A Higher Kick Frequency Swimming Training Program Optimizes Swim-to-Cycle Transition in Triathlon

ABSTRACT

Ambrosini, L, Presta, V, Vitale, M, Menegatti, E, Guarnieri, A, Bianchi, V, De Munari, I, Condello, G, and Gobbi, G. A higher kick frequency swimming training program optimizes swim-to-cycle transition in triathlon. J Strength Cond Res 38(5): 976-984, 2024-The purpose of this study was to evaluate the effect of an 8-week swimming training program on biomechanical and physiological responses during a swim-to-cycle simulation. Fifteen triathletes were randomly allocated to 3 groups: a 6-beat-kick group (K6), a 4-beat-kick group (K4), and a control group (CG). Biomechanical and physiological parameters were evaluated during a 400-m swim and a 10-minute cycle segment before (Pretraining) and after (Posttraining) the program. A lower stroke frequency ( p = 0.004) and a higher stroke length ( p = 0.002) was found in K6 compared with CG at Posttraining. A reduction in the K6 emerged between Pretraining and Posttraining during cycling for heart rate ( p = 0.005), V̇O 2 ( p = 0.014), and energy expenditure ( p = 0.008). A positive association emerged between swim kick index and cycling cadence in the K6 group. The improvement in stroke frequency and length observed in the K6 group could be explained as an improvement in swimming technique. Similarly, the reduction in energy expenditure during cycling at Posttraining for the K6 group suggests an improvement in the working economy. Triathlon coaches and athletes should consider the inclusion of high swim kick into their training programs to enhance swim and cycling performance, which can ultimately lead to an improvement in the swim-to-cycle transition and the overall triathlon performance.

Does ergogenic effect of caffeine supplementation depend on CYP1A2 genotypes? A systematic review with meta-analysis

BACKGROUND

The ergogenic effects of caffeine intake on exercise performance are well-established, even if differences exist among individuals in response to caffeine intake. The genetic variation of a specific gene, human cytochrome P450 enzyme 1A2 (CYP1A2) (rs762551), may be one reason for this difference. This systematic review and meta-analysis aimed to comprehensively evaluate the influence of CYP1A2 gene types on athletes' exercise performance after caffeine intake.

METHODS

A literature search through 4 databases (Web of Science, PubMed, Scopus, and China National Knowledge Infrastructure) was conducted until March 2023. The effect size was expressed as the weighted mean difference (WMD) by calculating fixed effects meta-analysis if heterogeneity was not significant (I2 ≤ 50% and p ≥ 0.1). Subgroup analyses were performed based on AA and AC/CC genotype of CYP1A2.

RESULTS

The final number of studies meeting the inclusion criteria was 12 (n = 666 participants). The overall analysis showed that the cycling time trial significantly improved after caffeine intake (WMD = -0.48, 95% confidence interval (95%CI): -0.83 to -0.13, p = 0.007). In subgroup analyses, acute caffeine intake improved cycling time trial only in individuals with the A allele (WMD = -0.90, 95%CI: -1.48 to -0.33, p = 0.002), but not the C allele (WMD = -0.08, 95%CI: -0.32 to 0.17, p = 0.53). Caffeine supplementation did not influence the Wingate (WMD = 8.07, 95%CI: -22.04 to 38.18, p = 0.60) or countermovement jump test (CMJ) performance (WMD = 1.17, 95%CI: -0.02 to 2.36, p = 0.05), and these outcomes were not influenced by CYP1A2 genotype.

CONCLUSION

Participants with the CYP1A2 genotype with A allele improved their cycling time trials after caffeine supplementation. However, compared to placebo, acute caffeine supplementation failed to increase the Wingate or CMJ performance, regardless of CYP1A2 genotype.

Defecation enhances cerebral perfusion and delays fatigue in elite triathletes

BACKGROUND

Rectal distension increases regulatory burden to autonomic nervous system in the brain.

PURPOSE

To determine the effect of rectal defecation on endurance performance and blood supply to the prefrontal brain and sub-navel regions of elite triathletes.

METHODS

Thirteen elite triathletes completed a cycling time trial (80% VO_2max) under defecated and non-defecated conditions, using a counterbalanced crossover design. Oxygenation and blood distribution in prefrontal brain and sub-navel regions were monitored by near-infrared spectroscopy (NIRS) during cycling.

RESULTS

Defecation moderately decreased systolic blood pressure (-4 mmHg, p < 0.05, d = 0.71), suggesting an alleviation of autonomic nervous activity. During the exercise trials, fatigue (cycling time to exhaustion) occurred when cerebral oxygenation decreased to ~ 5 % below baseline regardless of treatment conditions, suggesting a critical deoxygenation point for sustaining voluntary exertions. Cerebral blood (estimated by total hemoglobin) increased progressively throughout the entire exercise period. Defecation decreased sub-navel oxygenation levels below the non-defecated level, suggesting an increased sub-navel oxygen consumption. Exercise also decreased sub-navel blood distribution, with minimal difference between non-defecated and defecated conditions. Defecation improved blood pooling in the prefrontal brain during exercise (p < 0.05) and enhanced cycling performance in triathletes (Non-defecated: 1624 ± 138 s vs. defecated: 1902 ± 163 s, d = 0.51, p < 0.05).

CONCLUSION

Our results suggest that improved exercise performance after defecation is associated with greater blood availability to compensate deoxygenation in the prefrontal brain region during exercise. Further investigation is needed to examine the role of increasing sub-navel oxygen consumption in the performance improvement after defecation.

Exploring correlates of physical activity behaviour in UK children and their inter-relationships using a multidisciplinary approach: A concept mapping study

It is still unknown which correlates of physical activity behaviour (PAB) may be effective and how they may influence PAB in UK children. The objective of the current study was to generate a conceptual analysis of the correlates of PAB in UK children (5-12 years) using the input of researchers in the field of physical activity (PA experts; PAE) and other fields (non-PA experts; non-PAE). A concept mapping approach was used to identify potential (new) correlates of PAB in children, assess their importance based on rating of potential modifiability and effect, and generate a concept map depicting the associations between them. In the first (brainstorming) stage (n = 32 experts) yielded 93 correlates, including 14 new correlates not identified in previous reviews. In the second (rating and sorting) stage (n = 26 experts), 32 correlates were rated as important and a four-cluster concept map was generated including themes related to Society/community, Home/social setting, Personal/social setting and Psychological/emotional correlates. Two additional concept maps were generated for PAE and non-PAE. From expert opinion, we identified new correlates of PAB that warrant further research and we highlight the need to consider the interaction between intrapersonal and external correlates when designing interventions to promote PA in UK children.

