Effects of firefighting gloves styles on manual performance.

This study analyzes structural characteristics of firefighting gloves from the perspective of style design, to investigate the impact of the fit of four types of selected firefighting gloves on firefighters' manual operation efficiency. Seventeen male college students participated in the ergonomic trial to compare manual work done with bare hands and while wearing gloves. The results showed that the participants' hand dexterity decreased after wearing firefighting gloves, but there were significant differences between different styles of gloves. As glove thickness increased, the time to complete manual work increased continuously. But the change in the participant's hand and finger length did not affect the tactile perception of gloves. The construction of fingers had an inverse significant effect on dexterity and grip performance. To enhance manual performance, it is recommended that hand length, finger length and finger girth be considered when designing firefighting gloves based on the motion characteristics of firefighting operations.

Duration limits for exposure for the whole body and extremities with a military extreme cold protection clothing ensemble at an ambient temperature of -40°C.

Manual performance and body temperature responses were assessed in a 1-h trial at an ambient temperature (TAMB) of -40°C for 7 male participants (32 ± 14 (mean ± SD) years) wearing a typical military extreme cold protection clothing ensemble. The purpose was to establish duration limited exposure (DLIM) for these conditions, and it was hypothesized that (i) core temperature (TCORE) would remain normothermic, whereas extremity skin temperature (TSK) would decrease; (ii) decrements of manual performance would be in proportion to decreases of hand TSK; and (iii) DLIM would be determined by the hand or foot TSK responses. Linear regression was employed to assess associations of manual performance scores and body temperatures with DLIM assessed using the Required Clothing Insulation (IREQ) model and extremity temperatures in ISO 11079-2007. Results showed TCORE remained at ~37.3°C, whereas there were significant (0.0001 < p < 0.05) decreases in extremity TSK. Associations between manual performance and hand TSK showed coefficients of determination (R2) ranging from 0.48 < R2 < 0.98; 0.00005 ≤ p ≤ 0.08. The DLIM for the whole-body ensemble ranged from 2.2 h to > 8 h, whereas the DLIM for the extremities was 0.56 ± 0.20 h for TSK decreasing 15°C. In conclusion, the hypotheses of a stable core temperature and decreases of extremity skin temperature giving decrements in manual performance were accepted as was the hypothesis that duration limits for exposure would be determined by extremity skin temperatures of the hand and foot.

The Combined Effect of Cold and Moisture on Manual Performance.

Objective The aim of this study was to investigate the combined effect of cold and moisture on manual performance and tactile sensitivity. Background People working in the ocean environment often perform manual work in cold and wet conditions. Although the independent effects of cold and moisture on hand function are known, their combined effect has not been investigated. Method Participants completed sensory (Touch-Test, two-point discrimination) and motor (Purdue Pegboard, Grooved Pegboard, reef knot untying) tests in the following conditions: dry hand, wet hand, cold hand, and cold and wet hand. Results For the Purdue Pegboard and knot untying tasks, the greatest decrement in performance was observed in the cold-and-wet-hand condition, whereas the decrements seen in the cold-hand and wet-hand conditions were similar. In the Grooved Pegboard task, the performance decrements exhibited in the cold-and-wet-hand condition and the cold-hand condition were similar, whereas no decrement was observed in the wet-hand condition. Tactile sensitivity was reduced in the cold conditions for the Touch-Test but not the two-point discrimination test. CONCLUSION: The combined effect of cold and moisture led to the largest performance decrements except when intrinsic object properties helped with grasp maintenance. The independent effects of cold and moisture on manual performance were comparable. Application Tools and equipment for use in the cold ocean environment should be designed to minimize the effects of cold and moisture on manual performance by including object properties that enhance grasp maintenance and minimize the fine-dexterity requirements.

The Influence of Hand Immersion Duration on Manual Performance.

OBJECTIVE: To investigate the effect of hand immersion duration on manipulative ability and tactile sensitivity. BACKGROUND: Individuals in maritime settings often work with hands that have been immersed in water. Although research has shown that hand immersion duration differentially impacts skin adhesion and tactile sensitivity, the effect of hand immersion on manipulative ability has not been directly tested. Given how critical manipulative ability is for the safety and performance of those working at sea, the effect of hand immersion duration on manual performance was investigated. METHOD: Tests of manipulative ability (Purdue Pegboard, Grooved Pegboard, reef knot untying) and tactile sensitivity (Touch-Test) were completed following no-exposure, short-exposure, and long-exposure hand immersions in thermoneutral water. RESULTS: Compared to the no immersion condition, the Purdue Pegboard performance was reduced in both immersion conditions (short exposure, -11%; long exposure, -8%). A performance decrement was only observed in the short exposure condition (+15% in time to complete task) for the reef knot untying task. There were no statistical differences in the Grooved Pegboard or Touch-Test scores between exposure conditions. CONCLUSION: Immersing the hands in water decreases manipulative ability except for when object properties reduce the slipperiness between the hand and object. APPLICATION: Manual performance in a wet environment may be conserved by designing tools and objects with edges and textures that can offset the slipperiness of wet hands. To maintain safety, the time requirements for working with wet hands needs to be considered.

Age and practice effects on inter-manual performance asymmetry.

