Typing performance and body discomfort among overweight and obese office workers: A pilot study of keyboard modification.

Obesity in the workplace is associated with loss of productivity, high medical care expenses, and increased rates of work-related injuries and illness. Thus, effective, low-cost interventions are needed to accommodate the size of today's obese office worker while alleviating potential physical harm associated with musculoskeletal disorders. Utilizing a sample of 22 overweight and obese office workers, this pilot study assessed the impact of introducing an alternative, more ergonomically-sound keyboard on perceptions about design, acceptability, and usability; self-reported body discomfort; and typing productivity. Data were collected using self-reported questionnaires and objective typing tests administered before and after the intervention. The intervention duration was six weeks. After switching from their standard work keyboard to an alternative keyboard, all participants reported significant decreases in lower back discomfort (t = 2.14, P = 0.044); although obese participants reported significant decreases in both upper (t = 2.46, P = 0.032) and lower (t = 2.39, P = 0.036) back discomfort. No significant changes were observed in overall typing performance scores from baseline to follow-up. Findings suggest that such interventions may be introduced into the workforce with positive gains for workers without reducing short-term worker productivity.

Occupational risk factors and back injury.

Twenty-one risk factors affecting laborers in manual materials handling tasks were analyzed to determine what, if any, statistically significant relationships existed between the factors and the emergence of occupational back injury. The statistically significant risk factors (p ≤ .05) in the univariate analysis were determined to be weight lifted per hour (work intensity), trunk twists per hour, weight lifted per day, frequency of lift, trunk motions per hour, and trunk flexions per hour, with odds ratios (ORs) of 1.28-2.88. In addition, self-reported discomfort in the neck, middle back, knees, and lower back was associated with the outcome of back injury (p ≤ .05, OR 1.75-2.66). In the multivariate analysis, the statistically significant risk factors (p ≤ .05) were weight lifted per hour (work intensity), average weight of lift, and number of trunk twists per hour, with ORs of 1.74-4.98.

An in situ study of the habits of users that affect office chair design and testing.

OBJECTIVE: The purpose of this study was to perform an in situ assessment of office seating habits that influence chair testing and design. BACKGROUND: Many chair testing parameters were derived decades ago when the average weight of people within the United States was dramatically lower and the office work tasks less computer based. METHOD: For the study, 51 participants were randomly selected from Brazos Valley, Texas, businesses to participate in 8-hr assessments of office seating habits. Overall results were compared with current chair testing and design assumptions. Data were collected through written survey and through data logging of seat and back contact pressure and duration with the use of the X-SENSOR pressure mapping device and software. Additionally, I day per participant of caster roll distance was recorded with the use of a caster mounted digital encoder. Participants were grouped by body mass index (BMI) and weight (BMI <35 and weight < 102 kg or BMI >35 and weight >102 kg). RESULTS: It was determined that a significant difference did exist between the groups in mean seat time per shift (p < .001), back cycles per shift (p < .002), seat cycles per shift (p < .01), and caster distance rolled per shift (p < .001). CONCLUSION: Several key parameters and assumptions of current chair test methods and design specifications may no longer be valid for the upper quartile of weight range of the current U.S. population. APPLICATION: The data collected in this study will enable engineers to determine whether revision of design standards for testing office seating for both normal weight and extremely obese workers is indicated.

Seasonal changes in VO2max among Division 1A collegiate women soccer players.

