Carlos C. Marta

Physical fitness differences between prepubescent boys and girls.

Abstract Marta, CC, Marinho, DA, Barbosa, TM, Izquierdo, M, and Marques, MC. Physical fitness differences between prepubescent boys and girls. J Strength Cond Res 26(7): 1756–1766, 2012—The purpose of this study was to analyze in which physical capabilities boys and girls are closer or distant. An additional objective was to find which of the body fat, physical activity, and somatotype factors have a greater effect on prepubescent childrens physical fitness. This was a cross-sectional study involving 312 children (10.8 ± 0.4 years). The physical fitness assessment employed sets of aerobic fitness, strength, flexibility, speed, agility, and balance. The boys presented higher values in all selected tests, except tests of balance and flexibility, in which girls scored better. Gender differences in the physical fitness were greatest in the explosive strength of upper (p ⩽ 0.01, ) and lower limbs (p ⩽ 0.01, ), although with a medium-size effect of gender, and smaller in the abdominal (p > 0.05, ) and upper limbs (p > 0.05, ) muscular endurance, and trunk extensor strength and flexibility (p > 0.05, ). The endomorphic (p ⩽ 0.01, ) in the girls, and the ectomorphic (p ⩽ 0.01, ) and mesomorphic (p ⩽ 0.01, ) in the boys, had the high-sized effect on the physical fitness. The physical activity in the girls, and the endomorphic and body fat in the boys, did not have a significant effect. These findings can help in the planning of activities that take into account the success and motivation of both boys and girls and thus increase levels of physical activity and physical fitness at school. However, in prepubescent children, one cannot neglect the influence of genetic determinism, observed from the morphoconstitutional point of view.

Effects of Concurrent Training on Explosive Strength and VO2max in Prepubescent Children

The purpose of this study was to compare the effects of an 8-weeks training period of resistance training alone (GR), combined resistance and endurance training (GCON) and a control group (GC) on explosive strength and V(O2max) in a large sample of prepubescent boys and girls. 125 healthy children (58 boys, 67 girls), aged 10-11 years old (10.8±0.4 years) were assigned into 2 training groups to train twice a week for 8 weeks: GR (19 boys, 22 girls), GCON (21 boys, 24 girls) and a control group (GC: 18 boys, 21 girls; no training program). A significant but medium-sized increase from pre- to the post-training in the vertical jump (Effect size=0.22, F=34.44, p<0.01) and V(O2max) (Effect size=0.19, F=32.89, p<0.01) was observed. A significant large increase in the 1 kg (Effect size=0.53, F=202.17, p<0.01) and 3 kg (Effect size=0.48, F=132.1, p<0.01) ball throwing, standing long jump (Effect size=0.53, F=72.93, p<0.01) and running speed (Effect size=0.45, F=122.21, p<0.01) was also observed. The training group (GR and GCON) and sex factors did not significantly influence the evolution of strength variables from pre- to the post-training. The V(O2max) increased significantly only in GCON. Concurrent training is equally effective on training-induced explosive strength, and more efficient than resistance training only for V(O2max), in prepubescent boys and girls. This should be taken into consideration in order to optimize strength training school-based programs.

Effects of Body Fat and Dominant Somatotype on Explosive Strength and Aerobic Capacity Trainability in Prepubescent Children

Abstract Marta, CC, Marinho, DA, Barbosa, TM, Carneiro, AL, Izquierdo, M, and Marques, MC. Effects of body fat and dominant somatotype on explosive strength and aerobic capacity trainability in prepubescent children. J Strength Cond Res 27(12): 3233–3244, 2013—The purpose of this study was to analyze the influence of body fat and somatotype on explosive strength and aerobic capacity trainability in the prepubertal growth spurt, marked by rapid changes in body size, shape, and composition, all of which are sexually dimorphic. One hundred twenty-five healthy children (58 boys, 67 girls), aged 10–11 years (10.8 ± 0.4 years), who were self-assessed in Tanner stages 1–2, were randomly assigned into 2 experimental groups to train twice a week for 8 weeks: strength training group (19 boys, 22 girls), endurance training group (21 boys, 24 girls), and a control group (18 boys, 21 girls). Evaluation of body fat was carried out using the method described by Slaughter. Somatotype was computed according to the Heath-Carter method. Increased endomorphy reduced the likelihood of vertical jump height improvement (odds ratio [OR], 0.10; 95% confidence interval [CI], 0.01–0.85), increased mesomorphy (OR, 6.15; 95% CI, 1.52–24.88) and ectomorphy (OR, 6.52; 95% CI, 1.71–24.91) increased the likelihood of sprint performance, and increased ectomorphy (OR, 3.84; 95% CI, 1.20–12.27) increased the likelihood of aerobic fitness gains. Sex did not affect the training-induced changes in strength or aerobic fitness. These data suggest that somatotype has an effect on explosive strength and aerobic capacity trainability, which should not be disregarded. The effect of adiposity on explosive strength, musculoskeletal magnitude on running speed, and relative linearity on running speed and aerobic capacity seem to be crucial factors related to training-induced gains in prepubescent boys and girls.

