Background: Overtraining Syndrome (OTS) is a condition resulting from excessive physical activity without adequate recovery, predominantly affecting elite athletes and military personnel. While overreaching can be a temporary state, non-functional overreaching may progress to chronic OTS. This review explores various hypotheses regarding the pathogenesis of OTS, including glycogen depletion, dysregulated cytokine response, oxidative stress, and alterations in the autonomic nervous system function. It also highlights the systemic impact of OTS on multiple organ systems, immune function, and overall health, linking the condition to chronic inflammation and an increased disease susceptibility. Additionally, it addresses the role of the gut microbiome in health modulation through physical activity.
Methods: This narrative review was conducted through a structured search of peer-reviewed journal articles in databases such as PubMed, Web of Science, and Google Scholar, focusing on studies involving human participants and published in English.
Results: OTS has systemic effects on multiple organ systems, immune function, and overall health, leading to chronic inflammation and increased disease susceptibility. Athletes with OTS exhibit higher morbidity rates, influenced by factors such as sleep deprivation and stress. The review also emphasizes the role of the gut microbiome as a significant modulator of health through physical activity.
Conclusion: Balanced training and recovery are crucial for preventing OTS and maintaining optimal health and quality of life in physically active individuals. Understanding the complex pathophysiology of OTS is essential for developing effective prevention and treatment strategies.
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affected health, economies, and lifestyles, but little is known about its impact on children. We aimed to investigate changes in 24-hour (h) movement behaviours of pre-school children before and during COVID-19, and factors that influenced these. Children aged 3-6 years were recruited in Beijing in 2019, and their movement behaviours over 24 h assessed by questionnaire, as part of the International Study of Movement Behaviors in the Early Years (SUNRISE) study. We conducted the survey again during COVID-19, and compared the children’s movement behaviours before and during COVID-19 and associated factors. Overall, 196 parents completed the survey at both time points. The percentage of children meeting movement guidelines decreased during the pandemic (p < 0.01). Total physical activity decreased less among children getting good quality sleep or with more adults in the household (p < 0.01). Children who were not cared for primarily by their mother had a greater decrease in moderate to vigorous intensity physical activity (p = 0.02), but the decrease was smaller among children whose parents used the internet to support their physical activity and/or screen time (p < 0.05). Children who used electronic screen devices in the 2 h before bedtime or whose parents reported body temperature in webchats had a greater increase in sedentary screen time (p < 0.05). Children spending more time outdoors showed a smaller decrease in sleep (p < 0.01). Overall, children’s movement behaviours changed significantly during the pandemic.
Purpose: To examine the link between adherence to 24-h movement guidelines (isolated and combined) and muscular strength, cardiorespiratory fitness, and obesity indicators in Brazilian adolescents.
Methods: Data from 980 adolescents (14-19 years) in Florianópolis, Brazil, were analyzed. The dependent variables were body mass index (BMI), body fat, handgrip strength (HGS), maximal oxygen consumption (V˙O2max). The independent variables were physical activity (PA, IPAQ), screen time (ST), sleep (bedtime, wake-up time). Compliance was calculated for each behavior and combinations. Multiple linear regression models were employed.
Results: Overall compliance: 4.1% (boys), 4.9% (girls). Positive associations were found between PA adherence and HGS/ V˙O2max in both sexes, ST adherence and V˙O2max, and adherence to all three guidelines and V˙O2max. Girls showed positive associations between combined PA + sleep adherence and HGS, ST + sleep and V˙O2max, and negative associations between adherence to two guidelines and BMI. Boys exhibited a negative association between PA and body fat, positive between ST and HGS, and positive/negative between combined PA + ST adherence and HGS/body fat. Moreover, adherence to all three guidelines associated positively with HGS.
Conclusion: Adhering to 24-h movement guidelines, alone or in combination, benefits muscular strength and cardiorespiratory fitness in Brazilian adolescents. However, simultaneous adherence did not correlate with obesity indicators.
Background: The decreasing prevalence of physical activity (PA) among urban children in Sub-Saharan Africa is a growing public health concern. More emphasis should focus on examining the influence of parental PA behaviour on the children’s PA patterns. We explored associations of 24 hour (h) accelerometer-measured movement behaviours of guardian-child pairs in Nairobi City County, Kenya.
Methods: This cross-sectional study assessed 80 pairs consisting of children aged 9-14 years and their guardians in one area of low and one area of middle socioeconomic status (SES) (Embakasi Sub-County and Lang’ata Sub-County), in Nairobi City County, Kenya. The study used waist worn Tri-axial Actigraph (GT3X+ and ActiSleep+) accelerometers to quantify PA and sedentary time (SED). Association between guardians' and children’s PA was examined using linear regression, adjusting for guardians' educational attainment and household wealth.
Results: Of the children, 42 (52.5%) and 76 (96.2%) of the guardians were women. Children in low SES areas spent more time (p < 0.001) in moderate-to-vigorous physical activity compared to children from middle SES area. The guardians in low SES area were younger and spent more time in light PA (p = 0.036) while their counterparts had higher daily SED (p = 0.049). Guardian’s SED associated with higher children’s SED (p = 0.033) even after adjusting for guardians' educational attainment (p = 0.032) and wealth (p = 0.05). There was no association between guardians' and children’s MVPA.
Conclusion: Considered alongside the extant literature, these results suggest that health promotion strategies should aim to reduce parental SED time while also planning to increase children’s PA.
