Concurrent training in prepubertal children: an update

This paper affords an update review over the state of art regarding the importance of physical fitness and the significance of different combination approaches between resistance and aerobic training, as well as conditioning methods exercise alone on physical fitness improvements, specifically explosive strength and cardiorespiratory fitness in prepubertal children. The main research conclusions can be summarized as: i) Resistance training can be reliable to improve muscle strength in prepubertal children; ii) A proper and quantifiable exercise frequency and intensity in aerobic training remains unclear; iii) No differences have been found between prepubertal girls and boys on strength and aerobic capacity improvements after intra-session concurrent training, resistance or aerobic training alone; iv) In adults, concurrent resistance and aerobic training seems to be more effective on improvements of aerobic capacity than aerobic training alone; v) Aerobic training biomechanically specific to the concurrent resistance training may minimize adaptation interference when concurrently training; vi) In adolescents, concurrent resistance and aerobic training is equally effective to improve explosive strength compared to resistance training alone, and more efficient in aerobic capacity than resistance training alone; vii) Optimum training sequence was determined by the individual purposes of the training program; viii) Performing aerobic prior to resistance training produces endurance gains, while performing resistance prior to aerobic training appears to be more adequate to obtain strength improvements; ix) In adults, performing concurrent training in different sessions seems to be more effective to improve muscular strength than intra-session concurrent training. These results can be helpful for coaches, teachers and researchers to optimize explosive strength and cardiorespiratory fitness training in sports club and school-based programs, as well as a reliable source for further researches

The influence of ACE ID and ACTN3 R577X polymorphisms on lower-extremity function in older women in response to high-speed power training

Background: We studied the influence of the ACE I/D and ACTN3 R577X polymorphisms (single or combined) on lower-extremity function in older women in response to high-speed power training. Methods: One hundred and thirty-nine healthy older Caucasian women participated in this study (age: 65.5 ± 8.2 years, body mass: 67.0 ± 10.0 kg and height: 1.57 ± 0.06 m). Walking speed (S10) performance and functional capacity assessed by the “get-up and go” (GUG) mobility test were measured at baseline (T1) and after a consecutive 12-week period of high-speed power training (40-75% of one repetition maximum in arm and leg extensor exercises; 3 sets 4–12 reps, and two power exercises for upper and lower extremity). Genomic DNA was extracted from blood samples, and genotyping analyses were performed by PCR methods. Genotype distributions between groups were compared by Chi-Square test and the gains in physical performance were analyzed by two-way, repeated-measures ANOVA. Results: There were no significant differences between genotype groups in men or women for adjusted baseline phenotypes (P > 0.05). ACE I/D and ACTN3 polymorphisms showed a significant interaction genotype-training only in S10 (P = 0.012 and P = 0.044, respectively) and not in the GUG test (P = 0.311 and P = 0.477, respectively). Analyses of the combined effects between genotypes showed no other significant differences in all phenotypes (P < 0.05) at baseline. However, in response to high-speed power training, a significant interaction on walking speed (P = 0.048) was observed between the “power” (ACTN3 RR + RX & ACE DD) versus “non-power” muscularity-oriented genotypes (ACTN3 XX & ACE II + ID)]. Conclusions: Thus, ACE I/D and ACTN3 R577X polymorphisms are likely candidates in the modulation of exercise-related gait speed phenotype in older women but not a significant influence in mobility traits.The study was developed with the aid of a research fellowship, reference number SFRH/BD/47114/2008, funded by POPH – QREN, shared by the European Social Fund and the national funds of MCTES. This work was supported in part by the Spanish Department of Health and Institute Carlos III of the Government of Spain [Spanish Net on Aging and frailty; (RETICEF)] and Economy and Competitivity Department of the Government of Spain, under grants numbered RD12/043/0002, and DEP2011-24105, respectively

Relative contribution of arms and legs in 30 s fully tethered front crawl swimming

The relative contribution of arm stroke and leg kicking to maximal fully tethered front crawl swimming performance remains to be solved. Twenty-three national level young swimmers (12 male and 11 female) randomly performed 3 bouts of 30 s fully tethered swimming (using the whole body, only the arm stroke, and only the leg kicking). A load-cell system permitted the continuous measurement of the exerted forces, and swimming velocity was calculated from the time taken to complete a 50m front crawl swim. As expected, with no restrictions swimmers were able to exert higher forces than that using only their arm stroke or leg kicking. Estimated relative contributions of arm stroke and leg kicking were 70.3% versus 29.7% for males and 66.6% versus 33.4% for females, with 15.6% and 13.1% force deficits, respectively. To obtain higher velocities, male swimmers are highly dependent on themaximumforces they can exert with the arm stroke ( = 0.77, < 0.01), whereas female swimmers swimming velocity ismore related to whole-body mean forces ( = 0.81, < 0.01). The obtained results point that leg kicking plays an important role over short duration high intensity bouts and that the used methodology may be useful to identify strength and/or coordination flaws.The Portuguese Government supported this work by a grant of the Science and Technology Foundation (SFRH/BD/66910/2009). This work was also supported by the Strategic Projects PEst-OE/EME/UI4044/2013 and University of Beira Interior and Santander Totta Bank (UBI/FCSH/Santander/2010)

Schoolbag weight carriage in Portuguese children and adolescents: a cross-sectional study comparing possible influencing factors

Background Schoolbags and the consequences of carrying them, particularly those associated with overload, are often studied as a health concern. Modifications in gait and posture were reported when children carried loads that corresponded to more than 10% of their body weight (BW). The aims of this study were to verify the load that is carried by Portuguese students and how it is influenced by factors such as school grade, school schedule, lunch site, physical education, sex and body mass index (BMI). Acquiring a more specific knowledge of the Portuguese context and understanding the influence of these factors may allow us to generate proposals to control them in ways that benefit students.MethodsThe load carried by students in the 5th grade (10.60.4years) and 9th grade (14.70.6years) were weighed with a luggage scale on all days of the week, resulting in 680 evaluations. Data related to the school day were also collected, such as the student's lunch site, how he or she got to school and his or her school schedule for that day. Individual height and weight were also assessed. Results The 5th grade students carried greater loads than the 9th grade students, resulting in a substantial difference relative to their BW. The school loads of the 5th grade students were mostly greater than 10% of their BWs. Girls tended to carry heavier loads than boys, and overweight students also tended to carry heavier loads. Students who could eat lunch at home carried less weight, and on physical education days, the total load carried increased, but the backpacks of the 5th grade students were lighter.Conclusions The results of the current study describe excessive schoolbag weight among Portuguese students and expound on some of the factors that influence it, which can help researchers and professionals design a solution to decrease children's schoolbag loads.Funds through FCT - Portuguese Foundation for Science and Technology (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), and through the Project NanoSTIMA: Macro-to-Nano Human Sensing, Towards Integrated Multimodal Health Monitoring and Analytics (NORTE-01-0145-FEDER-000016), co-financed by Fundo Europeu de Desenvolvimento Regional (FEDER) -NORTE 2020