Somatotype is more interactive with strength than fat mass and physical activity in peripubertal children

Somatotype is More Interactive with Strength than Fat Mass and Physical Activity in Peripubertal Children The purpose of this study was to analyse the interaction between somatotype, body fat and physical activity in prepubescent children. This was a cross-sectional study design involving 312 children (160 girls, 152 boys) aged between 10 and 11.5 years old (10.8 ± 0.4 years old). Evaluation of body composition was done determining body mass index and body fat by means of skin-fold measurements, using the method described by Slaughter. Somatotype was computed according to the Carters method. Physical activity was assessed with the Baecke questionnaire. The physical activity assessment employed sets of curl-ups, push-ups, standing broad jump, medicine ball throw, handgrip strength and Margaria-Kalamen power stair. There were negative associations for body fat, endomorphy and mesomorphy with curl-ups, push-ups and broad jump tests and positive associations with ball throw, handgrip strength and Margaria-Kalamen power tests. The associations for ectomorphy were the inverse of those for endomorphy and mesomorphy. Non obese children presented higher values for curl-ups, push-ups and standing broad jump. In medicine ball throw, handgrip strength and Margaria-Kalamen power test obese children presented higher scores, followed by children who were overweight. The mesoectomorphic boys and ectomesomorphic girls performed higher in all tests. The morphological typology presented more interactions with strength than % of body fat and physical activity. These data seem to suggest that the presence/absence of certain physical characteristics is crucial in the levels of motor provision in prepubescent children.

Concurrent Training in Prepubescent Children: The Effects of 8 Weeks of Strength and Aerobic Training on Explosive Strength and V[combining Dot Above]o2max

Abstract Alves, AR, Marta, CC, Neiva, HP, Izquierdo, M, and Marques, MC. Concurrent training in prepubescent children: the effects of 8 weeks of strength and aerobic training on explosive strength and V[Combining Dot Above]O2max. J Strength Cond Res 30(7): 2019–2032, 2016—The purpose of this study was to compare the effects of 8-week training periods of strength training alone (GS), combined strength and aerobic training in the same session (GCOM1), or in 2 different sessions (GCOM2) on explosive strength and maximal oxygen uptake (V[Combining Dot Above]O2max) in prepubescent children. Of note, 168 healthy children, aged 10–11 years (10.9 ± 0.5), were randomly selected and assigned to 3 training groups to train twice a week for 8 weeks: GS (n = 41), GCOM1 (n = 45), GCOM2 (n = 38) groups, and a control group (GC) (n = 44; no training program). The GC maintained the baseline level, and trained-induced differences were found in the experimental groups. Differences were observed in the 1 and 3-kg medicine ball throws (GS: +5.8 and +8.1%, respectively; GCOM1: +5.7 and +8.7%, respectively; GCOM2: +6.2 and +8%, respectively, p < 0.001) and in the countermovement jump height and in the standing long jump length (GS: +5.1 and +5.2%, respectively; GCOM1: +4.2 and +7%, respectively; GCOM2: +10.2 and +6.4%, respectively, p < 0.001). In addition, the training period induced gains in the 20-m time (GS: +2.1%; GCOM1: +2.1%; GCOM2: +2.3%, p < 0.001). It was shown that the experimental groups (GCOM1, GCOM2, and GS) increased V[Combining Dot Above]O2max, muscular strength, and explosive strength from pretraining to posttraining. The higher gains were observed for concurrent training when it was performed in different sessions. These results suggest that concurrent training in 2 different sessions seems to be an effective and useful method for training-induced explosive strength and V[Combining Dot Above]O2max in prepubescent children. This could be considered as an alternative way to optimize explosive strength training and cardiorespiratory fitness in school-based programs.

Is Long Term Creatine and Glutamine Supplementation Effective in Enhancing Physical Performance of Military Police Officers

Abstract The objective of this study was to analyze the effect of supplementation with creatine and glutamine on physical fitness of military police officers. Therefore, an experimental double blind study was developed, with the final sample composed by 32 men randomly distributed into three groups: a group supplemented with creatine (n=10), glutamine (n=10) and a placebo group (n=12) and evaluated in three distinct moments, in an interval of three months (T1, T2 and T3). The physical training had a weekly frequency of 5 sessions x 90 min, including strength exercises, local muscular resistance, flexibility and both aerobic and anaerobic capacity. After analyzing the effect of time, group and interaction (group x time) for measures that indicated the physical capabilities of the subjects, a significant effect of time for the entire variable was identified (p<0,05). However, these differences were not observed when the univaried intragroups and intergroups analysis was performed (p>0,05). In face of the results it was concluded that supplementation with creatine and glutamine showed no ergogenic effect on physical performance in military police officers.

