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Rim Dhahri,1,2,&ast; Islam Mejri,2,3,&ast; Amine Ghram,3– 5 Abir Dghaies,1,2 Marwa Slouma,1,2 Soumaya Boussaid,2,4,6 Leila Metoui,1,2 Imen Gharsallah,1,2 Khadija Ayed,2,7 Zied Moatemri,2,3 Ramadan Abdelmoez Farahat,8,&ast; Ahmad AlHamdani,9,&ast; Ismail Dergaa9– 11,&ast; 1Department of Rheumatology, Military Hospital of Instruction, Tunis, Tunisia; 2University of Tunis el Manar, Faculty of Medicine of Tunis, Tunis, Tunisia; 3Department of Pneumology, Military Hospital of instruction, Tunis, Tunisia; 4Healthy Living for Pandemic Event Protection (HL-PIVOT) Network, Chicago, IL, USA; 5Research Laboratory “Heart Failure, LR12SP09”, Hospital Farhat HACHED of Sousse, Sousse, Tunisia; 6Department of Rheumatology, Rabta Hospital, Tunis, Tunisia; 7Aviation Medicine Center of Expertise, Tunis, Tunisia; 8Faculty of Medicine, Kafrelsheikh University, Kafrelsheikh, Egypt; 9Primary Health Care Corporation (PHCC), Doha, Qatar; 10Research Unit Physical Activity, Sport, and Health, UR18JS01, National Observatory of Sport, Tunis, Tunisia; 11High Institute of Sport and Physical Education, University of Sfax, Sfax, Tunisia&ast;These authors contributed equally to this workCorrespondence: Ismail Dergaa, Primary Health Care Corporation (PHCC), Doha, Qatar, Email Phd.dergaa@gmail.com; idergaa@phcc.gov.qaObjective: Spondyloarthritis (SpA) is a chronic inflammatory rheumatic disease that can lead to spinal ankylosis and consequently, restrictive pulmonary dysfunction. Thus, the present study aimed to assess the accuracy of diaphragm ultrasound compared to spirometry in the screening of restrictive pulmonary disorders in radiographic SpA patients.Methods: We conducted a cross-sectional study of 50 patients with radiographic SpA, over six months. Sociodemographic data, clinical characteristics of the disease, as well as biological, radiological, and therapeutic data, were collected. Spirometry and diaphragm ultrasound were performed.Results: The mean age of the study participants (N= 50) was 42.7± 11 years [range: 25– 66] with male predominance (N= 41). Spirometry showed a restrictive disorder in 32% of cases. The mean chest expansion (CE) value was 3.9± 1.81cm [range: 1– 9] with a median of 4 cm. A pathological value (< 5cm) was observed in 72% of cases. A significant positive correlation was found between the right inspiratory diaphragmatic thickness and forced vital capacity (FVC) (r= 0.36; p = 0.02) and the supine FVC (r=0.29; p = 0.04). The left inspiratory diaphragmatic thickness was correlated with the percentage of the FVC decrease (r= 0.35; p = 0.01) defined as the percentage of difference between FVC and supine FVC. The right expiratory diaphragmatic thickness was associated with the FVC (r=0.32; p = 0.02). A significant positive correlation was found between the CE and the presence of B lines (r=0.32; p = 0.02), but not between the CE and the FVC.Conclusion: The present study showed that diaphragm ultrasonography is correlated with spirometric findings in radiographic SpA patients. Further studies are required to assess its reliability, specificity, and sensitivity in this pathology.Keywords: spondyloarthritis, ultrasonography, diaphragm, restrictive pulmonary disorder, spirometry

Several studies examined the effects of creatine monohydrate supplementation on renal function, but no previous study has investigated its effects on kidney stones in humans.A renal ultrasound in a healthy young athlete (without a known renal morphological anomaly, normal kidney function, normal phospholipid and uric acid data) revealed a kidney stone of 11 mm in the lower right calyx. Extracorporeal shock wave lithotripsy was applied in order to break the down stone. Twentyone days later, a follow-up renal ultrasound showed the absence of stones in the kidney. One week later, the athlete started creatine monohydrate supplementation for two months. Fourteen months after stopping creatine monohydrate supplementation, a third renal ultrasound confirmed the absence of stones in the kidney.Two months of creatine monohydrate supplementation in an athlete with a history of kidney stones could not be associated with kidney stone recurrence in the long run.

