1,721,001 research outputs found
The College Players Present Albert Hiller's Directed by Gordon Ralph, Ashes to Ashes- Dust to Dust
No full textThe College Players Present Albert Hiller's Directed by Gordon Ralph, Ashes to Ashes- Dust to Dus
An evaluation of the effects of localised skin cooling on microvascular, inflammatory, structural, and perceptual responses to sustained mechanical loading of the sacrum: a study protocol: A study protocol
No full textThis study protocol aims to investigate how localised cooling influences the skin’s microvascular, inflammatory, structural, and perceptual tolerance to sustained mechanical loading at the sacrum, evaluating factors such as morphology, physiology, and perceptual responses. The protocol will be tested on individuals of different age, sex, skin tone and clinical status, using a repeated-measure design with three participants cohorts: i) young healthy (n=35); ii) older healthy (n=35); iii) spinal cord injured (SCI, n=35). Participants will complete three testing sessions during which their sacrum will be mechanically loaded (60 mmHg; 45 min) and unloaded (20 min) with a custom-built thermal probe, causing pressure-induced ischemia and post-occlusive reactive hyperaemia. Testing sessions will differ by the probe’s temperature, which will be set to either 38°C (no cooling), 24°C (mild cooling), or 16°C (strong cooling). We will measure skin blood flow (via Laser Doppler Flowmetry; 40 Hz); pro- and anti-inflammatory biomarkers in skin sebum (Sebutape); structural skin properties (Optical Coherence Tomography); and ratings of thermal sensation, comfort, and acceptance (Likert Scales); throughout the loading and unloading phases. Changes in post-occlusive reactive hyperaemia will be considered as the primary outcome and data will be analysed for the independent and interactive effects of stimuli’s temperature and of participant group on within- and between-subject mean differences (and 95% Confidence Intervals) in peak hyperaemia, by means of a 2-way mixed model ANOVA (or Friedman). Regression models will also be developed to assess the relationship between absolute cooling temperatures and peak hyperaemia. Secondary outcomes will be within- and between-subject mean changes in biomarkers’ expression, skin structural and perceptual responses. This analysis will help identifying physiological and perceptual thresholds for the protective effects of cooling from mechanically induced damage underlying the development of pressure ulcers in individuals varying in age and clinical status
Impact of Localised Skin Cooling at the Sacrum on Microvascular Responses to Sustained Pressure-induced Ischemia
No full text
Impact of localised skin cooling at the sacrum on microvascular responses to sustained pressure-induced ischemia
No full textThe effect of head and neck per-cooling on neuromuscular fatigue following exercise in the heat
Full text linkThe effect of localised head and neck per-cooling on central and peripheral fatigue during high thermal strain was investigated. Fourteen participants cycled for 60 min at 50% peak oxygen uptake on 3 occasions: thermoneutral control (CON; 18 °C), hot (HOT; 35 °C), and HOT with head and neck cooling (HOTcooling). Maximal voluntary force (MVF) and central activation ratio (CAR) of the knee extensors were measured every 30 s during a sustained maximal voluntary contraction (MVC). Triplet peak force was measured following cycling, before and after the MVC. Rectal temperatures were higher in HOTcooling (39.2 ± 0.6 °C) and HOT (39.3 ± 0.5 °C) than CON (38.1 ± 0.3 °C; P < 0.05). Head and neck thermal sensation was similar in HOTcooling (4.2 ± 1.4) and CON (4.4 ± 0.9; P > 0.05) but lower than HOT (5.9 ± 1.5; P < 0.05). MVF and CAR were lower in HOT than CON throughout the MVC (P < 0.05). MVF and CAR were also lower in HOTcooling than CON at 5, 60, and 120 s, but similar at 30 and 90 s into the MVC (P > 0.05). Furthermore, they were greater in HOTcooling than HOT at 30 s, whilst triplet peak force was preserved in HOT after MVC. These results provide evidence that central fatigue following exercise in the heat is partially attenuated with head and neck cooling, which may be at the expense of greater peripheral fatigue. Novelty Central fatigue was greatest during hyperthermia. Head and neck cooling partially attenuated the greater central fatigue in the heat. Per-cooling led to more voluntary force production and more peripheral fatigue.© 2020, The Author(s). This is an author produced version of a paper published in APPLIED PHYSIOLOGY NUTRITION AND METABOLISM uploaded in accordance with the publisher’s self- archiving policy. The final published version (version of record) is available online at the link. Some minor differences between this version and the final published version may remain. We suggest you refer to the final published version should you wish to cite from it.</p
Repeated pressure and shear stress at the posterior heel following localised skin cooling: protocol for a randomised cross-over study
No full textRepeated pressure and shear stress at the posterior heel following localised skin cooling: protocol for a repeated measures cohort study
