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Physical exercise has a positive impact on anxiety and depression. However, the evidence that associates strength training with a decrease in adolescents’ psychosocial disorders is scarce. Consequently, the objective was to analyze the effects of training with different modes of strength intervention on anxiety, stress, and depression in adolescents. The search was designed according to PRISMA®. We searched WoS, Scopus, SPORTDiscus, PubMed, and MEDLINE (2010–2020). Methodological quality and risk of bias were assessed with the Cochrane Collaboration. The analysis was carried out with a standardized mean difference (SMD) pooled using the Hedges g test (95% CI). The Main Outcome Measures were: anxiety, stress, and depression in adolescents post strength training. Nine studies were included in the systematic review and seven in the meta-analysis. These studies showed a large and significant effect of strength training on anxiety (SMD = −1.75; CI = 95%: −3.03, −0.48; p = 0.007) and depression (SMD = −1.61; CI = 95%: −2.54, −0.67, p = 0.0007). In conclusion, training with different modes of strength intervention have shown control over anxiety and depression in adolescents. However, conventional strength training seems to have better results than other modes of strength intervention.

The effects of a period without physical training on the civilian population are well established. However, no studies show the effects of a period without mandatory physical training on maximum oxygen uptake (VO 2 max) and anthropometric parameters in naval cadets. This study aimed to investigate changes in VO 2 max and anthropometric parameters after 12 weeks without mandatory physical training in naval cadets. The sample was 38 healthy and physically active naval cadets. The measured variables, including VO 2 max and anthropometric parameters, were evaluated through the 12-minute race test (12MRT) and the somatotype. Both variables had a separation of 12 weeks without mandatory physical training. A t-test for related samples was used to evidence changes between the test and post-test; effect size was calculated through Cohen’s d-test. Distance in 12MRT and VO 2 max showed significant decreases at the end of 12 weeks without mandatory physical training (p < 0.001). Likewise, the tricipital skinfold thickness and the endomorphic component showed significant increases (p < 0.05). 12 weeks without mandatory physical training significantly reduces the VO 2 max in naval cadets. Simultaneously, the same period without physical training increases both the tricipital skinfold thickness and the endomorphic component in this population.

There is evidence that both intra-serial variable resistance (I-sVR), as pre-activation within the post-activation performance enhancement cycle (PAPE), and creatine and caffeine supplementation increase athletic performance in isolation. However, the effect of the three conditioning factors on 30 m repeated sprint ability (RSA) performance in young soccer players is unknown. This study determined the summative and isolation effect of ergogenic aids and pre-activation in half-back squats (HBSs) with I-sVR on performance in an RSA test in young soccer players. Twenty-eight young soccer players were randomly assigned to either EG1 (n = 7, creatine + caffeine + I-sVR), EG2 (n = 7, creatine + placebo2 + I-sVR), EG3 (n = 7, placebo1 + caffeine + I-sVR), or EG4 (n = 7, placebo1 + placebo2 + I-sVR), using a factorial, four-group-matched, double-blind, placebo-controlled design. Creatine supplementation included 0.3 g/kg/day for 14 days, caffeine supplementation included 0.3 mg/kg per day, and pre-activation in HBS with I-sVR (1 × 5 at 30% 1RM [1.0–1.1 m/s] + 1 × 4 at 60% 1RM [0.6–0.7 m/s]). The RSA test and HBS outcomes were evaluated. Three-way ANOVA showed non-significant differences for the RSA test and HBS outcomes (p > 0.05). At the end of this study, it was found that the three ergogenic aids, together, do not generate a summative effect on the physical performance of young soccer players. However, it is important to analyze individual responses to these specific protocols.

