Alteration in HDEMG Spatial Parameters of Trunk Muscle Due to Handle Design during Pushing

Previous research identifies that pushing and pulling is responsible for approximately 9–18% of all low back injuries. Additionally, the handle design of a cart being pushed can dramatically alter a worker’s capacity to push (≅9.5%). Surprisingly little research has examined muscle activation of the low back and its role in muscle function. Therefore, the purpose of this study was to examine the effects of handle design combination of pushing a platform truck cart on trunk muscle activity. Twenty participants (10 males and 10 females, mean age = 24.3 ± 4.3 years) pushed 475 lbs using six different handle combinations involving handle orientation (vertical/horizontal/semi-pronated) and handle height (hip/shoulder). Multichannel high-density EMG (HDsEMG) was recorded for left and right rectus abdominis, erector spinae, and external obliques. Pushing at hip height with a horizontal handle orientation design (HH) resulted in significantly less (p < 0.05) muscle activity compared to the majority of other handle designs, as well as a significantly higher entropy than the shoulder handle height involving either the semi-pronated (p = 0.023) or vertical handle orientation (p = 0.028). The current research suggests that the combination of a hip height and horizontal orientation handle design may require increased muscle demand of the trunk and alter the overall muscle heterogeneity and pattern of the muscle activity.

Incidence of Low Back Injuries Among Iranian Athletes in 12 Disciplines of Olympic Sports

Purpose: The present research aimed to determine the prevalence and incidence rate of low back pain and injury in 12 Olympic sports athletes presenting to the injury surveillance system of the Sports Medicine Federation of Iran. Methods: A retrospective analysis was conducted on the data of athletes from the injury surveillance system of the Sports Medicine Federation of Iran, for three years. Descriptive statistic was used for the study. Results: The incidence rate of 6.7 injuries per 10000 athletes registered was calculated for low back complaints in 12 sports disciplines. Weightlifting, wushu, and judo had the highest, and gymnastic and soccer had the lowest low back injuries incidence. More than one-third of the low back complaints involved the lumbar spine. Also, females were at higher risk of low back pain and injury than males. Of age categories, adults and elderlies had the highest prevalence of low back complaints with more involvement in the lumbar spine. Conclusion: According to the results, wushu, judo, and especially weightlifting should be the priority of prevention. Furthermore, females and elderlies require more focus on preventive measures.

Lower Back Injuries in National Collegiate Athletic Association Football Players: A 5-Season Epidemiological Study

Background: Low back injuries are common in collegiate football players and can frequently lead to persistent pain, reinjuries, and time lost from participation. Purpose: To describe the epidemiology of back injuries in National Collegiate Athletic Association (NCAA) football players during the 2009/2010 through 2013/2014 academic years utilizing the NCAA Injury Surveillance Program (ISP) database. Study Design: Descriptive epidemiology study. Methods: A convenience sample of NCAA varsity football teams was utilized to determine the rates and patterns of back injuries as well as to generate national injury estimates. The rates and distribution of back injuries were identified within the context of mechanism of injury, injury chronicity, and time lost from sport. Injury rates were calculated as the number of injuries divided by the total number of athlete-exposures (AEs). Incidence rate ratios were calculated to compare the rates of injury between season, event type, mechanism of injury, injury chronicity, and time lost from sport. Results: Nationally, there were 267 low back injuries reported in the database. These were used to estimate 7076 back injuries over the 5-year period, approximately 82% of which were new injuries. The injuries occurred at a rate of 2.70 per 10,000 AEs. Overall, injuries were 3.12 times more likely to occur in competitions than in practices. Athletes were 4.67 times more likely to sustain a back injury during the preseason compared with the postseason but were 1.41 times more likely to sustain a low back injury during the preseason compared with the regular season. Both contact and noncontact were reported equally as the mechanism of injury (37.8% and 38.3%, respectively), and unspecified low back pain was the most common injury (64.2%). Only 1.6% of patients required surgery for their injury, and the majority of athletes (59.6%) returned to play within 24 hours. Conclusion: There was a relatively high rate of lumbar back injuries at the collegiate level (2.70/10,000 AEs), the majority of which were new injuries. About 18% of reported injuries were reinjuries. Although very few required surgery, a careful examination and work-up should be conducted to evaluate each injury. Regimented physical therapy and reconditioning programs are recommended to avert reinjuries.

Medical Care Spending and Labor Market Outcomes: Evidence from Workers’ Compensation Reforms

Medical care represents an important component of workers’ compensation benefits with the potential to improve health and post-injury labor outcomes, but little is known about the relationship between medical care spending and the labor outcomes of injured workers. We exploit the 2003–2004 California workers’ compensation reforms which reduced medical spending disproportionately for workers incurring low back injuries. We link administrative claims data to earnings records for injured workers and their uninjured coworkers. We find that workers with low back injuries experienced a 7.6 percent post-reform decline in medical care, and an 8.1 percent drop in post-injury earnings relative to other injured workers. (JEL I11, I12, I13, J24, J28, J31)

Effect of Load Weight and Starting Height on the Variability of Trunk Kinematics

Trunk kinematic variables have been used to understand the risk of low back injuries in the workplace. Variability in trunk kinematics has not been explored to the same level. In the current study, it was hypothesized that workplace variables (starting height and load weight) would have an impact on the variability in the kinematic variables describing trunk motion. Ten participants performed a repetitive lifting task under four different conditions representing two levels of load weight and starting height. The Lumbar Motion Monitor was used to capture key trunk kinematic variables from the concentric range of lifting motion. The dominant parameter in this experiment was found to be the starting height of the lift which significantly affected the variability of trunk kinematics in sagittal plane. In the transverse plane neither starting height of the load nor the weight of the load were found to influence the variability of trunk kinematics significantly.