Total Energy Expenditure Research Articles

Validity of predictive equations for total energy expenditure against doubly labeled water

Variations in physical activity energy expenditure can make accurate prediction of total energy expenditure (TEE) challenging. The purpose of the present study was to determine the accuracy of available equations to predict TEE in individuals varying in physical activity (PA) levels. TEE was measured by DLW in 56 adults varying in PA levels which were monitored by accelerometry. Ten different models were used to predict TEE and their accuracy and precision were evaluated, considering the effect of sex and PA. The models generally underestimated the TEE in this population. An equation published by Plucker was the most accurate in predicting the TEE in our entire sample. The Pontzer and Vinken models were the most accurate for those with lower PA levels. Despite the levels of accuracy of some equations, there were sizable errors (low precision) at an individual level. Future studies are needed to develop and validate these equations.

Preliminary field validity of ActiGraph-based energy expenditure estimation in wheelchair users with spinal cord injury.

Cross-sectional validation study. To develop a raw acceleration signal-based random forest (RF) model for predicting total energy expenditure (TEE) in manual wheelchair users (MWUs) and evaluate the preliminary field validity of this new model, along with four existing models published in prior literature, using the Doubly Labeled Water (DLW) method. General community and research institution in Pittsburgh, USA. A total of 78 participants' data from two previous studies were used to develop the new RF model. A seven-day cross-sectional study was conducted to collect participants' free-living physical activity and TEE data, resting metabolic rate, demographics, and anthropometrics. Ten MWUs with spinal cord injury (SCI) completed the study, with seven participants having valid data for evaluating the preliminary field validity of the five models. The RF model achieved a mean absolute error (MAE) of 0.59 ± 0.60 kcal/min and a mean absolute percentage error (MAPE) of 23.6% ± 24.3% on the validation set. For preliminary field validation, the five assessed models yielded MAE from 136 kcal/day to 1141 kcal/day and MAPE from 6.1% to 50.2%. The model developed by Nightingale et al. in 2015 achieved the best performance (MAE: 136 ± 96 kcal/day, MAPE: 6.1% ± 4.7%), while the RF model achieved comparable performance (MAE: 167 ± 99 kcal/day, MAPE: 7.4% ± 5.1%). Two existing models and our newly developed RF model showed good preliminary field validity for assessing TEE in MWUs with SCI and the potential to detect lifestyle change in this population. Future large-scale field validation studies and model iteration are recommended.

O-287 Body composition analysis and metabolic monitoring before fertility treatment: hype or hope?

