The bookmark method to establish minimum performance standards for intensive care flight paramedics performing helicopter winch rescue.

We aimed to use the bookmark method to establish minimum standards for selecting intensive care flight paramedics. Two subject matter expert (SME) focus groups reviewed nine videos of decreasing duration showing land and water helicopter rescue tasks. Focus Group 1 (FG1, n = 10) viewed videos individually off-site, whilst Focus Group 2 (FG2, n = 9) attended a face-to-face session. All SMEs selected the video they judged as the appropriate pace for the task then reviewed feedback. For both groups, the process was repeated until 80% agreement was achieved, or three rounds were completed (whichever occurred first). FG1 and FG2 achieved agreement after two rounds for the land task. For the water task, FG1 did not reach agreement. FG2 reached consensus after two rounds. The selected task durations were similar. The bookmark method is valuable to determine performance standards for performing winch rescue, and SMEs are more likely to reach consensus when face-to-face.

The physiological demand of a task simulation varies when developed by independent groups of experiential experts.

OBJECTIVE: To investigate the disparity in the specification and physiological demand of a task simulation when developed by two independent panels of experiential experts. DESIGN: Independent groups design. METHODS: Two groups of experiential experts from the Royal Australian Air Force (RAAF) worked independently to design, and then complete a simulation of a generic occupational task; the establishment of a security control point. Task duration, oxygen consumption, and cardiac frequency were measured whilst each panel completed the task simulation. Maximal acceptable work duration (MAWD) and the percentage of MAWD (%MAWD) were also calculated. Independent t-tests were used to determine differences (P < 0.05) between the measured variables. RESULTS: No differences were observed in the average oxygen consumption (1.26 ± 0.25 L min-1 and 1.28 ± 0.29 L min-1 respectively; P = 0.84), or cardiac frequency (134 ± 16.4 beats·min-1 and 125 ± 8.5 beats·min-1 respectively; P = 0.12) between Panel 1 and Panel 2. However, there was a significant difference between panels with respect to task duration (Panel 1: 15.5 ± 3.68 min; Panel 2: 34.20 ± 9.60 min; P < 0.01), and the %MAWD (Panel 1: 5.32 ± 3.17%, Panel 2: 12.15 ± 9.40%, P = 0.04). CONCLUSIONS: The physiological demand of a task simulation is dependent upon the group of experts consulted to develop the simulation. It is critical that input from a wide representation of experiential experts is considered when developing task simulations to avoid bias towards the perceptions of the experts consulted.

The physiological demands of helicopter winch rescue in water and over land.

Physically demanding water and over land winch rescues are critical tasks for helicopter paramedics. To assess the physiological demands of winch rescue, 14 intensive care flight paramedics (12 male, 2 female, mean (±SD) age 44.3 (±5.4) years, experience 7.1 (±5.2) years) completed land and water-based task simulations. For the land task, VO2 was 41.7 (±4.5) mL kg-1 min-1, or 86 (±11) % of VO2peak. Task duration was 7.0 (±3.6) min, or 53 (±27) % of maximal acceptable work duration (MAWD) (13.2 (±9.0) min). For the water task, VO2 was 36.7 (±4.4) mL kg-1 min-1, (81 (±12) % of VO2peak). Water task duration was 10.2 (±1.1) min, or 47.6 (±4.8) % of calculated MAWD (21.0 (±15.6) min). These results demonstrate that helicopter rescue paramedics work at very high physiological workloads for moderate durations, and these demands should be considered when developing selection tests and when deploying to rescues, to ensure staff are capable of task performance. Practitioner summary: Paramedics performed helicopter winch rescue task simulations in water and over land. Paramedics worked at 81% of VO2peak for 10.2 min and 86% of VO2peak for 7 min for swim and land tasks respectively. Rescue organisations should consider these demands when selecting and credentialing staff and when deploying to incidents. Abbreviations: HEMS: helicopter emergency medical service; ICFP: intensive care flight paramedic; MAWD: maximal acceptable work duration; PES: physical employment standards; SAR: search and rescue.