Aerobic capacity and body composition were measured at 3 time points over a 1-year period in 26 Division 1A women soccer players from Texas A&M University, in order to determine whether there were seasonal changes in these parameters. Subjects were tested in December, immediately following a 4-month competitive season; in April, following 15 weeks of strength and conditioning; and immediately prior to the start of the regular season in August, following a 12-week summer strength and conditioning program. A periodized strength and conditioning program design was incorporated in order to optimize anaerobic and oxidative capacity immediately prior to the regular competitive season. Significant differences in VO2max were measured between August (49.24 +/- 4.38 ml x kg(-1) x min(-1)) and December (44.87 +/- 4.61 ml x kg(-1) x min(-1)). No significant changes in aerobic capacity were found between April (47.43 +/- 4.01 ml x kg(-1) x min(-1)) and August (49.64 +/- 5.25 ml x kg(-1) x min(-1)). Significant increases in body fat were measured between August (15.71 +/- 2.92%) and December (18.78 +/- 2.79%), before and after the competitive season, respectively. No significant changes in body fat were found between April (16.24 +/- 2.95%) and August (15.71 +/- 2.92%). The results of this study suggest that decreases in muscle mass over the course of a regular competitive season contribute to decreases in aerobic capacity in collegiate women soccer players. Although it is unknown whether this decrease in muscle mass is the result of inadequate training or a normal adaptation to the physiological demands imposed by soccer, the results of the current study suggest that resistance training volume should be maintained during the competitive season, in order to maintain preseason levels of muscle mass.

Personal and non-occupational risk factors and occupational injury/illness.

BACKGROUND: The materials handling industry performs is an essential function in the world economy, however, it is plagued with occupationally related injuries and illnesses. Understanding the risk factors may assist this industry in alleviating these injuries and illnesses, as well as their associated costs. METHODS: Forty-eight personal and non-occupational risk factors were measured and evaluated for statistically significant relationships with occupational injury in 442 volunteer manual material handlers who worked for three different companies, at nine US locations, with 15 different job descriptions. OSHA 200 logs were used to ascertain evidence of occupational injury within this population for 1 year after the testing and measurement was completed. RESULTS: Higher occurrences of injury were significantly associated with six risk factors in the univariate model (odds ratios 1.51-4.00). The significantly (P < 0.05) related risk factors in the univariate model were aerobic power, smoking status, perceived fitness level, fishing/hunting as a hobby, speed limit obeyance, and witnessing or being involved in a violent fight. In the multivariate analysis, five risk factors (aerobic power, smoking status, percent body fat, body mass index, and sit-and-reach measured flexibility) were significantly (P < 0.05) associated with occupational injury. Odds ratios in the multivariate analysis varied from 1.42 to 10.11. CONCLUSION: Evidence of an association of occupational injury occurrence with certain risk factors presented in personal and non-occupational univariate and multivariate models is shown. In industry, effective injury reduction programs should go beyond traditional methods of job-related ergonomic risk factors and include personal factors such as smoking, weight control, and alcohol abuse.

Postural versus chair design impacts upon interface pressure.

An investigation of postural and chair design impacts upon seat pan interface pressure has been performed in an effort to identify whether differences in posture or chair design result in greater pressure differences. Investigation of postural variables focused on trunk-thigh angle and use of armrests. Twelve ergonomic office chairs were used to assess chair design differences. Both male and female subjects were included. Gender effects were controlled through use of a repeated Latin square design, with squares defined by gender. Significant gender-based interaction was observed amongst postural treatments and chair effects. Postural treatments, chairs designs, and participant effects all resulted in significant interface pressure differences, though gender-based interaction yielded some non-additivity of results between males and females. The final conclusion drawn from the results is that chair design differences had the greatest effect on seat pan interface pressure, followed by participant effects, and lastly postural treatments.

A prospective field study of the relationship of potential occupational risk factors with occupational injury/illness.

Twenty-one occupationally related risk factors were measured and prospectively evaluated for statistically significant relationships with occupational injury/illness in 442 manual material handlers, working for three different companies, at nine U.S. locations, and encompassing 15 different job descriptions. OSHA 200 logs were used to ascertain evidence of occupational injury/illness (dichotomous) within this population for 1 year after the testing and measurement were completed. The present study demonstrated evidence of a subset of critical variables significantly related to occupational injury/illness occurrence through the significantly related occupational risk factors presented in the univariate and multivariate models. Higher occurrences of injury/illness were significantly associated with nine risk factors in the univariate model, with odds ratios ranging from 1.11-2.27. The significantly (p<0.05) related risk factors in the univariate model were lifting frequency; weight lifted per day; weight lifted per hour; number of trunk flexions per hour; number of trunk twists per hour; number of trunk motions per hour; number of knee flexions per hour; number of shoulder flexions per hour; and static shoulder flexion. In the multivariate analysis two risk factors were associated with occupational injury/illness. The significantly (p<0.05) related risk factors in the multivariate model were lifting frequency (p=0.0010, odds ratio [OR]=4.47, 95% confidence interval [CI]=[2.38-8.40], and average weight of lift (p=0.0001, OR=1.71, 95% CI=[1.29-2.25]).