Interplay between Protein Kinase C Epsilon and Reactive Oxygen Species during Myogenic Differentiation

Reactive oxygen species (ROS) are currently recognized as a key driver of several physiological processes. Increasing evidence indicates that ROS levels can affect myogenic differentiation, but the molecular mechanisms still need to be elucidated. Protein kinase C (PKC) epsilon (PKCe) promotes muscle stem cell differentiation and regeneration of skeletal muscle after injury. PKCs play a tissue-specific role in redox biology, with specific isoforms being both a target of ROS and an up-stream regulator of ROS production. Therefore, we hypothesized that PKCe represents a molecular link between redox homeostasis and myogenic differentiation. We used an in vitro model of a mouse myoblast cell line (C2C12) to study the PKC-redox axis. We demonstrated that the transition from a myoblast to myotube is typified by increased PKCe protein content and decreased ROS. Intriguingly, the expression of the antioxidant enzyme superoxide dismutase 2 (SOD2) is significantly higher in the late phases of myogenic differentiation, mimicking PKCe protein content. Furthermore, we demonstrated that PKCe inhibition increases ROS and reduces SOD2 protein content while SOD2 silencing did not affect PKCe protein content, suggesting that the kinase could be an up-stream regulator of SOD2. To support this hypothesis, we found that in C2C12 cells, PKCe interacts with Nrf2, whose activation induces SOD2 transcription. Overall, our results indicate that PKCe is capable of activating the antioxidant signaling preventing ROS accumulation in a myotube, eventually promoting myogenic differentiation.

How divergent are children's divergent movements? The role of cognition and expertise in a class-randomized cross-over trial

This study aimed at investigating (1) the cognitive and motor predictors of divergent movement ability (DMA) in childhood and (2) the role of sport and enriched physical education (PE) experience. Participants were 165 fifth graders, aged 10-11 years, with different histories (onset and duration) of participation in enriched PE. They were assessed in cognitive/attentional and motor/sport skills and active play/sport habits at baseline, and six months later in DMA. Results of regression analyses showed an overall prediction of DMA by sport practice and a nuanced prediction of individual DMA indices (fluency, flexibility, originality) by decision making and spatial attention ability. Linear mixed models revealed better DMA in children exposed to enriched PE, with differential effects on DMA indices depending on its duration and earlier/later onset. The results identify novel cognitive determinants of children's DMA and suggest that sport practice and experience of designed enrichment in PE may benefit DMA.

Notational Analysis of Wheelchair Paralympic Table Tennis Matches

Paralympic table tennis is the third largest paralympic sport for the number of players. Performance analysis was conducted for the rally duration and interval and impact of serve, whilst none investigated the shots distribution among classes of physical impairment. Therefore, the purpose of this study was to conduct a notational analysis of international competitions in relation to the wheelchair classes. Five matches for each wheelchair class (C1-to-C5) were evaluated from 20 elite male right-handed players. Both players for each match were analyzed for the following performance indicators: strokes type, the area of ball bouncing, and the shots outcome. Backhand shots were the most used technique for all classes. The most used strokes for C1 players were backhand and forehand drive and backhand lob, while for C5 players they were backhand and forehand push and backhand topspin. Similar shots distribution was registered for C2-to-C5 players. The central and far-from-the-net zone was mainly reached by the serve for all classes. Errors shots were similar in all classes, whilst winning shots were more frequent in C1. The current notational analysis provided a meaningful performance modelling of indicators for coaches and athletes that can be used to design training programs for each class.

Evolution led humans to bipedalism, but we live in a sedentary society: Will "Sunday running" protect us from NCDs at no cost?

Evolution led humans to bipedal stance and movement. However, we live in a sedentary society that strongly challenges our willingness to be physically active. We (mis)understand that being at least a Sunday runner could protect us from sedentary-related diseases, but what if this compromises the healthier life expectancy anyway? Citing Paul Gauguin, we know where we come from and what we are, the question arises about where we are going. And also, how.

Interlink Between Physiological and Biomechanical Changes in the Swim-to-Cycle Transition in Triathlon Events: A Narrative Review

Triathlon is a multisport composed of swim, cycle, and run segments and two transition periods. The swim-to-cycle transition is considered a critical period for the change in body position and the modifications in physiological (heart rate, VO₂, lactate) and biomechanical parameters (cycling power and cadence, swimming stroke rate). Therefore, the aim of this review was to summarize the current evidence regarding the physiological and biomechanical changes and their interlink during the swim-to-cycle transition hinting at practical recommendations for coaches and athletes. The influence of the swim segment on cycle one is more evident for short-distance events. Greater modifications occur in athletes of lower level. The modulation of intensity during the swim segment affects the changes in the physiological parameters (heart rate, blood lactate, core temperature), with a concomitant influence on cycling gross efficiency. However, gross efficiency could be preserved by wearing a wetsuit or by swimming in a drafting position. A higher swim leg frequency during the last meters of the segment induces a higher cadence during the cycle segment. Training should be directed to the maintenance of a swimming intensity around 80–90% of a previous maximal swim test and with the use of a positive pacing strategy. When athletes are intended to train consecutively only swim and cycle segments, for an optimal muscle activation during cycling, triathletes could adopt a lower cadence (about 60–70% of their typical cadence), although an optimal pedaling cadence depends on the level and type of athlete. Future research should be focused on the combined measurements of physiological and biomechanical parameters using an intervention study design to evaluate training adaptations on swim kick rate and their effects on cycling performance. Coaches and athletes could benefit from the understanding of the physiological and biomechanical changes occurring during the swim-to-cycle transition to optimize the overall triathlon performance.