Comparison of swimming versus running maximal aerobic capacity in helicopter rescue paramedics.

Swimming is a critical task for helicopter rescue paramedics and aerobic capacity is assessed in this occupation to determine job suitability. We evaluated one treadmill-based and one pool-based assessment of maximal aerobic capacity (V̇O2peak) in 14 helicopter rescue paramedics. There was a small absolute difference (p = 0.11, d = 0.46) between V̇O2peak in the swim (45.5 ± 7.8 ml.kg-1.min-1) compared to the run (48.5 ± 5.5 ml.kg-1.min-1), with a moderate relationship noted (r = 0.74, 95% CI [0.35-, 0.91], p = 0.0023). Whilst not interchangeable, run V̇O2peak was a predictor of swim V̇O2peak. Maximal blood lactate was similar (p = 0.93) in swim (13.4 ± 3.8 mmol.L-1) and run (12.2 ± 3.0 mmol.L-1), and maximal heart rate 13% lower (p < 0.0001) in the swim (162 ± 11 bpm) versus the run (186 ± 10 bpm). To estimate swimming V̇O2peak in paramedics a treadmill test is sufficient but does not replace assessment of swimming proficiency. Practitioner Summary: We developed a swim protocol to assess maximal aerobic capacity in helicopter rescue paramedics. Compared to a treadmill-based test, our swim protocol generated 20% lower submaximal V̇O2 and 6% lower V̇O2peak. Although not interchangeable, a treadmill V̇O2peak test is indicative of maximal aerobic capacity in rescue paramedics whilst swimming. Abbreviations: HEMS: helicopter emergency medical service; PES: physical employment standards; ICFP: intensive care flight paramedic; RPE: rating of perceived exertion.

Is muscular strength a critical physical attribute for the apprehension of a simulated non-compliant suspect?

This investigation determined the influence of technique and experience on arm retraction force required to apprehend a non-compliant suspect. Phase-One: Nine experienced RAAF military-police completed four apprehension simulations, peak arm retraction force was measured; i) Control(CON), ii) Pressure-Point(PP), iii) Targeted-Striking(TS) and iv) 2-Person(2Per) techniques. Phase-Two: Experienced (EXP, n = 8) or Inexperienced (INEXP, n = 22) military-police completed CON, PP and Pressure-Point + Coaching(PP + C). Strength was assessed in INEXP. EXP produced more force (178.7 N ± 25.9) than INEXP during CON, but no participant successfully apprehended the suspect. All EXP were successful with PP, arm retraction force 357 N (CI: 233.7,480.2) was lower compared to CON, but no difference was observed between PP and CON for INEXP. PP + C, 82% of INEXP were successful, force declined 138.2 N (CI: 67.8,208.5) compared to CON. All EXP required PP for successful apprehension. INEXP required PP + C for apprehension success. Muscular strength had a limited relationship with arm retraction force. Practitioner summary: For law enforcement personnel, apprehension of a suspect is a critical and physically demanding task, where success is associated with muscular strength and technique. We observed success in the apprehension of a simulated suspect by military law enforcement personnel was primarily determined by participant skill and experience and not muscular strength.

Defining the characteristics of physically demanding winch rescue in helicopter search and rescue operations.

Helicopter emergency medical service search and rescue (HEMS SAR) paramedics perform physically demanding winch rescues. Rescue organisations require valid physical employment standards (PES) to ensure personnel can adequately perform duties. There are no studies describing validated PES for HEMS SAR. We convened a subject matter expert (SME) focus group to review historical case data and generate task descriptions for land and water winch rescue as the basis for development of task simulations to assess physiological workload. Sixteen helicopter rescue paramedics with a mean age of 47 (range, 36-52) years and 8 (2-20) years' experience in helicopter rescue participated in a SME focus group. When provided with data from historical cases, SMEs achieved consensus (≥80%) when generating descriptions of winch rescue. This method may be useful to develop simulations for assessment of physiological demands of winch rescue and similar tasks, and to enhance validity and reliability of PES for rescue organisations.