Abstract The effect of body mass index on both spontaneous and assisted fertility is well known: both lower and high indexes are correlated with negative outcome including live birth rate. Asides the dysmetabolic infertility that can develop by inflammation, insulin resistance and hyperandrogenemia, psychological and social factors deserve attention: a sexual self-image dysfunction is present in up to 20% of obese people with lower sexual desire and arousal. A positive note is that ART patients want to know about the impact of diet on fertility and ART success, asides the safety of the treatment and coping strategies, when asked about research priorities. Nevertheless, research in the field of preconception weight loss in the case of obesity in non-conclusive. The difference may lay in the strategy followed: lifestyle interventions may differ in approach, new weight-losing drugs might be involved or avoided, and targets and endpoints differ between studies. A first statement is to be made: body weight is a parameter of the past. In the world of nutrition, BMI is used to describe populations but fails to give accurate information about a single person. Body composition is more refined and can be used in follow-up. Asides dual energy X-ray absorptiometry (DXA), Bio Electrical Impedance Vector Analysis (BIVA) is used to endotype patients. Magnetic Resonance Imaging can, in a whole-body approach, provides very detailed information. In general, fat mass, fat free mass, phase angle (quantitative information) and fat infiltration of muscle (qualitative aspect) are considered ‘the kg of the future’. Associations between higher amounts of fat and poorer ART outcomes are published. As body composition is the result of food intake balanced to total energy expenditure (composed from basal energy expenditure, diet induced thermogenesis and physical activity level), the knowledge of these aspects can form a basis for a personalized approach. Techniques used in clinical practice relevant to this topic are food diary analysis by specialized dietitians (quantitative and qualitative analysis of food intake) and indirect calorimetry. This device will measure oxygen consumption and carbon dioxide production and calculate the basal metabolic rate in kcal/day. The concept of nutrition intake balanced to energy expenditure is validated in critically ill patients where it reduces mortality. It also showed benefit in a cancer population during active treatment. In a tertiary, university hospital in Brussels, Belgium, the forces of the fertility clinic and the nutrition department were combined: FerMet (Fertility-Metabolism). Patients seeking ART with a BMI <18;5 or higher than 30 are directed. Biophysical endotyping is performed by both metabolic screening, food intake analysis and baseline testing: body composition by BIVA and metabolic measurement by indirect calorimetry. A personalized intervention plan is developed in co-operation with the patient(s) by the dietitian and the supervising MD. Psychological reference or physical activity coaching is initiated if needed. Interim results: a total of 3793 men and woman in 3,5 years. In the population with a BMI below 20, which is only 6.4% of the entire group, body composition analysis reveals: only 9% are confirmed with alarmingly low body fat mass, such as seen in eating disorders. 23% has a fat mass percentage comparable to the general population and 66% represents what is known as ‘constitutional lean’. This might open opportunities to refine criteria to withhold ART based on body weight. In the overweight population, interventions can be tailored on individual metabolic rates and eating patterns, which is unique in the setting of ART. Whole Body MRi can be used in research settings. Benefits of this Biophysical Endotype based interventions to increase fertility outcomes need to be proven by further research.

Validity of 24-Hour Physical Activity Recall To Estimate Total Daily Energy Expenditure in an Urban, Relatively Active Brazilian Adult Sample

Validity of 24-Hour Physical Activity Recall To Estimate Total Daily Energy Expenditure in an Urban, Relatively Active Brazilian Adult Sample

Changes in energy expenditure and physical activity over 15 years of environmental changes: The Maycoba project.

This work aimed to parse out the role of changing environments on body composition, total energy expenditure, and physical activity in the Mexican Pima, a population experiencing rapid industrialization. Using doubly labeled water, we compared energy expenditure and physical activity in a longitudinal cohort of Mexican Pima (n = 26; female: 12) in 1995 and 2010. Body mass and composition were assessed by bioimpedance analysis. To determine the effects of environmental factors on body weight independent of age, we compared the 1995 longitudinal cohort with an age- and sex-matched cross-sectional cohort (n = 26) in 2010. Body mass, fat mass, and fat-free mass all significantly increased between 1995 and 2010. Despite a 13% average increase in body weight, weight-adjusted total daily energy expenditure decreased significantly. Measured physical activity levels also decreased between 1995 and 2010, after we adjusted for weight. Our results suggest that the recent industrialization of the Maycoba region in Sonora, Mexico,has contributed to a decrease in physical activity, in turn contributing to weight gain and metabolic disease among the Mexican Pima.

Determining the Effects of a 12-Week Moderate Intensity Circuit Exercise Program on Body Composition and Physical Fitness among Overweight Women of Working Age

