Ischemic preconditioning and exercise performance: are the psychophysiological responses underestimated?

The findings of the ischemic preconditioning (IPC) on exercise performance are mixed regarding types of exercise, protocols and participants' training status. Additionally, studies comparing IPC with sham (i.e., low-pressure cuff) and/or control (i.e., no cuff) interventions are contentious. While studies comparing IPC versus a control group generally show an IPC significant effect on performance, sham interventions show the same performance improvement. Thus, the controversy over IPC ergogenic effect may be due to limited discussion on the psychophysiological mechanisms underlying cuff maneuvers. Psychophysiology is the study of the interrelationships between mind, body and behavior, and mental processes are the result of the architecture of the nervous system and voluntary exercise is a behavior controlled by the central command modulated by sensory inputs. Therefore, this narrative review aims to associate potential IPC-induced positive effects on performance with sensorimotor pathways (e.g., sham influencing bidirectional body-brain integration), hemodynamic and metabolic changes (i.e., blood flow occlusion reperfusion cycles). Overall, IPC and sham-induced mechanisms on exercise performance may be due to a bidirectional body-brain integration of muscle sensory feedback to the central command resulting in delayed time to exhaustion, alterations on perceptions and behavior. Additionally, hemodynamic responses and higher muscle oxygen extraction may justify the benefits of IPC on muscle contractile function.

Effect of the COVID-19 pandemic on food habits and perceptions: A study with Brazilians.

BACKGROUND: Following the COVID-19 pandemic (caused by the SARS-CoV-2 coronavirus) at the beginning of 2020, containment measures have been taken by different countries around the globe. Citizens were forced to stay in quarantine, affecting their food consumption habits and food sector. These impacts have not yet been properly understood. Thus, it is important to describe the consequences of COVID-19 on food consumption habits globally, especially in the context of developing countries, such as Brazil. SCOPE AND APPROACH: In this study, the Brazilian's food consumption habits and perceptions during the COVID-19 pandemic were assessed, highlighting the food consumption changes and selection of food products. Consumer perceptions about issues related to food safety and food marketing were also assessed. An online survey was performed and data were analyzed by descriptive analysis; independence and per cell chi-square test; and factor analysis. KEY FINDINGS AND CONCLUSIONS: Brazilians perceptions indicated that the COVID-19 pandemic context (assessed in May 2020) changed their food consumption and purchase. Respondents stated that they are eating and buying a greater amount of food, indicating a perception of a less healthy diet, mainly by women. On other hand, they are prioritizing homemade preparations and fresh food. Moreover, they reduced their shopping trips to markets and are starting to use delivery services and shopping platforms. Basic products of animal, vegetable, and bakery origin are being preferred during this period, in addition to economical packaging and products. Brazilians also indicated that they are more concerned with food safety and hygienic practices. However, at a time when global health is threatened, government agencies must create measures that ensure the food supply and consumer's awareness, in order to guarantee the country's food security during the current crisis.

A Practical Approach for Ischemic Preconditioning Intervention in Sports: A Pilot Study for Cuff Thigh Occlusion Pressure Estimation Based on Systolic Blood Pressure.

For the ischemic preconditioning (IPC) intervention, the accuracy of the protocol is paramount for mediating its possible ergogenic effects. However, the lack of standardization and widespread use of arbitrary cuff pressures (ranging from 130 to >300 mmHg) have been predominantly observed, potentially affecting the results and compromising the reproducibility of findings. Thus, the purpose of this study was to determine an appropriate cuff pressure during IPC. Seventeen healthy male participants were enrolled in the study. Anthropometric measurements were initially conducted, followed by systolic and diastolic blood pressure measurements. Subsequently, we determined the individual thigh occlusion pressure (TOP) for the right leg using a hand-held Doppler device. Based on these findings, we developed an estimation equation for TOP, considering the current brachial systolic blood pressure (SBP) values. We then conducted a retrospective analysis of its capacity to mediate occlusion. We observed the ability to estimate TOP using the equation (p = 0.01; ES: 0.86), presenting ~6% superiority in absolute values for occlusion compared to direct measurement (TOP equation: 169.9 ± 9.1; TOP direct measured: 161.2 ± 11.1). However, TOP estimation was insufficient to produce complete occlusion in two out of 17 subjects (11.8%). In conclusion, the estimation of TOP incorporating SBP values may offer a valid and practical means for cuff administration during IPC protocols with potential to minimize adverse effects and maximize its positive effects.

