Introduction: The effect of mechanoreflex on central blood pressure (BP) is unclear, although the influence of metaboreflex has been investigated. A relatively small contribution of the mechanoreflex to the pressor response to exercise has been considered in humans because many studies have failed to isolate the mechanoreflex-mediated pressor response. In a recent study, we successfully isolated a mechanoreflex-mediated pressor response using static passive stretching (SPS) in the forearm. Thus, it is possible to isolate the effect of the mechanoreflex on the central BP using this recently developed method. We investigated the effect of muscle mechanoreflex on central BP and compared the changes in the shape of the central BP waveform during mechanoreflex and metaboreflex.
Methods: We measured 12 healthy males (age, 26 ± 2 years; height, 171.1 ± 5.2 cm; body mass, 63.3 ± 10.3 kg; body fat, 16.7% ± 3.9%; means ± standard deviation [SD]) in this study. All participants performed static passive stretching (SPS) of the forearm for 60 s to isolate the muscle mechanoreflex. They also performed 120 s of isometric handgrip (IHG) at 30% maximal voluntary contraction and underwent 180 s of post-exercise ischemia (PEI) to isolate the muscle metaboreflex. The carotid BP (cBP) waveform was obtained from the right common carotid artery as the central BP waveform. We evaluated the first systolic peak (P1) and second systolic peak (P2) from the cBP waveform.
Results: SPS increased cBP with an increase in P1 (p < 0.05), whereas PEI increased cBP with an increase in P2 (p < 0.05). SPS did not alter augmentation pressure (AP) (p > 0.05), whereas PEI increased it (p < 0.05). The relative change from rest (Δ) in P1 during SPS was positively correlated with that in stroke volume (r = 0.68; p < 0.05), and the ΔAP during PEI was positively correlated with that in total peripheral resistance TPR (r = 0.61; p < 0.05).
Conclusion: These results suggest different effects of mechano- and metaboreflex on the change in shape of the central BP waveform; mechanoreflex and metaboreflex deform P1 and P2, respectively.
Background: Tennis performance is highly influenced by serve speed. This review aimed to evaluate and quantitatively compare the efficacy of popular strength and conditioning (S&C) training methods in enhancing the speed of the ball in the serves of tennis players.
Methods: Following PRISMA guidelines, a systematic search was conducted in the Scopus, Web of Science, SportsDiscuss, and PubMed databases without date constraints, up to July 2024. Studies included in this meta-analysis met PICOS criteria: a) randomized controlled trials with healthy tennis players, b) isolated or combined S&C training programs, c) evaluation of tennis serve speed, and d) adequate data to compute effect sizes (ESs). The PEDro scale was used to assess methodological quality.
Results: Out of 271 identified papers, 16 studies of moderate to high quality were included in the meta-analysis. Resistance training demonstrated a small but significant effect on serve speed (ES = 0.53; p < 0.001), while multimodal training exhibited a moderate and significant effect (ES = 0.79; p = 0.001). However, core training did not have a significant effect on serve speed (ES = 0.32, p = 0.231).
Conclusion: The findings suggested that S&C interventions, including resistance and multimodal training, were beneficial for increasing serve speed in tennis players. Further high-quality research is recommended to confirm this conclusion.
Systematic review registration: https://www.crd.york.ac.uk/prospero/display_ record.php?RecordID=519790, identifier CRD42024519790.
Background: Instability resistance training (IRT) has been the focus of extensive research because of its proven benefits to balance ability, core stability, and sports performance for athletes. However, there is a lack of systematic reviews explicitly evaluating IRT's impact on athletes' balance ability. This study aims to conduct a systematic review of the effects of IRT on balance ability among athletes.
Method: This study used guidelines for the systematic review and meta-analysis of PRISMA, Web of Science, EBSCOhost (SPORTDiscus), PubMed, Scopus, and Google Scholar to collect original references in electronic databases. The PICOS method was selected for the inclusion criteria. The physiotherapy evidence database (PEDro) scale was used to assess the scoring for articles' risk range of bias. The scoring of 20 studies ranges from 4-8, and study quality is moderate to high.
Results: Out of 285 identified studies, only 20 articles fulfilled all the eligibility criteria after screening. IRT could significantly improve reciprocal, static, and dynamic balance ability among judo athletes, basketball players, weightlifters, archery athletes, soccer players, rhythmic gymnasts, badminton players, track and field athletes, handball players, volleyball players, and gymnasts using unstable surfaces or environments (i.e., BOSU, Swiss, Wobble boards, Suspension trainer, Sissel pillows, Inflated disc and foam surface, Airex balance pad, Togu power ball, Thera-Band, Elastic band strap, Sand surface and so on).
Conclusion: The finding suggests that different types of IRT benefit athletes as this training method can effectively enhance reciprocal, static, and dynamic balance ability in athletes. Therefore, this review suggests that IRT should be considered in athletes' daily training routines for the physical fitness of reciprocal, static, and dynamic balance ability.
