Volume 2, Issue 4

Introduction Lipid droplets (LDs) are omnipresent intracellular organelles. Their number, size, and composition exhibit considerable heterogeneity within cells. Dysregulated lipid accumulation or depletion is not only a hallmark but also a potential contributor to various human pathologies. This narrative review aims to elucidate the impact of excessive LDs on health in various tissues, summarize the potential mechanisms by which exercise-induced amelioration of related diseases through the regulation of LDs homeostasis, and provide important reference evidence for the prevention and treatment of related diseases. Content This review elucidates the life cycle, tissue specificity and functions of LDs. Furthermore, it examines the regulatory effects of exercise on LDs metabolism, focusing on mechanisms involving inflammatory factors, liposomes, LDs-associated proteins and immune function, glomerular filtration rate, and insulin sensitivity. Additionally, it highlights the activation of key signaling pathways, including IL-15, AMPK and CaMKII, as well as the enhancement of lysosomal activity in diseases characterized by excessive LDs accumulation and aberrant distribution. Summary and outlook LDs are formed in the endoplasmic reticulum and are primarily degraded through lipolysis and lipophagy, exhibiting distinct tissue specificity and multifunctionality. While moderate levels of lipid droplets can protect against lipotoxicity, excessive accumulation may trigger various diseases by promoting inflammation, viral infection, and tumor cell proliferation. Exercise has a significant ameliorative effect on these related diseases. Future research will focus on leveraging lipid droplets and their derivatives as signaling nodes to gain deeper insights into cellular signal transduction and the regulatory role of exercise in these processes.

The ongoing advancement of aerospace technology globally offers technical support for human exploration of outer space. Nevertheless, astronauts encounter microgravity environments during their missions in outer space, which significantly affects the functionality of various physiological systems, including the skeletal, muscular and immune systems. Among them, microgravity-induced bone loss is particularly severe. Bone loss markedly elevates the risk of osteoporosis and fractures, presenting a substantial obstacle to astronauts’ ability to perform tasks in the space environment and maintain their physical health. Consequently, implementing scientifically grounded preventive and therapeutic measures is essential for mitigating microgravity-induced bone loss. Currently, numerous intervention strategies have been demonstrated to effectively address microgravity-induced bone loss, such as pharmacological treatment, nutritional supplementation, and exercise intervention. However, the efficacy of these interventions varies, and some may result in adverse effects. Therefore, this narrative review analyzes and summarizes the effects of various interventions on bone loss caused by microgravity, aiming to provide a scientific theoretical basis for determining the optimal intervention strategy.

Introduction Despite the well-documented benefits of exercise for adolescents’ physical and mental health, exercise remains an underutilized strategy for improving the health of trans adolescents. This is notable because, compared to their cisgender peers, trans adolescents experience greater health challenges and systemic barriers to being physically active. To date, no research has evaluated an evidence-based exercise service within specialist paediatric gender services in Australia. Methods The study is a non-randomised type 2 effectiveness-implementation hybrid trial for adolescents engaged with Child and Adolescent Health Service Gender Diversity Service at Perth Children’s Hospital, Western Australia. The participant group will receive the intervention alongside standard care. The design of the program has incorporated input from the GENder idenTity Longitudinal Experience (GENTLE) Cohort Consumer Advisory group; trans young people, families, and health professionals; guidelines for common medical presentations within paediatric gender services and international physical activity guidelines for adolescents. Program implementation and feasibility (i.e., participant engagement, perceptions and experiences of the intervention), as well as preliminary effectiveness of the targeted exercise program on health outcomes (i.e., quality of life, wellbeing and markers of physical health), will be evaluated as part of a pilot trial. Discussion This project addresses a significant gap in research and healthcare and aims to enhance service delivery by integrating exercise into standard care for specialist paediatric gender services in Australia. Anticipated impacts include shaping current and future practices by defining safe, effective exercise for trans adolescents while laying the groundwork for larger scale implementation and research on long-term health benefits.