Intermittent fasting (IF) has recently gained popularity, and has been used for centuries in many religious practices. The Ramadan fasting is a mandatory form of IF practiced by millions of healthy adult Muslims globally for a whole lunar month every year. In Islam, the “Sunna” also encourages Muslims to practice IF all along the year (e.g.;two days a week). The 2019-Coronavirus disease (COVID-19) pandemic in the context of Ramadan has raised the question whether fasting is safe practice during the COVID-19 pandemic health crisis, and what would be the healthy lifestyle behaviors while fasting that would minimize the risk of infection. As COVID-19 lacks a specific therapy, IF and physical activity could help promote human immunity and be part of holistic preventive strategy against COVID-19. In this commentary, the authors focus on this dilemma and provide recommendations to the fasting communities for safely practicing physical activity in time of COVID-19 pandemic. © 2021 Institute of Sport. All rights reserved.

High-intensity interval training (HIIT) appears to be safe and effective in cardiovascular diseases. However, there is a paucity of data on the effect of HIIT for patients with acute pulmonary embolism (PE). The present randomized controlled trial (RCT) therefore examined the efficiency and safety of HIIT in patients with acute PE.In single-center parallel open-label RCT, 24 patients (5 women) discharged recently with a diagnosis of intermediate-high-risk acute PE were randomized (1:1) to supervised HIIT (n = 12) or control (n = 12) group. The primary outcomes were exercise capacity evaluated in terms of the estimated maximal oxygen uptake (eV˙O2max), lung function (forced expiratory volume in 1 s [FEV1]), right ventricular (RV) function (RV/left ventricular diameter [LV] ratio), and health-related quality of life (HRQoL). Safety was the secondary outcome.Eight weeks of HIIT improved eV˙O2max (+65%, P0.001), FEV1 (%) (+17%, P = 0.031), and RV/LV ratio diameter (-27%, P = 0.005), as well as HRQoL. All patients in the HIIT group tolerated exercise training without serious adverse events. The control group did not improve (P0.05) eV˙O2max, RV/LV ratio diameter, or HRQoL; however, FEV1 (%) was slightly reduced (-6%, P = 0.030).The present RCT of a tailored center-based HIIT intervention provides preliminary evidence that this intervention could improve exercise capacity, lung function, RV function, and HRQoL without serious adverse events, which could provide marked clinical benefits after PE. Further larger multicenter randomized controlled studies are needed to confirm these promising findings.

Background: The purpose of the present study was to assess the impacts of plantar-flexors and dorsi-flexors fatigue following isokinetic contractions on postural control in nine young healthy national level judo athletes. Methods: Participants were required to stand still on a force plate with opened and closed eyes in feet together (FT) and single leg (SL) stance before (PRE) and after (POST) an isokinetic fatigue protocol. Mediolateral sway (ML sway), anteroposterior sway (AP sway), and velocity sway were calculated and used to assess the postural control. Results: Velocity sway POST was significantly (P < 0.001) higher than PRE in FT stance and SL stance. Velocity sway POST was significantly higher in the SL stance than the FT stance (P = 0.01). During eyes closed, a significant interaction postural task by fatigue for all parameters was found. All parameters increased significantly after fatigue compared to PRE. After fatigue, ML sway, AP sway, and velocity sway were significantly higher for the SL stance than the FT stance. Conclusions: Ankle muscle fatigue led to reduced postural stability during different stances in young healthy judo athletes. This effect was more accentuated when vision was removed and the base of support was reduced. Alteration of postural control depended on the difficulty of the postural stance.