Manual dexterity declines with increasing age, however, the way in which inter-manual asymmetry responds to aging is unclear. Our purpose was to determine the effect of age and practice on inter-manual performance asymmetry in an isometric force pinch line tracing task that varied in difficulty within segments. Thirty right-handed participants, five males and five females in each of three age groups, young (Y20), young-old (O70), and old-old (O80), practiced an isometric force pinch task for 10 trials with each hand on each of five consecutive days. Inter-manual performance asymmetry of the right and left hands was analyzed with a repeated measures analysis of variance (ANOVA) of asymmetry with age groups, practice, task difficulty, and hand as factors. The within-individual magnitude of asymmetry was also analyzed with a repeated measures ANOVA of manual asymmetry calculated as an asymmetry index (AI). Post hoc pair-wise comparisons were performed when significance was found. We observed no inter-manual performance asymmetry on this isometric tracing task among any of the age groups, either in the hand performance differences or in the magnitude of the AI. Age and practice interacted in terms of manual performance: the Y20 and O70 group improved accuracy and task time across the 5 days of practice but the O80 group did not. However, practice did not differentially affect the AI for accuracy or task time for any group. Accuracy of performance of the two hands was differentially affected by practice. All age groups exhibited poorer performance and larger AIs on the most difficult segments of the task (3 and 6) and this did not change with practice.

Corpus callosal microstructure influences intermanual transfer in chimpanzees.

Learning a new motor skill with one hand typically results in performance improvements in the alternate hand. The neural substrates involved with this skill acquisition are poorly understood. We combined behavioral testing and non-invasive brain imaging to study how the organization of the corpus callosum was related to intermanual transfer performance in chimpanzees. Fifty-three chimpanzees were tested for intermanual transfer of learning using a bent-wire task. Magnetic resonance and diffusion tensor images were collected from 39 of these subjects. The dominant hand showed greater performance benefits than the nondominant hand. Further, performance was associated with structural integrity of the motor and sensory regions of the CC. Subjects with better intermanual transfer of learning had lower fractional anisotropy values. The results are consistent with the callosal access model of motor programming.

Efeito da prática regular de atividade física no desempenho motor em idosos / Effect of regular practice of physical activity in motor performance in the elderly

Os efeitos do envelhecimento contribuem para uma maior lentidão no processamento da informação, nomeadamente ao nível do tratamento da informação sensorial, decisão e programação dos movimentos. O presente estudo investigou o tempo de reação simples e o tempo de antecipação-coincidência, em idosos praticantes e não praticantes de atividade física. Constituíram a amostra 66 idosos de ambos os sexos com idade cronológica entre os 65 e os 89 anos (M = 74,3; SD = 6,0 anos), dos quais 34 eram praticantes de atividade física regular e 32 não praticantes de atividade física regular. Os instrumentos utilizados foram o "Multi-Choice Reaction Time Apparatus" para avaliar o tempo de reação simples (TRS) e o "Bassin Anticipation Timer" para avaliar a antecipação-coincidência (AC). Estas capacidades são relevantes no bem-estar e funcionalidade da população mais envelhecida. Cada participante realizou com a mão preferida um total de seis tentativas na tarefa de TRS e 20 tentativas na tarefa de AC. Os resultados revelaram que o grupo de praticantes de atividade física demonstrou desempenhos superiores tanto na tarefa de TRS como na tarefa de AC. O sexo foi fator influente apenas no grupo de praticantes no desempenho das duas tarefas, sendo os homens mais rápidos e precisos do que as mulheres. Um processamento da informação mais rápido nos homens pode estar na base destes resultados. Como as duas capacidades avaliadas neste estudo constituem uma expressão da integridade funcional do sistema nervoso central, os resultados sugerem que a prática de atividades motoras sistemáticas pode retardar e ser um importante protetor contra os efeitos de envelhecimento nos processos perceptivo-motores inerentes a este tipo de tarefas.

The slowing down in information processing, particularly at the level of sensory information, decision and movement programming in elderly is a consequence of aging. The present study investigated simple reaction time and coincidence-anticipation in 44 physical active and in 33 non-physical active male and female elderly individuals, with chronological age between 60- to 89-years-old (M = 73.7; SD = 7.4 years). The Multi-Choice Reaction Time was used to measure simple reaction time (SRT) and the Bassin Anticipation Timer was used to evaluate coincidence-anticipation (CA). These abilities play a major role in the functionality and well being of the elderly. Each participant performed with the preferred hand a total of six trials in the SRT task and twenty trials in the CA task. The results showed that the physical active group outperformed the non-physical active group in both tasks and only in this group males were better than females. A faster information process in males could underlie this outcome. Since the two abilities evaluated in this study constitute an expression of the functional integrity of the central nervous system, the results suggest that systematic practice of physical activity can delay and be an important protector against the effects of aging in the perceptual-motor processes involved in this type of tasks.

Effects of Mild and Moderate Acute Hypobaric Hypoxia on Manual Performance / 航天医学与医学工程

Objective To explore the effects of mild and moderate acute hypobaric hypoxia on manual performance.Methods Using hypobaric chamber to simulate hypoxia conditions and devising 4 kinds of objective ergonomic testing items(Insert sticks into holes-board,ISIHB;nut-bolt assembly task,NBAT;shape discrimination,SD;and Grip strength,GS including fatigue and tolerance)and one subjective research item(questionnaire subjective sense)to examine manual work efficiency varieties of 9 subjects exposed to a hypobaric chamber with 5 simulated altitudes(3 500,4 000,4 500,5 000 and 5 500 m),for(25?5)min.Results Compared to control group(50 m,the altitude of Beijing):Accomplish time(AT)performance of ISIHB and NBAT significantly decreased(P

Study on Range of Motion of Manual Performance for Ergonomics Evaluation / 航天医学与医学工程

Objective To search for perfect and logical evaluation indexes of range of motion of manual performance and maximal voluntary range of motion. Methods From mechanism of hand movement and characteristics of manual action,some relative comprehensive evaluation indexes on range of motion of manual performance were provided.Twenty six undergraduates (14 male and 12 female)participated in the test for 16 indexes. Results The maximal voluntary range of motion of thumb,four fingers and wrist were obtained. Conclusion The results can provide foundation for ergonomics design of spacesuit gloves.