Effects of Exercise Training on Muscle Mass and Physical Function in Patients with Hepatocellular Carcinoma After Diagnosis: A Systematic Review.

BACKGROUND AND AIMS: Decreased muscle mass and physical function are common complications in hepatocellular carcinoma (HCC) patients who are associated with increased morbidity and mortality. Thus, there have been targeted efforts to prevent and/or improve both by enrolling these patients in exercise training programs. We performed a systematic review to evaluate the effects of exercise training on muscle mass and physical function in people with HCC after diagnosis. METHODS: A systematic literature search was conducted using the Medline, Base, PubMed, Cochrane and Scopus, and trial registries, through April 2023 for studies that assessed the effects of an exercise training program in adults with HCC. The primary outcomes were muscle mass and physical function. To assess the risk of bias, we used the Quality Assessment Tool for Quantitative Studies from the Effective Public Health Practice Project. RESULTS: Eight studies met inclusion criteria, comprising a total of 809 participants. Interventions included aerobic exercise training, resistance exercise training, balance and flexibility training, or home-based exercise training. Four studies showed statistically significant improvements in at least one muscular outcome. Three studies showed a maintenance of muscular outcomes, and one study showed a decrease in muscle mass. Four articles showed statistically improvements in at least one physical fitness variable, and two showed a maintenance of physical function variable. CONCLUSION: Together, the results suggest that patients may benefit from physical exercise training after treatment to improve muscle mass and physical function.

The effect of acute and chronic exercise on hepatic lipid composition.

Exercise is recommended for those with, or at risk of nonalcoholic fatty liver disease (NAFLD), owing to beneficial effects on hepatic steatosis and cardiometabolic risk. Whilst exercise training reduces total intrahepatic lipid in people with NAFLD, accumulating evidence indicates that exercise may also modulate hepatic lipid composition. This metabolic influence is important as the profile of saturated (SFA), monounsaturated (MUFA), and polyunsaturated fatty acids (PUFA) dramatically affect the metabolic consequences of hepatic lipid accumulation; with SFA being especially lipotoxic. Relatedly, obesity and NAFLD are associated with hepatic PUFA depletion and elevated SFA. This review summarizes the acute (single bout) and chronic (exercise training) effects of exercise on hepatic lipid composition in rodents (acute studies: n = 3, chronic studies: n = 13) and humans (acute studies: n = 1, chronic studies: n = 3). An increased proportion of hepatic PUFA after acute and chronic exercise is the most consistent finding of this review. Mechanistically, this may relate to an enhanced uptake of adipose-derived PUFA (reflecting habitual diet), particularly in rodents. A relative decrease in the proportion of hepatic MUFA after chronic exercise is also documented repeatedly, particularly in rodent models with elevated hepatic MUFA. This outcome is related to decreased hepatic stearoyl-CoA desaturase-1 activity in some studies. Findings regarding hepatic SFA are less consistent and limited by the absence of metabolic challenge in rodent models. These findings require confirmation in well-controlled interventions in people with NAFLD. These studies will be facilitated by recently validated magnetic resonance spectroscopy techniques, able to precisely quantify hepatic lipid composition in vivo.

Physically active men present a healthier cardiometabolic profile in response to a balanced meal compared to inactive men.

PURPOSE: Post-meal cardiometabolic responses are critical for health, and may be influenced by physical activity. The objective of this study was to investigate the effect of habitual physical activity level on the metabolic, autonomic nervous system and cardiovascular responses to a balanced meal in healthy men. METHODS: 12 active and 12 inactive healthy males, matched for age and body composition, attended the laboratory in fasting condition. Participants were asked to sit quietly and comfortably in an armchair for the whole duration of the experiment (~ 2h30). Metabolic, autonomic nervous system and cardiovascular measurements were performed in fasting conditions, and at regular intervals until one hour after the end of a balanced breakfast. RESULTS: No significant difference was observed between groups in glycaemia or energy expenditure throughout the experiment. Fat oxidation rate was significantly higher one-hour post-meal in active vs inactive men (Respiratory Quotient: 0.78 ± 0.04 vs 0.88 ± 0.03; p < 0.01). Heart rate was significantly lower in active compared to inactive individuals (p < 0.001) throughout the experiment and active participants displayed significantly enhanced vagal tone one-hour post-meal (square root of the sum of successive differences between adjacent normal R-R intervals squared: 72.4 ± 27.9 vs 46.4 ± 14.1 ms; p < 0.05). CONCLUSION: In healthy men, habitual physical activity level seems discriminant to decipher specific profiles in terms of cardiometabolic responses to a meal. Overall, it may suggest pre-signal cardiometabolic impairments in healthy inactive individuals and highlight the need to consider primary prevention in inactive subjects as a key factor for health management.