Ergonomic program effectiveness: ergonomic and medical intervention.

The implementation of a successful ergonomic and medical intervention program designed to reduce the number and severity of injuries and illnesses and the associated levels of discomfort in the workplace is presented. Because of the recent activity concerning the on-again-off-again Occupational Safety and Health Administration (OSHA) Ergonomic Program Standard questions have been raised as to the value and effectiveness of an organization's ergonomics program. In light of these concerns, the immense cost associated with work-related injury and illness, and the related pain and suffering associated with such injuries and illnesses, it is important to present a workable and effective ergonomic and medical intervention program. The results of this applied study demonstrate that through the application of an ergonomic and medical intervention program, workplace-related injuries and illnesses can be reduced or eliminated.

The effects of training history, player position, and body composition on exercise performance in collegiate football players.

Performance data for 261 NCAA Division 1A collegiate football players were analyzed to determine if player position, body weight, body fat, and training time were correlated with changes in performance in the following events: power clean (PC), bench press (BP), squat (SQ), vertical jump (VJ), 40-yd dash (40yd), and 20-yd shuttle (20yd). Individual positions were combined into the following groups: (A) wide receivers, defensive backs, and running backs, (B) linebackers, kickers, tight ends, quarterbacks, and specialists, and (C) linemen. Increases in body weight were positively correlated with increases in BP and PC performance for all groups. Increases in body fat were negatively correlated with performance in the PC and VJ for all groups. For group C, increases in body fat were also negatively correlated with performance in the 40yd and 20yd. Group and training time exhibited no linear relationship with performance in any of the tested events. No linear relationships were observed between the independent variables and performance in the SQ. When individual training data were analyzed longitudinally, a nonlinear increase in performance in the PC, BP, and SQ was observed as training time increased, with the greatest rate of change occurring between the first and second semesters of training.

Development of a System for Improved Transportation and Handling of Full-Sized Pregnant Sows at a Metropolitan Research Facility.

The need of investigators for ready access to neonatal pigs that were less expensive than neonatal miniature swine prompted development of a sow transport system and an in-house farrowing program for full-sized sows. Pregnant sows weighed 200 to 250 kg. Offspring of these large sows may be overlooked for use in research because domestic pregnant sows are presumed to be difficult to transport and handle in urban laboratory animal facilities. In 1994, ergonomists analyzed risk factors involved in a sow transport system designed in 1990 and implemented manual material assist devices. The ergonomic interventions improved safety, decreased expenses, and reduced manpower requirements for handling sows during transit. Engineering solutions provided in 1994 facilitated the transport and handling of more than 80 pregnant sows that were at approximately day 100 of gestation.

Defending the Wrist Deviation Test for Carpal Tunnel Syndrome Screening: A Comparison of Vibration Thresholds and Distal Motor Latency.

This research used distal motor latency (DML) and vibration thresholds (VT) to evaluate 84 hand activity and wrist deviation combinations to determine the best association with carpal tunnel syndrome (CTS). Female volunteers, 2 healthy and 2 CTS diagnosed, were age matched and operated a keyboard for 4 hrs a day. Room temperature was 28°C(±2). Beginning DML and VT were taken with a relaxed neutral posture hand. The wrist was deviated in a randomly selected combination, and determinations were taken at 5-min intervals. The trial ended at 20 min or when discomfort was felt. The CTS conditions were discriminated by pain four times, DML once, and VT 14 times. Vibrometry was the most consistent CTS discriminator. The best VT results for wrist positions were obtained with wrist extension and extended extension, whereas the unclenched, clenched, and loaded power grip activities proved to be the most consistent hand activities.