Effects of Aerobic and Speed Training Versus Active Control on Repeated Sprint Ability and Measures of Self-confidence and Anxiety in Highly Trained Male Soccer Players.

BACKGROUND: While there is ample evidence on the effects of single-mode aerobic and speed training on physical fitness in soccer players, less is known on the combined effects of these exercise regimens on physical and psychological factors. AIM: This study aimed to compare the effects of aerobic and speed training with soccer-specific training versus soccer-specific training only on aerobic performance during the YOYO intermittent fitness test level 1 (final velocity, total distance [TD], maximal oxygen consumption [VO2max]), repeated sprint ability (best, total sprint time [RSABT, RSATT], sprint decrement [RSA dec]) performance and somatic anxiety (SA), cognitive anxiety (CA), and self-confidence (SC) adaptations in soccer players. METHODS: Thirty-eight highly trained male athletes aged 18.9 ± 0.5 years were randomly assigned to an aerobic and speed training group (COMB-G; n = 20) or an active control group (CON-G; n = 18). Aerobic training comprised intermittent exercises at 110-120% of the final velocity achieved at the end of the YOYO IL1 test. Speed training involved maximal sprints over 15-20-m with 5-6 sets per session. Aerobic or speed training lasted 20 min per session and replaced parts of the soccer-specific training. CON-G performed the soccer-specific training including technical, tactical drills and small-sided games. Training volume was similar between groups. Pre, post intervention, all participants performed a repeated-sprint ability (RSA) test, the YO-YO IL1 test and the players completed a Competitive Scale Anxiety Inventory (CSAI-2). RESULTS: A two (group: COMB-G, CON-G) by two (time: pre, post) mixed ANOVA (group-by-time) was computed. Significant group-by-time interactions were found for RSATT (F = 117.3; p < 0.001; Pη2 = 1.78), RSABT (F = 82.4; p < 0.001; Pη2 = 1.53), final velocity (F = 85.8; p < 0.001; Pη2 = 1.53), TD (F = 87.1; p < 0.001; Pη2 = 1.56), and VO2max (F = 18.0; p < 0.001; Pη2 = 0.72). In addition, significant group-by-time interactions were observed for SC (F = 90.2; p < 0.001; d = 1.60), SA (F = 60.5; p < 0.001; Pη2 = 1.70), and CA (F = 20.7; p < 0.001; Pη2 = 0.75). Post-hoc analyses indicated significant improvements for all dependent variables from pre- to post-training in favor of COMB-G. CONCLUSION: Aerobic and speed training in combination with soccer-specific training is a safe and effective training method as it exerts positive effects not only for physical fitness but also for self-confidence and the coping of anxiety in male soccer players.

Effects of 8-Week In-Season Contrast Strength Training Program on Measures of Athletic Performance and Lower-Limb Asymmetry in Male Youth Volleyball Players.

Strength training using high and lower load such as contrast training (CST) seems to be beneficial as it addresses larger adaptive reserves in youth athletes. Therefore, the aim of this study was to investigate the effects of CST on dynamic balance (composite score during dynamic balance test (CS-YBT)), one repetition maximum lower-limb back squat (1RM), jumping performance (single-leg hop (SLH) or countermovement jump height (CMJ)), lower-limb asymmetry (predicted from the single-leg jump performance between two legs [ILA]) in elite youth male volleyball players. Thirty-one male youth volleyball players aged 14 years were randomly assigned to a CST group (n = 16) or a control group (n = 15). The tests were performed before and after 8 weeks of training. Significant group × time interactions was observed for CS-YBT [p < 0.001, ηp2 = 0.70], 1RM [p < 0.001, ηp2 = 0.95], SLH with right and left leg [p < 0.001, ηp2 = 0.69 and 0.51], CMJ [p < 0.001, ηp2 = 0.47]), whilst it was not notable in ILA [p < 0.294]. Post hoc tests showed that CST group demonstrated greater improvement in all of the dependent variables from medium to large effect size (for all p < 0.001). As a result, 8 weeks of CST twice a week can be an effective and efficient training along with volleyball training to improve skill-related fitness measures, except for lower-limb asymmetry in young volleyball players.

The Effects of Combined Verbal Encouragement and Technical Instruction on Technical Skills and Psychophysiological Responses During Small-Sided Handball Games Exercise in Physical Education.