Weight loss does not affect the sit-to-stand metabolic cost in adolescents with obesity.

PURPOSE: There is considerable interest in simple and effective methods to reduce sitting time and increase energy expenditure, and standing breaks have emerged as a realisable approach in individuals with obesity. The aim of the present study was to determine the extent to which energy expenditure in standing differs from sitting, and whether this energetic and metabolic-related responses are modified following a weight loss program in adolescents with obesity. METHODS: After body composition assessment (DXA), cardiorespiratory and metabolic variables were continuously recorded (indirect calorimetry) during 10 min while sitting and then during 5 min standing posture before (n = 21; T1) and at the end of a multidisciplinary intervention (n = 17; T2) in adolescents with obesity. RESULTS: Before and after the intervention, energy expenditure and fat oxidation rates were significantly increased in standing compared with sitting. Weight loss did not change the relationship between sitting and standing energy expenditure. Sitting energy expenditure represented 1.0 and 1.1 Metabolic Equivalent of Task at T1 and T2, and increased to 1.1 and 1.2 during standing at T1 and T2, respectively. The percentage of change of android fat mass between T1 and T2 was positively associated with the percentage of change in energy expenditure from sitting to standing at T2. CONCLUSION: The vast majority of the adolescents with obesity significantly increased their energy expenditure between sitting and standing, both before and after a weight loss intervention. However, the standing posture did not allow breaking the sedentary threshold. Abdominal fat mass is associated with energic profile.

Association between alanine aminotransferase as surrogate of fatty liver disease and physical activity and sedentary time in adolescents with obesity.

To compare patterns of sedentary (SED) time (more sedentary, SED + vs less sedentary, SED-), moderate to vigorous physical activity (MVPA) time (more active, MVPA + vs less active, MVPA-), and combinations of behaviors (SED-/MVPA + , SED-/MVPA-, SED + /MVPA + , SED + /MVPA-) regarding nonalcoholic fatty liver diseases (NAFLD) markers. This cross-sectional study included 134 subjects (13.4 ± 2.2 years, body mass index (BMI) 98.9 ± 0.7 percentile, 48.5% females) who underwent 24-h/7-day accelerometry, anthropometric, and biochemical markers (alanine aminotransferase (ALT) as first criterion, and aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), AST/ALT ratio as secondary criteria). A subgroup of 39 patients underwent magnetic resonance imaging-liver fat content (MRI-LFC). Hepatic health was better in SED- (lower ALT, GGT, and MRI-LFC (p < 0.05), higher AST/ALT (p < 0.01)) vs SED + and in MVPA + (lower ALT (p < 0.05), higher AST/ALT (p < 0.01)) vs MVPA- groups after adjustment for age, gender, and Tanner stages. SED-/MVPA + group had the best hepatic health. SED-/MVPA- group had lower ALT and GGT and higher AST/ALT (p < 0.05) in comparison with SED + /MVPA + group independently of BMI. SED time was positively associated with biochemical (high ALT, low AST/ALT ratio) and imaging (high MRI-LFC) markers independently of MVPA. MVPA time was associated with biochemical markers (low ALT, high AST/ALT) but these associations were no longer significant after adjustment for SED time. CONCLUSION: Lower SED time is associated with better hepatic health independently of MVPA. Reducing SED time might be a first step in the management of pediatric obesity NAFLD when increasing MVPA is not possible. WHAT IS KNOWN: • MVPA and SED times are associated with cardiometabolic risks in youths with obesity. • The relationships between NAFLD markers and concomitant MVPA and SED times have not been studied in this population. WHAT IS NEW: • Low SED time is associated with healthier liver enzyme profiles and LFC independent of MVPA. • While low SED/high MVPA is the more desirable pattern, low SED/low MVPA pattern would have healthier liver enzyme profile compared with high MVPA/high SED, independent of BMI, suggesting that reducing SED time irrespective of MVPA is needed to optimize liver health.