Background: The aim of this study was to determine the effect of purslane supplementation on oxidative stress, inflammation and muscle damage biomarkers after completing high-intensity interval exercise (HIIE). Methods: Nine healthy female runners completed a HIIE treadmill protocol comprising 1 min at 100% of the peak treadmill velocity attained in a preliminary exhaustive incremental treadmill test, interspersed by 1 min of passive recovery, until they had run for 2.5 km. Athletes repeated this test following 10 days of supplementation with 1000 mg per day of purslane. Results: At baseline (i.e., absence of purslane supplementation) the HIIE protocol increased 9-HODE (p < 0.001), 13-HODE (p < 0.001), IL-17 (p < 0.001), TNF-α (p < 0.001), and LDH (p < 0.001). After purslane consumption, resting 9-HODE, 13-HODE, IL-17, TNF-α, and LDH were lowered (p < 0.001) and IL-10 was increased (p < 0.001) compared to before purslane supplementation. After purslane consumption and following the HIIE protocol, the responses of these biomarkers were lower compared to baseline (p < 0.001). Conclusion: Ten days of purslane supplementation blunted the perturbation to biomarkers of oxidative stress, inflammation and muscle damage in female runners completing a HIIE protocol.

The novel pandemic called coronavirus disease 2019 (COVID-19), as a global public health emergency, seems to be having a major impact on physical activity (PA) behaviors. Older adults are at high risk of death from the severe acute respiratory syndrome coronavirus 2 (SARS CoV-2). Health authorities around the world have been implementing preventive health measures, including quarantine and self-isolation, to mitigate the COVID-19 outbreak. This period is characterized by the cessation of outdoor exercising. During this period of lockdown, PA has been one of the rare reasons for going out in some countries. To avoid the harmful effects of periods of exercise cessation, PA could be prescribed to older adults, which is of great importance for breaking their sedentary lifestyle and improving their immunity. The present review discusses the potential impacts of the COVID-19 pandemic on sedentary behavior and physical inactivity in older adults. The importance of performing PA to reduce the harmful effects of the COVID-19 pandemic is discussed, and useful recommendations on home-based exercise for the older adults to maintain their level of independence, physical and mental health as well as their well-being are provided.

Apoptosis is a specific form of programmed cell death that plays an important role in tissue homeostasis and also occurs during aging. In addition, exercise training may alter apoptosis-related signaling in muscles, including the cardiac muscle. However, the effects of high-intensity interval training (HIIT) on apoptosis markers in the heart have not yet been studied. Thus, the aim of the present study was to investigate the effects of HIIT on Bcl-2 and Bax expression protein levels in young and old cardiac muscles. Four and 24-month old C57BL/6J mice were used as our young adult and old groups, respectively. Animals were randomly assigned to four groups: young control (YC), young trained (YT), old control (OC), and old trained (OT). The trained groups performed HIIT 5 sessions per week for 4 weeks. RNA extraction and synthesis of cDNA was performed, and Bax and Bcl2 heart gene levels were determined by RT-PCR analysis. Training induced significant increases in Bcl-2 gene expression in YT group comparing to the YC group (p = 0.010) and in OT group comparing to OC group (p = 0.002). Training induced non-significant decrease (p > 0.05) in Bax gene expression and in Bax/Bcl-2 ratio in YT group comparing to the YC group and in OT group comparing to OC group. Aging showed no significant effect in Bcl-2 gene expression, Bax gene expression, and Bax/Bcl-2 ratio in CY group comparing to the OC group and in YT group comparing to OT group (p > 0.05). In conclusion, 4 weeks of HIIT increased Bcl-2 level for young and old heart muscles, and no effect of aging was revealed, indicating that HIIT ameliorated anti-apoptotic signaling in the young and old heart of mice.

Summary Purpose The aim of the present study was to evaluate the effect of high intensity interval training (HIIT) on clinical, as assessed by the Conners’ Parent Rating Scale (CPRS), and anthropometric measures, and laboratory parameters of adolescents with attention deficit hyperactivity disorder (ADHD). Methods Forty-three adolescents with ADHD diagnosis were randomly assigned into two groups: Intervention group (male/female, n = 9/17) and Control group (male/female, n = 11/6). Intervention group performed 20 m running program repetitions with 20–30 s resting between intervals at 85% max heart rate for 6 weeks. Anthropometric and body composition measures (body mass index-Z-score; BMI-Z-score, body fat mass; BFM), Interleukin-13 (IL-13), Interleukin-16 (IL-16), lactate, and CPRS were evaluated at baseline and after 6 weeks. Data were analyzed by means of Kolmogorov-Smirnov test, two-way ANOVA, and Tukey HSD post-hoc test. The statistical significance was set at P Results After 6 weeks, BMI-Z-score and BFM reduced significantly in the intervention group (P 0.05). Conclusion HIIT seems to exert beneficial effects for adolescents with ADHD.