Objectives. The study aimed to examine the effects of a 12-week moderate-intensity circuit exercise program on body composition and physical fitness among overweight women of working age. Materials and methods. Twenty-nine overweight women of working age were divided into two groups: the control group (CG, n = 14) had a normal daily life, and the moderate intensity circuit exercise group (MICE, n = 15) underwent training that included 3 sessions of MICE (40–50 seconds followed by 60 seconds of rest for each exercise and 90 seconds of recovery between sessions at 64–76% of maximum heart rate). The training was conducted for 60 minutes per day, three days per week. Body composition and physical fitness were measured before (2 days prior) and after (2 days post) a 12-week training period. Results. After the 12-week training, the MICE showed a considerable improvement in a number of key health indicators, including body weight, BMI, fat mass, skeletal muscle mass, visceral adipose tissue, total energy expenditure, resting energy expenditure, waist circumference, and waist-to-hip ratio (-0.65%, -0.73%, -2.16%, 2.53%, -7.12%, 10.85%, 0.71%, -3.13%, and -2.67%, respectively, p < 0.05) when compared to the CG. Similarly, the MICE demonstrated a significantly larger improvement in the sit and reach test, the back extension test, the hand grip strength of the right hand, hand grip strength of the left hand, leg strength, the 60-second chair stand test (also known as sit-to-stand test), and the maximum oxygen consumption (18.98%, 16.53%, 10.69%, 7.68%, 9.97%, 26.25%, and 8.87%) compared to the CG (-4.10%, -1.19%, -0.26%, -1.53%, -1.44%, 0.24%, and -0.70%), respectively. Conclusions. Moderate-intensity circuit exercise has been found to have positive effects on improving body composition and physical fitness in overweight working women. Thus, the implementation of MICE with appropriate sessions, resting, duration, and training periods can achieve maximum benefit.

Determining the Effects of a 12-Week Moderate Intensity Circuit Exercise Program on Body Composition and Physical Fitness among Overweight Women of Working Age

Objectives. The study aimed to examine the effects of a 12-week moderate-intensity circuit exercise program on body composition and physical fitness among overweight women of working age. Materials and methods. Twenty-nine overweight women of working age were divided into two groups: the control group (CG, n = 14) had a normal daily life, and the moderate intensity circuit exercise group (MICE, n = 15) underwent training that included 3 sessions of MICE (40–50 seconds followed by 60 seconds of rest for each exercise and 90 seconds of recovery between sessions at 64–76% of maximum heart rate). The training was conducted for 60 minutes per day, three days per week. Body composition and physical fitness were measured before (2 days prior) and after (2 days post) a 12-week training period. Results. After the 12-week training, the MICE showed a considerable improvement in a number of key health indicators, including body weight, BMI, fat mass, skeletal muscle mass, visceral adipose tissue, total energy expenditure, resting energy expenditure, waist circumference, and waist-to-hip ratio (-0.65%, -0.73%, -2.16%, 2.53%, -7.12%, 10.85%, 0.71%, -3.13%, and -2.67%, respectively, p < 0.05) when compared to the CG. Similarly, the MICE demonstrated a significantly larger improvement in the sit and reach test, the back extension test, the hand grip strength of the right hand, hand grip strength of the left hand, leg strength, the 60-second chair stand test (also known as sit-to-stand test), and the maximum oxygen consumption (18.98%, 16.53%, 10.69%, 7.68%, 9.97%, 26.25%, and 8.87%) compared to the CG (-4.10%, -1.19%, -0.26%, -1.53%, -1.44%, 0.24%, and -0.70%), respectively. Conclusions. Moderate-intensity circuit exercise has been found to have positive effects on improving body composition and physical fitness in overweight working women. Thus, the implementation of MICE with appropriate sessions, resting, duration, and training periods can achieve maximum benefit.

Energy supply during nocturnal endurance flight of migrant birds: effect of energy stores and flight behaviour