Background The 6-minute rowing ergometer test (6-min.sub.RT ) is valid and reliable for establishing maximal aerobic power (MAP) in amateur male rowers. However, ventilatory thresholds (VTs) have not yet been established with their mechanical correspondence in this test. Objective The primary objective was to determine the VTs in the 6-min.sub.RT achieved by amateur male rowers, while the secondary objective was to determine the correspondence between ventilatory, mechanical, and heart rate (HR) outcomes of the 6-min.sub.RT . Methods Sixteen amateur male rowers were part of the study. All participants were instructed to perform an incremental test (IT) and a 6-min.sub.RT . Determination of the ventilatory parameters for the first ventilatory threshold (VT1), the second ventilatory threshold (VT2), and 6min.sub.RT VO.sub.2max were performed by correlating the outcomes of VT1, VT2, and VO.sub.2max obtained in the IT, with the outcomes of 6-min.sub.RT . For these purposes, Pearson's test was used, with the following criteria: trivial, 0.9. The significance level was p<0.05. Results The IT analysis determined that VT1 and VT2 correspond to 55 and 80% of VO.sub.2max , respectively. A high correlation was observed between IT outcomes in VT1, VT2, and VO.sub.2max , with the outcomes of 6-min.sub.RT (r > 0.6). Conclusion Based on IT ventilatory parameters and concordance analysis, VT1 and VT2 of 6-min.sub.RT are determined at 55 and 80%, respectively, of both ventilatory parameters and their corresponding mechanical outcomes and HR.

The objectives of this study were: (a) to determine asymmetries, both lower limb (LL) and upper limb (UL), in Chilean older adults, and (b) to relate asymmetries to FA in both LL and UL. Forty-one older adults voluntarily participated in this study (mean ± standard deviation [SD]: age 72.0 ± 8.0 years, LL asymmetries 13.78 ± 14.87%, UL asymmetries 10.70 ± 8.85%, FA 40.35 ± 16.26 points). The variables were: (1) asymmetries of LL and UL, assessed through a force platform and handgrip, respectively; (2) FA, assessed through the Latin American Group for Maturity (GDLAM) and the GDLAM index of autonomy (GI) protocol. The relationship between the variables was performed through Spearman’s correlation. The analysis showed that 39% of the participants presented asymmetries above 15% in the LL. Likewise, this 39% of older adults presented a lower FA than their peers with asymmetries below 15% in the LL (≤15%: 35.64 ± 12.26 points vs. >15%: 47.69 ± 19.23 points, p = 0.003). The analysis showed a small correlation between LL and GI asymmetries (r = 0.27, p = 0.07) and a small but negative correlation between UL and GI (r = −0.21). The mean values of asymmetries of both LL and UL are within ‘normal’ parameters. However, several older adults were identified as being at risk. In parallel, older adults who presented a higher level of asymmetries in LL showed a lower level of FA.

Recent research has shown that good sleep quality has a positive effect on physical performance. However, sleep quality in Chilean professional soccer players is unknown. The purpose of this study was to determine sleep quality in Chilean professional soccer players. It was a cross-sectional, explanatory study with observable variables. The sample consisted of 94 Chilean male soccer players belonging to four professional clubs. The main variable was the Sleep Quality Index, evaluated through the Pittsburgh questionnaire (Spanish version). After estimating sleep quality individually, the four professional soccer clubs’ comparison was performed through a one-factor ANOVA. The Pearson test was used to relate the questionnaire variables; the significance level was p < 0.05. In the global analysis of the Pittsburgh Sleep Quality Index, a value of 4.75 ± 2.29 on a scale of 0–21 was observed, with no significant differences between the clubs evaluated (p > 0.05). Based on the results obtained, Chilean male professional soccer players present good sleep quality. However, the high values of “sleep latency” and “sleep disturbances” are indicators that should be worked on by the multidisciplinary team of each professional club. They should develop strategies to improve sleep hygiene, encourage good sleep, and fall asleep efficiently.

Introduction: Block strength training has been proposed as a useful and practical strategy to reverse the effects of aging in community-dwelling older adults. However, the effects of block strength training based on the nature of exertion on functional autonomy and life quality of older women living in the community are unknown. Objective: To determine the effects of a Block Strength Training program based on the level of effort on functional autonomy and self-perceived life quality in community-dwelling older women. Methodology: Eighteen older women (71.1 ± 8.01 years) residing in the community volunteered for the study. The study had a pre-experimental design with pre- and post-tests. The block strength training is 12 weeks and divided into three blocks of 4 weeks each. The study variables were functional autonomy, assessed with the GDLAM protocol, and self-perceived life quality, assessed with WHOQOL-BREF. Differences between pre- and post-intervention were performed using t-tests and Wilcoxon tests, both for related samples (p < 0.05). Results: After applying the 12-week block strength training, 4 of the five tests of the GDLAM protocol showed significant improvements (p < 0.05). Likewise, 2 of the four dimensions of the WHOQOL-Bref showed significant improvements (p < 0.05). Conclusions: A Block Strength Training program based on the level of effort significantly improves functional autonomy and self-perceived life quality in older women community residents. Consequently, this methodology is effective and practical for promoting healthy aging in the community.