The objective of this design was to conduct an observational study comparing anthropometric characteristics, cognitive functions, as well as gross and fine motor skills. The study included 118 preschool-aged children (47 boys, 71 girls) enrolled in childcare centers. They were categorized into two groups based on their nap habits. The nap group comprised 59 children (23 boys, 36 girls), age (mean ± standard deviation) ([3.96 ± 0.54] years) who took naps after lunch, while the no-nap group included 59 children (24 boys, 35 girls) age (mean ± standard deviation) ([4.18 ± 0.61] years) who remained awake during this period. The results showed that the napping group had significantly higher scores for body mass index (BMI) (p < 0.000 1), height-for-age z score (HAZ) (p = 0.003), and higher BAZ (BMI-for-age z score) scores (p < 0.000 1), compared to the No-nap group. In terms of cognitive function, the study revealed that the napping group had better working memory performance compared to the No-nap group (p = 0.002), but no significant impact on inhibition was observed. The results also showed that taking a nap may improve functional mobility (p = 0.003) and upper body strength (p = 0.026) especially in boys. Future research could investigate the long-term effects of inadequate nap time on children's health and development and also develop and evaluate interventions to improve nap time habits in preschool children.
This study retrospectively evaluated data from an athlete management system on the impact of a 6-week, 12-session risk-reduction athletic development training program on maximal isometric strength in post-rehabilitative and healthy men and women. Maximal isometric quadriceps and hamstrings strength were evaluated bilaterally before and after the training program. Out of 55 athletes that had participated in the program, a total of 37 athletes' (13-28 years old) recorded outcomes were utilized in analyses. Thirty-one athletes had undergone rehabilitation (post-rehabilitative athletes) after orthopedic knee surgeries. Six athletes with no previous surgeries performed (healthy athletes) also completed the 6-week program. Repeated measures analyses of variance (leg × time) assessed changes in quadriceps and hamstrings strength at an alpha of p ≤ 0.05. There was a main effect for time where the post-rehabilitative athletes’ quadriceps and hamstrings strength increased by (mean difference ± standard error) (4.2 ± 0.7) kg (p < 0.01) and (4.5 ± 0.9) kg (p < 0.01) respectively, with legs (operative [OP]) and non-operative [NOP]) combined. With time points combined, the OP limb was weaker than the NOP limb for quadriceps strength by (2.9 ± 0.7) kg (p < 0.01) with no differences in hamstrings strength. For the healthy athletes, there were no changes for quadriceps strength and hamstring strength improved across time by (5.3 ± 1.4) kg (p = 0.01) with legs combined.
In conclusion, there were improvements in post-rehabilitative and healthy athletes’ isometric strength after the training program. However, between-limb strength asymmetries were still apparent in the post-rehabilitation cohort.
China has a high prevalence rate of Metabolic-associated fatty liver disease (MAFLD), and there is currently limited understanding of the levels of exercise self-efficacy (ESE) among individuals with MAFLD. The objective was to explore the potential ESE patterns in older adults with MAFLD. A cross-sectional study was conducted on 800 older adults with fatty liver disease from five communities from April 20, 2023 to August 15, 2023. Latent profile analysis (LPA) and k-means clustering were used to determine the optimal number of ESE groups. Using univariate analysis and multivariate logistic regression to investigate the factors influencing profiles of ESE. A sample of 775 subjects met the diagnostic criteria for MAFLD. LPA yielded three profiles: the low-ESE, mild-ESE, and high-ESE groups, which comprised 25%, 28%, and 47% of the sample, respectively. K-means clustering further supported the categorization of ESE into three distinct classes. The multivariate logistic regression analysis revealed that diabetes, arthritis and/or arthrosis, as well as companionship during PA were significant influencing factors for the different profiles (p < 0.05). Our findings suggest that the ESE of older patients with MAFLD is primarily at a moderate level or above. There was population heterogeneity in ESE among older patients with MAFLD. Diabetes mellitus, arthritis, and/or arthrosis, as well as companionship during PA were significant factors in influencing the likelihood of having high ESE.
Purpose: Lateral ankle sprains (LAS) are associated with corticospinal pathway deficits. Existing evidence is primarily based on cross-sectional investigations and noncausal speculations. This study aims to determine whether maladaptive corticospinal pathway alterations occur pre- and postligament transection in LAS mouse models. Additionally, this study explores whether the alterations are more pronounced in adolescent mice than adults.
Methods: Twenty-four 8-week-old adolescent and twenty-four 24-week-old adult mice were randomly assigned to lateral ankle ligament transection or sham surgery. Diffusion-weighted imaging of the corticospinal pathway was performed presurgery and 8 weeks postsurgery. Fractional anisotropy (FA) values, reflecting fiber integrity within the corticospinal subregions of the medulla, pons, midbrain, and cerebrum, were extracted.
Results: Overall, 41 mice completed repeated image acquisition. Before surgery, no significant group effects on FA within the four corticospinal subregions were detected in either adolescent or adult mice. Two months after surgery, the adolescent cohort displayed a significant reduction in FA in the medulla subregion following ankle ligament transection (β-baseline-adjusted = −0.083, 95% CI, −0.145 to −0.021, p-corrected = 0.048). Conversely, no significant effects of ankle ligament transection on corticospinal FA were observed in the adult cohort.
Conclusion: The maladaptive alterations in the corticospinal tract could be observed in the adolescent LAS mouse model, characterized by reduced fiber integrity in the medulla subregion. While these results are derived from an animal model, they provide a foundation for future investigations into the mechanisms underlying neurological deficits following musculoskeletal injuries.
Proficiency in fundamental movement skills in children is linked to numerous positive physical, behavioral, and cognitive outcomes. The Test of Gross Motor Development is a widely used tool in research to measure this outcome. However, its application faces several limitations and challenges, such as subjectivity in rater judgements, limitation in data precision, and inconsistencies in score aggregations. In this commentary, we discuss these issues and explore how new technology might help address some of the challenges. Nonetheless, a consensus to how scores should be aggregated is still needed, and this could only be achieved through further discussions among researchers in the field.