Modeling Fitness Variable Responses to Training in Prepubescent Children.

Alves, AR, Marta, C, Neiva, HP, Nunes, C, Izquierdo, M, and Marques, MC. Modeling fitness variable responses to training in prepubescent children. J Strength Cond Res 34(8): 2352-2359, 2020-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.

Effects of Suspension Versus Traditional Resistance Training on Explosive Strength in Elementary School-Aged Boys.

PURPOSE: 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, ηp2=.463), medium (P < .001, ηp2=.395), and small effect sized (P ≤ .001, ηp2=.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.

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.

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

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.

Concurrent Training in Prepubescent Children: The Effects of 8 Weeks of Strength and Aerobic Training on Explosive Strength and V[Combining Dot Above]O2max.

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.

Effect of Gender, Energetics, and Biomechanics on Swimming Masters Performance.

The purpose of this study was to analyze the effect of gender and energetics on biomechanics and performance of masters swimmers over 1 season. Twenty-five masters swimmers (14 male and 11 female) were assessed 3 times (TP1, TP2, and TP3) during a season (male personal record in 200-m freestyle event: 173.00 ± 31.41 seconds: female personal record in 200-m freestyle event: 200.73 ± 25.02 seconds). An incremental 5 × 200-m step test was selected to evaluate velocity at 4 mmol·l⁻¹ of blood lactate concentration (v4), maximal blood lactate concentration after exercise (La(peak)), maximal oxygen uptake (V̇O2max), stroke frequency, stroke length (SL), stroke index (SI), and propelling efficiency of the arm stroke (η(p)). The 200-m freestyle performance and average swimming velocity (v200) were also monitored. Significant differences were observed between males and females for the 200-m freestyle performance, SL, SI, and La(peak). Performance (205.18 ± 24.47 seconds; 197.45 ± 20.97 seconds; 193.45 ± 18.12 seconds), SL (1.69 ± 0.17 m; 1.79 ± 0.13 m; 1.78 ± 0.15 m), SI (1.68 ± 0.31 m²·c⁻¹·s⁻¹; 1.83 ± 0.27 m²·c⁻¹·s⁻¹; 1.85 ± 0.27 m²·c⁻¹·s⁻¹), η(p) (0.32 ± 0.04; 0.33 ± 0.03; 0.33 ± 0.04), and V̇O2max (38.71 ± 3.44 ml·kg⁻¹·min⁻¹; 43.43 ± 3.71 ml·kg⁻¹·min⁻¹; 43.95 ± 7.02 ml·kg⁻¹·min⁻¹) have changed significantly throughout the season (TP1, TP2, and TP3, respectively) in female swimmers. In male, significant changes were found in η(p) (0.33 ± 0.07; 0.36 ± 0.05; 0.36 ± 0.06) and V̇O2max (41.65 ± 7.30 ml·kg⁻¹·min⁻¹; 45.19 ± 6.55 ml·kg⁻¹·min⁻¹; 50.19 ± 9.65 ml·kg⁻¹·min⁻¹) over the season (TP1, TP2, and TP3, respectively). Gender presented a significant effect on SL (TP2: η(p)² = 0.29; TP3: η(p)² = 0.37), SI (TP2: η(p)² = 0.25), and La(peak) (TP3: η(p)² = 0.42). v4 (TP1: η(p)² = 0.23), SL (TP1: η(p)² = 0.46), SI (TP1: η(p)² = 0.78; TP2: η(p)² = 0.37; TP3: η(p)² = 0.32), and η(p) (TP1: η(p)² = 0.28) had a significant effect on performance. Male masters swimmers have better performance, SL, SI, and La(peak) than female counterparts. Female masters swimmers enhanced significantly the 200-m freestyle performance over the season due to the improvement in swimming technique (SL, SI, and η(p)) and energetic factors (v4 and V̇O2max). Nonsignificant improvements were observed for the males' performance. Gender has a significant effect on SL, SI, and La(peak). Therefore, performance is more dependent on technical factors than energetics.

Differentiating maturational influence on training-induced strength and endurance adaptations in prepubescent children.

OBJECTIVE: To analyze the effect of biological maturation on training-induced strength and endurance adaptations in the prepubertal growth spurt. METHODS: One hundred and twenty-five healthy children (58 boys, 67 girls), aged 10-11 years old (10.8 ± 0.4 years), who were self-assessed as belonging to Tanner stages I and II, were randomly divided into two experimental groups, a strength training group (19 boys, 22 girls) and an endurance training group (21 boys, 24 girls) that would train twice a week for 8 weeks, as well as a control group (18 boys, 21 girls; no training program). RESULTS: After 8 weeks of training, there were improvements in all strength and endurance measures (P < 0.01) for both groups of Tanner stage I and II children. No significant differences in training response were observed relative to biological maturity or gender (P > 0.05). CONCLUSIONS: These data suggest that more biologically mature prepubescent children seem to have no advantage in training-induced strength and endurance adaptations compared with their less mature peers. Additionally, gender did not affect the training-induced changes in strength or aerobic fitness. These results are meaningful for the development of optimized well-rounded training programs in prepubertal children. Am. J. Hum. Biol. 26:469-475, 2014. © 2014 Wiley Periodicals, Inc.

Effects of body fat and dominant somatotype on explosive strength and aerobic capacity trainability in prepubescent children.

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.

Physical fitness differences between prepubescent boys and girls.

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 children's 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, η(p)(2) = 0.09) and lower limbs (p ≤ 0.01, η(p)(2) = 0.08), although with a medium-size effect of gender, and smaller in the abdominal (p > 0.05, η(p)(2) = 0.007) and upper limbs (p > 0.05, η(p)(2) = 0.003) muscular endurance, and trunk extensor strength and flexibility (p > 0.05, η(p)(2) = 0.001). The endomorphic (p ≤ 0.01, η(p)(2) = 0.26) in the girls, and the ectomorphic (p ≤ 0.01, η(p)(2) = 0.31) and mesomorphic (p ≤ 0.01, η(p)(2) = 0.26) 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.

Gender's Effect on a School-Based Intervention in The Prepubertal Growth Spurt.

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, η_p^2= 0.16, Power= 0.29) and aerobic (p> 0.05, η_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.

Is long term creatine and glutamine supplementation effective in enhancing physical performance of military police officers?

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 × 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 × 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.

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 Carter's 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.