The use of creatine monohydrate (Cr) in professional soccer is widely documented. However, the effect of low doses of Cr on the physical performance of young soccer players is unknown. This study determined the effect of a low dose of orally administered Cr on muscle power after acute intra-session fatigue in young soccer players. Twenty-eight young soccer players (mean age = 17.1 ± 0.9 years) were randomly assigned to either a Cr (n = 14, 0.3 g·kg−1·day−1 for 14 days) or placebo group (n = 14), using a two-group matched, double-blind, placebo-controlled design. Before and after supplementation, participants performed 21 repetitions of 30 m (fatigue induction), and then, to measure muscle power, they performed four repetitions in half back squat (HBS) at 65% of 1RM. Statistical analysis included a two-factor ANOVA (p ˂ 0.05). Bar velocity at HBS, time: p = 0.0006, ŋp2 = 0.22; group: p = 0.0431, ŋp2 = 0.12, time × group p = 0.0744, ŋp2 = 0.02. Power at HBS, time: p = 0.0006, ŋp2 = 0.12; group: p = 0.16, ŋp2 = 0.06, time × group: p = 0.17, ŋp2 = 0.009. At the end of the study, it was found that, after the induction of acute intra-session fatigue, a low dose of Cr administered orally increases muscle power in young soccer players.

Background and Aims Due to increased urbanization and industry, environmental pollution is a serious public health concern. Globally, the quality of life is particularly lowered by exposure to high amounts of particulate matter (PM). Chile has five industrial zones with high pollution levels, called “sacrifice zones.” However, the effect of polluted air on the quality of life and functional autonomy (FA) of older people living in industrial zones with high pollution levels is unknown. Therefore, this study aimed to determine the quality of life and FA differences between Chilean older women (OW) living in areas with lower and higher PM levels. Materials and Methods Seventy‐two OW volunteered for this study. The sample was divided into Zone 1 (PM2.5 ≤ 15 µg/m3, n = 36) and Zone 2 (PM2.5 > 15 µg/m3, n = 36). The variables were quality of life—assessed through the SF‐36v2.0 questionnaire, and FA—assessed through the GDLAM protocols. Differences between zones were tested by Student's t‐test and Mann–Whitney test, both for independent samples (p < 0.05). Results All eight dimensions of quality of life were lower in Zone 2, of which the role emotional (RE) showed significant differences between zones (p < 0.05). Performance on the GDLAM protocols and the FA index were lower in Zone 2 (p ˃ 0.05). Conclusion OW in Zone 2 showed lower quality of life and FA. PM could affect the older population's physical and mental health and, therefore, the quality of life. Key points The quality of life and the functional autonomy (FA) of individuals are conditioned by environmental factors present throughout life. Exposure to air and soil pollutants decreases the quality of life and FA of older people living in the community. Controlling environmental pollution would make it possible to reduce the risk factors that condition people's FA and quality of life.

The peak velocity of an athlete’s throws is a determining factor for sports performance. The aim of this study was to analyze the effects of a post-activation performance enhancement (PAPE) protocol with functional electro-mechanical dynamometry (FEMD) on throwing velocity. Thirteen international-level female handball players voluntarily participated in the study. The PAPE protocol considered four sets of eight repetitions controlled by FEMD (four at 30% of 1RM followed by another four at 60% of 1RM). After each series, the athletes’ throwing velocity was measured. Significant differences (p < 0.01) were found in the effect size (ES), which measures the strength of the statistical relationship between two variables by group with the repeated measures ANOVA statistic with an effect size ω2 = 0.028. The effect size analysis identified measurements that are considered null for the baseline—PAPE 1 comparison and small baseline—PAPE 2, baseline—PAPE 3, and baseline—PAPE 4. When resistance is controlled during the run as with an FEMD device, only two sets of eight repetitions (four repetitions at 30% and four repetitions at 60% of 1RM) are required for the improvement of throwing speed in elite handball players.