Differentiating Maturational Influence on Training-Induced Strength and Endurance Adaptations in Prepubescent Children

To analyze the effect of biological maturation on training‐induced strength and endurance adaptations in the prepubertal growth spurt.

Does Intrasession Concurrent Strength and Aerobic Training Order Influence Training-Induced Explosive Strength and V[Combining Dot Above]O2max in Prepubescent Children?

Abstract Alves, AR, Marta, C, Neiva, HP, Izquierdo, M, and Marques, MC. Does intrasession concurrent strength and aerobic training order influence training-induced explosive strength and V[Combining Dot Above]O2max in prepubescent children?. J Strength Cond Res 30(12): 3267–3277, 2016—The aim of this study was to analyze the interference of strength and aerobic training order over an 8-week period on explosive skills and maximal oxygen uptake (V[Combining Dot Above]O2max) in prepubescent children. One hundred twenty-eight prepubescent children aged 10–11 years (10.9 ± 0.5 years) were randomly selected and assigned to 1 of the 3 groups: intrasession concurrent aerobic before (GAS: n = 39) or after strength training (GSA: n = 45) or control group (GC: n = 44; no training program). The GC maintained their baseline level performance, and training-induced differences were found in the experimental groups. Increases were found in the 1-kg and 3-kg medicine ball throws: GAS: +3%, +5.5%, p ⩽ 0.05, p < 0.001; GSA: +5.7%, +8.7%, p < 0.001, respectively; in the counter movement jump height and standing long jump length: GAS: +6.5%, +3.4%, p ⩽ 0.05; GSA: +7%, +4.5%, p < 0.001, respectively; in the 20-m shuttle-run time: GAS: +2.3%; GSA: +4.6%, p < 0.001; and, in the V[Combining Dot Above]O2max: GAS: +7.3%, p < 0.001; GSA: +3.8%, p < 0.001 from pretraining to post-training. All programs were effective, but GSA produced better results than GAS for muscle strength variables, and GAS produced better results than GSA for aerobic capacity variables. The present study explored an unknown issue and added useful information to the literature in this area. These training methods should be taken into consideration to optimize explosive strength and cardiorespiratory fitness training in school-based programs and sports club programs.

Gender’s Effect on a School-Based Intervention in the Prepubertal Growth Spurt

Abstract Children aged 10-11 years pass through a dynamic developmental period marked by rapid changes in body size, shape, and composition, all of which are sexually dimorphic. The purpose of this study was to analyze the effects of gender on a school-based intervention in the prepubertal growth spurt. One hundred twenty-five healthy children (58 boys, 67 girls), fifth and sixth grade students from an urban public elementary school in Portugal (10.8 ± 0.4 years), were randomly assigned into two experimental groups: a strength training group (19 boys, 22 girls), and an endurance training group (21 boys, 24 girls); and a control group (18 boys, 21 girls; no training program). Training program for the two experimental groups was conducted twice a week for 8 weeks. Compared with the values at the beginning of the protocol, both strength and endurance training programs produced significant improvements (p< 0.05) in vertical and horizontal jumps, a 1 kg and 3 kg medicine ball throw, a 20 m sprint and VO2max, for both boys and girls. No significant changes were observed related to gender in training-induced strength (p> 0.05, ƞ_p^2= 0.16, Power= 0.29) and aerobic (p> 0.05, ƞ_p^2= 0.05, Power= 0.28) capacity. The results of the present study should be taken into consideration in order to optimize strength training school-based programs.

Effects of order and sequence of resistance and endurance training on body fat in elementary school-aged girls

The purpose of this study was to analyse the effects of order and sequence of concurrent resistance and endurance training on body fat percentage (BFP) in a large sample of elementary school-aged girls. One hundred and twenty-six healthy girls, aged 10-11 years (10.95 ± 0.48 years), were randomly assigned to six groups to perform different training protocols per week for 8 weeks: Resistance-only (R), Endurance-only (E), Concurrent Distinct Endurance-Resistance (CDER), Concurrent Parallel Endurance-Resistance (CPER), Concurrent Parallel Resistance-Endurance (CPRE), and a Control group (C). In R and E, the subjects performed single sessions of resistance or endurance exercises, respectively (two days per week). In CDER, resistance-endurance training was performed on different days each week (four days per week). CPER and CPRE performed single-session combined endurance-resistance training or combined resistance-endurance training, respectively, each week (two days per week). After an 8-week training period, BFP decreased in all experimental groups (CPER: 13.3%, p< 0.05; CPRE: 13.8%, p<0.001; E: 1.9%, p>0.05; R: 5.0%, p>0.05; and CDER: 5.6%, p>0.05). However, a significant difference was found in CPER and CPRE when compared to CDER, E, and R, indicating that training sequence may influence BFP. All programmes were effective, but CPER and CPRE obtained better results for BFP than CDER, E, or R. The effects of concurrent resistance and endurance training on body fat percentage can be mediated by order and sequence of exercise. These results provide insight into optimization of school-based fat loss exercise programmes in childhood.