Vascular function in the aging human brain during muscle exertion

To determine how brain oxygenation is stably maintained during advancing age, cerebral oxygenation and hemoglobin were measured real-time at 10 Hz using near-infrared spectroscopy (NIRS) at rest (30 seconds) and during a 10-repeated handgrip strength test (30 seconds) for 834 adults (M/F = 45/55%) aged 20-88 y. The amplitude of cerebral hemodynamic fluctuation was reflected by converting 300 values of % oxygen saturation and hemoglobin of each 30-second phase to standard deviation as indicatives of brain oxygenation variability (BOV) and brain hemodynamic variability (BHV) for each participant. Both BOV (+21-72%) and BHV (+94-158%) increased during the maximal voluntary muscle exertions for all age levels (α < 0.05), suggesting an increased vascular recruitment to maintain oxygen homeostasis in the brain. Intriguingly, BHV was >100 folds for both resting and challenged conditions (α < 0.001) in >80% of adults aged above 50 y despite similar BOV compared with young age counterparts, indicating a huge cost of amplifying hemodynamic oscillation to maintain a stable oxygenation in the aging brain. Since vascular endothelial cells are short-lived, our results implicate a hemodynamic compensation to emergence of daily deficits in replacing senescent endothelial cells after age 50 y.

Effects of a novel inclined-adaptive footwear on change-of-direction performance in male athletes

BACKGROUND

Although enhancing change of direction (COD) performance is a crucial factor for improving athletic performance in many sports, few studies have explored its effective methods.

RESEARCH QUESTION

This study aimed to investigate the effects of inclined-adaptive footwear (IAF) on force-time characteristics during a COD task.

METHODS

Thirteen male team sport athletes were randomly assigned to wear IAF or footwear without adaptive technology to perform a COD60° task at their best effort. A three-dimensional force plate was used to obtain the force-time curve and related parameters at the turning step (plant foot).

RESULTS

IAF led to a significantly higher resultant ground reaction force (GRF), horizontal GRF, vertical GRF, and horizontal/vertical ratio during the braking phase, followed by a significantly shorter contact time and higher resultant horizontal GRF and vertical GRF during the propulsive phase.

SIGNIFICANCE

This indicated that a greater GRF output, redistributed GRF, and shorter contact time occurred with the IAF. Therefore, IAF has the potential to enhance COD performance for sports involving multi-directional footwork and contribute to the development of new functional footwear.

Fostering Holistic Development with a Designed Multisport Intervention in Physical Education: A Class-Randomized Cross-Over Trial

Physical education (PE) is acknowledged as a relevant context for holistic child and youth development promotion. However, interventional research mostly builds on individual theories focused on specific outcome domains. This study presents a multisport enriched PE intervention that capitalizes on the intersection of different theory-based approaches to motor, cognitive and socio-emotional skills development promotion. With a cross-over design, 181 fifth graders, coming from a past class-randomized trial of enriched or traditional PE in their 1st–3rd grade, were stratified (based on their previous PE experience) and class-randomized to multisport enriched PE or control group. They completed pre-post assessments in motor and sport skills, cool (inhibition, working memory) and hot (decision making) executive functions, prosocial (empathy, cooperation) and antisocial (quick-temperedness, disruptiveness) behaviors. Children in the enriched PE group showed advantages in motor and prosocial skills after the intervention, which were linked by a mediation path, and an interactive effect of past and actual PE experience on decision making but no differential effects on other variables. The results suggest that a PE intervention designed with an integrative theory base, although not allowing disentangling the contribution of individual components to its efficacy, may help pursue benefits in motor and non-motor domains relevant to whole-child development.

Reduced stem cell aging in exercised human skeletal muscle is enhanced by ginsenoside Rg1

Background: Stem cell aging, characterized by elevated p16^INK4a expression, decreases cell repopulating and self-renewal abilities, which results in elevated inflammation and slow recovery against stress.

Methods: Biopsied muscles were analyzed at baseline and 24 h after squat exercise in 12 trained men (22 ± 2 y). Placebo (PLA) and immunostimulant Rg1 (5 mg) were supplemented 1 h before a squat exercise, using a double-blind counterbalanced crossover design.

Results: Perceived exertion at the end of resistance exercise session was significantly lowered after Rg1 supplementation. Exercise doubled endothelial progenitor cells (EPC) (p < 0.001) and decreased p16^INK4a mRNA to 50% of baseline (d = 0.865, p < 0.05) in muscle tissues, despite p16^INK4a+ cell and beta-galactosidase⁺ (ß-Gal⁺) cell counts being unaltered. Rg1 further lowered p16INK4a mRNA to 35% of baseline with greater effect size than the PLA level (d = 1.302, p < 0.01) and decreased myeloperoxidase (MPO) mRNA to 39% of baseline (p < 0.05). A strong correlation between MPO and p16^INK4a expression in muscle tissues was observed (r = 0.84, p < 0.001).

Conclusion: EPC in skeletal muscle doubled 1 d after an acute bout of resistance exercise. The exercised effects in lowering EPC aging and tissue inflammation were enhanced by immunostimulant Rg1, suggesting the involvement of immune stimulation on EPC rejuvenation.

Does Branched-Chain Amino Acids (BCAAs) Supplementation Attenuate Muscle Damage Markers and Soreness after Resistance Exercise in Trained Males? A Meta-Analysis of Randomized Controlled Trials

Previous studies have reported the positive effects of branched-chain amino acids (BCAAs) supplementation on lowering plasma markers of muscle damage and subjective soreness after resistance exercise. However, a variety of factors can potentially moderate its efficacy. This meta-analysis aimed to summarize the evidence regarding the effect of BCAAs supplementation on plasma muscle damage markers and soreness after resistance exercise in only trained males, by considering the plasma lactate dehydrogenase (LDH) and creatine kinase (CK). Randomized controlled trials were identified through a computerized literature search for the period 2010–2020. The pooled data were analyzed with the random-effects model and heterogeneity using I². Cochrane Collaboration tools was used for the assessment of risk of bias. Nine studies met the inclusion criteria. A positive effect was found for CK at <24, 24, and 48 h after exercise and for muscle soreness at <24 h only. However, the positive effect was not evident for plasma LDH at any follow-up time. Different outcomes for post-exercise responses may suggest that BCAAs supplementation can attenuate muscle damage and ameliorate muscle soreness after resistance exercise in trained males.

Correction to: Biological determinants of physical activity across the life course: a "Determinants of Diet and Physical Activity" (DEDIPAC) umbrella systematic literature review

An amendment to this paper has been published and can be accessed via the original article.