BackgroundMigrating birds fly non-stop for hours or even for days. They rely mainly on fat as fuel complemented by a certain amount of protein. Studies on homing pigeons and birds flying in a wind-tunnel suggest that the shares of fat and protein on total energy expenditure vary with flight duration and body fat stores. Also, flight behaviour, such as descending flight, is expected to affect metabolism. However, studies on free flying migrant birds under natural conditions are lacking.MethodsOn a Swiss Alpine pass, we caught three species of nocturnal migrant passerines out of their natural migratory flight. Since most night migrants start soon after dusk, we used time since dusk as a measure of flight duration. We used plasma concentrations of metabolites of the fat, protein, and carbohydrate metabolism as indicators of relative fuel use. We used flight altitudes of birds tracked with radar and with atmospheric pressure loggers to characterize flight behaviour.ResultsThe indicators of fat catabolism (triglycerides, very low-density lipoproteins, glycerol) were positively correlated with body energy stores, supporting earlier findings that birds with high fat stores have a higher fat catabolism. As expected, plasma levels of triglycerides, very low-density lipoproteins, glycerol and ß-hydroxy-butyrate increased at the beginning of the night, indicating that nocturnal migrants increased their fat metabolism directly after take-off. Surprisingly, fat catabolism as well as glucose levels decreased in the second half of the night. Data from radar observations showed that the number of birds aloft, their mean height above ground and vertical flight speed decreased after midnight. Together with the findings from atmospheric pressure-loggers put on three species, this shows that nocturnal migrants migrating over continental Europe descend slowly during about 1.5 h before final landfall at night, which results in 11–30% energy savings according to current flight models.ConclusionsWe suggest that this slow descent reduces energy demands to an extent which is noticeable in the plasma concentration of lipid, protein, and carbohydrate metabolites. The slow descent may facilitate the search for a suitable resting habitat and serve to refill glycogen stores needed for foraging and predator escape when landed.

The contribution of energy systems during 30-second lower body Wingate anaerobic test in combat sports athletes: Intermittent versus single forms and gender comparison.

Combat sports, encompassing a range of activities from striking and grappling to mixed and weapon-based disciplines, have witnessed a surge in popularity worldwide. These sports are demanding, requiring athletes to harness energy from different metabolic pathways to perform short, high-intensity activities interspersed with periods of lower intensity. While it is established that the anaerobic alactic (ATP-PC) and anaerobic lactic systems are pivotal for high-intensity training sessions typical in combat sports, the precise contribution of these systems, particularly in varied training modalities such as single (SMT) and intermittent (IST) forms of the 30-second Wingate test, remains inadequately explored. This study aims at comparing performance outputs, physiological responses and gender differences during the SMT and IST forms of the 30-second Wingate test. Thirty-three highly trained combat sports athletes (17 women, 16 men; 10 boxing, 8 wrestling, 8 taekwondo and 7 karate) randomly performed SMT and IST. The IST consisted of three 10-second all-out attempts separated by 30 seconds of passive recovery, whereas the SMT was a single 30-second maximal effort. Resting, exercise and post-exercise oxygen uptake and peak blood lactate value were used to determine the metabolic energy demands via the PCr-LA-O2 method. The findings showed that total metabolic energy expenditure (TEE), ATP-PCr system contribution and the output of mechanical variables were higher in the IST than in the SMT form (all p<0.001). In contrast, the contribution of glycolytic and oxidative systems was higher in the SMT form (all p<0.001). However, exercise form and gender interaction were not significant (p>0.05). In combat sports, performance is not only determined by physiological and technical skills but also by metabolic energy input and efficiency. Therefore, our results can provide a comparison regarding the effects of exercise type and gender on metabolic energy metabolism to design the training of combat sports athletes.

Nutritional Issues in Children with Dysphagia.

(1) Background: Pediatric dysphagia presents significant nutritional challenges, often impacting growth and development due to reduced oral intake, increased nutritional needs, and gastrointestinal complications; (2) Methods: This prospective quasi-experimental study assessed 117 children under 14 years old (20 patients were under 1 year old, 80 were aged 1-7 years, and 17 were older than 7 years), diagnosed with swallowing disorders, to analyze their caloric, macro-, and micronutrient intake and identify potential deficiencies. The severity of dysphagia was established using functional oral intake scales, and dietary records were reviewed over a 3-day period; (3) Results: The study revealed that 39.8% of participants did not meet their total energy expenditure (TEE), highlighting a high prevalence of malnutrition among these children. Furthermore, patients using feeding devices exhibited a significantly lower caloric intake, and over half required significantly modified food textures. After individualized speech therapy and nutritional rehabilitation, participants showed significant improvements in caloric intake, with their energy coverage increasing from 958% to 1198% of the daily requirement. Rehabilitation also improved tolerance to a broader range of food textures; (4) Conclusions: This research underscores the importance of multidisciplinary, individualized nutritional strategies to address the specific challenges of pediatric dysphagia, emphasizing the role of enteral nutrition and therapeutic interventions in improving the quality of life and nutritional outcomes of these children. Further studies are recommended to assess the long-term impact of such strategies.