Background: Vision, vestibular sense, proprioception and muscle strength are required to maintain balance. However, gender could also play a crucial role in postural sway. Objectives: This study was used to examine (i) the impact of gender, surface type, and vision on postural sway; (ii) the effects of gender and vision on the limb symmetry of postural sway; and (iii) to understand the effects of gender, stance, surface type and vision on the alterations of dynamic postural sway alterations. Methods: This was a cross-sectional study in which young, healthy men (n = 15) and women (n = 12) underwent a balance control assessment using a force plate (SATEL, 40 Hz). Postural stances were evaluated in different conditions: Opened eyes (EO) and closed eyes (EC), on different surface foam vs. firm, a dominant leg stance (DL) vs. a non-dominant leg stance (NDL), and a mediolateral stance (ML) vs. an anteroposterior stance (AP). The mediolateral sway (ML sway), anteroposterior sway (AP sway), and sway area were calculated from the centre of pressure displacements. Results: ML sway, AP sway and sway area increased when eyes were closed (P < 0.000). Foam surface perturbs balance control more than firm surface under EO and EC conditions for both genders, as observed in the AP sway curve (P < 0.000). A functional symmetry exists between the DL and NDL for all sway parameters: The ML sway, AP sway, and sway area (P = 0.720; P = 0.292; P = 0.954). The AP stance is more stable for the ML sway than the ML stance for both genders (P < 0.001). For the AP sway, the ML stance is more stable than the AP sway AP direction stance for both genders (P < 0.001). Women were significantly more stable than men in the ML stance when vision was absent (P < 0.01). Conclusions: Postural sway was altered more significantly on a foam surface than on a firm surface and symmetry between the DL and NDL was observed. Furthermore, we concluded that women have better dynamic balance control than men.

Patients with stress urinary incontinence (SUI) may be afraid to increase intra-abdominal pressure to avoid incontinence. This could lead to weak expiratory muscles. The aim of this study was to investigate the association between respiratory muscle strength, physical function, and SUI in patients with SUI. A cross-sectional study was conducted in the Physical Medicine and Functional Rehabilitation Department. Thirty-one incontinent women (IG) and twenty-nine women in a control group (CG) were enrolled in this study. Anthropometric data, respiratory muscle strength (maximal inspiratory pressure; maximal expiratory pressure), SUI (Urogenital Distress Inventory-6; Incontinence Impact Questionnaire-7; Pad test), and physical function (waist circumference; timed-up-and-go test; abdominal muscle strength) were assessed. Body fat, body mass index, body weight, and waist circumference were higher in IG than CG (p < 0.01), while postural gait and abdominal muscles were lower (p < 0.001). Respiratory muscle strength displayed moderate correlations with SUI severity, especially for maximal expiratory pressure (p < 0.01). Maximal expiratory pressure was moderately associated with physical function. Deterioration in respiratory muscle strength is a characteristic of women with SUI. In this population, pelvic floor muscle training may be prescribed to improve continence. By feeling more confident about increasing intra-abdominal pressure, women with SUI would strengthen their expiratory muscles and eventually improve their physical function.

The aim of this study was to compare the effectiveness of acute of contract–relax (CR) and contract–relax–antagonist–contraction (CRAC) targeting the quadriceps, hamstrings, anterior tibialis, and calf muscles and warm-up without stretching on medio-lateral (ML) and antero-posterior (AP) dynamic balance control in healthy young men applied by a physiotherapist in comparison to a control intervention without stretching. Twenty healthy young men between the age of 18 and 25 performed three interventions in randomized days after standard warm-up: CR intervention, CRAC intervention, and control intervention. ML and AP dynamic balance control was carried out before (Pre) and immediately after (Post) each intervention. Antero-posterior sway (AP sway) and medio-lateral sway (ML sway) under vision and no vision condition were analyzed by posturography. CRAC intervention improved significantly ML dynamic balance control by decreasing ML sway (vision, p = 0.006 and no vision, p