Thermoeffector threshold plasticity: The impact of thermal pre-conditioning on sudomotor, cutaneous vasomotor and thermogenic thresholds.

To better understand the relationships between changes in body temperature and displacements of the thermoeffector thresholds (critical temperatures), the passive cooling (and heating) of pre-heated (and pre-cooled) individuals was investigated. Such experiments are necessary to understand the inter-dependence of those thresholds, and may possibly yield human evidence for the existence of separate central controllers. Eight males participated in four trials; two when normothermic, one following pre-experimental heating and the fourth following pre-cooling. Subjects were exposed to passive, whole-body cooling and heating when normothermic (the control trials), and again following pre-heating and pre-cooling (respectively). Cutaneous vasomotor, thermogenic, as well as precursor and discharged sudomotor thresholds from different body segments were compared across those dynamic thermal states. Following pre-heating, the critical mean body temperatures for vasoconstriction (0.37 °C ±â€¯0.10) and thermogenesis (0.67 °C ±â€¯0.20) were significantly elevated during passive cooling, relative to the corresponding control trial (both P < 0.05). When passive heating followed pre-cooling, the thresholds for vasodilatation were reduced (0.37 °C ±â€¯0.07; P < 0.05). Conversely, but with the exception of forehead precursor sweating, the sudomotor thresholds were elevated (averaging 0.16 °C ±â€¯0.02; P < 0.05). Most thermoeffectors revealed unique and adjustable activation thresholds, with the threshold displacements for thermogenesis and vasomotion appearing to be linked to the change in mean body temperature. Following pre-cooling, the critical temperatures for vasodilatation and sudomotor activation varied independently, with the exception of forehead precursor sweating. Collectively, those observations are consistent with the presence of independent central controllers for thermally dependent vasomotor and sudomotor responses, and perhaps also for shivering thermogenesis.

Understanding Anthropometric Characteristics Associated With Performance in Manual Lifting Tasks.

Beck, B, Middleton, KJ, Billing, DC, Caldwell, JN, and Carstairs, GL. Understanding anthropometric characteristics associated with performance in manual lifting tasks. J Strength Cond Res 33(3): 755-761, 2019-Manual lifting is an essential military job task and is commonly linked to occupational injury. Methods to reduce injury risk focus on ensuring that employees have the requisite physical capacity to safely conduct critical job tasks. The aim of this study was to investigate which anthropometric characteristics are associated with lifting performance to inform targeted training programs for job-critical lifting tasks. Sixty-three (42 men and 21 women) participants conducted 3 maximal lifts to a platform (pack lift to 1.5 m, box lift to 1.3 m and box lift to 1.5 m). A dual-energy x-ray absorptiometry scan was used to quantify anthropometric characteristics (body region-specific lean mass and fat mass). Although anthropometric measures were strongly associated with each other, multivariable linear regression revealed that a significant proportion of the total variation in lifting performance in each of the 3 tasks was explained by upper-arm lean mass (pack lift: ß = 5.42, p < 0.001; box lift 1.3 m: ß = 5.64, p < 0.001; box lift 1.5 m: ß = 7.00, p < 0.001). Leg lean mass also significantly contributed to the variation of pack lift performance (ß = 0.93, p = 0.01). When controlling for key anthropometric characteristics in these 3 tasks, separate analyses showed no significant effect of sex or stature on lift performance. These results suggest that the perceived limitations of stature and sex may be overcome by targeted training programs to improve specific physical characteristics associated with lifting performance.

A vascular mechanism to explain thermally mediated variations in deep-body cooling rates during the immersion of profoundly hyperthermic individuals.