Objectives To determine whether providing a choice between high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) within a 4-week diabetes prevention program may lead to greater perceived autonomy support, motivation regulation, free-living physical activity, and cardiorespiratory fitness 6 months post-intervention when compared to imposed exercise. Methods In a preliminary pragmatic randomized trial, 77 individuals at risk of type 2 diabetes ( M age =61.5 (±9.8) years; N females =58) were randomized to one of three exercise conditions: HIIT, MICT, or the choice thereof (CHOICE). Perceived autonomy support was assessed post-intervention. Changes in motivation, physical activity, and cardiorespiratory fitness were assessed 6 months post-intervention. Linear mixed models and Bonferroni-adjusted pairwise comparisons on estimated marginal means were used to derive effect estimates after adjusting for stratified allocation factors. Results Perceived autonomy support was not different among conditions [ F (2, 47)=0.068, p=0.934]. No effects were detected for motivation regulation, physical activity, or cardiorespiratory fitness ( ps >0.05). Participants in the CHOICE condition self-reported significantly more physical activity 6 months post-intervention compared to pre-intervention [ t (31)=2.922, p=0.019]. Improvements in cardiorespiratory fitness were seen in CHOICE [ t (65)=2.509, p=0.044] and MICT [ t (65)=3.492, p=0.003]. Conclusions Providing choice between HIIT and MICT did not significantly affect individuals’ perceived autonomy support or motivation regulation compared to imposed exercise. However, physical activity and cardiorespiratory fitness improved over time for the CHOICE condition. Providing choice between HIIT and MICT may be a feasible exercise strategy among this population.

Objectives This study examined the effects of step-reduction and subsequent step-recovery and exercise rehabilitation on systemic metabolism in older adults. Methods Participants were 66 eligible participants from the ENDURE randomised controlled trial allocated to an intervention group (n=32; 25 % male) or control group (n=34; 21 % male). The intervention group was instructed to limit their daily steps to a maximum of 2000 for two weeks (Period I), followed by a four-week exercise rehabilitation program (Period II) involving twice-weekly sessions of whole-body resistance and bicycle ergometer-based endurance training. Fasting blood samples were collected at baseline, after Period I, and after Period II. Systemic metabolism was assessed using high-throughput proton nuclear magnetic resonance spectroscopy. Data were normalised using Box-Cox transformation and analysed with linear mixed-effects models including random intercepts. Results Period I and Period II had largely opposing effects on systemic metabolism. For instance, compared to the control group, Period one led to increases in VLDL-phospholipids (0.54 SD, P  = 0.005), VLDL-cholesterols (0.41 SD, P  = 0.012) and VLDL-triglycerides (0.79 SD, P  = 0.002), and decreases in HDL-phospholipids (−0.31 SD, P  = 0.037) and HDL-cholesterols (−0.47 SD, P  = 0.011), alongside an increase in HDL-triglycerides (0.64 SD, P  = 0.011). These changes reversed during Period II. Glycoprotein acetylation biomarker GlycA levels were unaffected by either intervention. Conclusions These findings suggest that short-term inactivity does not markedly influence the inflammatory state but adversely affects lipoprotein metabolism and glycolytic pathways; however, these changes are reversible through the resumption of physical activity.

