The effect of habitual exercise on respiratory-muscle function in older adults

Older adults' participation in habitual exercise might be affected by alterations to respiratory mechanics such as decreased respiratory-muscle strength. This reduction can cause a decrease in efficiency of the ventilatory pump, potentially compromising exercise participation. This research examined the role of habitual exercise in respiratory-muscle function and the associated implications for exercise performance. Seventy-two healthy older adults (36 men, 64.9 ± 8.6 years, 177.2 ± 8.4 cm, 82.5 ± 11.9 kg; 36 women, 64.9 ± 9.5 years, 161.7 ± 6.4 cm, 61.6 ± 9.2 kg) undertook respiratory-function and walking-performance tests. Active men and women achieved higher scores than their inactive counterparts for all tests except spirometry, where no differences were evident. The results indicate that a significant amount of the elevated fitness level might be accounted for by increased endurance capacity of the inspiratory muscles. Inactive older individuals might be at risk for inadequate respiratory-muscle strength, so interventions should be considered

Responses to a 5-Day Sport-Specific Heat Acclimatization Camp in Elite Female Rugby Sevens Athletes.

PURPOSE: To describe the physiological (resting core temperature, exercising heart rate, and sweat rate) and psychophysical (rating of perceived exertion, thermal sensation, and thermal comfort) responses to a short-term heat acclimatization (HA) training camp in elite female rugby sevens athletes. METHODS: Nineteen professional female rugby sevens athletes participated in a 5-day HA camp in Darwin, Australia (training average: 32.2°C and 58% relative humidity). Training involved normal team practice prescribed by appropriate staff. Markers of physiological and psychophysical adaptations to HA were collected at various stages during the camp. Partial eta-squared effect sizes (from linear mixed-effects models), rank-biserial correlations (from Freidman tests), and P values were used to assess changes across the protocol. RESULTS: Resting core temperature did not significantly change. Exercising heart rate showed a large and significant reduction from day 1 to day 5 (175 [13] vs 171 [12] beats·min-1), as did sweat rate (1.1 [0.3] vs 1.0 [0.2] L·h-1). Thermal sensation showed a large and significant reduction between day 1 and day 5 (median [interquartile range] = 5 [5-5.5] vs 4.5 [4-5]). Changes in rating of perceived exertion and thermal comfort were unclear. CONCLUSIONS: Beneficial cardiovascular adaptations were observed simultaneously across a full squad of elite female rugby sevens players (without expensive facilities/equipment or modifying training content). However, beneficial changes in resting core temperature, sweat rate, and thermal/effort perceptions likely require a greater thermal impulse. These data contribute to the development of evidence-informed practice for minimal effective HA doses in female team-sport athletes, who are underrepresented in the current research

Rugby sevens match demands and measurement of performance: A review

© 2018, University of Zagreb - Faculty of Kinesiology. All rights reserved. The purpose of this review is to summarize the research that has examined the match demands of elite-level, men’s rugby sevens, and provide enhanced understanding of the elements contributing to successful physical and technical performance. Forty-one studies were sourced from the electronic database of PubMed, Google Scholar and SPORTDiscus. From these, twelve original investigations were included in this review. Positive match outcomes are the result of an interplay of successful physical, technical, and tactical performances. The physical performance of players (activity profile measurement from GPS) includes high relative total distance and high-speed distance values in comparison to other team sports. The technical performance of players (skill involvement measurement from match statistics) involves the execution of a range of specific offensive and defensive skills to score points or prevent the opponent from scoring. The factors influencing change in these performance constructs has not been investigated in rugby sevens. There is a paucity in the literature surrounding the situational and individual factors affecting physical and skill performance in elite rugby sevens competition. Future studies should investigate the factors likely to have the strongest influence on player performance in rugby sevens. This should include larger sample sizes and account for repeated measures within players. This will allow coaches and scientists to improve their interpretation of activity and skill profile data, and make more informed decisions on players’ athletic preparation program

Exploiting zinc oxide re-emission to fabricate periodic arrays

The synthesis of hexagonal ring-shaped structures of zinc oxide using nanosphere lithography and metal/metal oxide sputtering is demonstrated. This synthesis exploits the surface re-emission of zinc oxide to deposit material in regions lying out of the line-of-sight of the sputtering source. These rings can nucleate the hydrothermal growth of zinc oxide crystals. Control over the growth could be exercised by varying growth solution concentration or temperature or by applying an external potential. © 2010 American Chemical Society

Additional Clothing Increases Heat Load in Elite Female Rugby Sevens Players.