Current Perspectives of Cross-Country Mountain Biking: Physiological and Mechanical Aspects, Evolution of Bikes, Accidents and Injuries.

Mountain biking (MTB) is a cycling modality performed on a variety of unpaved terrain. Although the cross-country Olympic race is the most popular cross-country (XC) format, other XC events have gained increased attention. XC-MTB has repeatedly modified its rules and race format. Moreover, bikes have been modified throughout the years in order to improve riding performance. Therefore, the aim of this review was to present the most relevant studies and discuss the main results on the XC-MTB. Limited evidence on the topic suggests that the XC-MTB events present a variation in exercise intensity, demanding cardiovascular fitness and high power output. Nonetheless, these responses and demands seem to change according to each event. The characteristics of the cyclists differ according to the performance level, suggesting that these parameters may be important to achieve superior performance in XC-MTB. Moreover, factors such as pacing and ability to perform technical sections of the circuit might influence general performance. Bicycles equipped with front and rear suspension (i.e., full suspension) and 29″ wheels have been shown to be effective on the XC circuit. Lastly, strategies such as protective equipment, bike fit, resistance training and accident prevention measures can reduce the severity and the number of injuries.

Three-Month vs. One-Year Detraining Effects after Multicomponent Exercise Program in Hypertensive Older Women.

Background: Chronic diseases are the leading causes of death and disability in older women. Physical exercise training programs promote beneficial effects for health and quality of life. However, exercise interruption periods may be detrimental for the hemodynamic and lipidic profiles of hypertensive older women with dyslipidemia. Methods: Nineteen hypertensive older women with dyslipidemia (exercise group: 67.5 ± 5.4 years, 1.53 ± 3.42 m, 71.84 ± 7.45 kg) performed a supervised multicomponent exercise training program (METP) during nine months, followed by a one-year detraining period (DT), while fourteen hypertensive older women (control group: 66.4 ± 5.2 years, 1.56 ± 3.10 m, 69.38 ± 5.24 kg) with dyslipidemia kept their continued daily routine without exercise. For both groups, hemodynamic and lipidic profiles and functional capacities (FCs) were assessed four times: before and after the METP and after 3 and 12 months of DT (no exercise was carried out). Results: The METP improved hemodynamic and lipidic profiles (p < 0.05), while three months of DT decreased all (p < 0.05) parameters, with the exception of diastolic blood pressure (DBP). One year of DT significantly (p < 0.01) decreased systolic blood pressure (7.85%), DBP (2.29%), resting heart rate (7.95%), blood glucose (19.14%), total cholesterol (10.27%), triglycerides (6.92%) and FC­agility (4.24%), lower- (−12.75%) and upper-body strength (−12.17%), cardiorespiratory capacity (−4.81%) and lower- (−16.16%) and upper-body flexibility (−11.11%). Conclusion: Nine months of the exercise program significantly improved the hemodynamic and lipid profiles as well as the functional capacities of hypertensive older women with dyslipidemia. Although a detraining period is detrimental to these benefits, it seems that the first three months are more prominent in these alterations.

Is Social Media Spreading Misinformation on Exercise and Health in Brazil?

Instagram (IG) reaches millions of people, sharing personal content and all kinds of information, including those related to exercise and health. However, the scientific quality of the posted information is questionable. Thus, this study aimed to analyze whether exercise and health information posted by popular Brazilian IG influencers has technical-scientific accuracy. A personal IG account was created to identify Brazilian IG profiles. The inclusion criteria of the accounts were: (1) having 50% of all the shared posts related to topics about exercise and health, such as nutrition, health and wellness, medicine, or physical fitness; and (2) having over 100,000 followers. Qualitative analysis revealed a low quality percentage (38.79 ± 25.43%) for all analyzed posts. Out of all the posts, only 13 (~2.7%) cited a reference endorsing the information. Moreover, the higher quality-ratio score of the posts was not directly associated with the higher educational qualification of the influencers (r = 0.313; p = 0.076). Nevertheless, the number of followers was inversely correlated with the educational qualification of the influencers (r = -0.450; p = 0.009), but not with the quality-ratio score of the posts (r = -0.178 p = 0.322). We conclude that prominent Brazilian IG influencers disseminate low-quality information about exercise and health, contributing to the wide-spreading of misinformation to millions of followers.