Introduction: Training at altitude or in a hypoxic environment has gained attention among athletes, coaches, and scientists to enhance sea-level performance. However, the efficacy of “Living-Low, Training-High, Training-Low” (LLTHTL) strategy to escalate the mechanisms associated with enhancing performance in the human athletes is still unknown. The present study aimed to investigate the effect of the LLTHTL on Hypoxia-Inducible Factor-1 alpha (HIF-1α) and peroxisome Proliferator-activated Receptor-Gamma Coactivator-1alpha (PGC-1α) levels in elite endurance runners. Methods: The study has a crossover design in University laboratory. Eight elite male runners (Mean±SD age: 24.50±3.96 years; Mean±SD height: 179.75±4.62 cm; Mean±SD body mass: 67.37±3.42 kg; Mean±SD body mass index: 20.85±1.11 kg/m²) took part in the research. After 4 weeks of Living-Low (LL), the athletes performed 4 weeks Training-High (TH) and then, 3 weeks training-low (TL). Main Outcome Measures: Anthropometric parameters, time trial (1500 m), PGC-1α, and HIF-1α levels were measured in four different time points: pre-LL, post-LL, post-TH, and post-TL. Results: There were no significant differences between the 4 time points for body mass and body mass index (P>0.05). The time trial was improved significantly (p

Purslane supplementation has anti-oxidative, anti-inflammatory, skeletal muscle-relaxant activities. However, it is unknown if the ingestion of purslane will affect the oxidative stress and cytokines in exercise-induced muscle damage. The aim of the present study was to examine the effect of purslane supplementation after high-intensity interval exercise (HIIE) on oxidative stress, cytokines, and muscle damage level in young athlete male runners. Seven healthy young male runners performed 2.5 km HIIE treadmill protocol. Athletes repeated this protocol following 10 days of purslane seed supplementation (1000 mg/day). Blood samples were collected at baseline and following HIIE protocol and analyzed for oxidative stress (9-HODE and 13-HODE), cytokines (IL-17, and TNF-α), and muscle damage (LDH) biomarkers. At baseline and following HIIE protocol, 9-HODE, 13-HODE, IL-17, TNF-α, LDH levels were significantly (p

Introduction: The Elevation Training Mask 2.0 (ETM) has been introduced as a novel tool to allow for respiratory muscle training and altitude exposure during exercise that can improve performance and hematological markers in elite and well-trained athletes. Thus, the aim of the present study was to assess the effect of wearing ETM while training on erythropoietin (EPO), vascular endothelial growth factor (VEGF), peak oxygen consumption (VO2max), lactate, and 1000-m kayaking performance in elite Kayaking girls. Methods: Thirty elite Kayaking girls (14 to 18-year-old) were equally and randomly assigned into mask, no mask, and control groups. The mask and no-mask groups completed 8 weeks of repeated sprint training, while the control group performed their routine kayaking training programs. Pre- and post-training tests included EPO, VEGF, VO2max, lactate, and 1000-m kayaking performance. Results: 1000-m time trial significantly decreased for mask (p < 0.001) and control (p = 0.035) groups, and was significantly lower in mask group than control (p = 0.014) and no mask (p = 0.009) groups. EPO did not show any significant changes for all groups. VEGF was increased significantly for mask (p = 0.04) and no mask (p = 0.014) groups. Lactate was decreased significantly for mask group (p = 0.025). VO2max increased significantly for no mask group (p = 0.021). Conclusion: Wearing the ETM while participating in 8 weeks of repeated sprint training might improve specific blood markers and endurance performance, especially anaerobic pathways. Performing repeated sprint training while wearing ETM has the potential to enhance performance in Kayak racing.

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that originated in China in December 2019 has become a global public health emergency and has had a major impact on physical activity behaviors globally. The resulting COVID-19 pandemic has produced major lifestyle changes for both the general and special populations. Health authorities around the world have been implementing preventive health measures including quarantine and self-isolation to contain the COVID-19 outbreak. During the lockdown period, physical activity is one of the reasons for going outside one’s own home. Indeed, physical activity plays an important role in reducing sedentary lifestyles in general and specific populations including healthy children, adolescents, adults, elderly, athletes, and individuals with Down syndrome. This chapter describes the impact of the COVID-19 pandemic on sedentary behavior and physical inactivity in general and special populations mentioned before. This chapter also demonstrates the importance of physical activity to reduce the harmful effects of the COVID-19 pandemic and provides recommendations on home-based exercise for people to maintain their well-being, level of independence, and physical and mental health.