Realistic 3D human saccades generated by a 6-DOF biomimetic robotic eye under optimal control.

We recently developed a biomimetic robotic eye with six independent tendons, each controlled by their own rotatory motor, and with insertions on the eye ball that faithfully mimic the biomechanics of the human eye. We constructed an accurate physical computational model of this system, and learned to control its nonlinear dynamics by optimising a cost that penalised saccade inaccuracy, movement duration, and total energy expenditure of the motors. To speed up the calculations, the physical simulator was approximated by a recurrent neural network (NARX). We showed that the system can produce realistic eye movements that closely resemble human saccades in all directions: their nonlinear main-sequence dynamics (amplitude-peak eye velocity and duration relationships), cross-coupling of the horizontal and vertical movement components leading to approximately straight saccade trajectories, and the 3D kinematics that restrict 3D eye orientations to a plane (Listing's law). Interestingly, the control algorithm had organised the motors into appropriate agonist-antagonist muscle pairs, and the motor signals for the eye resembled the well-known pulse-step characteristics that have been reported for monkey motoneuronal activity. We here fully analyse the eye-movement properties produced by the computational model across the entire oculomotor range and the underlying control signals. We argue that our system may shed new light on the neural control signals and their couplings within the final neural pathways of the primate oculomotor system, and that an optimal control principle may account for a wide variety of oculomotor behaviours. The generated data are publicly available at https://data.ru.nl/collections/di/dcn/DSC_626870_0003_600.

Impact of MCT Oil and Caffeine on Substrate Metabolism during Submaximal Exercise

Introduction: Recent research has suggested that medium-chain triglyceride (MCT) supplementation may increase fat oxidation (FatOx) during aerobic exercise, sparing muscle glycogen and, perhaps, enhancing performance. As both MCT and caffeine (CAF) are theorized to elicit these effects, this pilot study’s purpose was to compare the physiological responses of their combined supplementation during submaximal cycling exercise. Methods: Eight aerobically trained males (mean±SD; age 23.6±4.4 years; body mass 82.3±15.8 kg; height 180.9±8.7 cm) completed one aerobic capacity (VO2peak) test and three 45-min exercise trials at 60% VO2peak. Blinded and counterbalanced, one-hour prior to each trial, participants consumed: MCT+CAF (20 mL + 100 mg), long-chain triglycerides (LCT)+CAF (40 mL + 100 mg), or CAF (100 mg). Oxygen consumption (VO2), carbon dioxide output (VCO2), and minute ventilation (VE) were measured, subsequently calculating respiratory exchange ratio (RER), energy expenditure (EE), carbohydrate oxidation (CarbOx), and FatOx. Results: No significant differences between conditions were observed for average VO2 (p=0.474; η2=0.101), VE (p=0.323; η2=0.149), (RER (p=0.323; η2=0.149), EE (p=0.474; η2=0.101), CarbOx (p=0.274; η2=0.169), or FatOx (p=0.478; η2=0.100) or for total EE (p=0.474; η2=0.101), CarbOx (p=0.274; η2=0.169), or FatOx (p=0.478; η2=0.100). Conclusions: Co-ingestion of MCT+CAF didn’t produce any significantly different physiological responses compared to co-ingestion of LCT+CAF or the CAF control.

Physical Activity, Anxiety, Depression, and Body Image in Trans Individuals: An Exploratory Study.