Can Exercise Help Regulate Blood Pressure and Improve Functional Capacity of Older Women with Hypertension against the Deleterious Effects of Physical Inactivity?

BACKGROUND: Sedentarism and inactivity are risk factors for the development of hypertension. Thus, the prevention of the natural process of biological and physiological aging of older women through physical exercise results in higher benefits in preventing cardiovascular diseases and can be a key factor for its treatment. Multicomponent exercise (METP) is a training method that may help older women with hypertension by improving their quality of life and their response to treatment. METHODS: Twenty-eight older Caucasian women with hypertension (66.7 ± 5.3 years, 1.59 ± 0.11 m) performed a supervised METP program of nine months followed by three months of detraining (DT), and seventeen older women (68.2 ± 4.7 years, 1.57 ± 0.16 cm) with hypertension maintained their daily routine, without exercise. Blood pressure (BP), resting heart rate, and functional capacity (FC) were evaluated at the beginning and at the end of the program, and after three months of DT. RESULTS: The ME program improved (p < 0.05) systolic BP (-5.37%), diastolic BP (-5.67%), resting heart rate (-7.8%), agility (9.8%), lower body strength (27.8%), upper body strength (10.0%), and cardiorespiratory capacity (8.6%). BP and FC deteriorated after the DT period (p < 0.05). CONCLUSION: Nine months of multicomponent exercise were sufficient to improve functional capacity and promote benefits in blood pressure, although was not sufficient to allow BP to reach the normal values of older women. The three month DT period without exercise caused the reversal of BP improvements but maintained the functional capacity of older women.

Multicomponent Exercise Program for Improvement of Functional Capacity and Lipidic Profile of Older Women with High Cholesterol and High Triglycerides.

BACKGROUND: Physical inactivity is a primary cause of most chronic diseases. In addition, the negative effects of aging, physical inactivity and dyslipidemia are risk factors for cardiovascular diseases of older women. Exercise is considered fundamental for the treatment and prevention due to the benefits in the health of this population, but detraining periods after exercise can reverse them. Multicomponent exercise (ME) is a combined method of aerobic and resistance training that can improve the lipidic profile of older women with high cholesterol and triglycerides. METHODS: Seventeen older women (EG: 65.3 ± 4.7 years, 1.52 ± 4.12 m) followed a supervised ME program of nine months and three months of detraining (DT), and fifteen older women (CG: 66.4 ± 5.2 years, 1.54 ± 5.58 cm) continued their daily routine, without exercise. Total cholesterol (TC), triglycerides (TG), blood glucose (GL) and functional capacity (FC) were evaluated at the beginning and at the end of the program and after three months of DT. RESULTS: ME program improved (p < 0.05) lipidic profile: GL (-15.6%), TC (-15.3%), TG (-19.3%) and FC: agility (-13.3%), lower body strength (27.78%), upper body strength (26.3%), cardiorespiratory capacity (11.2%), lower body flexibility (66.67%) and upper body flexibility (85.72%). DT declined the lipidic profile and FC (p < 0.05). CONCLUSION: Lipidic profile and functional capacity can be improved with nine months of ME. Besides the negative effects of DT, three months were not enough to reverse the benefits of exercise in older women with high values of TG and TC.

Is It High Time to Increase Elite Soccer Substitutions Permanently?

Rules determine how team sport matches occur. Match-induced fatigue is specific to each sport, and may be associated with injury incidence. For example, the injury rate in soccer is distinctly higher during matches than in training sessions. Understanding the differences between team sports rules might be useful for enhancing rules (e.g., safer sport). Therefore, this study aimed to evaluate the impact of the rule-induced physical demands between soccer, futsal, basketball, and handball, focusing on substitution rules. Data from the elite team sports' rules (e.g., absolute and relative court dimensions; the number of players, substitutions allowed, total game time, time-outs) were collected, including the changes due to the coronavirus disease (COVID-19) pandemic in soccer substitutions, and comparisons were performed. The data showed that soccer has higher rule-induced physical demands: e.g., substantially lower substitution rate, higher dimensions in absolute (eight to fifteen times), and relative (four to eight times) values. Simulations also showed that soccer has extremely large differences, even considering COVID-19 substitution changes (from three to up to five). We conclude that elite soccer has remarkably higher overall rule-induced physical demands than elite futsal, basketball and handball, and increasing soccer substitutions permanently (e.g., unlimited) might mitigate overall soccer demands.