Cardiometabolic and neuromuscular analyses of the sit-to-stand transition to question its role in reducing sedentary patterns.

To counteract the detrimental health effect of sitting all day long, it has been suggested to regularly break sitting time by standing. However, while the difference in energy expenditure, neuromuscular and/or cardiovascular demand of various postures from lying, sitting, and standing is well documented, little is known regarding the dynamic changes occurring during the sit-to-stand transition itself. The aim of the present study was then to describe the cardiometabolic and neuromuscular responses from sitting to standing and specifically during the time-course of this transition. Twelve healthy young participants were asked to perform standardized raises from sitting posture, while cardiometabolic (cardiorespiratory and hemodynamic variables) and neuromuscular (calf muscles' myoelectrical activity, spinal and supraspinal excitabilities) parameters were monitored. As a result, while there was a rapid adaptation for all the systems after rising, the neuromuscular system displayed the faster adaptation (~ 10 s), then hemodynamic (~ 10 to 20 s) and finally the metabolic variables (~ 30 to 40 s). Oxygen uptake, energy expenditure, ventilation, and heart rate were significantly higher and stroke volume significantly lower during standing period compared to sitting one. In calf muscles, spinal excitability (H-reflexes), was lowered by the sit-to-stand condition, while supraspinal drive (V-wave) was similar, indicating different cortico-spinal balance from sitting to standing. Although very heterogenous among participants in terms of magnitude, the present results showed a rapid adaptation for all the systems after rising and the health benefit, notably in terms of energy expenditure, appears rather modest, even if non negligeable.

Feasibility and acceptability of "active" classroom workstations among French university students and lecturers: a pilot study.

BACKGROUND: Sedentary lifestyles plague today's society in terms of physical, psychosocial and cognitive health. Students are particularly at risk because they spend most of their daily time sitting and inactive. The current pedagogical model must be rethought in order to promote students' health, well-being and therefore their success. The objective of this project was to equip one classroom of the sport science department at a university with various active workstations (standing desks, Swiss balls, cycling desks, pedal- or stepper-board) and to evaluate the feasibility and influence of these types of active workstations on the cognitive and psychological factors of the students, and to collect the feedback of lecturers during this experience. METHODS: Participation in the study was voluntary and students had the opportunity to choose or not to use an active workstation during lectures. A total of 663 students and 14 lecturers completed a survey to evaluate subjective feelings about physical, psycho-cognitive and academic aspects after their first experience with active workstations in the classroom. RESULTS: The majority of students and lecturers reported positive effects of active workstations in reducing fatigue, distraction, and boredom. The preferred active workstations were the cycling desks and the Swiss balls. Finally, 89.4% of students favoured using active workstations in future lectures if they had the option, as well as 71% of lecturers, demonstrating the acceptance of such active workstations. CONCLUSION: The present study brings promising results toward a more general implementation of active workstations in universities. Once a familiarisation period is observed, having such workstations in the classroom could help prevent the deleterious effect of sedentary behaviour and promote a more active daily life for the future.

Role of exercise-induced hepatokines in metabolic disorders.

The health-promoting effects of physical activity to prevent and treat metabolic disorders are numerous. However, the underlying molecular mechanisms are not yet completely deciphered. In recent years, studies have referred to the liver as an endocrine organ, since it releases specific proteins called hepatokines. Some of these hepatokines are involved in whole body metabolic homeostasis and are theorized to participate in the development of metabolic disease. In this regard, the present review describes the role of Fibroblast Growth Factor 21, Fetuin-A, Angiopoietin-like protein 4, and Follistatin in metabolic disease and their production in response to acute exercise. Also, we discuss the potential role of hepatokines in mediating the beneficial effects of regular exercise and the future challenges to the discovery of new exercise-induced hepatokines.

Validation of a Photoplethysmographic Heart Rate Monitor: Polar OH1.