NEW FINDINGS: What is the central question of this study? Does the cold-water immersion (14°C) of profoundly hyperthermic individuals induce reductions in cutaneous and limb blood flow of sufficient magnitude to impair heat loss relative to the size of the thermal gradient? What is the main finding and its importance? The temperate-water cooling (26°C) of profoundly hyperthermic individuals was found to be rapid and reproducible. A vascular mechanism accounted for that outcome, with temperature-dependent differences in cutaneous and limb blood flows observed during cooling. Decisions relating to cooling strategies must be based upon deep-body temperature measurements that have response dynamics consistent with the urgency for cooling. ABSTRACT: Physiologically trivial time differences for cooling the intrathoracic viscera of hyperthermic individuals have been reported between cold- and temperate-water immersion treatments. One explanation for that observation is reduced convective heat delivery to the skin during cold immersion, and this study was designed to test both the validity of that observation, and its underlying hypothesis. Eight healthy men participated in four head-out water immersions: two when normothermic, and two after exercise-induced, moderate-to-profound hyperthermia. Two water temperatures were used within each thermal state: temperate (26°C) and cold (14°C). Tissue temperatures were measured at three deep-body sites (oesophagus, auditory canal and rectum) and eight skin surfaces, with cutaneous vascular responses simultaneously evaluated from both forearms (laser-Doppler flowmetry and venous-occlusion plethysmography). During the cold immersion of normothermic individuals, oesophageal temperature decreased relative to baseline (-0.31°C over 20 min; P < 0.05), whilst rectal temperature increased (0.20°C; P < 0.05). When rendered hyperthermic, oesophageal (-0.75°C) and rectal temperatures decreased (-0.05°C) during the transition period (<8.5 min, mostly in air at 22°C), with the former dropping to 37.5°C only 54 s faster when immersed in cold rather than in temperate water (P < 0.05). Minimal cutaneous vasoconstriction occurred during either normothermic immersion, whereas pronounced constriction was evident during both immersions when subjects were hyperthermic, with the colder water eliciting a greater vascular response (P < 0.05). It was concluded that the rapid intrathoracic cooling of asymptomatic, hyperthermic individuals in temperate water was a reproducible phenomenon, with slower than expected cooling in cold water brought about by stronger cutaneous vasoconstriction that reduced convective heat delivery to the periphery.

Indirect hand and forearm vasomotion: Regional variations in cutaneous thermosensitivity during normothermia and mild hyperthermia.

In this experiment, hand and forearm vasomotor activity was investigated during localised, but stable heating and cooling of the face, hand and thigh, under open-loop (clamped) conditions. It was hypothesised that facial stimulation would provoke the most potent vascular changes. Nine individuals participated in two normothermic trials (mean body temperature clamp: 36.6°C; water-perfused suit and climate chamber) and two mildly hyperthermic trials (37.9°C). Localised heating (+5°C) and cooling (-5°C) stimuli were applied to equal surface areas of the face, hand and thigh (perfusion patches: 15min), while contralateral forearm or hand blood flows (venous-occlusion plethysmography) were measured (separate trials). Thermal sensation and discomfort votes were recorded before and during each thermal stimulation. When hyperthermic, local heating induced more sensitive vascular responses, with the combined thermosensitivity of both limb segments averaging 0.011mL·100mL-1·min-1·mmHg-1·°C-1, and 0.005mL·100mL-1·min-1·mmHg-1·°C-1 during localised cooling (P<0.05). Inter-site comparisons among the stimulated sites yielded minimal evidence of variations in local thermal sensation, and no differences were observed for vascular conductance (P>0.05). Therefore, regional differences in vasomotor and sensory sensitivity appeared not to exist. When combined with previous observations of sudomotor sensitivity, it seems that, during mild heating and cooling, regional representations within the somatosensory cortex may not translate into meaningful differences in thermal sensation or the central integration of thermoafferent signals. It was concluded that inter-site variations in the cutaneous thermosensitivity of these thermolytic effectors have minimal physiological significance over the ranges investigated thus far.