Ischemia-Reperfusion Intervention: From Enhancements in Exercise Performance to Accelerated Performance Recovery-A Systematic Review and Meta-Analysis.

It has been demonstrated that brief cycles of ischemia followed by reperfusion (IR) applied before exercise can improve performance and, IR intervention, applied immediately after exercise (post-exercise ischemic conditioning-PEIC) exerts a potential ergogenic effect to accelerate recovery. Thus, the purpose of this systematic review with meta-analysis was to identify the effects of PEIC on exercise performance, recovery and the responses of associated physiological parameters, such as creatine kinase, perceived recovery and muscle soreness, over 24 h after its application. From 3281 studies, six involving 106 subjects fulfilled the inclusion criteria. Compared to sham (cuff administration with low pressure) and control interventions (no cuff administration), PEIC led to faster performance recovery (p = 0.004; ES = -0.49) and lower increase in creatine kinase (p < 0.001; effect size (ES) = -0.74) and muscle soreness (p < 0.001; ES = -0.88) over 24 h. The effectiveness of this intervention is more pronounced in subjects with low/moderate fitness level and at least a total time of 10 min of ischemia (e.g., two cycles of 5 min) is necessary to promote positive effects.

Declines in exercise performance are prevented 24 hours after post-exercise ischemic conditioning in amateur cyclists.

Brief moments of blood flow occlusion followed by reperfusion may promote enhancements in exercise performance. Thus, this study assessed the 24-h effect of post-exercise ischemic conditioning (PEIC) on exercise performance and physiological variables in trained cyclists. In a randomized, single-blind study, 28 trained cyclists (27.1 ± 1.4 years) performed a maximal incremental cycling test (MICT). The outcome measures were creatine kinase (CK), muscle soreness and perceived recovery status, heart rate, perceived exertion and power output. Immediately after the MICT, the cyclists performed 1 of the following 4 interventions: 2 sessions of 5-min occlusion/5-min reperfusion (PEIC or SHAM, 2 x 5) or 5 sessions of 2-min occlusion/2-min reperfusion (PEIC or SHAM, 5 x 2). The PEIC (50 mm Hg above the systolic blood pressure) or SHAM (20 mm Hg) treatment was applied unilaterally on alternating thighs. At 24 h after the interventions, a second MICT was performed. In all the groups, the CK levels were increased compared with the baseline (p < 0.05) after the 24-h MICT. The PEIC groups (2 x 5 and 5 x 2) felt more tired at 24 h post intervention (p < 0.05). However, both PEIC groups maintained their performance (2 x 5: p = 0.819; 5 x 2: p = 0.790), while the SHAM groups exhibited decreased performance at 24 h post intervention compared to baseline (2 x 5: p = 0.015; 5 x 2: p = 0.045). A decrease in the maximal heart rate (HR) was found only in the SHAM 2 x 5 group (p = 0.015). There were no other significant differences in the heart rate, power output or perceived exertion after 24 h compared with the baseline values for any of the interventions (p > 0.05). In conclusion, PEIC led to maintained exercise performance 24 h post intervention in trained cyclists.

Mechanical demands and pacing profile adopted by elite mountain bikers during different cross-country events / Demandas mecânicas e perfil de ritmo adotado por ciclistas de montanha de elite durante diferentes eventos do cross-country

ABSTRACT Different competitive environments appears to affect the physical demands during the sports competitions. Thus, the aim of this study was to report the mechanical demand and pacing behaviour of twelve male elite mountain bikers on cross-country short track (XCC) and cross-country Olympic (XCO). During both competition, total race time, speed, power output (PO) and cadence (CA) were recorded. As the race time in the XCC is shorter (21.0 ± 0.5 vs 84.0 ± 3.0 min; p<0.01), the average speed (26.6 ± 0.6 vs 17.8 ± 0.6 km/h; p<0.01), PO (365.0 ± 26.7 vs 301.0 ± 26.2 watts; p<0.01) and CA (81.2 ± 4.7 vs 77.4 ± 4.3 rev∙min−1; p=0.01) were higher than the XCO. While a variable pacing was adopted during XCC, a positive profile was adopted in XCO. In addition, athletes adopted a more conservative starting pace during XCC (below average race speed) but a faster start during XCO (above average race speed). These findings demonstrated that mechanical parameters and pacing profile adopted by cyclists are different between XCC and XCO. Therefore, mountain bikers and coaches must develop specific strategy and training methods in order to obtain success in each competition.