This study assessed the validity of a photoplethysmographic heart rate (HR) monitor, the Polar OH1 in various sports performed in ecological conditions: running, cycling, soccer, kayaking, walking, tennis and fitness. Seventy trained athletes (56 males, 14 females) wore the Polar OH1 armband and the H7 chest belt during training. A total of 390 h and 38 min of recording were compared using a 20-bpm window to assess data quality, and Bland-Altman agreements and ICC analyses were used to test accuracy. Linear regression analyses evaluated the HR accuracy and correlation with skin tone. Training loads (TRIMPs) were compared for each session. Reliability was high for endurance sports (>99%) and lower for sports involving arm movements (92~95%). Biases were slightly negative for all sports, whereas widths of limits of agreement varied from 7-20bpm. Bland-Altman agreements were all under 5% except tennis, kayak and fitness. HR accuracy was positively correlated to skin tone (p<0.05). Finally, TRIMPs from the OH1 device were inferior to criterion's (except walking and soccer), within a 3% range from reference. Hence, OH1 represents a valid tool to monitor instantaneous HR and training load, especially for endurance sports.

Physiological Pattern Changes in Response to a Simulated Competition in Elite Women's Artistic Gymnasts.

Isacco, L, Ennequin, G, Cassirame, J, and Tordi, N. Physiological pattern changes in response to a simulated competition in elite women's artistic gymnasts. J Strength Cond Res 33(10): 2768-2777, 2019-The outstanding progress in women's artistic gymnastics in recent decades has led to increased technical and physiological demands. The aim of this study was to investigate (a) the physiological demands of elite French gymnasts and (b) the impact of a competitive routine on physiological pattern changes. Fourteen French elite female gymnasts performed anthropometric measurements, physical fitness tests, and a simulated 4-event competition. Heart rate (HR) was continuously recorded throughout the duration of the simulated competition. Blood lactate concentrations were assessed at rest, before the beginning and at 2, 4, and 10 minutes after completion of the routine on each apparatus. Isometric handgrip strength and anaerobic endurance and power were assessed during the simulated competition. The highest values of HR and blood lactate concentrations were reached during the floor and uneven bar exercises. Blood lactate concentrations and HR kinetics were apparatus dependent and values remained significantly increased at 10 minutes of recovery compared with resting data. Anaerobic endurance and power decreased significantly as the competition progressed (p < 0.001). The present results show specifically cardiorespiratory and anaerobic apparatus-dependent responses throughout a simulated competition. Recovery approaches seem relevant to prevent and minimize fatigue and optimize performance in these athletes.

Exercise training and return to a well-balanced diet activate the neuregulin 1/ErbB pathway in skeletal muscle of obese rats.

KEY POINTS: Some studies suggest that neuregulin 1 (NRG1) could be involved in the regulation of skeletal muscle energy metabolism in rodents. Here we assessed whether unbalanced diet is associated with alterations of the NRG1 signalling pathway and whether exercise and diet might restore NRG1 signalling in skeletal muscle of obese rats. We show that diet-induced obesity does not impair NRG1 signalling in rat skeletal muscle. We also report that endurance training and a well-balanced diet activate the NRG1 signalling in skeletal muscle of obese rats, possibly via a new mechanism mediated by the protease ADAM17. These results suggest that some beneficial effects of physical activity and diet in obese rats could be partly explained by stimulation of the NRG1 signalling pathway. ABSTRACT: Some studies suggest that the signalling pathway of neuregulin 1 (NRG1), a protein involved in the regulation of skeletal muscle metabolism, could be altered by nutritional and exercise interventions. We hypothesized that diet-induced obesity could lead to alterations of the NRG1 signalling pathway and that chronic exercise could improve NRG1 signalling in rat skeletal muscle. To test this hypothesis, male Wistar rats received a high fat/high sucrose (HF/HS) diet for 16 weeks. At the end of this period, NRG1 and ErbB expression/activity in skeletal muscle was assessed. The obese rats then continued the HF/HS diet or were switched to a well-balanced diet. Moreover, in both groups, half of the animals also performed low intensity treadmill exercise training. After another 8 weeks, NRG1 and ErbB expression/activity in skeletal muscle were tested again. The 16 week HF/HS diet induced obesity, but did not significantly affect the NRG1/ErbB signalling pathway in rat skeletal muscle. Conversely, after the switch to a well-balanced diet, NRG1 cleavage ratio and ErbB4 amount were increased. Chronic exercise training also promoted NRG1 cleavage, resulting in increased ErbB4 phosphorylation. This result was associated with increased protein expression and phosphorylation ratio of the metalloprotease ADAM17, which is involved in NRG1 shedding. Similarly, in vitro stretch-induced activation of ADAM17 in rat myoblasts induced NRG1 cleavage and ErbB4 activation. These results show that low intensity endurance training and well-balanced diet activate the NRG1-ErbB4 pathway, possibly via the metalloprotease ADAM17, in skeletal muscle of diet-induced obese rats.