Effects of a 4-month judo program on gait performance in older adults

BACKGROUND

Falls prevention is a critical goal of training program for older individuals. This study explored the effects of a judo program on gait performance in older adults.

METHODS

Pre- and post-intervention (15 weeks, 1-hr session, twice a week) step length (cm), gait cycle time (s), speed (m·s-1) and cadence (step·min-1) mean values (AVG) and coefficients of variation (CV) were assessed in a judo (JG: N.=16 novice judoka; age=69.3±3.9 years) and a control (CG: N.=14 healthy older adults; age=70.1±4.5 years) group. Two 3 (motor complexity: flat, corridor, hurdling) ×2 (group: JG, CG) ×2 (time: pre, post) MANOVAs with repeated measures were applied to ascertain differences in gait parameters.

RESULTS

A significant Time×Motor Complexity×Group interaction was found for AVG and CV. For AVG, JG showed improvements for flat and hurdling conditions in step length (flat: ∆=+2.6%, d=0.4; hurdling: ∆=+3.2%, d=0.4), gait cycle (flat: ∆=-4.3%, d=0.4; hurdling: ∆=-4.0%, d=0.5), speed (flat: ∆=+6.6%, d=0.7; hurdling: ∆=+6.7%, d=0.6) and cadence (flat: ∆=4.3%, d=0.4; hurdling: ∆=3.9%, d=0.5). For CV, JG improved step length for flat (∆=-20.9%, d=0.6) and hurdling (∆=-16.3%, d=0.8) conditions, whereas CG showed a deterioration in the step length for the corridor condition (∆=+22.3%, d=0.7).

CONCLUSIONS

The findings demonstrated the effectiveness of an adapted judo program for improving gait performance in older individuals, suggesting a potential protective effect for fall risk.

Minireview: Current status of endoscopic duodenal mucosal resurfacing

Several strategies are being pursued to overcome the alarming pandemics of obesity and type 2 diabetes (T2D). In recent years, duodenal mucosal resurfacing (DMR) has shown its potential to improve glycemic indices. Following animal studies, which demonstrated feasibility and safety, the procedure has been applied in two human studies. The DMR procedure has been considered feasible and safe in humans with a limited occurrence of complications and adverse events. Reductions in glycated haemoglobin, weight, fasting plasma glucose, and alanine transaminase have been proven at different follow-up time-points. The length of the ablation may induce different outcomes, having the patients with long duodenal segment ablated showed greater beneficial effects. The current evidence does not still prove the apparent insulin-sensitizing mechanism explaining the impact of the DMR procedure on hepatic glucose production. However, the initial findings have demonstrated a positive risk-benefit ratio and an effect on the treatment of metabolic diseases, such as T2D. Future studies should clarify the mechanisms underlying the positive effects and durability of the treatment using controlled trial conditions on larger number of patients.

Validity and Reliability of a Photoelectric Cells System for the Evaluation of Change of Direction and Lateral Jumping Abilities in Collegiate Basketball Athletes

The validity and reliability of the Optojump system were investigated for jumping height and flight time in vertical jump tests. Conversely, the purpose of the present study was to investigate the validity and reliability of the Optojump system for measuring contact time and lateral displacement in change of direction and lateral jump tests. Thirty basketball collegiate athletes were tested on two 10 m sprints with a 60° (COD60) or 180° (COD180) change of direction, lateral controlled (CLRJ) and maximal (MLRJ) rebound jump, and lateral countermovement (LCMJ) and squat (LSJ) jump with the concomitant use of two force plates and the Optojump system for the measurement of contact time in COD60, COD180, CLRJ, MLRJ, and lateral jumping distance in all the lateral jump tests. Almost perfect coefficients (r ≥ 0.95) emerged for contact time in COD60, COD180, CLRJ, MLRJ, although a systematic bias was found for COD60 (-0.01 s). Good-to-excellent reliability was found for almost all the measurements of contact time and lateral jumping distance for change of direction and lateral jump tests. Therefore, the use of Optojump system for testing change of direction and lateral jumping abilities should be executed with caution, avoiding misinterpretation of data.

Effects of Judo Training on Bones: A Systematic Literature Review

Ciaccioni, S, Condello, G, Guidotti, F, and Capranica, L. Effects of judo training on bones: a systematic literature review. J Strength Cond Res 33(10): 2882-2896, 2019-The aim of this study was to provide a systematic literature review on the osteogenic effects of judo (PROSPERO: CRD42016041803). The online search was conducted according to the inclusion criteria: observational studies and clinical/interventional trials in English from inception to June 2016; bone health, bone mineral density (BMD), diameters, impact force, and bone turnover marker (BTM) outcomes. Thirty-four studies were included and graded for their methodological quality ("fair" quality: 79.4%). The most used assessment method (44.1%) was X-ray absorptiometry. A positive association between judo and bone health/status emerged. Findings support site-specific BMD accrual in children, adolescents, adult athletes, and in premenopausal and postmenopausal female practitioners. Bone turnover markers revealed a hypermetabolic status in high-level judo athletes. The osteogenic stimuli of judo seem to protect athletes from alterations in bone metabolic balance due to weight loss cycling. Sexual dimorphism was found between judoka in bone diameters and mass, and significant differences in bone breadths emerged between elite and nonelite judokas. The fall techniques reduced bone impact force and velocity with respect to "natural" fall. Further longitudinal, cross-sectional, and interventional researches are required. This article provides useful information on bone for health sport scientists, coaches, and practitioners, stimulating future research lines on judo. In particular, coaches and physical trainers should consider introducing judo fall techniques in their training plans to prevent fall-related injuries, especially relevant in the older population. Conversely, coaches are urged to carefully control weight cycling dietary habits of their athletes, which can produce serious metabolic responses on bones.