The sensitivity of a military-based occupational fitness test of muscular strength.

The risk of low back pain and injury during manual materials handling is increased if personnel are not physically capable of safely performing such tasks. To establish predictive relationships and develop a test cut-score, 69 participants performed a critical military lifting task to a 1.5-m platform (pack lift) and two task-related predictive tests (box lift to 1.5 m and 1.3 m). The pack lift was strongly correlated with both the 1.5-m (R2 = 0.85) and 1.3-m box lifts (R2 = 0.82). Both tests had similar sensitivity (range 0.85-0.94) with the 1.3-m test having higher specificity when compared with the 1.5-m lift. Increasing the test cut-score with the application of a safety factor increased the number of false positives and true negatives for both tests. Organisations must carefully assess their risk acceptance when applying safety factors to test cut-scores as the classification (pass/fail) of personnel may be affected.

Modifiable Anthropometric Characteristics Are Associated With Unilateral and Bilateral Carry Performance.

Beck, B, Carstairs, GL, Billing, DC, Caldwell, JN, and Middleton, KJ. Modifiable anthropometric characteristics are associated with unilateral and bilateral carry performance. J Strength Cond Res 31(2): 489-494, 2017-A mismatch between physical ability and task requirements can increase the risk of on-the-job injury. Therefore, understanding key anthropometric characteristics associated with job performance is important in developing targeted training programs and selecting employees in physically demanding occupations. The aims of this study were to understand which anthropometric and demographic (age/sex) characteristics were associated with performance in a unilateral stretcher carry and bilateral jerry can and kettle bell carries. Sixty-seven enlisted Australian Army soldiers (46 men and 21 women) participated in this investigation. Body composition was quantified using dual-energy X-ray absorptiometry. Univariate and multivariable regression techniques were used to quantify correlations between anthropometric characteristics and carry performance. Median carry distance was 650 m (interquartile range [IQR] = 425-1,025 m) in the stretcher carry, 300 m (IQR = 215-445 m) in the jerry can carry, and 265 m (IQR = 200-400 m) in the kettle bell carry. Univariate analyses demonstrated that whole body, trunk, upper arm, forearm, and leg lean mass, as well as stature and body mass were associated with performance across the 3 carry tasks. Of these, leg lean mass was shown to be a key characteristic associated with carry performance. Subsequently, it is suggested that training programs focus on whole-body lean mass with specific emphasis on leg lean mass. Additionally, we demonstrated that age and sex were not significantly associated with carry performance when controlling for leg lean mass, indicating that modifiable factors can be targeted in training programs to improve job performance.

Non-thermal modulation of sudomotor function during static exercise and the impact of intensity and muscle-mass recruitment.

Aim: Static muscle activation elicits intensity-dependent, non-thermal sweating that is presumably controlled by feedforward (central command) mechanisms. However, it is currently unknown how the size of the recruited muscle mass interacts with that mechanism. To investigate the possible muscle-size dependency of that non-thermal sweating, the recruitment of two muscle groups of significantly different size was investigated in individuals within whom steady-state thermal sweating had been established and clamped. Methods: Fourteen passively heated subjects (climate chamber and water-perfusion garment) performed 60-s, static handgrip and knee-extension activations at 30% and 50% of maximal voluntary force, plus a handgrip at 40% intensity (143.4 N) and a third knee extension at the same absolute force. Local sweating from four body segments (averaged to represent whole-body sudomotor activity), three deep-body and eight skin temperatures, heart rates and perceptions of physical effort were measured continuously, and analyzed over the final 30 s of exercise. Results: In the presence of thermal clamping and low-level, steady-state sweating, static muscle activation resulted in exercise-intensity dependent changes in the whole-body sudomotor response during these handgrip and knee-extension actions (P < 0.05). However, there was no evidence of a dependency on the size of the recruited muscle mass (P > 0.05), yet both dependencies were apparent for heart rate, and partially evident for the sensations of physical effort. Conclusion: These observations represent the first evidence that exercise-related sudomotor feedforward is not influenced by the size of the activated muscle mass, but is instead primarily dictated by the intensity of the exercise itself.