In a cross-sectional study, 75 Portuguese transgender individuals (M = 23.68; SD ± 6.59) were recruited to participate in this study. The participants completed three questionnaires related to the assessment of physical activity (IPAQ), depressive and anxious symptomatology (HADS), and satisfaction with body image (BISQp). Trans individuals showed a total energy expenditure of 3316.40 metabolic equivalent tasks (METS), had a moderate level of anxiety symptomatology, and low levels of satisfaction with body image. Satisfaction with body image was negatively associated with anxiety (r = -0.441, p < 0.01) and depression symptomatology (r = -0.600, p < 0.01). The implementation of inclusive programs that promote body acceptance and coping strategies, particularly within the context of physical exercise, may help alleviate distress related to body image dissatisfaction while also addressing underlying anxiety and depression symptoms.

Do Iranian Female Dancers Face a Risk of Chronic Negative Energy Balance? A Study on Energy Intake and Expenditure Among Non-professional Female Dancers

Background: Female dancers are at risk of negative energy balance and its adverse effects. However, there is no evidence regarding the energy balance of Iranian female dancers in the literature. Methods: In a cross-sectional study of 25 female nonprofessional dancers, dietary intake was assessed using self-reported food diaries and recall interviews on three different days: One dance day, one workday without dance, and one weekend day without dance. Nutrient intake was analyzed and converted into protein, carbohydrate, and fat components, and subsequently into energy equivalents. Total energy expenditure was calculated based on physical activity measurements taken on dance, work, and rest days. The average daily energy intake and expenditure over a 7-day period were then compared. Results: Significant daily energy deficiency was observed based on the average over 7 days (- 772.7 kcal +/- 450 kcal, P-value &lt; 0.05). Dancers consumed less protein and carbohydrates and more fat than the recommended daily values (P-value &lt; 0.05). Conclusions: It appears that Iranian female dancers suffer from negative energy balance and nutritional malpractice. This may be related to underlying eating disorders or perceptions of body image, as well as inadequate nutritional knowledge. Consulting experienced sports nutritionists and other necessary specialists is recommended.

The use of accelerometers to improve estimation of the thermic effect of food in whole room calorimetry studies.

We tested whether spontaneous physical activity (SPA) from accelerometers could be used in a whole room calorimeter to estimate thermic effect of food (TEF). Eleven healthy participants (n = 7 females; age: 27 ± 4 yr; body mass index: 22.8 ± 2.6 kg/m2) completed two 23-h visits in randomized order: one "fed" with meals provided and one "fasted" with no food. SPA was measured by ActivPAL and Actigraph accelerometers. Criterion TEF was calculated as the difference in total daily energy expenditure (TDEE) between fed and fasted visits and compared with three methods of estimating TEF: 1) SPA-adjusted TEF (adjTEF)-difference in TDEE without SPA between visits, 2) Wakeful TEF-difference in energy expenditure obtained from linear regression and basal metabolic rate during waking hours, 3) 24-h TEF-increase in TDEE above SPA and sleeping metabolic rate. Criterion TEF was 9.4 ± 4.5% of TDEE. AdjTEF (difference in estimated vs. criterion TEF: activPAL: -0.3 ± 3.3%; Actigraph: -1.8 ± 8.0%) and wakeful TEF (activPAL: -0.9 ± 6.1%; Actigraph: -2.8 ± 7.6%) derived from both accelerometers did not differ from criterion TEF (all P > 0.05). ActivPAL-derived 24-h TEF overestimated TEF (6.8 ± 5.4%, P = 0.002), whereas Actigraph-derived 24-h TEF was not significantly different (4.3 ± 9.4%, P = 0.156). TEF estimations using activPAL tended to show better individual-level agreement (i.e., smaller coefficients of variation). Both accelerometers can be used to estimate TEF in a whole room calorimeter; wakeful TEF using activPAL is the most viable option given strong group-level accuracy and reasonable individual agreement.NEW & NOTEWORTHY Two research-grade accelerometers can effectively estimate spontaneous physical activity and improve the estimation of thermic effect of food (TEF) in whole room calorimeters. The activPAL demonstrates strong group-level accuracy and reasonable individual-level agreement in estimating wakeful TEF, whereas a hip-worn Actigraph is an acceptable approach for estimating 24-h TEF. These results highlight the promising potential of accelerometers in advancing energy balance research by improving the assessment of TEF within whole room calorimeters.