Comparison of oxygen consumption in rats during uphill (concentric) and downhill (eccentric) treadmill exercise tests.

The study of the physiological adaptations of skeletal muscle in response to eccentric (ECC) contraction is based on protocols in which exercise intensities are determined relative to the concentric (CON) reference exercise (as percentage of the CON maximal oxygen consumption, or VO2max). In order to use similar exercise protocols in rats, we compared the VO2 values during uphill (CON) and downhill (ECC) running tests. VO2 was measured in 15 Wistar rats during incremental treadmill running exercises with different slopes: level (0%), positive (+15% incline: CON+15%) and negative (i15% incline: ECC-15%; and 130% incline: ECC-30%). Similar VO2 values were obtained in the ECC-30% and CON+15% running conditions at the three target speeds (15, 25 and 35 cm/sec). Conversely, VO2 values were lower (p < 0.05) in the ECC-15% than in the CON+15% condition (CON+15% VO2/ECC-15% VO2 ratios ranging from 1.86 to 2.05 at the three target speeds). Thus, doubling the downhill slope gradient in ECC condition leads to an oxygen consumption level that is not significantly different as in CON condition. These findings can be useful for designing animal research protocols to study the effects of ECC and CON exercise in ageing population or subjects suffering from cardiovascular diseases. Key PointsVO2 in rats during treadmill race in eccentric and concentric conditions were measured.A novel breath-by-breath device allowing direct access to the animal was used.THREE DIFFERENT SLOPES: +15%, -15% and -30% were used.VO2 values obtained in the -30% eccentric and the +15% concentric conditions were not significantly different.

Voluntary exercise fails to prevent metabolic dysfunction-associated steatotic liver disease progression in male rats fed a high-fat high-cholesterol diet.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health issue with a worldwide prevalence of 30%-32%. In animal models, voluntary exercise may be an alternative to forced physical activity, avoiding stress, potential injuries, and being logistically simpler. Here, we assessed voluntary exercise (Vex) in Sprague-Dawley rats fed a high-fat, high-cholesterol diet for 18 weeks to induce MASLD. We quantified workload (speed and distance) using exercise wheels and evaluated energy expenditure using calorimetric cages. MASLD progression was assessed using circulating and hepatic biochemical and gene markers of steatosis, inflammation, and fibrosis. The animals ran an average of 301 km during the study period, with the average daily distance peaking at 4937 m/day during Weeks 3-4 before decreasing to 757 m/day by the end of the study. Rats exposed to Vex showed no improvement in any of the MASLD-associated features, such as steatosis, inflammation, or fibrosis. Rats exposed to Vex exhibited a higher total energy expenditure during the night phase (+0.35 kcal/h; p = 0.003) without resulting in any effect on body composition. We conclude that, in our experimental conditions, Vex failed to prevent MASLD progression in male Sprague-Dawley rats exposed to a high-fat high-cholesterol diet for 18 weeks.

Effects of pre-exercise, endurance, and recovery designer sports drinks on performance during tennis tournament simulation.

Sports drinks are often used before, during, and after tennis tournaments, but their ability to influence physiological and psychological variables and the characteristics of tennis match play remains uncertain. The objective of this study was to evaluate the impact of ingesting specially formulated pre-exercise, endurance, and recovery sports drinks on glycemia and performance indices during a simulated tennis tournament. Eight well-trained male tennis players performed two 3-match round-robin tennis tournaments although ingesting sports drinks (SPDs) or placebos (PLAs) before, during, and after each match (crossover study design). Before the first tournament, match and drink order were randomized (SPDs or PLAs first) and players were placed under controlled nutritional and hydration conditions. Glycemia, heart rate response, rate of perceived exertion, and notational/match analysis were assessed during each match. Sports drinks maintained higher glycemia levels during match 2 and 3 of the tennis tournament compared with PLAs (p < 0.01). Moreover, higher mean heart rates (p < 0.01) and stroke frequencies (p < 0.01) concomitantly with lower rates of perceived exertion (p < 0.01) were recorded throughout the duration of the tournament, when players used the SPDs. During a 3-match tennis tournament, SPDs allow higher stroke frequency during play, with decreased rates of perceived exertion.