Autonomic Stress Response and Perceived Effort Jointly Inform on Dual Tasking in Aging

The study investigated, through neuroendocrinological, subjective and behavioral assessments, how aging individuals cope with locomotor-cognitive dual-tasking and whether physical activity habits influence the acute response to locomotor-cognitive performance. Seventy-nine healthy participants aged 55–85 years were assessed on locomotor (gait speed, stride length) and cognitive (working memory) performances under single- and dual-task (ST, DT) conditions, and habitual physical activity (daily steps). Rating of perceived exertion (RPE) was assessed immediately after performance. Salivary α-amylase (sAA) was measured prior, immediately and 5 min after performance. Gait and working memory variables, the area under the curve of sAA (AUC) and DT–ST differences (DT effects) were computed. AUC was higher when the ST or DT performance involved a locomotor component and showed a pre-to-post increment after DT only, whereas RPE was higher when performance involved a cognitive component. Daily steps neither predicted sAA, nor RPE. Associations between DT effects on sAA, RPE and performance emerged in high-active participants only. In aging individuals, DT walking elicits an autonomic stress response presumably led by the challenge to share resources relying upon common neural substrates. This autonomic response seems tuned to gait performance and subjective evaluation of effort in those more accustomed to walking.

Dual-career through the elite university student-athletes' lenses: The international FISU-EAS survey

Athletes have the right to combine their sport and higher education careers (e.g., dual career), but differences in the recognition of the student-athlete’s status and availability of dual career programmes and services exist worldwide. The purpose of this study was to investigate the dual career phenomenon through the international student-athletes’ views. Student-athletes competing at the 2017 Summer Universiade were recruited to respond a 31-item online survey encompassing demographic characteristics (Q1-8), sport and university engagement (Q9-13), student-athletes’ knowledge and possible sources of information regarding dual career (Q14-22); and dual career support at personal, sport, and academic levels (Q23-31). Four hundred twenty-six respondents (males: 46%, females 54%), competing in 22 different sports (individual: 74%, team: 26%) from Africa (4%), America (20%), Asia (34%), Europe (39%), and Oceania (3), had experienced previous international sports events (94%). Differences among continents emerged for sport (p<0.001) and university (p = 0.039) engagement, and transfer time from home to the training venue (p = 0.030). Individual sports student-athletes showed higher sport engagement (p = 0.003) compared to team sports counterparts. Differences among university majors emerged for university engagement (p<0.001). Long absence from classes (57%), limited leisure time (50%), financial uncertainty (44%), reduction of training due to education (42%), and overload feelings (37%) emerged. The majority of the sample resulted not familiar with dual career programmes (60%) and public authorities (69%), envisaging national dual career policies at university (37%) and sport (25%) levels. Multiple relevant dual career supporters at personal, sport, and university levels were identified, mainly parents (86%) and coaches (65%). To strengthen the potential of the student-athletes of the future, a dual career network should be established among several stakeholders, for transnational cooperation and sharing of knowledge and best practices through extensive communication between policy-makers, practitioners and those having a strong supportive dual career role (e.g., parents, coaches, and university sport staff).

Technical and Tactical Aspects in Italian Youth Rugby Union in Relation to Different Academies, Regional Tournaments, and Outcomes

Ungureanu, AN, Condello, G, Pistore, S, Conte, D, and Lupo, C. Technical and tactical aspects in Italian youth rugby union in relation to different academies, regional tournaments, and outcomes. J Strength Cond Res 33(6): 1557-1569, 2019-This study aimed to analyze the technical and tactical aspects of the Italian under-18 Academy Rugby Union in relation to different academies, regional tournaments, and game outcomes. A notational analysis (44 indicators) was performed on 16 games (2014-15 season) to evaluate strong differences (p ≤ 0.05; moderate-large effect sizes [ESs]) according to variables. Among academies, strong differences were showed for defensive breakdown, in which the defending support is much (range = 77-87%), equal (range = 11-32%), and less (range = 2-12%) numerous than the attacking support, total tackles (range = 64-122), and passes (range = 72-151), pass to possession ratio (range = 6-10), possession lost due to an error (range = 28-59%), and ball in play in own (range = 8-25%) and opponent (range = 7-31%) 22-m area indicators. For tournaments, effects emerged for offensive breakdown when the ball is used quickly using maximum 2 attacking supports (range = 20-30%) and is not used quickly (range = 28-41%), total penalty kicks (range = 11-16), and sequences period 0-10 (range = 26-35%) and 10-40 seconds (range = 47-55%). Conversely, winning and losing academies reported differences with small ESs. These results highlight that the technical and tactical aspects of the Italian under-18 Academy Rugby Union are quite homogeneous, suggesting that FIR coaching staffs are more oriented to players' skills than successful games. However, tactical and strength and conditioning coaches can benefit from the findings of this study, focusing training on cognitive, strength, and repeated sprint abilities with and without change of direction for improving the occurrence of "set pieces won/regained" and "ball in play in opponent 22 m area," which appear as the key of the game in this rugby competition level.

ANALYSIS OF CHANGEMENT DE PIED, ECHAPPÉ AND SISSONNE FERMÉ JUMPS IN FEMALE BALLET DANCERS

In classical ballet, jumping should stand more on technique and elegance rather than maximal height. This study aimed to investigate dancers’ ability to perform stable jumps with classical ballet technique. Twenty-two female dancers [divided in two groups: Expert: n=12; Novice, n=10] were recruited to perform three vertical jump protocols: 1) Changement de Pied (CHA), composed by 5 consecutive jumps; 2) Echappé (ECH), composed by two consecutive ‘Echappé’ jumps; and 3) Sissonne Fermé (SF) jumps. Through an Optojump Next system were measured: a) Height (H) of jumps; b) Jumping Point Gap (JPG) and c) Used Area (UA). The CHA analysis showed differences between consecutive jumps for JPG (p=0.003). An approach to significance (p=0.52) and a difference (p=0.42) between groups were found for H and JPG respectively, while no differences were found for UA. The ECH analysis revealed main differences between jumps for H (p< 0.001), JPG (p=0.003) and UA (p< 0.001), post-hoc analysis showed differences (p<0.05) between each jump from the fifth position to the second one and vice versa for H and UA whilst differences between groups emerged only for UA (p=0.001). The SF analysis showed no differences for all parameters. The results showed as in CHA dancers carried out a control on the jump height to maintain their “aplomb” and limit the mediolateral displacement, which was also influenced by the dancers’ experience (NOV group showed higher H and JPG values). The dancers’ skill was also demonstrated by their ability to perform similar jumps in each of the two echappé cycles. Key words: classical ballet, dance, ability, jumps

Effects of a Judo Training on Functional Fitness, Anthropometric, and Psychological Variables in Old Novice Practitioners

This study aimed to investigate the effects of a 4-month judo training (1 hr session, biweekly) on physical and mental health of older adults (69.7 ± 4.2 years). Participants (N = 30) were assigned to a judo novice practitioners group (n = 16) or a control group (n = 14), which did not receive any training. Before and after the program, they underwent anthropometric (body mass index and waist and hip circumferences); functional fitness (upper and lower body flexibility and strength, coordination); and psychological assessments (perceived physical and mental health, body image, and fear of falling). The judo group showed reductions of waist circumference (Δ = -1%, d = 0.2) and improvements for lower and upper body flexibility (Δ = +69%, d = 0.4 and Δ = +126%, d = 0.5, respectively) and strength (Δ = +12%, d = 0.6 and Δ = +31%, d = 1.6, respectively). The control group showed a decline in lower body strength (Δ = -12%, d = 0.8). Psychological variables did not reveal statistically significant effects. Judo seems beneficial for improving anthropometric and functional fitness variables, relevant aspects of successful aging.