The purpose of this study was to compare the effects of unilateral ankle fatigue versus the knee muscles with and without vision on bipedal postural control. Elite judo athletes who competed at the national level with at least 10 years of training experience, were randomised into KNEE (n = 10; 20 ± 2 years) and ANKLE (n = 9; 20 ± 3 years) groups, who performed dynamic isokinetic fatiguing contractions (force decreased to 50% of initial peak torque for three consecutive movements) of the knee flexors and extensors or ankle dorsiflexors and plantar flexors, respectively. Static bipedal postural control (French Posturology Association normative standards) with eyes open and eyes closed was examined before and immediately after the fatiguing task. Postural variables examined were the centre of pressure (CoP) sway in the medio-lateral and antero-posterior directions, total CoP area sway and CoP sway velocity. Although unilateral ankle and knee fatigue adversely affected all bipedal postural measures, with greater disturbances with eyes closed, there were no significant main group or interaction effects between KNEE and ANKLE groups. Unilateral lower limb fatigue adversely affected bipedal balance, with knee extension/flexion fatigue affecting bipedal postural control to a similar extent as unilateral ankle dorsiflexion/plantar flexion fatigue. Hence unilateral fatigue can affect subsequent bilateral performance or also have implications for rehabilitation exercise techniques. Our findings may be limited to judo athletes as other populations were not tested.

The purpose of this study was to investigate the effects of green tea (GT) consumption combined with different training modalities on orexin-A and apelin in overweight and obese women, and then to explore the relationship between apelin, orexin-A and body composition changes in response to training protocols. Forty-eight obese women participated in the study and were randomly assigned to one of four groups: aerobic training group, resistance training group, combined training group, and control group (3 days a week for 10 weeks). All groups ingested the same dose of GT. Blood samples were collected to analyze fasting glucose, insulin resistance, apelin and orexin-A concentrations. Insulin resistance was measured by homeostasis model assessment of insulin resistance index (HOMA-IR). Blood samples were collected before each exercise training and 24 h after of the last session. Orexin-A and apelin were decreased significantly after all exercise training modalities, whereas no changes in response to control group. Aerobic group showed greater reduction of blood samples than resistance and combined group. No benefit of GT supplementation only (Control group) on apelin and orexin-A was observed. In addition, Correlation was found between apelin and orexin-A after exercise training. All training modalities cause a reduction in insulin resistance, HOMA-IR, orexin-A and apelin in obese women. 10 weeks of aerobic exercise cause greater decreases in apelin and orexin-A than resistance and combined exercise trainings. In addition, the decrease in plasma apelin levels may contribute to reduction in orexin-A levels.

The purpose of this study was to identify the acute effects of two types of warm-up (i.e. plyometric and isometric) interventions on jump performance. Forty-five subjects volunteered to participate in our study. Participants were randomly assigned in a plyometric group (n = 15; age 14.79 ± 0.43; mass 57.64 ± 4.52; height 174.61 ± 5.97), isometric group (n = 15; age 14.80 ± 0.41; mass 57.13 ± 4.78; height 174.57 ± 5.75), and control group (n = 15; age 14.67 ± 0.49; mass 57.93 ± 4.09; height 175.30 ± 4.93). Pre- and post-measures (before, immediately, 5, 10, and 15 min after) for sargent jump test (SJT) and five jump test (5JT) were analyzed using a repeated measures ANOVA. There was a significant (p

The present study aimed to investigate the effect of two different exercise training protocols on myocardial fibrosis and the expression of some growth factors in aged rats.Twenty-four male Wistar rats were randomly assigned to high-intensity interval training (HIIT) group, continuous exercise training (CET) group, and the control group. After 6 weeks of experiment, mRNA levels of fibroblast growth factor-2 (FGF-2), vascular endothelial growth factor (VEGF), adropin proteins, and myocardial fibrosis were assessed.HIIT and CET induced a significant increase in the FGF-2 and adropin and a decrease in the myocardial fibrosis in compared with the control group. HIIT induced a significant increase in the VEGF if compared with the control group. There was no significant difference between CET and control group.Six weeks of HIIT and CET attenuated age-related myocardial fibrosis thereby an increase in angiogenesis-related molecules in cardiac and endothelial tissues.