PURPOSE: To determine whether elite female rugby sevens players are exposed to core temperatures (Tc) during training in the heat that replicate the temperate match demands previously reported and to investigate whether additional clothing worn during a hot training session meaningfully increases the heat load experienced. METHODS: A randomized parallel-group study design was employed, with all players completing the same approximately 70-minute training session (27.5°C-34.8°C wet bulb globe temperature) and wearing a standardized training ensemble (synthetic rugby shorts and training tee [control (CON); n = 8]) or additional clothing (standardized training ensemble plus compression garments and full tracksuit [additional clothing (AC); n = 6]). Groupwise differences in Tc, sweat rate, GPS-measured external locomotive output, rating of perceived exertion, and perceptual thermal load were compared. RESULTS: Mean (P = .006, ηp2=.88) and peak (P 6 minutes. Additional clothing is a viable and effective method to increase heat strain in female rugby sevens players without compromising training specificity or external locomotive capacity

Using fNIRS to study working memory of infants in rural Africa

A pilot study was conducted to assess the feasibility of using fNIRS as an alternative to behavioral assessments of cognitive development with infants in rural Africa. We report preliminary results of a study looking at working memory in 12–16-month-olds and discuss the benefits and shortcomings for the potential future use of fNIRS to investigate the effects of nutritional insults and interventions in global health studies

Identification of chemokine receptors as potential modulators of endocrine resistance in oestrogen receptor–positive breast cancers

Introduction Endocrine therapies target oestrogenic stimulation of breast cancer (BC) growth, but resistance remains problematic. Our aims in this study were (1) to identify genes most strongly associated with resistance to endocrine therapy by intersecting global gene transcription data from patients treated presurgically with the aromatase inhibitor anastrazole with those from MCF7 cells adapted to long-term oestrogen deprivation (LTED) (2) to assess the clinical value of selected genes in public clinical data sets and (3) to determine the impact of targeting these genes with novel agents. Methods Gene expression and Ki67 data were available from 69 postmenopausal women with oestrogen receptor–positive (ER+) early BC, at baseline and 2 weeks after anastrazole treatment, and from cell lines adapted to LTED. The functional consequences of target genes on proliferation, ER-mediated transcription and downstream cell signalling were assessed. Results By intersecting genes predictive of a poor change in Ki67 with those upregulated in LTED cells, we identified 32 genes strongly correlated with poor antiproliferative response that were associated with inflammation and/or immunity. In a panel of LTED cell lines, C-X-C chemokine receptor type 7 (CXCR7) and CXCR4 were upregulated compared to their wild types (wt), and CXCR7, but not CXCR4, was associated with reduced relapse-free survival in patients with ER+ BC. The CXCR4 small interfering RNA variant (siCXCR4) had no specific effect on the proliferation of wt-SUM44, wt-MCF7 and their LTED derivatives. In contrast, siCXCR7, as well as CCX733, a CXCR7 antagonist, specifically suppressed the proliferation of MCF7-LTED cells. siCXCR7 suppressed proteins associated with G1/S transition and inhibited ER transactivation in MCF7-LTED, but not wt-MCF7, by impeding association between ER and proline-, glutamic acid– and leucine-rich protein 1, an ER coactivator. Conclusions These data highlight CXCR7 as a potential therapeutic target warranting clinical investigation in endocrine-resistant BC