RESUMO Diferentes ambientes competitivos parecem afetar as demandas físicas durante as competições esportivas. Assim, o objetivo deste estudo foi reportar as demandas mecânicas e o comportamento do pacing de doze homens ciclistas de montanha da categoria elite durante o cross-country de pista curta (XCC) e o cross-country Olímpico (XCO). Durante ambas as competições, o tempo total de corrida, velocidade, potência (PO) e cadência (CA) foram gravados. Como o tempo de prova do XCC é menor (21,0±0,5 vs 84,0±3,0 min; p<0,01), a velocidade média (26,6±0,6 vs 17,8±0,6 km/h; p<0,01), PO (365,0±26,7 vs 301,0±26,2 watts; p<0,01) e CA (81,2±4,7 vs 77,4±4,3 rev∙min−1; p=0,01) foram maiores que no XCO. Enquanto um ritmo variável foi adotado no XCC, um perfil positivo foi adotado no XCO. Além disso, os atletas adotaram um ritmo inicial mais conservador durante o XCC (abaixo da velocidade média da prova), mas um início mais rápido durante o XCO (velocidade acima da média da prova). Esses achados demonstraram que os parâmetros mecânicos e o ritmo adotados pelos ciclistas são diferentes entre o XCC e XCO. Portanto, ciclistas e treinadores devem desenvolver estratégias e métodos de treinamento específicos para obter sucesso em cada competição.

The relative peak power output of amateur mountain bikers is inversely correlated with body fat but not with fat-free mass

Abstract Aims: To evaluate whether body mass (BM) and body composition may influence mountain bike cycling performance. Methods: Forty male amateur mountain bikers attended the laboratory on two non-consecutive days. At the first visit, anthropometric measures (height, BM, body fat [BF], fat-free mass [FFM] and body mass index [BMI]) and familiarization to incremental cycling test were performed. On the second visit, cyclists performed again the incremental cycling test to measure peak power output (PPO), peak power output relative to BM (PPO-BM), and time to exhaustion (TE), which were posteriorly correlated with BM and anthropometric measures. Results: A low and moderate significant correlation were observed between TE and BM (p<0.01; r=0.40) and FFM (p<0.01; r=0.56). Moderate significant correlation was found between PPO and BM (p<0.01; r=0.45), BMI (p=0.03; r=0.35) and strong with FFM (p<0.01; r=0.59). Also, PPO-BM significantly correlated with BM (p=0.04; r=-0.31), BMI (p=0.02; r=-0.35) and BF (p<0.01; r=-0.55). No other significant correlations were observed. Conclusion: Considering PPO-BM as mainly performance variable, BM and BF can be a determining factor in mountain biking performance but FFM did not.

Ischemic preconditioning delays the time of exhaustion in cycling performance during the early but not in the late phase

Aims: To investigate the early and late ischemic preconditioning (IPC) effect on the trained cyclists' performance during incremental cycling test until exhaustion. Methods: Twenty-one male cyclists allocated to an IPC (2 x 5-min of blood flow occlusion at 50 mm Hg above systolic pressure followed + 5-min of deflation), SHAM (2 x 5-min at 20 mm Hg) or control (CON; no occlusion) interventions, performed three incremental cycling test (ICT) until exhaustion on separate days. The ICT were conducted pre interventions (baseline), 5-min and 24-h after interventions. The heart rate (HR) and power output (PO) were recorded during all ICT. Results: The IPC group increased ICT performance (4.4 ± 4.0 %; effect size (ES) = 0.27) 5-min post intervention, accompanied by HR mean reduction, compared to baseline (p < 0.05). However, there were no changes in SHAM (2.2 ± 4.2%; ES = 0.07) and CON (2.9 ± 5.0%; ES = 0.06) groups. In 24-h post intervention, SHAM (0.2 ± 4.7%; ES = 0.02) and CON (-1.0 ±1.6; ES = 0.03) maintained (p > 0.05) and IPC group decreased the performance (-4.6 ± 3.6 %; ES = 0.16) compared to 5-min post intervention (p < 0.05), but all groups were similar to baseline (p > 0.05). There were no difference (p > 0.05) among groups for PO peak, HR and ICT performance in all moments (baseline, 5-min and 24-h post intervention). Conclusion: The IPC increases early but not late incremental cycling test performance.(AU)