Evaluation of Energy Balance Estimated From Total Energy Expenditure and Body Composition Changes in Junior Sumo Wrestlers: An Observational Study Over Six Months.

Background Sumo is a sport that requires wrestlers to develop their physique from childhood for athletic advantage. However, the energy expenditure and energy balance required for the growth of junior Sumo wrestlers remain unclear. This study aimed to determine the energy balance of junior Sumo wrestlers over six months usingdoubly labeled water (DLW) and bioelectrical impedance analysis (BIA). Methodology A total of 12 male Sumo wrestlers were affiliated with a local Sumo club (average age = 15 ± 1 years). The total energy expenditure (TEE) was measured using DLW, whereas body composition was evaluated using BIA. Daily physical activity was quantified using a tri-accelerometer (Active style Pro HJA-750C). Results The TEE was 4,194 ± 734 kcal/day, while daily physical activity without training was 786 ± 50 minutes. Within six months, the body weight increased by 2.0 ± 3.2 kg, fat-free mass (FFM) was augmented by 2.1 kg, while fat mass did not change significantly. The surplus energy accumulated was 5.6 ± 213 kcal/day. Conclusions The excess energy of junior Sumo wrestlers predominantly increases their FFM. To increase their physical prowess, wrestlers adhere to a lifestyle characterized by high-intensity training and attenuated daily physical activity.

ANTHROPOMETRIC AND PHYSICAL QUALITIES OF SEMI-PROFESSIONAL RUGBY LEAGUE PLAYERS

AIM The aim of the current study was to investigate the physiological and anthropometric characteristics of semi-professional rugby league players across a typical season, including pre- and post-season data. METHODS Thirty-five semi-professional rugby league players, mean age 25.38 ± 2.35 years were measured for height, body mass, sum of skinfolds, and speed (20m sprint). Global positioning system (GPS) data, sampling at 10 Hz, were collected, two pre-season and eighteen Queensland Cup rugby league matches in the 2023 season for 10 players (backs and forwards). Data was categorized into total distance (km), sprint distance (m), power plays, energy expenditure (kcal), player load, and top speed (m/s). RESULTS Compared with forwards the backs had significantly lower body mass (99.4kg vs 90.8kg), and significantly greater speed during 20m sprint (3.00 vs 3.1sec). Sum of skinfolds, no differences between backs and forwards across the three time points, 104.2 vs 106.2mm, 103.9 vs 110.9mm and 93.8 vs 108.1mm. Reviewing the GPS data across the trial and cup games revealed a number of significant differences between backs and forwards, backs greater overall distance (6.63km vs 5.26km), sprint distance (467.53 vs 264.63m), power plays (37 vs 25), energy expenditure (1002.42 vs 778.90 kcal), player load (311.50 vs 275.16), top speed (8.02 vs 7.02m/s). CONCLUSION Retrospective analysis of our data has allowed us to understand the activity demands between match types and differences in activity demands between seasonal phases of training in semi-professional male rugby league players and will permit further specificity of training and improve performance. Determining the fitness and physiological profiles and how they relate to training and match demands will allow the coaching staff to develop more targeted training strategies in order to optimally develop the fitness characteristics that predominantly underpin match demands.

Restricting lumbar spine flexion redistributes and changes total mechanical energy expenditure during lifting