How Older Adults Cope with Cognitive Complexity and Environmental Constraints during Dual-Task Walking: The Role of Executive Function Involvement

This cross-sectional study investigated the interactive dual-task (DT) effects of executive function demands and environmental constraints on older adults' walking and the moderating role of habitual physical activity (PA). Locomotor performance under different environmental constraints (flat versus obstructed walking) and cognitive performance with different executive function involvement (backward counting versus random number generation) were assessed under single-task (ST) and DT conditions in 135 participants (mean age 68.1 ± 8.4). The weekly number of daily steps was measured. Reciprocal DT effects of walking on cognitive performance and of the cognitive task on gait performance were computed and submitted to analyses of covariance with age, PA level, and cognitive functioning as covariates, followed by linear regressions with PA level as predictor. Cognitive task demands and environmental constraints individually and jointly affected gait variability (p = 0.033, ηp2 = 0.08) and executive function performance (p = 0.009, ηp2 = 0.09). Physical activity level predicted a low but significant percentage of variance of DT effects on gait only in flat walking (R2 = 0.04, p = 0.027). Results suggest that older individuals may adopt variable task prioritization in dual tasking depending on the type of executive function involvement and the environmental constraints on walking. Their DT ability was slightly affected by habitual PA.

Policy determinants of physical activity across the life course: a 'DEDIPAC' umbrella systematic literature review

Background

Despite the large number of studies and reviews available, the evidence regarding the policy determinants of physical activity (PA) is inconclusive. This umbrella systematic literature review (SLR) summarizes the current evidence on the policy determinants of PA across the life course, by pooling the results of the available SLRs and meta-analyses (MAs).

Methods

A systematic online search was conducted on MEDLINE, ISI Web of Science, Scopus and SPORTDiscus databases up to April 2016. SLRs and MAs of observational studies investigating the association between policy determinants of PA and having PA as outcome were considered eligible. The extracted data were assessed based on the importance of the determinants, the strength of evidence and the methodological quality.

Results

Fourteen reviews on 27 policy determinants of PA were eligible for this umbrella SLR. The majority of the reviews were of moderate quality. Among children, a clear association between time spent outdoors and PA emerged. Among adults, working hours were negatively associated with PA, though evidence was limited. At the population level, community- and street-scale urban design and land use policies were found to positively support PA levels, but levels of evidences were low.

Conclusions

With this umbrella SLR the policy determinants of PA at individual-level and population-level have been summarized and assessed. None of the investigated policy determinants had a convincing level of evidence, and very few had a probable level of evidence. Further research is needed, preferably by using prospective study designs, standardized definitions of PA and objective measurement of PA.

Biological determinants of physical activity across the life course: a "Determinants of Diet and Physical Activity" (DEDIPAC) umbrella systematic literature review

BACKGROUND

Despite the large number of studies and reviews available, the evidence regarding the biological determinants of physical activity (PA) is inconclusive. In this umbrella review, we summarized the current evidence on the biological determinants of PA across the life course, by pooling the results of the available systematic literature reviews (SLRs) and meta-analyses (MAs).

METHODS

We conducted an online search on MEDLINE, ISI Web of Science, Scopus, and SPORTDiscus databases up to January 2018. SLRs and MAs of observational studies that investigated the association between biological determinants of PA and having PA as outcome were considered eligible. The extracted data were assessed based on the importance of the determinants, the strength of evidence, and the methodological quality.

RESULTS

We identified 19 reviews of which most were of moderate methodological quality. Determinants that were studied most frequently among all ages and demonstrated evidence suggesting a positive association to PA were younger age, being male, higher health status, and higher physical fitness levels. Among adults, normal birth weight was found to be positively associated to PA with convincing strength of evidence, while findings among adolescents were inconsistent and with limited strength of evidence.

CONCLUSIONS

Different social or behavioral factors may contribute to the decrease of PA with age and among females versus males, and creating programmes targeted at diverse ages, female population, and adults with abnormal birth weight is recommended. Future studies should use prospective study designs, standardized definitions of PA, and objective measurement methods of PA assessment.

Socio-cultural determinants of physical activity across the life course: a 'Determinants of Diet and Physical Activity' (DEDIPAC) umbrella systematic literature review

OBJECTIVE

Regular physical activity (PA) reduces the risk of disease and premature death. Knowing factors associated with PA might help reducing the disease and economic burden caused by low activity. Studies suggest that socio-cultural factors may affect PA, but systematic overviews of findings across the life course are scarce. This umbrella systematic literature review (SLR) summarizes and evaluates available evidence on socio-cultural determinants of PA in children, adolescents, and adults.

METHODS

This manuscript was drafted following the recommendations of the 'Preferred Reporting Items for Systematic reviews and Meta-Analyses' (PRISMA) checklist. The MEDLINE, Web of Science, Scopus, and SPORTDiscus databases were searched for SLRs and meta-analyses (MAs) on observational studies published in English that assessed PA determinants between January 2004 and April 2016. The methodological quality was assessed and relevant information on socio-cultural determinants and any associations with PA was extracted. The available evidence was evaluated based on the importance of potential determinants and the strength of the evidence.

