Individual thermal profiles as a basis for comfort improvement in space and other environments.

BACKGROUND: The development of individualized countermeasures to address problems in thermoregulation is of considerable importance for humans in space and other extreme environments. A methodology is presented for evaluating minimal/maximal heat flux from the total human body and specific body zones, and for assessing individual differences in the efficiency of heat exchange from these body areas. The goal is to apply this information to the design of individualized protective equipment. METHODS: A multi-compartment conductive plastic tubing liquid cooling/warming garment (LCWG) was developed. Inlet water temperatures of 8-45 degrees C were imposed sequentially to specific body areas while the remainder of the garment was maintained at 33 degrees C. RESULTS: There were significant differences in heat exchange level among body zones in both the 8 degrees and 45 degrees C temperature conditions (p < 0.001). The greatest amount of heat was absorbed/released by the following areas: thighs (8 degrees C: -2.12 +/- 0.14 kcal min(-1); 45 degrees C: +1.58 +/- 0.23); torso (8 degrees C: -2.12 +/- 0.13 kcal min(-1); 45 degrees C: +1.31 +/- 0.27); calves (8 degrees C: -1.59 +/- 0.26 kcal min(-1); 45 degrees C: +1.53 +/- 0.24); and forearms (8 degrees C: -1.67 +/- 0.29 kcal x min(-1); 45 degrees C: +1.45 +/- 0.20). These are primarily zones with relatively large muscle mass and adipose tissue. Calculation of absorption/release heat rates standardized per unit tube length and flow rate instead of zonal surface area covered showed that there was significantly greater heat transfer in the head, hands, and feet (p < 0.001). The areas in which there was considerable between-subject variability in rates of heat transfer and thus most informative for individual profile design were the torso, thighs, shoulders, and calves or forearms. CONCLUSIONS: The methodology developed is sensitive to individual differences in the process of heat exchange and variations in different body areas, depending on their size and tissue mass content. The design of individual thermal profiles is feasible for better comfort of astronauts on long-duration missions and personnel in other extreme environments.

Grip form and graphomotor control in preschool children.

OBJECTIVE: The purpose of this study was to examine the utility of the grip scale presented by Schneck and Henderson, the effect of grip form on drawing accuracy, and the effect of implement diameter on grip form and drawing accuracy. METHOD: Sixty boys and girls who were 3, 4, and 5 years of age performed 20 trials of a precision drawing task, 4 trials each with five implements of varying diameters (4.7, 7.9, 11.1, 14.3, and 17.5 mm). RESULTS: First, all 1,200 grips could be coded according to Schneck and Henderson's 10-grip whole-configuration assessment system, but the interrater reliability was lower than expected (.67 proportion of perfect agreement). Second, using Schneck's five-level scoring system, the level of grip significantly affected drawing accuracy, with the highest grip level used most often with the highest accuracy scores and the lowest observed grip level used most often with the lowest accuracy scores. Third, increasing implement diameter led to significantly lower level grips but did not significantly affect accuracy. CONCLUSIONS: Therapists are recommended to use Schneck and Henderson's 10-grip scale only for documenting the persons' grips and changes in their grips, but if comparisons between individual persons are desired, then Schneck's five-level scale, which affords greater generalizability, should be used. Further, children with graphomotor performance deficits are not likely to benefit from grip manipulations because such strategies were shown to make better only performance that is already good.

Reliability of an in-shoe pressure measurement system during treadmill walking.

We examined the reliability of in-shoe foot pressure measurement using the Pedar in-shoe pressure measurement system for 25 participants walking at treadmill speeds of 0.89, 1.12, and 1.34 meters/sec. The measurement system uses EMED insoles, which consist of 99 capacitive sensors, sampled at 50 Hz. Data were collected for 20 seconds at two separate times while participants walked at each gait speed. Differences in some of the loading variables across speed relative to the total foot and across the different anatomical regions were detected. Different anatomical regions of the foot were loaded differently with variations in walking speed. The results indicated the need to control speed when evaluating loading parameters using in-shoe pressure measurement techniques. Coefficients of reliability were calculated. Variables such as peak force for the total foot required two steps to achieve a coefficient of reliability of 0.98. To achieve excellent reliability (> 0.90) in the peak force, force time integral, peak pressure, and pressure time integral across the total foot and the seven regions, a maximum of eight steps was needed. In general, timing variables, such as the instant of peak force and the instant of peak pressure, tended to be the least reliable measures.