Physical inactivity remains a pressing global public health concern. Prolonged periods of sedentary behavior have been linked to heightened risks of non-communicable diseases such as cardiovascular diseases and type 2 diabetes, while engaging in any form of physical activity can elicit favorable effects on health. Nevertheless, epidemiological research indicates that people often struggle to meet recommended physical activity guidelines, citing time constraints, lack of exercise equipment, and environmental limitations as common barriers. Exercise snacks represents a time-efficient approach with the potential to improve physical activity levels in sedentary populations, cultivate exercise routines, and enhance the perception of the health benefits associated with physical activity. We review the existing literature on exercise snacks, and examine the effects of exercise snacks on physical function and exercise capacity, while also delving into the potential underlying mechanisms. The objective is to establish a solid theoretical foundation for the application of exercise snacks as a viable strategy for promoting physical activity and enhancing overall health, particularly in vulnerable populations who are unable to exercise routinely.
Background
Postural control deficits and persistent joint stability issues are prevalent in population with anterior cruciate ligament (ACL) injuries or reconstructions. Postural control is typically assessed using the center of pressure (CoP) parameters during the static single-leg stance with a force plate. However, previous studies have reported unclear definitions and descriptions of the CoP parameters, causing inconsistent results of postural control deficits in a specific population.
Objective
To 1) summarize CoP parameters commonly used to evaluate postural control deficits in ACL injured or reconstructed population, and 2) identify the differences in CoP parameters with opened and closed eyes during the single-leg stance between ACL injured or reconstructed and control groups.
Methods
PubMed, Embase, Cochrane Library, CINAHL, Scopus, Web of Science, and SPORTDiscus databases were searched up to July 2023. Data were obtained from the selected articles and underwent quality and risk of bias assessment and meta-analysis using random-effect models. Subgroup analysis within ACL injured or reconstructed group were also performed.
Results
A total of 14 articles were included in the analysis after screening. The injured knee of the ACL injured or reconstructed group differed insignificantly in sway amplitude, sway area, and sway velocity during static single-leg stance under opened and closed eyes when compared with the control group. In the subgroup analysis, we found that there was only significant difference in sway velocity with open eyes (SMD = 0.47, p = 0.001) between ACL reconstructed group and control group.
Conclusion
This study summarized the common CoP parameters used to evaluate postural control in ACL injured or reconstructed population. The results only showed weak difference in sway velocity between ACL reconstructed population and healthy individuals with opened eyes during the static single-leg stance.
Efficient signal transduction that mediates mitochondrial turnover is a strong determinant of metabolic health in skeletal muscle. Of these pathways, our focus was aimed towards the enhancement of antioxidant capacity, mitophagy, and mitochondrial biogenesis. While physical activity is an excellent inducer of mitochondrial turnover, its ability to ubiquitously activate and enhance mitochondrial turnover prevents definitive differentiation of the contribution made by each pathway. Therefore, we employed three agents, Sulforaphane (SFN), Urolithin A (UroA), and ZLN005 (ZLN), which are activators of important biological markers involved in antioxidant signaling, mitophagy, and biogenesis, respectively. We investigated the time-dependent changes in proteins related to each mechanism in C2C12 myotubes. SFN treatment resulted in increased nuclear localization of the transcription factor Nuclear factor (erythroid-derived 2)-like 2 (Nrf-2) after 4 hour (h), with subsequent 2-fold increases in the antioxidant enzymes Nicotinamide Quinone Oxidoreductase 1 (NQO1) and Heme-Oxygenase-1 (HO-1) by 24 h and 48 h. Mitochondrial respiration and ATP production were significantly increased by both 24 h and 48 h. UroA showed a 2-fold increase in AMP-activated Protein Kinase (AMPK) after 4 h, which led to a modest 30% increase in whole cell mitophagy markers p62 and LC3, after 48 h. This was accompanied by a reduction in cellular Reactive Oxygen Species (ROS), detected with the CellROX Green reagent. Mitophagy flux measurements showed mitophagy activation as both LC3-II and p62 flux increased with UroA at 24-h and 48-h time points, respectively. Finally, AMPK activation was observed by 4 h, in addition to a 2-fold increase in Mitochondrial Transcription Factor A (TFAM) promoter activity by 24 h of ZLN treatment following transient transfection of a TFAM promoter-luciferase construct. Mitochondrial respiration and ATP production were enhanced by 24 h. Our results suggest that early time points of treatment increase upstream pathway activity, whereas later time points represent the increased phenotypic expression of related downstream markers. Our findings suggest that the spatiotemporal progression of these mechanisms following drug treatment is another important factor to consider when examining subcellular changes towards mitochondrial turnover in muscle.
