Raechel M. Laing

Compression Garments and Exercise

Compression garments (CGs) provide a means of applying mechanical pressure at the body surface, thereby compressing and perhaps stabilizing/ supporting underlying tissue. The body segments compressed and applied pressures ostensibly reflect the purpose of the garment, which is to mitigate exercise-induced discomfort or aid aspects of current or subsequent exercise performance. Potential benefits may be mediated via physical, physiological or psychological effects, although underlying mechanisms are typically not well elucidated. Despite widespread acceptance of CGs by competitive and recreational athletes, convincing scientific evidence supporting ergogenic effects remains somewhat elusive. The literature is fragmented due to great heterogeneity among studies, with variability including the type, duration and intensity of exercise, the measures used as indicators of exercise or recovery performance/physiological function, training status of participants, when the garments were worn and for what duration, the type of garment/ body area covered and the applied pressures. Little is known about the adequacy of current sizing systems, pressure variability within and among individuals, maintenance of applied pressures during one wear session or over the life of the garment and, perhaps most importantly, whether any of these actually influence potential compression-associated benefits.During exercise, relatively few ergogenic effects have been demonstrated when wearing CGs. While CGs appear to aid aspects of jump performance in some situations, only limited data are available to indicate positive effects on performance for other forms of exercise. There is some indication for physical and physiological effects, including attenuation of muscle oscillation, improved joint awareness, perfusion augmentation and altered oxygen usage at sub-maximal intensities, but such findings are relatively isolated. Sub-maximal (at matched work loads) and maximal heart rate appears unaffected by CGs. Positive influences on perceptual responses during exercise are limited.During recovery, CGs have had mixed effects on recovery kinetics or subsequent performance. Various power and torque measurements have, on occasions, benefitted from the use of CGs in recovery, but subsequent sprint and agility performance appears no better. Results are inconsistent for post-exercise swelling of limb segments and for clearance of myocellular proteins and metabolites, while effects on plasma concentrations are difficult to interpret. However, there is some evidence for local blood flow augmentation with compression. Ratings of post-exercise muscle soreness are commonly more favourable when CGs are worn, although this is not always so. In general, the effects of CGs on indicators of recovery performance remain inconclusive. More work is needed to form a consensus or mechanistically-insightful interpretation of any demonstrated effects of CGs during exercise, recovery or — perhaps most importantly — fitness development. Limited practical recommendations for athletes can be drawn from the literature at present, although this review may help focus future research towards a position where such recommendations can be made.

Clothing and bedding and its relevance to sudden infant death syndrome: Further results from the New Zealand Cot Death Study

As part of a large nationwide case‐control study covering a region with 78% of all births in New Zealand during 1987–90, the clothing and bedding of infants dying of sudden infant death syndrome (SIDS) and that of an appropriate control group were recorded. Cases consisted of 81% (n= 393) of all cases of SIDS in the study area and 88.4% (n= 1592) of 1800 control infants randomly selected from the hospital births and who completed a home interview.

A light-weight cooling vest enhances performance of athletes in the heat

During the 1990s, emphasis on the health and safety of people who exercise in hot, humid conditions increased and many organizations became aware of the need for protection against heat-related disorders. A practical, pre-cooling strategy applicable to several sporting codes, which is low cost, easy to use, light-weight and which enhances cooling of the human body prior to and following exercise, was developed and tested. Eight males and eight females participated in a maximal oxygen consumption ([Vdot]O2max) test and four trials: a control (without cooling) and wearing each of three different cooling vests (A, B, C). Vests were worn during the rest, stretch, warm-up (50% [Vdot]O2max) and recovery stages of the protocol, but not during the 30 min run (70% [Vdot]O2max). Core and skin temperatures during exercise were reduced (by approximately 0.5°C, rectal; 0.1 – 1.4°C, abdominal skin temperature) and sweat rates were lower (by approximately 10 – 23%). Endurance times for running at 95% of [Vdot]O2max were increased by up to 49 s. Perceptions of the thermal state and skin wetness showed changes to greater levels of satisfaction. Physiological and sensory responses were related to design features of the vests.

Development of sizing systems for protective clothing for the adult male

The aim of the study was to obtain comprehensive anthropometric data from which to develop a sizing system appropriate for inclusion in specifications for protective clothing; and for purchases of other selected equipment. Fifty-five body dimensions on a male sample of the New Zealand Fire Services (n = 691, approximately 7% of employees) were obtained by direct measurement. Descriptive statistics and selected percentiles (5th, 50th, 95th) are given. The body dimensions accounting for most of the variance in the data were established by factor analysis and are reported here. Size groups for various body sections based on the relevant measurements of that section were established by cluster analysis around a control variable.

Fibers from three cultivars of New Zealand flax (Phormium tenax)

Botanists recognize only two kinds of New Zealand flax (Phormium tenax and Phormium colensoi), while Māori weavers recognise over fifty different cultivars that have specific end-uses. Selected properties of muka 4 (sclerenchyma fiber aggregates extracted from harakeke (P. tenax)) from three of these cultivars (Arawa, Tapamangu, Makaweroa) are examined. Māori consider these three cultivars to provide excellent fibers that are easy to process. Tapamangu and Arawa are similar in terms of muka length, linear density, tenacity, extension at maximum load, and maximum extension, and the ultimate fibers of these cultivars have similar dimensions (width, length). Muka from Makaweroa is longer, not as tough, but with a linear density similar to the other cultivars. The ultimate fiber length of Makaweroa is greater, but the width is similar to Tapamangu and Arawa. Muka from the keel is longer, of higher linear density, and tougher (similar tenacity, higher maximum extension) compared to margin muka. The side of the leaf from which muka is extracted does not affect the properties measured.