Objectives Valid estimation of energy expenditure remains a challenge, particularly when using ankle- and thigh-worn devices. The Move 4 is a research-grade accelerometer previously tested for predicting metabolic equivalents (METs) when worn at the waist or wrist. This study aimed to calibrate and evaluate regression models to estimate METs from Move 4 data when worn at the ankle and thigh. Methods Participants completed walking and jogging tasks under laboratory conditions while wearing Move 4 sensors and with indirect calorimetry as a reference measure. Models were calibrated using study 1 (n=160) and evaluated in an independent dataset (study 2; n=15). Performance was assessed using mean absolute error (MAE), root mean square error (RMSE), and Bland-Altman analyses. Results The MET models demonstrated strong agreement across both locations and datasets. For the thigh position, the MAE ranged from 0.60 METs (walking) to 1.38 METs (jogging), with RMSE of 0.82 and 1.70 in the evaluation data. Calibration metrics were comparable (jogging: MAE=1.24, RMSE=1.63). The ankle models showed similar accuracy, with MAEs of 0.66 (walking) and 1.39 (jogging), and RMSEs of 0.85 and 1.67, respectively. Systematic bias remained low (mean differences between −0.34 and −0.01 METs). Conclusions This study provides the first calibration and evaluation for estimating METs from ankle- and thigh-worn Move 4 accelerometers. The model indicated accurate, high-resolution MET estimation for walking and jogging. Future work should expand independent performance evaluations, including diverse activities such as static activities, and diverse samples under free-living conditions.

Objectives The effect of attentional focusing on muscular activities and motor skills has been well established. It is known that internal focusing (on body movement or the action itself) results in increased muscular activity. However, external focusing (on apparatus or the effect of action) results in decreased motor responses. In this study, the impact of attentional focusing has been investigated by exploring the three major components of hamstrings: the semitendinosus, the semimembranosus and the biceps femoris via EMG activity on 20 amateur football players during leg curl exercises. Methods To measure muscle activities of the participants, Integrated EMG (IEMG) was calculated on the data’s MVC values. Paired sampled t-tests with Bonferroni correction (α=0.0167) were performed on the average IEMG values to determine if there is a significant difference between participants’ muscles activities under various attentional focus conditions. Results The results showed that the semimembranosus exhibited significantly reduced activity under both external (p=0.0124) and internal focus (p=0.0008), while the semitendinosus displayed a small but non-significant reduction under external focus (p=0.0355 > 0.0167). The biceps femoris showed no significant motor response regarding change between attentional focus instructions. Conclusions This study improves understanding of the mind-muscle connection by showing muscle-specific differences in attentional focus effects, with semimembranosus being most responsive.

With a plethora of anthropometric and body composition measurements, may be challenging for soccer technical staff determining the most suitable protocol for their players. Objectives Therefore, the aim of the study was to analyze the correlations of anthropometric measures and fat percentage obtained by different protocols with the physical performance of male professional soccer players. Additionally, the study aimed to propose cutoff points for anthropometric measures and fat percentage. Methods Fifty-two male soccer players (24.60 ± 4.98 years) from a state championship’s second division participated. The sum of skinfolds and fat percentage were obtained using four reference protocols (Pollock seven-skinfolds, Jackson and Pollock three-skinfolds, Jackson and Pollock three-skinfolds of the upper limbs, and Faulkner four-skinfolds). Physical performance was assessed by squat jump, counter movement jump, 30 cm drop jump, 20 m sprint, and YoYo intermittent recovery level 1 (YoYoIRL1) tests. Pearson, Spearman, and ROC curve analysis were used considering α <0.05 as significance level. Results Significant correlations occurred between the abdominal skinfold (r=−0.579), chest, abdominal, and front thigh skinfolds sum (rho=−0.518), and the Jackson and Pollock fat percentage protocol using these skinfolds (r=−0.534) with the YoYoIRL1 (all p<0.001). Cutoff points for these measurements were determined to be 20 mm (area under the curve (AUC)=0.800, sensitivity=92.7 %, specificity=63.6 %), 33 mm (AUC=0.783, sensitivity=68.3 %, specificity=81.8 %), and 13 % (AUC=0.787, sensitivity=95.1 %, specificity=54.5 %), respectively. Conclusions Therefore, the soccer technical staff can implement these measures, largely associated with physical performance, in players with characteristics similar to the evaluated group. The proposed cut-off points provide a practical alternative for integration into other monitoring strategies.