Prolonged hyperglycemia conditions are a risk factor for chronic degenerative diseases such as diabetes and obesity. Testosterone is known to cause muscle hypertrophy, reduced fat mass, and increased body strength. The study aimed to verify possible alterations and differences in the influence of testosterone on the physical performance in post-exercise conditions of young and old animals with alloxan-induced hyperglycemia. We randomly assigned 32 young Wistar rats to groups of untreated non-diabetic young, treated non-diabetic young, untreated diabetic young, and treated diabetic young rats, and 32 aged Wistar rats to groups of untreated non-diabetic elderly, treated non-diabetic elderly, untreated diabetic elderly, and treated diabetic elderly rats, with eight animals each group. The treated non-diabetic and treated diabetic groups received injections of 15 mg/kg weight Durateston™. All the trained groups performed aquatic training with an overload of 5% of the body mass. Following the experiment, we anesthetized and euthanized the animals after exercise (exhaustion). Hemoglobin, erythrocytes, and hematocrit values were higher in the treated groups. The treated diabetic elderly group had the highest leukocyte and neutrophil counts compared to the untreated young groups (p < 0.05). As for the lipid profile, untreated rats had the highest values. Glucose concentration was higher at rest and after exercise in the untreated diabetic groups (p < 0.05). Lactate was more elevated in the untreated diabetic groups, and the testosterone-treated groups performed the longest swimming time after the maximal test (p < 0.05). The use of testosterone in conjunction with physical exercise improved physical performance in water, blood glucose, and lipid profiles.
Exercise training in pulmonary arterial hypertension (PAH) has been gaining popularity with guidelines now recommending it as an important adjunct to medical therapy. Despite improvements in function and quality of life, an understanding of metabolic changes and their mechanisms remain unexplored. The objective of this study was therefore to understand the metabolic basis of exercise in a monocrotaline model of PAH. 24 male Wistar rats (age: 8-12 weeks and mean body weight: [262.16 ± 24.49] gms) were assigned to one of the four groups (i.e., Control, PAH, Exercise and PAH + Exercise). The exercise groups participated in treadmill running at 13.3 m/min, five days a week for five weeks. Demographic and clinical characteristics were monitored regularly. Following the intervention, LC-MS based metabolomics were performed on blood samples from all groups at the end of five weeks. Metabolite profiling, peak identification, alignment and isotope annotation were also performed. Statistical inference was carried out using dimensionality reducing techniques and analysis of variance.Partial-least-squares discrimination analysis and variable importance in the projection scores showed that the model was reliable, and not over lifting. The analysis demonstrated significant perturbations to lipid and amino acid metabolism, arginine and homocysteine pathways, sphingolipid (p < 0.05), glycerophospholipid (p < 0.05) and nucleotide metabolism in PAH. Exercise, however, was seen to restore arginine (p < 0.05) and homocysteine(p < 0.000 1) levels which were independent effects, irrespective of PAH.Dysregulated arginine and homocysteine pathways are seen in PAH. Exercise restores these dysregulated pathways and could potentially impact severity and outcome in PAH.
Little is known about differences in physical activity among children from urban and rural areas in low-to middle-income countries and some previous investigations revealed disparities in physical activity levels among children and adolescents residing in urban and rural environments. We aimed to: (i) assess the proportion of preschool-aged children (3.0-4.9 years) meeting the global movement guidelines, (ii) evaluate the feasibility of the methods for the SUNRISE study, (iii) examine gender- and urban-rural differences in health and behavior outcomes. Urban and rural location was based on national classifications. Physical activity (waist-worn ActiGraph); sleep duration, screen time and movement behaviors; Gross and fine motor skills (Lower body strength and mobility, Supine-Timed up and go [S-TUG], One-leg standing balance test, hand grip dynamometer, 9-hole peg-board test); and executive functions (visual-spatial working memory and inhibition) were assessed in 112 preschoolers (n = 50 boys, 33 urban), (n = 62 girls, 41 urban). The results showed that only 18% of children met all movement guidelines, with 53% and 41% meeting the recommendations for sedentary screen time and total physical activity, respectively. A large proportion of children (81%) met the recommended sleep duration of 10-13 hours (h) per day. There is a clear need to promote healthy movement behaviours among preschool-aged children through targeted interventions that address their unique challenges related to gender and urban/rural residence.
