FEDER) allocated by European Union through the COMPETE 2020 Programme (POCI-01- 0145-FEDER-006969) Competitiveness and Internationalization (POCI). ; The aim of this study was to determine the effects of an 8-week program of resistance training (RT) or suspension training (ST) on explosive strength in prepubescent boys. Methods: Fifty-seven boys aged 10–11 years were assigned to 2 training groups, RT or ST or a control group (no training program). Boys trained twice weekly for 8 weeks. Results: A significant interaction was reported with a large (P < .001, η2p = .463), medium (P < .001, η2p = .395), and small effect sized (P ≤ .001, η2p = .218) in the 1-kg ball throw, 3-kg ball throw, and time-at-20-m test, respectively. There was no significant interaction in the countermovement vertical jump or the standing long jump. Changes from preintervention to postintervention for the 1-kg ball throw were 5.94% and 5.82% for the ST and RT, respectively, and 8.82% and 8.14% in the 3-kg ball throw for the ST and RT, respectively. The improvement in the 20-m sprint was 1.19% for the ST and 2.33% for the RT. Conclusion: Traditional RT and ST seem to be effective methods for improving explosive strength in prepubescent boys. ST could be considered as an alternative modality to optimize explosive strength training in school-based programs.