This study evaluated the performance of 6 commercially available hard hat designs—differentiated by shell design, number of suspension points, and suspension tightening system—in regard to their ability to attenuate accelerations during vertical impacts to the head. Tests were conducted with impactor materials of steel, wood, and lead shot (resembling commonly seen materials in a construction site), weighing 1.8 and 3.6 kg and dropped from 1.83 m onto a Hybrid III head/neck assembly. All hard hats appreciably reduced head acceleration to the unprotected condition. However, neither the addition of extra suspension points nor variations in suspension tightening mechanism appreciably influenced performance. Therefore, these results indicate that additional features available in current hard hat designs do not improve protective capacity as related to head acceleration metrics.
Arthur Alves Dos Santos, James Sorce, Alexandra Schonning, and Grant Bevill
Shanie A.L. Jayasinghe, Rui Wang, Rani Gebara, Subir Biswas, and Rajiv Ranganathan
Impairment of arm movements poststroke often results in the use of compensatory trunk movements to complete motor tasks. These compensatory movements have been mostly observed in tightly controlled conditions, with very few studies examining them in more naturalistic settings. In this study, the authors quantified the presence of compensatory movements during a set of continuous reaching and manipulation tasks performed with both the paretic and nonparetic arm (in 9 chronic stroke survivors) or the dominant arm (in 20 neurologically unimpaired control participants). Kinematic data were collected using motion capture to assess trunk and elbow movement. The authors found that trunk displacement and rotation were significantly higher when using the paretic versus nonparetic arm (P = .03). In contrast, elbow angular displacement was significantly lower in the paretic versus nonparetic arm (P = .01). The reaching tasks required significantly higher trunk compensation and elbow movement than the manipulation tasks. These results reflect increased reliance on compensatory trunk movements poststroke, even in everyday functional tasks, which may be a target for home rehabilitation programs. This study provides a novel contribution to the rehabilitation literature by examining the presence of compensatory movements in naturalistic reaching and manipulation tasks.
Brendan L. Pinto, Daniel Viggiani, and Jack P. Callaghan
The lumbar extensor spinae (LES) has an oblique orientation with respect to the compressive axis of the lumbar spine, allowing it to counteract anterior shear forces. This mechanical advantage is lost as spine flexion angle increases. The LES orientation can also alter over time as obliquity decreases with age and is associated with decreased strength and low back pain. However, it is unknown if LES orientation is impacted by recent exposures causing adaptations over shorter timescales. Hence, the effects of a 10-minute sustained spine flexion exposure on LES orientation, thickness, and activity were investigated. Three different submaximally flexed spine postures were observed before and after the exposure. At baseline, orientation (P < .001) and thickness (P = .004) decreased with increasingly flexed postures. After the exposure, obliquity further decreased at low (pairwise comparison P < .001) and moderately (pairwise comparison P = .008) flexed postures. Low back creep occurred, but LES thickness did not change, indicating that decreases in orientation were not solely due to changes in muscle length at a given posture. Activation did not change to counteract decreases in obliquity. These changes encompass a reduced ability to offset anterior shear forces, thus increasing the potential risk of anterior shear-related injury or pain after low back creep-generating exposures.
Jack P. Callaghan
Ali Brian, Angela Starrett, Adam Pennell, Pamela Haibach-Beach, Emily Gilbert, Alexandra Stribing, Sally Taunton Miedema, and Lauren Lieberman
Youth with visual impairments are more likely to be overweight than peers without visual impairments and often struggle with their locomotor skills. Locomotor development can combat unhealthy body weight statuses by supporting physical activity behaviors. There are no longitudinal investigations concerning the locomotor skill and body mass index (BMI) developmental trajectories of youth with visual impairments. The purpose of this study was to examine the 3-year developmental trajectory of the locomotor skills and BMI of youth with visual impairments including differential effects of self-reported gender and degree of vision. Participants (N = 34, Mage = 11.75 years, 47% female) showed severely delayed and arrested locomotor development with increases in BMI across 3 years regardless of self-reported gender or degree of vision. Participants failed to breech a proficiency barrier of motor competence to combat against increases in BMI across time. Additional longitudinal inquiries are needed.
Ryota Ashizawa, Kazuma Yamashita, Koki Take, Kengo Okawara, Eri Mochizuki, Asuka Sakamoto, and Yoshinobu Yoshimoto
The purpose of this single-masked randomized clinical trial was to examine whether nonleisure-time physical activity guidance (NLTPAG) improves physical activity levels in patients after minor ischemic stroke. Patients who had been hospitalized for minor ischemic stroke in an acute care hospital (National Health Institute Stroke Scale ≤ 5) were randomized to either an NLTPAG group (n = 17) or a leisure-time physical activity guidance group (n = 16). NLTPAG focused on reducing sedentary behavior and increasing the frequency of walking for shopping and household activities to improve physical activity levels in daily life. Physical activity levels significantly improved only in participants in the NLTPAG group (initial assessment: metabolic equivalents of task = 12.6; final assessment: metabolic equivalents of task = 14.8; p = .035, r = .51). These results suggest that NLTPAG may be effective for improving physical activity levels in patients after minor ischemic stroke.
T.N. Kirk, Justin A. Haegele, and Xihe Zhu
The purpose of this inquiry was to examine the relationship between barriers to physical activity, expectancy-value variables, and physical activity engagement among adults with visual impairments. Using a descriptive correlational approach, a sample of 214 adults with visual impairments (M age = 43.14, SD = 13.67) completed questionnaires pertaining to barriers to physical activity, expectancy-value beliefs about physical activity, and physical activity engagement. Data were analyzed via correlation and hierarchical regression. The final regression model explained 20.30% of variance in physical activity (p < .001). Intrinsic value (β = 0.26, p = .01) and expectancy beliefs (β = 0.33, p < .001) each emerged as significant predictors of physical activity engagement, which suggests that expectancy-value theory may have some utility for investigating the physical activity engagement of individuals with visual impairments. However, the lack of significant contribution of other variables such as attainment and utility values, as well as barriers factors, underscores the need for additional research in this area.
Tomoko Aoki and Koji Kadota
The present study examined the effects of daily activities of the hands on finger motor function in older adults. Maximum tapping frequency with each finger during single-finger tapping and alternate movements of index–middle, middle–ring, and ring–little finger pairs during double-finger tapping were compared between older adults who used their hands actively in their daily lives and those who did not. The active participants had significantly faster tapping rates for the ring finger in the single-finger tapping and the middle–ring finger pair in the double-finger tapping than did the inactive participants. Thus, daily activity of the hands in older adults could be effective at preventing the loss of dynamic motor function in individual fingers, especially with greater difficulty in movement, resulting from the degeneration with age.
Matías Henríquez, Aitor Iturricastillo, Arturo González-Olguín, Felipe Herrera, Sonny Riquelme, and Raul Reina
This study compared physical performance in a group of international cerebral palsy football players during two formats of small-sided games (SSGs) and performance in a simulated game (SG) according to players’ sport classes (FT1, FT2, and FT3). Internal load (heart rate and rating of perceived exertion) and external load (total distance, distance covered at different velocities, maximum speed reached, acceleration, and deceleration) were obtained with global positioning system devices during two formats of SSGs (2-a-side/SSG2 and 4-a-side/SSG4) and an SG (7-a-side). SSG2 demands faster actions compared with SSG4/SG, and significant differences and large effect sizes were found in the distance covered in Speed Zones 5 (16.0−17.9 km/hr) and 6 (>18.0 km/hr; p < .05;