RESULTS

Twenty SLRs and three MAs encompassing 657 eligible primary studies investigated potential socio-cultural PA determinants, with predominantly moderate methodological quality. Twenty-nine potential PA determinants were identified that were primarily assessed in children and adolescents and investigated the micro-environmental home/household level. We found probable evidence that receiving encouragement from significant others and having a companion for PA were associated with higher PA in children and adolescents, and that parental marital status (living with partner) and experiencing parental modeling were not associated with PA in children. Evidence for the other potential determinants was limited, suggestive, or non-conclusive. In adults, quantitative and conclusive data were scarce.

CONCLUSIONS

A substantial number of SLRs and MAs investigating potential socio-cultural determinants of PA were identified. Our data suggest that receiving social support from significant others may increase PA levels in children and adolescents, whereas parental marital status is not a determinant in children. Evidence for other potential determinants was limited. This was mainly due to inconsistencies in results on potential socio-cultural determinants of PA across reviews and studies.

TRIAL REGISTRATIONS

This umbrella SLR was recorded on PROSPERO (Record ID: CRD42015010616 ).

Cytotoxic and Apoptotic Activities of Prunus spinosa Trigno Ecotype Extract on Human Cancer Cells

The aim of this work was to demonstrate that a natural compound, not-toxic to normal cells, has cytotoxic and sensitizing effects on carcinoma cells, with the final goal of combining it with chemotherapeutic drugs to reduce the overall dose. Prunus spinosa Trigno ecotype (PsT) drupe extract with a nutraceutical activator complex (NAC) made of amino acids, vitamins and mineral salt blends, has shown in vitro anticancer activity. The cytotoxic effect of (PsT + NAC)^® has been evaluated on human cancer cells, with an initial screening with colorectal, uterine cervical, and bronchoalveolar cells, and a subsequent focus on colon carcinoma cells HCT116 and SW480. The viability reduction of HCT116 and SW480 after treatment with (PsT 10 mg/mL + NAC)^® was about 40% (p < 0.05), compared to control cells. The cell’s survival reduction was ineffective when the drug vehicle (NAC) was replaced with a phosphate buffer saline (PBS) or physiological solution (PS). The flow cytometry evaluation of cancer cells’ mitochondrial membrane potential showed an increase of 20% depolarized mitochondria. Cell cycle analysis showed a sub G1 (Gap 1 phase) peak appearance (HCT116: 35.1%; SW480: 11.6%), indicating apoptotic cell death induction that was confirmed by Annexin V assay (HCT116: 86%; SW480: 96%). Normal cells were not altered by (PsT + NAC)^® treatments.

Psychological determinants of physical activity across the life course: A "DEterminants of DIet and Physical ACtivity" (DEDIPAC) umbrella systematic literature review

Low levels of physical activity (PA) are reported to contribute to the occurrence of non-communicable diseases over the life course. Although psychological factors have been identified as an important category concerning PA behavior, knowledge on psychological determinants of PA is still inconclusive. Therefore, the aim of this umbrella systematic literature review (SLR) was to summarize and synthesize the scientific evidence on psychological determinants of PA behavior across the life course. A systematic online search was conducted on MEDLINE, ISI Web of Science, Scopus, and SPORTDiscus databases. The search was limited to studies published in English from January 2004 to April 2016. SLRs and meta-analyses (MAs) of observational studies investigating the association of psychological variables and PA were considered eligible. Extracted data were evaluated based on importance of determinants, strength of evidence, and methodological quality. The full protocol is available from PROSPERO (Record ID: CRD42015010616). Twenty reviews (14 SLRs and 6 MAs), mostly of moderate methodological quality, were found eligible. Convincing evidence was found for self-efficacy (positive association with PA) in children and adolescents, and stress (negative association with PA) regardless of age. Most of the evidence revealing an association between psychological determinants and PA is probable and limited, mainly due to differences in the definition of PA and of psychological determinants across reviews. Thus, scholars are urged to reach a consensus on clear definitions of relevant psychological determinants of PA, subsuming cultural biases and allowing the possibility to obtain clear interpretations and generalizability of findings. Finally, most psychological determinants should be considered within a larger framework of other multi-level determinants that may interact or mediate some of the effects.

A life course examination of the physical environmental determinants of physical activity behaviour: A "Determinants of Diet and Physical Activity" (DEDIPAC) umbrella systematic literature review

BACKGROUND

Participation in regular physical activity is associated with a multitude of health benefits across the life course. However, many people fail to meet PA recommendations. Despite a plethora of studies, the evidence regarding the environmental (physical) determinants of physical activity remains inconclusive.

OBJECTIVE

To identify the physical environmental determinants that influence PA across the life course.

METHODS

An online systematic literature search was conducted using MEDLINE, ISI Web of Science, Scopus and SPORTDiscus. The search was limited to studies published in English (January 2004 to April 2016). Only systematic literature reviews (SLRs) and meta-analyses (MAs) of observational studies, that investigated the association between physical determinants and physical activity outcomes, were eligible for inclusion. The extracted data were assessed on the importance of determinants, strength of evidence and methodological quality.

RESULTS

The literature search identified 28 SLRs and 3 MAs on 67 physical environmental characteristics potentially related to physical activity that were eligible for inclusion. Among preschool children, a positive association was reported between availability of backyard space and outdoor toys/equipment in the home and overall physical activity. The availability of physical activity programs and equipment within schools, and neighbourhood features such as pedestrian and cyclist safety structure were positively associated with physical activity in children and adolescents. Negative street characteristics, for example, lack of sidewalks and streetlights, were negatively associated with physical activity in adults. Inconsistent associations were reported for the majority of reviewed determinants in adults.

CONCLUSION

This umbrella SLR provided a comprehensive overview of the physical environment determinants of physical activity across the life course and has highlighted, particularly amongst youth, a number of key determinants that may be associated with overall physical activity. Given the limited evidence drawn mostly from cross-sectional studies, longitudinal studies are needed to further explore these associations.

REGISTRATION

PROSPERO CRD42015010616.