No full textBackground: pressure in combination with shear forces can deform soft tissues and lead to development of pressure ulcers. The prevalence rate of pressure ulcers in the UK remains unacceptably high and can occur across the human lifespan. The posterior heel represents a common anatomical site for pressure ulcers, due to soft tissues lying adjacent to bony prominences and exposed to pressure and shear during lying postures. Localised cooling and interface materials which reduce shear may offer potentially therapeutic benefits in the development of pressure ulcers. Yet, the physiological mechanisms underpinning the potential benefits of localised cooling are not fully understood. Objectives : this study protocol aims to investigate how localised cooling influences the skin’s microvascular, inflammatory, structural, and perceptual tolerance to repeated shear loading at the heel.Methods: the protocol will be tested on individuals of different age, sex, skin tone and comorbidities, using a repeated-measure design. Three cohorts will be recruited: i) young healthy (n=35); ii) older healthy (n=35); iii) spinal cord injured (n=35). Participants will complete three testing sessions using a custom-built shearing rig with integrated thermal plate, during which the posterior aspect of the heel will be exposed to a standardised mechanical stimulus to elicit repeated pressure and shear loading. The experimental condition of each session will be determined by the temperature of the thermal plate, which will be set to either 36 °C (no cooling), 24 °C (mild cooling), or 16 °C (strong cooling). Continuous measurements will include kinetic coefficient of friction (CoF) and skin blood flow (via Laser Doppler Flowmetry; 40 Hz). Pro- and anti-inflammatory biomarkers in skin sebum (Sebutape), structural skin properties (Optical Coherence Tomography), skin conductance (µs) and ratings of thermal sensation, comfort, and acceptance (Likert Scales) will also be assessed before and after the shear stress protocol. Results: recruitment began in January 2024. As of February 2025, 43 participants have been enrolled on to the study. Data collection and analysis are ongoing, published findings are expected to be available in early 2026. Discussion: this analysis will help identify mechanisms of skin damage following repeated shear stress at the heel, furthering our understanding of superficial pressure ulcers. It will also establish physiological and perceptual thresholds for the protective effects of cooling from shearing-induced damage at the heel.<br/
Passive hyperthermia reduces maximal but not explosive torque production
No full textIntroduction: hyperthermia can reduce maximal voluntary force/torque (MVT) of skeletal muscle due to reduced neural activation (Todd et al., 2005). Rate of force/torque development (RTD) may be a more functionally relevant measure of neuromuscular performance than MVT; however, the effect of hyperthermia on RTD has received little attention. Primary determinants of RTD include neural activation and electrically evoked involuntary RTD (Maffiuletti et al., 2016), and whilst neural activation may decrease with hyperthermia, increased muscle temperature improves involuntary RTD, so it is unclear how voluntary RTD will be affected by hyperthermia. This study aimed to investigate the effects of progressive passive whole-body hyperthermia on MVT and voluntary RTD, as well as the neural and contractile factors contributing to any effects.Methods: nine male participants completed two trials; one involving passive heating to a rectal temperature (Tre) of 39.5˚C (HOT) and the other (CON) where Tre was maintained at ~37˚C. The same neuromuscular measurements of the knee extensors were completed when participants first entered the chamber (Tre ~37˚C; Base), and at Tre=38.5˚C (ModHyp) and Tre=39.5˚C (SevHyp), in the HOT trial, and at equivalent time points into the CON trial. MVT, voluntary activation (VA) determined via interpolated twitch, and EMG at MVT normalised to maximal M-wave (EMGMVT) were measured during MVCs. Explosive voluntary RTD and normalised EMG were measured over 0-50 (RTD50; EMG50) and 0-100 (RTD100; EMG100) from torque/EMG onsets during explosive contractions. Involuntary RTD50 was measured during evoked octets at 300Hz.Results: in the HOT trial, MVT declined throughout and was 15% lower at SevHyp than Base (P=0.016), which coincided with declines in EMGMVT (-44%; P<0.005) and VA (-16%; P<0.005) from Base to SevHyp. In contrast, voluntary RTD50 and RTD100 remained unaffected in the HOT trial (P>0.05), despite 23-31% decreases in EMG50 and EMG100 from Base to SevHyp (P<0.001). Involuntary RTD50 however, increased from Base to ModHyp (10%; P<0.001) and from ModHyp to SevHyp (4%; P<0.001). There were no changes in any dependent variables throughout the CON trial.Conclusion: as expected MVT declined as a result of passive hyperthermia which was largely due to reduced neural activation (i.e., EMGMVT and VA). In contrast, this study provides novel evidence that voluntary RTD was largely unaffected by passive hyperthermia, despite considerable reductions in explosive neural activation, which likely occurred due to the increased involuntary RTD, and thus cancelling out of neural and contractile effects.<br/
- …