Aerobic training with blood flow restriction (AT-BFR) has shown promise in enhancing both aerobic capacity and exercise performance. The aim of this review was to systematically analyze the evidence regarding the effectiveness of this novel training method on aerobic capacity, muscle strength, and hypertrophy in young adults. Studies were identified through a search of databases including PubMed, Scopus, Web of Science, SPORTDiscus, CINAHL, Cochrane Library, and EMBASE. A total of 16 studies, involving 270 subjects, were included in the meta-analysis. The results revealed that AT-BFR induced greater improvements in VO2max (SMD = 0.27, 95%CI: [0.02, 0.52], p < 0.05), and muscle strength (SMD = 0.39, 95%CI: [0.09, 0.69], p < 0.05), compared to aerobic training with no blood flow restriction (AT-noBFR). However, no significant effect was observed on muscle mass (SMD = 0.23, 95%CI: [-0.09, 0.56], p = 0.162). Furthermore, no moderating effects on the outcomes were found for individual characteristics or training factors. In conclusion, AT-BFR is more effective than AT-noBFR in improving aerobic capacity and muscle strength, making it a promising alternative to high-intensity training.
Systematic review registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42024559872.
Purpose: While it is common practice for schools across the United States to include neurodivergent children in physical education classes, many programs outside of school-such as those at home or in the community-are not effectively tailored to meet their support needs. This gap contributes to lower levels of physical activity among neurodivergent children. Our objective was to address this issue by systematically adapting the InPACT (Interrupting Prolonged sitting with ACTivity) at Home program to enable neurodivergent children to safely engage in physical activity at home.
Methods: The rapid-cycle research adaptation process involved several key steps: (1) sorting and grouping video content based on different types of skills and exercises (problem exploration); (2) assembling an expert team to guide the development of the instructions (knowledge exploration); and (3) using generative artificial intelligence (AI) to create concise instructions and cue words for each skill/exercise (solution development). These outputs were then fine-tuned by the expert team. The refinements were guided by the Universal Design for Learning (UDL) principle of "Representation," which acknowledges that learners perceive and understand information in diverse ways.
Results: From the 132 InPACT at Home videos, over 500 activities were identified and categorized into main skill groups: jumping, core, lateral, sport, upper body, lower body, and compound movements. Expert meetings emphasized the importance of the "Three C's"-consistency, conciseness, and clarity-in crafting instructions, along with the use of simple, elementary sight words. AI was employed to generate and refine prompts like "Provide simplified step-by-step instructions for a jumping jack, suitable for a neurodivergent child" and "Condense the step-by-step instructions for a jumping jack, suitable for a neurodivergent child".
Discussion: The adaptation of the existing InPACT at Home program was guided by dissemination and implementation science frameworks, aiming to increase equitable access to structured youth physical activity opportunities for neurodivergent children. By incorporating AI and UDL principles, we aim to further enhance the program's accessibility. Our next steps include evaluating the effectiveness of our program adaptations in encouraging participation in the InPACT at Home program and subsequently increasing physical activity levels among neurodivergent children.
Assessing muscle mass in critically ill patients remains challenging. This retrospective cohort study explores the potential of phase angle (PA°) derived from bioelectrical impedance analysis (BIA) as a surrogate marker for muscle mass monitoring by associating it with daily creatinine excretion (DCE), a structural and metabolic muscle mass marker. In 20 ICU patients, we observed a linear relationship between PA° and DCE at initial (S1) and follow-up (S2) points, with Rho values of 0.78 and 0.65, respectively, as well as between their percentage changes (Rho = 0.80). Multivariate analysis confirmed a strong association between changes in PA° and DCE (adjusted R2 of 0.73), while changes in the extracellular water to total body water (ECW/TBW) ratio showed no significant association. This study establishes a relationship between a BIA-derived independent-weight parameter and DCE, highlighting the potential of PA° for muscle mass monitoring during acute changes, such as those seen in ICU settings. Integrating PA° into clinical practice could provide a non-invasive and reliable tool to enhance muscle assessment and support targeted interventions in critically ill patients.
Introduction: Access to electric light has exposed living organisms to varying intensities of light throughout the 24 h day. Dim light at night (DLAN) is an inappropriate signal for the biological clock, which is responsible for the circadian organization of physiology. During the gestational period, physiological adaptations occur to ensure a successful pregnancy and optimal fetal development. Environmental maternal conditions, such as disruptions of maternal circadian rhythms, could negatively affect offspring health. We have previously demonstrated that exposure of female Wistar rats to DLAN results in circadian, metabolic, and behavioral alterations. A relevant behavior during adolescence is social play, primarily regulated by the nucleus accumbens (NAc) which is crucial for the proper performance of important behaviors in adulthood. Throughout development, microglia are responsible for the remodeling of diverse brain regions via synaptic pruning. During adolescence, this process occurs within the NAc, where immune-mediated remodeling directly impacts social play behavior.
Methods: This study investigated the effects of maternal exposure to DLAN or a light-dark cycle (LD) before (5 weeks) and during the gestational period (21-23 days) on the metabolism and behavior of offspring in adolescence and adulthood. Body mass was measured every 5 days from postnatal day 1 (PN1) to PN25 and every 10 days from PN40 to PN90; food consumption was monitored weekly from PN40 to PN90. Social play behavior was evaluated at PN40. The quantification and morphology of microglia in the NAc were measured on PN30. An open field test was conducted at PN60, and anhedonia test was assessed at PN90.
Results and discussion: Male and female offspring from mothers exposed to DLAN showed increased body mass gain at PN25. DLAN male offspring had lower food consumption, while DLAN females exhibited increased food consumption. In social play behavior, no differences were found between DLAN and LD female offspring. In contrast, DLAN male offspring exhibited a significant decrease in social play behavior compared to LD animals, which was associated with higher numbers of microglia in the NAc that had more ramified morphology. Importantly, at PN90, DLAN offspring presented increased anxiety-like behaviors. These results demonstrate that DLAN exposure induces intergenerational behavioral alterations that persist until adulthood.
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