Heat strain during military training activities: The dilemma of balancing force protection and operational capability.

Military activities in hot environments pose 2 competing demands: the requirement to perform realistic training to develop operational capability with the necessity to protect armed forces personnel against heat-related illness. To ascertain whether work duration limits for protection against heat-related illness restrict military activities, this study examined the heat strain and risks of heat-related illness when conducting a military activity above the prescribed work duration limits. Thirty-seven soldiers conducted a march (10 km; ∼5.5 km h-1) carrying 41.8 ± 3.6 kg of equipment in 23.1 ± 1.8°C wet-bulb globe temperature. Body core temperature was recorded throughout and upon completion, or withdrawal, participants rated their severity of heat-related symptoms. Twenty-three soldiers completed the march in 107 ± 6.4 min (Completers); 9 were symptomatic for heat exhaustion, withdrawing after 71.6 ± 10.1 min (Symptomatic); and five were removed for body core temperature above 39.0°C (Hyperthermic) after 58.4 ± 4.5 min. Body core temperature was significantly higher in the Hyperthermic (39.03 ± 0.26°C), than Symptomatic (38.34 ± 0.44°C; P = 0.007) and Completers (37.94 ± 0.37°C; P<0.001) after 50 min. Heat-related symptom severity was significantly higher among Symptomatic (28.4 ± 11.8) compared to Completers (15.0 ± 9.8, P = 0.006) and Hyperthermic (13.0 ± 9.6, P = 0.029). The force protection provided by work duration limits may be preventing the majority of personnel from conducting activities in hot environments, thereby constraining a commander's mandate to develop an optimised military force. The dissociation between heat-related symptoms and body core temperature elevation suggests that the physiological mechanisms underpinning exhaustion during exertional heat stress should be re-examined to determine the most appropriate physiological criteria for prescribing work duration limits.

Predicting Endurance Time in a Repetitive Lift and Carry Task Using Linear Mixed Models.

OBJECTIVES: Repetitive manual handling tasks account for a substantial portion of work-related injuries. However, few studies report endurance time in repetitive manual handling tasks. Consequently, there is little guidance to inform expected work time for repetitive manual handling tasks. We aimed to investigate endurance time and oxygen consumption of a repetitive lift and carry task using linear mixed models. METHODS: Fourteen male soldiers (age 22.4 ± 4.5 yrs, height 1.78 ± 0.04 m, body mass 76.3 ± 10.1 kg) conducted four assessment sessions that consisted of one maximal box lifting session and three lift and carry sessions. The relationships between carry mass (range 17.5-37.5 kg) and the duration of carry, and carry mass and oxygen consumption, were assessed using linear mixed models with random effects to account for between-subject variation. RESULTS: Results demonstrated that endurance time was inversely associated with carry mass (R2 = 0.24), with significant individual-level variation (R2 = 0.85). Normalising carry mass to performance in a maximal box lifting test improved the prediction of endurance time (R2 = 0.40). Oxygen consumption presented relative to total mass (body mass, external load and carried mass) was not significantly related to lift and carry mass (ß1 = 0.16, SE = 0.10, 95%CI: -0.04, 0.36, p = 0.12), indicating that there was no change in oxygen consumption relative to total mass with increasing lift and carry mass. CONCLUSION: Practically, these data can be used to guide work-rest schedules and provide insight into methods assessing the physical capacity of workers conducting repetitive manual handling tasks.

Predicting stretcher carriage: Investigating variations in bilateral carry tests.