Older adults are at an increased risk of developing knee osteoarthritis. High internal knee abduction moment during daily activities may elevate the risk of knee osteoarthritis. Incline walking exercise has been found to decrease knee abduction moment in healthy young adults. However, it is unknown if this occurs in healthy older adults. The purpose of this study was to quantify the internal knee abduction moment at different treadmill grades to determine if incline walking could reduce the knee abduction moment in healthy older adults. Twelve healthy older adult males walked on a treadmill at five incline grades (0%, 5%, 10%, 15%, and 20%) at 1.34 m⋅s-1. The primary outcome variable was the internal knee abduction moment. A one-way repeated measures multivariate analysis of variance was performed to determine differences in the dependent variables among incline gradients. Peak knee abduction moment significantly decreased from level walking at all gradients in 10% increments (0%-10%, p < 0.001; 5%-15%, p < 0.002; and 10%-20%, p = 0.04). A reduction in knee abduction moment during incline walking could result in decreased knee joint loading on the medial knee compartment. For older adults, who are looking to exercise to improve their health, incline walking may be beneficial to promote lower body strength and cardiovascular ability without inflicting further harm to the aging knee joints. However, because the frontal plane knee joint was of primary interest in this study, further research is needed to determine the effects of incline walking on other joints and in other planes of motion.
Increased neck strength has been linked to a potential decrease in traumatic brain injuries (TBI). The purpose was to determine the efficacy of a neck-strengthening protocol using a novel neck-strengthening device to increase isometric neck strength and rate of force development (RFD). Utilizing self-generated centripetal force, participants trained for 14 weeks. A linear mixed model was used to analyze the relationship between post-assessment measurements and pre-assessments measurements, while accounting for repeated measure random effect at the individual level, and a regular random error term. RFD values were 4.344 times higher in the clockwise direction and 5.978 times higher in the counterclockwise direction when comparing pre and post assessment measurements. Isometric neck strength increased significantly (p < 0.05) in the cervical extension (p = 0.010) and left lateral flexion (p = 0.009) directions. The results can be used in strength training and clinical settings to potentially reduce the incidence of TBI.
Little is known about the physiological and psychobiological responses that occur during and after high intensity functional training (HIFT). We compared physiological and psychobiological responses during and after a HIFT session with a high intensity continuous training (HICT) session. Twenty-one trained and healthy men were submitted to 20-min session of HIFT and HICT on separate days. The heart rate, blood lactate concentration [Lac], levels of state anxiety, rates of perceived exertion (RPE) and perceived discomfort (RPE-D), and affective valence were measured. Exercise intensity of the HICT was adjusted to the mean heart rate obtained in the HIFT session. The highest heart rate in the training sessions was significantly higher in HIFT (mean ± standard deviation [SD]: [187 ± 9] bpm) than in HICT (mean ± SD: [178 ± 8] bpm, p < 0.001). The [Lac] was significantly higher immediately after the HIFT (median [interquartile range (IQR)]: 6.8 [4.4] mmol/L) than the HICT (median [IQR]: 3.2 [1.9], p = 0.021) and 10 min after (median [IQR]: HIFT = 6.8 [4.9] mmol/L, HICT = 2.9 [2.4] mmol/L, p = 0.003). The RPE was also significantly higher in the HIFT (median [IQR]: HIFT = 20 [2], HICT = 15 [5], p = 0.009). The physiological and psychobiological responses compared between HIFT and HICT sessions are similar, except for the higher heart rate obtained during the sessions, [Lac] and RPE. Probably, the results found for the higher heart rate obtained during the sessions, [Lac] and RPE may be explained by the higher participation of the anaerobic glycolytic metabolism during the HIFT session.