Summary Objective Muscle stretching is plenty used prior to training and competition. Considering the importance of balance control in performance, muscle stretching is expected to have positive effects on balance. However, there is a lack of studies investigating the effects of contract-relax proprioceptive neuromuscular facilitation (CR PNF) stretching on balance control. The purpose of this study was to investigate the effects of CR PNF stretching on static postural balance. Methods Fourteen subjects were tested before and after a 5-minute cycle warm-up followed by 10 minutes of CR PNF stretching (stretching condition) and the same cycle warm-up with 10-minute rest periods (control condition). The four muscle groups stretched were the quadriceps, hamstrings, anterior tibialis, and calf muscles of both legs in an alternating manner. Postural balance was assessed in a bipedal static stance before and after each condition with eyes opened (EO) and eyes closed (EC). Results No significant interactions for any postural parameters. However, there was a significant main effect of condition for sway area (P 0.05). Conclusion It appears that the stretching and control conditions impaired static balance control by increasing postural sway. CR PNF stretching was unable to compensate for the warm-up and its effects of induced alteration in postural balance.

Summary Objective The purpose of the present study was to assess the effect of exponential taper and electrostimulation training during two weeks of tapering on anaerobic performances after resistance training program. Methods Twenty-eight healthy male (age: 17.7 ± 0.8 years; height: 187.1 ± 3.9 cm; weight: 76.7 ± 6.6 kg, and body mass index: 21.9 ± 1.6 kg⋅m−2) were divided into three groups: control group, exponential taper group and electrostimulation taper group. During resistance period, all groups followed the same training program during 5 weeks (3 sets × 10 repetitions with 2 min of rest; intensity = 10 repetition maximum). At the taper period, control group continued with the same program. In contrast, both exponential groups had a diminution of training volume. Participants were tested in three periods (i.e., before and after the resistance training and after the tapering phase) for the determination of maximum repetition, squat jump and countermovement jump. Subjects answered to questionnaire of rating of perceived exertion after every training session. Results Resistance training showed a significant improvement of muscle strength and power in the three groups. However, in response to tapering phase, vertical jump performances and maximum repetition increased significantly only in both tapering groups. No significant difference was showed between exponential taper group and electrostimulation taper group after two weeks of taper.

OBJECTIVE: This study aimed to investigate the effect of the contract-relax proprioceptive neuromuscular facilitation (CR PNF) stretching protocol on dynamic balance. METHODS: Twenty healthy young male performed two sessions in a randomized order; a session with CR PNF stretching protocol, and a session without the stretching protocol. Bipedal dynamic balance was measured in anterior-posterior and medio-lateral directions before and after the completion the two experimental sessions with eyes opened and closed. RESULTS: the present study showed that there is no significant difference between the two sessions (with vs without the CR PNF stretching protocol) in the anterior-posterior direction. However, in the medio-lateral direction, the CR PNF stretching protocol significantly enhanced dynamic balance, when compared with the no stretch protocol condition. CONCLUSION: This study concluded that CR PNF stretching might be effective to improve dynamic balance control. OBJETIVO: Este estudo teve como objetivo investigar o efeito de um protocolo de alongamento por facilitação neuromuscular proprioceptiva de contração-relaxamento sobre o equilíbrio dinâmico. MÉTODOS: Vinte jovens saudáveis do sexo masculino realizaram duas sessões oredenadas aleatoriamente; uma sessão com protocolo de alongamento por facilitação neuromuscular proprioceptiva de contração-relaxamento, e uma sessão sem esse protocolo. O equilíbrio dinâmico bipedal foi medido nas direções ântero-posterior e médio-lateral antes e após a conclusão das duas sessões experimentais, com os olhos abertos e fechados. RESULTADOS: O estudo mostrou que não há diferença significativa entre as duas sessões (com vs sem o protocolo de alongamento) no sentido ântero-posterior. No entanto, na direção médio-lateral, o protocolo de alongamento aumentou significativamente o equilíbrio dinâmico, quando comparado com a condição de protocolo sem alongamento. CONCLUSÃO: Este estudo permite concluir que o protocolo de alongamento por facilitação neuromuscular proprioceptiva de contração-relaxamento pode ser eficaz para melhorar o controle de equilíbrio dinâmico.