Salivary alpha-amylase, salivary cortisol, and anxiety during a youth taekwondo championship: An observational study

The aim of this study was to assess the stress-related responses and the coach's capability to match perceived efforts of youth athletes during a taekwondo championship.Using a cross-sectional study design, salivary cortisol (sC) and alpha-amylase (sAA) were measured in 6 males and 3 females young (11.0 ± 0.9 years) athletes at awakening, 5 minutes before, and 1 minute and 30 minutes after official combats. State anxiety was recorded 60 minutes before the first competition, whereas coach's and athletes' ratings of perceived exertion (RPE) were obtained at the end of the combats. Time-matched (awakening and pre-competition) salivary samples and trait anxiety were collected 7-day postcompetition during a resting day.No effect for match outcome emerged. No difference emerged between athletes and coach RPEs. Higher (P = .03) state anxiety (41.6 ± 10.9 points) was shown than trait anxiety (34.8 ± 7.1 points). Time-matched sAA were similar. Peak sAA observed at the end of the combat (114.2 ± 108.1 U/mL) was higher (P < .01) than the other samples (range: 20.6-48.1 U/mL), whereas sC increased (P < .05) from awakening (8.0 ± 1.5 nmol/L), with peak levels observed at 30 minutes into the recovery phase (19.3 ± 4.3 nmol/L). Furthermore, pre-competition sC (16.5 ± 4.5 nmol/L) values were higher (P < .01) with respect to time-matched samples during the resting day (4.6 ± 1.0 nmol/L). The 3 athletes engaged in consecutive matches showed a tendency toward increasing sAA and sC.Taekwondo combats pose a high stress on young athletes, eliciting a fast reactivity of the sympathetic-adreno-medullary system relative to the hypothalamic-pituitary-adrenocortical system. Understanding the athlete's efforts during combats, coaches are recommended to apply effective recovery strategies between matches.

Behavioral determinants of physical activity across the life course: a "DEterminants of DIet and Physical ACtivity" (DEDIPAC) umbrella systematic literature review

Background

Low levels of physical activity (PA) are a global concern and increasing PA engagement is becoming a priority in current public health policies. Despite the large number of studies and reviews available, the evidence regarding the behavioral determinants of PA is still inconclusive. Thus, the aim of this umbrella systematic literature review (SLR) was to summarize the evidence on the behavioral determinants of PA across the life course.

Methods

A systematic online search was conducted on MEDLINE, ISI Web of Science, Scopus, and SPORTDiscus databases. The search was limited to studies published in English from January, 2004 to April, 2016. SLRs and meta-analyses (MAs) of observational studies that investigated the behavioral determinants of PA were considered eligible. The extracted data were assessed based on the importance of the determinants, the strength of evidence, and the methodological quality. The full protocol is available from PROSPERO (PROSPERO 2014:CRD42015010616).

Results

Seventeen reviews on 35 behavioral determinants of PA were eligible for this umbrella SLR. Regardless of age, the most investigated determinants were those related with ‘screen use’ and ‘smoking’. For youth, probable positive evidence emerged for ‘previous PA’ and ‘independent mobility and active transport’ among children and adolescents. For the adult population, ‘transition to university’ and ‘pregnancy/having a child’ showed probable negative associations.

Conclusions

Although the majority of the evidence was limited and most of the determinants were not associated with PA, this umbrella SLR provided a comprehensive overview of the associations between behavioral determinants and PA. Youth should be physically active in the early years and increase active transportation to/from school, independent mobility, and ‘free-range activities’ without adult supervision, whilst adult PA behaviors are mostly influenced by the life events. Finally, more research is needed that incorporates prospective study designs, standardized definitions of PA, objective measurement methods of PA assessment, and the use of interactionist and mediational approaches for the evaluation of different behavioral determinants influencing PA behaviors.

Steps to Health in Cognitive Aging: Effects of Physical Activity on Spatial Attention and Executive Control in the Elderly

The purpose of this study was to investigate whether physical activity (PA) habits may positively impact performance of the orienting and executive control networks in community-dwelling aging individuals and diabetics, who are at risk of cognitive dysfunction. To this aim, we tested cross-sectionally whether age, ranging from late middle-age to old adulthood, and PA level independently or interactively predict different facets of the attentional performance. Hundred and thirty female and male individuals and 22 adults with type 2 diabetes aged 55–84 years were recruited and their daily PA (steps) was objectively measured by means of armband monitors. Participants performed a multifunctional attentional go/no-go reaction time (RT) task in which spatial attention was cued by means of informative direct cues of different sizes followed by compound stimuli with local and global target features. The performance efficiency of the orienting networks was estimated by computing RT differences between validly and invalidly cued trials, that of the executive control networks by computing local switch costs that are RT differences between switch and non-switch trials in mixed blocks of global and local target trials. In regression analyses performed on the data of non-diabetic elderlies, overall RTs and orienting effects resulted jointly predicted by age and steps. Age predicted overall RTs in low-active individuals, but orienting effects and response errors in high-active individuals. Switch costs were predicted by age only, with larger costs at older age. In the analysis conducted with the 22 diabetics and 22 matched non-diabetic elderlies, diabetic status and daily steps predicted longer and shorter RTs, respectively. Results suggest that high PA levels exert beneficial, but differentiated effects on processing speed and attentional networks performance in aging individuals that partially counteract the detrimental effects of advancing age and diabetic status. In conclusion, adequate levels of overall PA may positively impinge on brain efficiency and attentional control and should be therefore promoted by actions that support lifelong PA participation and impact the built environment to render it more conducive to PA.

Technical-tactical analysis of youth olympic taekwondo combat

The purpose of this study was to define the technical and tactical profiles of official youth taekwondo competitions played under the most recent rules of the International Taekwondo Federation. Tactical actions (i.e., attack, defense, and block), technical executions (from 1- to 4-point scores), kicking legs (i.e., front/rear and right/left), and overall technical effectiveness were investigated in relation to match outcome of semifinal and final competitions (n = 50) of youth (aged 13-14 years) black belt athletes during the Italian Taekwondo Cadet Championship. Differences (p < 0.001) were found among all action typologies (Attack: 50.9 ± 2.2%; Defense: 27.7 ± 1.5%; Block: 21.3 ± 1.6%), with winners showing fewer (p = 0.005) offensive actions and more (p = 0.001) defensive actions with respect to non-winners. Independently from match outcome, technical exchanges showed differences (p < 0.001) for technical executions. Winners resulted more efficient (p < 0.001) for both technical and tactical variables. In general, these findings showed that Cadets tend to adopt an offensive strategy. In considering that the adoption of the new electronic system requires athletes to execute correct technical actions to have a score assigned, coaches should emphasize the effectiveness of scoring techniques and help athletes to effectively improve their defense and counterattack capabilities.