Minimizing lumbar spine flexion during lifting requires greater lower extremity joint motion. However, the effects of these kinematic changes on lumbar and lower extremity joint kinetics are unknown. Further, it is unclear whether the distribution of biomechanical demands throughout the lumbar spine and lower extremity during lumbar spine flexion restricted lifting are modulated by task factors like lift origin height and object mass. This study examined the influence of restricting lumbar spine flexion during lifting on the distribution of biomechanical demands, operationalized as mechanical energy expenditure (MEE), across the lumbar spine and lower extremity joints during lifting tasks. Twenty participants performed a series of lifting tasks that varied by lift origin height, object mass and presence or absence of lumbar spine motion restricting harness. MEE was quantified for the lumbar spine and lower extremity joints and summed across all joints to represent the total MEE. Distributions of MEE were compared across combinations of the three task factors. Total MEE was greater when lifting with restricted spine motion (p < 0.001). MEE was redistributed away from the lumbar spine and predominantly to the hips in the spine restricted conditions (p < 0.001). The nature and magnitude of this effect was modulated by lift origin height for the lumbar spine (p < 0.001) and hips (p < 0.001). Findings demonstrated that biomechanical demands can be shifted from the lumbar spine to the lower extremity when lifting with restricted spine flexion, which might help mitigate overuse injuries through coordinative variability.

The metabolic effects of habitual leg shaking: A randomized crossover trial.

The adverse effects of sedentary behavior on obesity and chronic diseases are well established. However, the prevalence of sedentary behavior has increased, with only a minority of individuals meeting the recommended physical activity guidelines. This study aimed to investigate whether habitual leg shaking, a behavior traditionally considered unfavorable, could serve as an effective strategy to improve energy metabolism. A randomized crossover study was conducted, involving 15 participants (mean [SD] age, 25.4 [3.6]; mean [SD] body mass index, 22 [3]; 7 women [46.7%]). The study design involved a randomized sequence of sitting and leg shaking conditions, with each condition lasting for 20 min. Energy expenditure, respiratory rate, oxygen saturation, and other relevant variables were measured during each condition. Compared to sitting, leg shaking significantly increased total energy expenditure [1.088 kj/min, 95% confidence interval, 0.69-1.487 kj/min], primarily through elevated carbohydrate oxidation. The average metabolic equivalent during leg shaking exhibited a significant increase from 1.5 to 1.8. Leg shaking also raised respiratory rate, minute ventilation, and blood oxygen saturation levels, while having no obvious impact on heart rate or blood pressure. Electromyography data confirmed predominant activation of lower leg muscles and without increased muscle fatigue. Intriguingly, a significant correlation was observed between the increased energy expenditure and both the frequency of leg shaking and the muscle mass of the legs. Our study provides evidence that habitual leg shaking can boost overall energy expenditure by approximately 16.3%. This simple and feasible approach offers a convenient way to enhance physical activity levels.

Acute interval running induces greater excess post-exercise oxygen consumption and lipid oxidation than isocaloric continuous running in men with obesity

Studies seem to show that high-intensity interval training (HIIT) is a more time-efficient protocol for weight loss, compared with moderate-intensity continuous training (MICT). Our aim was to compare the acute effects of energy expenditure (EE) matched HIIT vs. MICT on excess post-exercise oxygen consumption (EPOC) and substrate metabolism in male college students with obesity. Twenty-one untrained male college students (age, 22 ± 3 years; body fat, 28.4 ± 4.5%) completed two acute interventions (~ 300 kcal) on a treadmill in a randomized order: (1) HIIT: 3 min bouts at 90% of maximal oxygen uptake (VO2max) with 2 min of recovery at 25% of VO2max; (2) MICT: 60% of VO2max continuous training. EPOC and substrate metabolism were measured by indirect calorimetry during and 30 min after exercise. Results showed that EPOC was higher after HIIT (66.20 ± 14.36 kcal) compared to MICT (53.91 ± 12.63 kcal, p = 0.045), especially in the first 10 min after exercise (HIIT: 45.91 ± 9.64 kcal and MICT: 34.39 ± 7.22 kcal, p = 0.041). Lipid oxidation rate was higher after HIIT (1.01 ± 0.43 mg/kg/min) compared to MICT (0.76 ± 0.46 mg/kg/min, p = 0.003). Moreover, the percentage of energy from lipid was higher after HIIT (37.94 ± 14.21%) compared to MICT (30.09 ± 13.54%, p = 0.020). We conclude that HIIT results in greater total EE and EPOC, as well as higher percentage of energy from lipid during EPOC than EE matched MICT in male college students with obesity.