Odor Intensity in Apparel Fabrics and the Link with Bacterial Populations

Nine apparel fabrics varying in fiber (cotton, wool, polyester) and knit structure (1 × 1 rib, interlock, single jersey) were investigated for their retention of axillary odor following wear. As axillary odor results from bacterial metabolism of apocrine and sebaceous secretions, counts of total aerobic bacteria and corynebacteria on the fabrics were carried out. Odor intensity was strongly associated with the fiber type, with polyester fabrics rating high in odor intensity and cotton and wool mid-low odor intensity. A structure effect was apparent for polyester fabrics, with the lightweight single jersey fabric rated less odorous than the heavier-weight interlock and 1 × 1 rib structures. The relationship between fiber type and odor was not influenced by bacterial numbers present, with counts after one day similar for all fabrics. However, the number of bacteria declined more rapidly on polyester fabrics than on either the cotton or wool fabrics. Counts of odor-associated corynebacteria subgroup (A) remained largely unchanged on wool fabrics for 28 days.

Standardizing a Pre-treatment Cleaning Procedure and Effects of Application on Apparel Fabrics

The objective of this work was to develop a pre-treatment (cleaning) procedure for a wide range of apparel fabrics and to determine whether differences observed in the properties of fabrics which had and had not been pre-treated were significant. Properties relevant to the manufacture and/or performance of apparel included mass per unit area, thickness, bending length, flex-ural rigidity, drape coefficient, air permeability, water vapor permeability, liquid absorptive capacity, drying time, ‘dry’ thermal resistance, ultra-violet transmission. Results for the same property on the same fabric measured when the fabrics had and had not been pre-treated generally differed significantly, confirming the importance of pre-treatment prior to measuring these properties, particularly when claiming in-use attributes of fabrics. A procedure for pre-treatment is recommended: six consecutive cleaning cycles following procedure 8A of British Standard EN ISO 6330: 2001 (i.e. not dried between cycles), and dried flat following procedure C of this standard.

Solar Protection — Effect of Selected Fabric and Use Characteristics on Ultraviolet Transmission

Clothing is worn in single- and multiple-layer arrangements and during use subjected to conditions such as extension and wetting. This study investigated how selected variables affected transmission of ultraviolet radiation (UVR) through fabrics and whether these variables interacted to modify transmission. Using a spectrophotometer the effect of i) fabric type (two knitted, two woven), color (black and white), wetness (dry, damp, wet), and extension (relaxed, extended (10 × 10%, 10 × 20%)), and ii) fabric type and layering (1, 2, 3 layers) of white fabrics, on UVR (290—400 nm), UVA (315—400 nm), UVB (290—315 nm), and ultraviolet protection factor (UPF) rating was investigated. Differences among variables were identified using univariate and repeated measures ANOVA, and interactions among variables identified and described. Selecting dark colors, limiting extension and layering fabric were shown to be effective ways of increasing UV protection and UPF by decreasing transmittance. However, the effect of color, extension and layering varied among fabric types and modified UVA and UVB transmittance differently.

Retention of axillary odour on apparel fabrics

Abstract Clothing worn in close proximity to the human axilla can retain and emanate human body odour even remaining odorous long after removal from the body. Intensity of odour is affected by the fibre type from which the garment is made. Headspace analysis of axillary volatile compounds released from three interlock fabrics (cotton, wool, polyester) following wear were measured using an online monitoring instrument, proton transfer reaction-mass spectrometry (PTR-MS). Compounds likely to be short-chain carboxylic acids increased in the headspace above the polyester fabrics after 7 days. This increase was not evident above either the wool or cotton fabrics. The intensity of axillary odour emanating from these fabrics was inversely related to fibre hygroscopicity. The relationship between a textile fibre/fabrics ability to retain and emanate odour is likely to be related to the metabolic versatility of resident microbial strains and/or the chemical and physical morphology of the fibre and its ability to absorb volatile compounds and precursors to odour.

Helmet design to facilitate thermoneutrality during forest harvesting

The purpose of this investigation was to evaluate the ventilatory characteristics of vented and non-vented helmets for use in forestry harvesting operations. A ventilation index developed by Birnbaum and Crockford (1978) was used to determine the ventilation capacity of twelve helmets varying in design and presence, location, and dimension of vents. Helmets with top vents had higher ventilation indices than non-vented, side and side/top-vented helmets. Ten physically fit men participated in a maximal oxygen consumption test and four trials wearing a non-vented, round-side-vented, round-top-vented or rectangulartop-vented helmet. Trials simulated typical summer environmental conditions (28°C, 80% rh) and physiological work loads (40% V O 2 max) experienced during forest harvesting in New Zealand. The temperature and humidity under the helmet was typically lowest when the helmet with the largest vented area (288 mm 2) in the crown was worn, although physiological responses (temperatures at the tympanum, ear and scalp; humidity at the centre of the helmet) of the participants to wearing the helmets differed significantly during some rest periods only. Top-vented helmets (in this experiment measured 288 mm 2) should be worn to minimize temperature and humidity of the head during forest harvesting operations.