To examine the effects of combined positive verbal encouragement and general technical guidelines on technical and psychophysiological parameters in pupils during a small-sided handball passing game. Twenty secondary school pupils (age, 16 ± 1 years; body mass, 55.3 ± 6.6 kg; body height, 1.77 ± 0.13 m; BMI, 22.6 ± 2.2 kg m-1) performed small-sided games (2 × 10 min) with three conditions: small-sided game (1) with combined verbal encouragement and technical instruction; (2) with technical instruction; (3) without any instruction (control) in which the passes for each pupil in each set was measured together with the rate of perceived exertion (RPE) and feeling mood after the first and second set. Results: A two-way analysis of variance demonstrated that the combined condition resulted in more passes compared to the technical instruction and control conditions, while the number of passes increased in set 2 for all conditions. RPE and the feeling mood were also differently between the conditions. Combined verbal encouragement and technical instruction during handball exercise were more beneficial for optimal passing numbers, positive mood with less perception of physical effort compared to only technical instruction and a control condition. The results evidenced positive acute effects of combined verbal encouragement and technical instruction during handball, indicating the usefulness of these training methods for optimal passing numbers, positive mood with less perception of physical effort in physical education pupils. Future studies should evaluate the applicability combined verbal encouragement and technical skills in the training of other conditioning capacities and the individual responsiveness of players toward verbal encouragement tasks.

Acute effects of maximal versus submaximal hurdle jump exercises on measures of balance, reactive strength, vertical jump performance and leg stiffness in youth volleyball players.

Background: Although previous research in pediatric populations has reported performance enhancements following long-term plyometric training, the acute effects of plyometric exercises on measures of balance, vertical jump, reactive strength, and leg stiffness remain unclear. Knowledge on the acute effects of plyometric exercises (i.e., maximal versus submaximal hurdle jumps) help to better plan and program warm-up sessions before training or competition. Objectives: To determine the acute effects of maximal vs. submaximal hurdle jump exercise protocols executed during one training session on balance, vertical jump, reactive strength, and leg stiffness in young volleyball players. Materials and methods: Thirty male youth volleyball players, aged 12-13 years, performed two plyometric exercise protocols in randomized order. In a within-subject design, the protocols were conducted under maximal (MHJ; 3 sets of 6 repetitions of 30-cm hurdle jumps) and submaximal (SHJ; 3 sets of 6 repetitions of 20-cm hurdle jumps) hurdle jump conditions. Pre- and post-exercise, balance was tested in bipedal stance on stable (firm) and unstable surfaces (foam), using two variables [center of pressure surface area (CoP SA) and velocity (CoP V)]. In addition, the reactive strength index (RSI) was assessed during countermovement maximal jumping and leg stiffness during side-to-side submaximal jumping. Testing comprised maximal countermovement jumps (CMJ). Results: Significant time-by-condition interactions were found for CoP SA firm (p < .0001; d = 0.80), CoP SA foam (p < .0001; d = 0.82), CoP V firm (p < .0001; d = 0.85), and CoP V foam (p < .0001; d = 0.83). Post-hoc analyses showed significant improvements for all balance variables from pretest to posttest for MHJ but not SHJ. All power tests displayed significant time-by-group interactions for countermovement jumps (p < .05; d = 0.42), RSI (p < .0001; d = 1.58), and leg stiffness (p < .001; d = 0.78). Post-hoc analyses showed significant pre-post CMJ (p < .001, d = 1.95) and RSI (p < .001, d = 5.12) improvements for MHJ but not SHJ. SHJ showed larger pre-post improvements compared with MHJ for leg stiffness (p < .001; d = 3.09). Conclusion: While the MHJ protocol is more effective to induce acute performance improvements in balance, reactive strength index, and vertical jump performance, SHJ has a greater effect on leg stiffness. Due to the importance of postural control and muscle strength/power for overall competitive performance in volleyball, these results suggest that young volleyball players should implement dynamic plyometric protocols involving maximal and submaximal hurdle jump exercises during warm-up to improve subsequent balance performance and muscle strength/power.

Acute Effects of Different Plyometric and Strength Exercises on Balance Performance in Youth Weightlifters.

Background: High-intensity muscle actions have the potential to temporarily improve the performance which has been denoted as postactivation performance enhancement. Objectives: This study determined the acute effects of different stretch-shortening (fast vs. low) and strength (dynamic vs. isometric) exercises executed during one training session on subsequent balance performance in youth weightlifters. Materials and Methods: Sixteen male and female young weightlifters, aged 11.3±0.6years, performed four strength exercise conditions in randomized order, including dynamic strength (DYN; 3 sets of 3 repetitions of 10 RM) and isometric strength exercises (ISOM; 3 sets of maintaining 3s of 10 RM of back-squat), as well as fast (FSSC; 3 sets of 3 repetitions of 20-cm drop-jumps) and slow (SSSC; 3 sets of 3 hurdle jumps over a 20-cm obstacle) stretch-shortening cycle protocols. Balance performance was tested before and after each of the four exercise conditions in bipedal stance on an unstable surface (i.e., BOSU ball with flat side facing up) using two dependent variables, i.e., center of pressure surface area (CoP SA) and velocity (CoP V). Results: There was a significant effect of time on CoP SA and CoP V [F(1,60)=54.37, d=1.88, p<0.0001; F(1,60)=9.07, d=0.77, p=0.003]. In addition, a statistically significant effect of condition on CoP SA and CoP V [F(3,60)=11.81, d=1.53, p<0.0001; F(3,60)=7.36, d=1.21, p=0.0003] was observed. Statistically significant condition-by-time interactions were found for the balance parameters CoP SA (p<0.003, d=0.54) and CoP V (p<0.002, d=0.70). Specific to contrast analysis, all specified hypotheses were tested and demonstrated that FSSC yielded significantly greater improvements than all other conditions in CoP SA and CoP V [p<0.0001 (d=1.55); p=0.0004 (d=1.19), respectively]. In addition, FSSC yielded significantly greater improvements compared with the two conditions for both balance parameters [p<0.0001 (d=2.03); p<0.0001 (d=1.45)]. Conclusion: Fast stretch-shortening cycle exercises appear to be more effective to improve short-term balance performance in young weightlifters. Due to the importance of balance for overall competitive achievement in weightlifting, it is recommended that young weightlifters implement dynamic plyometric exercises in the fast stretch-shortening cycle during the warm-up to improve their balance performance.