Influence of the different hormonal status changes during their life on fat mass localisation in women: a narrative review.

CONTEXT: Independently of the total body fat mass, upper body fat mass deposition is strongly associated with cardiometabolic comorbidities. The mechanisms underlying fat mass localisation are not fully understood, but evidences indicate sex-specific fat mass distribution. Currently, data on women are scarce and the link between hormonal status changes during their life and fat mass distribution is overlooked. METHOD: For this narrative review, literature data were extracted from the PubMed and CENTRAL databases to examine the relationship between hormonal status and adipose tissue localisation in women. RESULTS: Menopause strongly influences fat mass localisation, while the effect of the menstrual cycle phases, oral contraception use and pregnancy has not been unambiguously determined. CONCLUSION: Reliable data are lacking on the relationship between hormonal variations throughout the lifespan and body fat mass localisation in women. Future studies should take into account the hormonal status of women to reduce the risk of cardiometabolic diseases.

Lightest weight-class athletes are at higher risk of weight regain: results from the French-Rapid Weight Loss Questionnaire.

CONTEXT: Rapid weight loss (RWL) is a common precompetitive strategy used by athletes in weight-class sports and carries with it an increased risk to future cardiometabolic health. The Rapid Weight Loss Questionnaire (RWLQ) is a self-reported tool designed to identify and characterize such weight loss practices. OBJECTIVES: After developing a reliable and reproducible French version of the RWLQ (RWLQ-FR), the present study aims to analyse RWL patterns among French weight-class athletes and to point out potential relationships between such practices and risk of subsequent weight gain. METHODS: A test-retest analysis was performed in 54 athletes to test the questionnaire reproducibility before applying it in a cohort of 168 weight-cycling athletes (23.78 ± 9.25 y, 67.6 ± 12.6 kg, 81 males and 87 females, n = 24 strength sports and n = 144 various combat sports). RESULTS: The test-retest showed good agreement of the RWLQ-FR (Rho = 0.794, [0.696-0.893]). Athletes reported losing an average of 4.1 ± 2.9% of their initial weight in 13.1 ± 9.6 days, with the main methods used being an increase in exercise, training in rubber or plastic suits, and gradual dieting. The average weight recovery in a week was 3.5 ± 2.8% and results showed that the athletes with the lower inter-season weight (weight outside of the training and competition season) regained the more weight (p = 0.025). The average RWLQ-FR score was 31.9 ± 17.3 and athletes who began to lose weight earlier in their competitive carrier had the higher scores (p = 0.032). CONCLUSION: The present study demonstrates relationships between the pattern of RWL practices and potential increased risk of subsequent weight gain in weight-cycling athletes, and the need to better understand the long-term health-related risks.

Non-invasive biomarkers of non-alcoholic fatty liver disease in patients with Metabolic Syndrome: insights from the RESOLVE study.

BACKGROUND: The aim of the present study was to evaluate i) the presence of liver steatosis using Fatty Liver Index (FLI), Hepatic Steatosis Index (HSI) and Liver Fat Score (LFS) in patients suffering from MS and ii) the association of FLI, HSI and LFS with the cardiometabolic risks. METHODS: A total of 91 patients with MS (MS; 39 men, 52 women) and 44 age matched healthy subjects (Control; 23 men and 21 women) were enrolled in the study. A continuous cardiometabolic score (MetsScore) and the noninvasive tests of hepatic steatosis were calculated for comparison and association analysis. RESULTS: Liver steatosis was detected in 86%, 84% and 80% of people diagnosed with MS using FLI, HSI and LFS respectively and MetsScore increases with FLI severity (p<0,05). Also, FLI and LFS were positively associated with MetsScore (p<0.01 and p<0.05 respectively) but not HSI. Multivariate linear regression models revealed that FLI has a stronger association with MetsScore compared with HSI and LFS (p<0,001). CONCLUSIONS: FLI is associated with the severity of MS and represent a good indicator to assess the relation between liver steatosis and a cardiometabolic disorders in clinical routine.