Cooling athletes with a spinal cord injury

Cooling strategies that help prevent a reduction in exercise capacity whilst exercising in the heat have received considerable research interest over the past 3 decades, especially in the lead up to a relatively hot Olympic and Paralympic Games. Progressing into the next Olympic/Paralympic cycle, the host, Rio de Janeiro, could again present an environmental challenge for competing athletes. Despite the interest and vast array of research into cooling strategies for the able-bodied athlete, less is known regarding the application of these cooling strategies in the thermoregulatory impaired spinal cord injured (SCI) athletic population. Individuals with a spinal cord injury (SCI) have a reduced afferent input to the thermoregulatory centre and a loss of both sweating capacity and vasomotor control below the level of the spinal cord lesion. The magnitude of this thermoregulatory impairment is proportional to the level of the lesion. For instance, individuals with high-level lesions (tetraplegia) are at a greater risk of heat illness than individuals with lower-level lesions (paraplegia) at a given exercise intensity. Therefore, cooling strategies may be highly beneficial in this population group, even in moderate ambient conditions (~21 °C). This review was undertaken to examine the scientific literature that addresses the application of cooling strategies in individuals with an SCI. Each method is discussed in regards to the practical issues associated with the method and the potential underlying mechanism. For instance, site-specific cooling would be more suitable for an athlete with an SCI than whole body water immersion, due to the practical difficulties of administering this method in this population group. From the studies reviewed, wearing an ice vest during intermittent sprint exercise has been shown to decrease thermal strain and improve performance. These garments have also been shown to be effective during exercise in the able-bodied. Drawing on additional findings from the able-bodied literature, the combination of methods used prior to and during exercise and/or during rest periods/half-time may increase the effectiveness of a strategy. However, due to the paucity of research involving athletes with an SCI, it is difficult to establish an optimal cooling strategy. Future studies are needed to ensure that research outcomes can be translated into meaningful performance enhancements by investigating cooling strategies under the constraints of actual competition. Cooling strategies that meet the demands of intermittent wheelchair sports need to be identified, with particular attention to the logistics of the sport

Actin binding to WH2 domains regulates nuclear import of the multifunctional actin regulator JMY

© The Author(s), 2012. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molecular Biology of the Cell 23 (2012): 853-863, doi:10.1091/mbc.E11-12-0992.Junction-mediating and regulatory protein (JMY) is a regulator of both transcription and actin filament assembly. In response to DNA damage, JMY accumulates in the nucleus and promotes p53-dependent apoptosis. JMY's actin-regulatory activity relies on a cluster of three actin-binding Wiskott–Aldrich syndrome protein homology 2 (WH2) domains that nucleate filaments directly and also promote nucleation activity of the Arp2/3 complex. In addition to these activities, we find that the WH2 cluster overlaps an atypical, bipartite nuclear localization sequence (NLS) and controls JMY's subcellular localization. Actin monomers bound to the WH2 domains block binding of importins to the NLS and prevent nuclear import of JMY. Mutations that impair actin binding, or cellular perturbations that induce actin filament assembly and decrease the concentration of monomeric actin in the cytoplasm, cause JMY to accumulate in the nucleus. DNA damage induces both cytoplasmic actin polymerization and nuclear import of JMY, and we find that damage-induced nuclear localization of JMY requires both the WH2/NLS region and importin β. On the basis of our results, we propose that actin assembly regulates nuclear import of JMY in response to DNA damage.This work was supported by grants from the National Institutes of Health, an American Heart Association Predoctoral Fellowship (J.B.Z.), the Robert Day Allen Fellowship Fund (J.B.Z.), and a National Science Foundation Predoctoral Fellowship (B.B.)

High Resolution MEMS Accelerometers to Estimate VO2 and Compare Running Mechanics between Highly Trained Inter-Collegiate and Untrained Runners

BACKGROUND: The purposes of this study were to determine the validity and reliability of high resolution accelerometers (HRA) relative to VO(2) and speed, and compare putative differences in HRA signal between trained (T) and untrained (UT) runners during treadmill locomotion. METHODOLOGY: Runners performed 2 incremental VO(2max) trials while wearing HRA. RMS of high frequency signal from three axes (VT, ML, AP) and the Euclidean resultant (RES) were compared to VO(2) to determine validity and reliability. Additionally, axial rms relative to speed, and ratio of axial accelerations to RES were compared between T and UT to determine if differences in running mechanics could be identified between the two groups. PRINCIPAL FINDINGS: Regression of RES was strongly related to VO(2), but T was different than UT (r = 0.96 vs 0.92; p<.001) for walking and running. During walking, only the ratio of ML and AP to RES were different between groups. For running, nearly all acceleration parameters were lower for T than UT, the exception being ratio of VT to RES, which was higher in T than UT. All of these differences during running were despite higher VO(2), O(2) cost, and lower RER in T vs UT, which resulted in no significant difference in energy expenditure between groups. CONCLUSIONS/SIGNFICANCE: These results indicate that HRA can accurately and reliably estimate VO(2) during treadmill locomotion, but differences exist between T and UT that should be considered when estimating energy expenditure. Differences in running mechanics between T and UT were identified, yet the importance of these differences remains to be determined