Integrative systems toxicology to predict human biological systems affected by exposure to environmental chemicals.

Biological systems are disturbed by several factors that are defined by the exposome. Environmental substances, including endocrine disruptors (EDs), represent the chemical exposome. These stressors may alter biological systems, that could lead to toxic health effects. Even if scientific evidence provide links between diverse environmental substances and disorders, innovative approaches, including alternative methods to animal testing, are still needed to address the complexity of the chemical mechanisms of action. Network science appears to be a valuable approach for helping to decipher a comprehensive assessment of the chemical exposome. A computational protein system-system association network (pS-SAN), based on various data sources such as chemical-protein interactions, chemical-system links, and protein-tissue associations was developed. The integrative systems toxicological model was applied to three EDs, to predict potential biological systems they may perturb. The results revealed that several systems may be disturbed by theses EDs, such as the kidney, liver and endocrine systems. The presented network-based approach highlights an opportunity to shift the paradigm of chemical risk assessment towards a better understanding of chemical toxicology mechanisms.

Time-restricted feeding influences immune responses without compromising muscle performance in older men.

OBJECTIVE: This study examined the effect of 12 wk of time-restricted feeding (TRF) on complete blood cell counts, natural killer cells, and muscle performance in 20- and 50-year-old men. METHODS: Forty active and healthy participants were randomly divided into young experimental, young control, aged experimental, and aged control group. Experimental groups participated in TRF. Before (P1) and after (P2) TRF, participants performed a maximal exercise test to quantify muscle power. Resting venous blood samples were collected for blood count calculation. RESULTS: No changes were identified in muscle power in all groups after TRF (P > 0.05). At P1, red cells, hemoglobin, and hematocrit were significantly higher in young participants compared with elderly participants (P < 0.05). At P2, this age effect was not found in red cells between the young experimental group and the aged experimental group (P > 0.05). At P1, white blood cells and neutrophils were significantly higher in young participants compared with elderly participants (P < 0.05). At P2, only neutrophils decreased significantly (P < 0.05) in experimental groups without significant (P > 0.05) difference among them. Lymphocytes decreased significantly in the aged experimental group at P2 (P < 0.05), whereas NKCD16+ and NKCD56+ decreased significantly in experimental groups at P2 (P < 0.05). TRF had no effect on CD3, CD4+, and CD8+ levels (P > 0.05). CONCLUSION: TRF decreases hematocrit, total white blood cells, lymphocytes, and neutrophils in young and older men. TRF may be effective in preventing inflammation by decreasing natural killer cells. As such, TRF could be a lifestyle strategy to reduce systemic low-grade inflammation and age-related chronic diseases linked to immunosenescence, without compromising physical performance.

Self-confidence and affect responses to short-term sprint interval training.

The study aimed to investigate the effects of repeated sprint (RS) training on somatic anxiety (SA), cognitive anxiety (CA), self-confidence (SC), rating of perceived exertion (RPE) and repeated sprint ability (RSA) indicators in elite young soccer players. Thirty elite soccer players in the first football league (age: 17.8±0.9years) volunteered to participate in this study. They were randomly assigned to one of two groups: a repeated sprint training group (RST-G; n=15) and a control group (CON-G; n=15). RST-G participated in 6weeks of intensive training based on RS (6×(20+20m) runs, with 20s passive recovery interval between sprints, 3 times/week). Before and after the 6-week intervention, all participants performed a RSA test and completed a Competitive Scale Anxiety Inventory (CSAI-2) and the RPE. After training RST-G showed a very significant (p<0.000) increase in RSA total time performance relative to controls. Despite the faster sprint pace, the RPE also decreased significantly (p<0.005) in RST-G, and their self confidence was significantly greater (p<0.01), while the cognitive (p<0.01) and somatic (p<0.000) components of their anxiety state decreased. When practiced regularly, short bouts of sprint exercises improve anaerobic performance associated with a reduction in anxiety state and an increase in SC which may probably boost competitive performance.