Stand Up to Excite the Spine: Neuromuscular, Autonomic, and Cardiometabolic Responses During Motor Imagery in Standing vs. Sitting Posture.

Motor imagery (MI) for health and performance strategies has gained interest in recent decades. Nevertheless, there are still no studies that have comprehensively investigated the physiological responses during MI, and no one questions the influence of low-level contraction on these responses. Thus, the aim of the present study was to investigate the neuromuscular, autonomic nervous system (ANS), and cardiometabolic changes associated with an acute bout of MI practice in sitting and standing condition. Twelve young healthy males (26.3 ± 4.4 years) participated in two experimental sessions (control vs. MI) consisting of two postural conditions (sitting vs. standing). ANS, hemodynamic and respiratory parameters, body sway parameters, and electromyography activity were continuously recorded, while neuromuscular parameters were recorded on the right triceps surae muscles before and after performing the postural conditions. While MI showed no effect on ANS, the standing posture increased the indices of sympathetic system activity and decreased those of the parasympathetic system (p < 0.05). Moreover, MI during standing induced greater spinal excitability compared to sitting posture (p < 0.05), which was accompanied with greater oxygen consumption, energy expenditure, ventilation, and lower cardiac output (p < 0.05). Asking individuals to perform MI of an isometric contraction while standing allows them to mentally focus on the motor command, not challenge balance, and produce specific cardiometabolic responses. Therefore, these results provide further evidence of posture and MI-related modulation of spinal excitability with additional autonomic and cardiometabolic responses in healthy young men.

Effect of Fat Mass Localization on Fat Oxidation During Endurance Exercise in Women.

Independent of total body fat mass, predominant upper body fat mass distribution is strongly associated with cardio-metabolic comorbidities. However, the mechanisms underlying fat mass localization are not fully understood. Although a large body of evidence indicates sex-specific fat mass distribution, women are still excluded from many physiological studies and their specific features have been investigated only in few studies. Moreover, endurance exercise is an effective strategy for improving fat oxidation, suggesting that regular endurance exercise could contribute to the management of body composition and metabolic health. However, no firm conclusion has been reached on the effect of fat mass localization on fat oxidation during endurance exercise. By analyzing the available literature, this review wants to determine the effect of fat mass localization on fat oxidation rate during endurance exercise in women, and to identify future research directions to advance our knowledge on this topic. Despite a relatively limited level of evidence, the analyzed studies indicate that fat oxidation during endurance exercise is higher in women with lower upper-to-lower-body fat mass ratio than in women with higher upper-to-lower-body fat mass ratio. Interestingly, obesity may blunt the specific effect of upper and lower body fat mass distribution on fat oxidation observed in women with normal weight during endurance exercise. Studying and understanding the physiological responses of women to exercise are essential to develop appropriate physical activity strategies and ultimately to improve the prevention and treatment of cardio-metabolic diseases.

Rapid weight loss influences the physical, psychological and biological responses during a simulated competition in national judo athletes.

The effect of rapid energy restriction-induced weight loss on judo-related performance remains unclear, and there is a paucity of information regarding the influence of the fight successions during competition. Thus, the aim of this study was to compare the cumulative effect of judo fights on physical performance, biological and psychological profiles, of national judo competitors with vs without rapid weight loss. After one month of weight maintenance (Baseline), 20 subjects were randomly divided into two groups the week before a simulated competition: (i) a Weight Loss group (WL; weight loss ≥ 3% of body mass); (ii) a Weight Stable group (WS). The simulated competition was composed of five fights (F1 to F5) separated by 30 min rest. Anthropometric assessments were performed at baseline and on the morning of the simulated competition (T0). Psychological, biological and physical assessments (maximal handgrip strength, upper limb anaerobic capacity) were performed at T0 and after each fight. The variation of body mass between baseline and T0 was significantly different between groups (+1.2% vs -3%; p < .01). The dimensions of the Profile of Mood State questionnaire, the rate of perceived exertion, ammonia, urea and free fatty acid concentrations, maximal strength and time sustained at maximal strength showed a significant group x time interaction at F4 and F5. The study shows that cumulative fights lead to uncoupled responses in physical, psychological and biological parameters in judo competitors who underwent or not rapid weight loss. Specific recovery strategies in terms of nutrition and active recovery should be considered.