Carrying a casualty on a stretcher is a critical task within military and emergency service occupations. This study evaluated the impact of manipulating carry speed and the object type in bilateral carries on the ability to predict performance and reflect the physical and physiological requirements of a unilateral stretcher carry. We demonstrated that three task-related predictive tests; a jerry can carry performed at 4.5 km h(-1)or 5.0 km h(-1) and a kettle-bell carry performed at 5.0 km h(-1) were strongly predictive of the physical and physiological demands of an individual participating as part of a four-person stretcher carry team. Therefore, bilateral predictive assessments have the utility for predicting the suitability of employees to effectively and safely conduct a four-person unilateral stretcher carry.

Interactions of mean body and local skin temperatures in the modulation of human forearm and calf blood flows: a three-dimensional description.

AIM: The inter-relationships between mean body and local skin temperatures have previously been established for controlling hand and foot blood flows. Since glabrous skin contains many arteriovenous anastomoses, it was important to repeat those experiments on non-glabrous regions using the same sample and experimental conditions. METHODS: Mild hypothermia (mean body temperature 31.4 °C), normothermia (control: 36.0 °C) and moderate hyperthermia (38.3 °C) were induced and clamped (climate chamber and water-perfusion garment) in eight males. Within each condition, five localised thermal treatments (5, 15, 25, 33, 40 °C) were applied to the left forearm and right calf. Steady-state forearm and calf blood flows were measured (venous occlusion plethysmography) for each of the resulting 15 combinations of clamped mean body and local skin temperatures. RESULTS: Under the normothermic clamp, cutaneous blood flows averaged 4.2 mL 100 mL(-1) min(-1) (±0.28: forearm) and 5.4 mL 100 mL(-1) min(-1) (±0.27: calf). When mildly hypothermic, these segments were unresponsive to localised thermal stimuli, but tracked those changes when normothermic and moderately hyperthermic. For deep-body (oesophageal) temperature elevations, forearm blood flow increased by 5.1 mL 100 mL(-1) min(-1) °C(-1) (±0.9) relative to normothermia, while the calf was much less responsive: 3.3 mL 100 mL(-1) min(-1) °C(-1) (±1.5). Three-dimensional surfaces revealed a qualitative divergence in the control of calf blood flow, with vasoconstrictor tone apparently being released more gradually. CONCLUSION: These descriptions reinforce the importance of deep-tissue temperatures in controlling cutaneous perfusion, with this modulation being non-linear at the forearm and appearing linear for the calf.

Water-displacement plethysmography: a technique for the simultaneous thermal manipulation and measurement of whole-hand and whole-foot blood flows.

The purpose of this project was to design, construct and validate water-displacement plethysmographs for the forearm, hand and foot that could clamp segmental skin temperature whilst simultaneously measuring cutaneous blood flow. Two experiments were performed. In the first, the forearm plethysmograph was validated against a mercury-in-silastic plethysmograph under thermoneutral conditions, with and without forearm heating. Cutaneous vascular conductance was elevated almost three-fold by this treatment, however, there were no significant differences between the two forms of plethysmography in either state (P > 0.05). In study two, hand and foot blood flows were measured under clamped thermoneutral conditions, but with three local skin temperature treatments (5, 25, 40 °C). The hand had significantly higher blood flows than the foot at both 25 °C (4.07 versus 2.20 mL.100 mL( - 1).min( - 1); P < 0.05) and 40 °C (8.20 versus 4.47 mL.100 mL( - 1).min( - 1); P < 0.05). The foot was maximally constricted during the two lower temperatures, yet the cutaneous thermal sensitivity of the hand was almost two-fold greater (P < 0.05). This evidence supports the significant role played by these appendages in heat loss and conservation, and these plethysmographs will now be used to map cutaneous vascular responses (forearm, hand, calf, foot) across combinations of core and local skin temperatures.