Anticipatory Effects on Lower Extremity Neuromechanics During a Cutting Task

Context: Continued research into the mechanism of noncontact anterior cruciate ligament injury helps to improve clinical interventions and injury-prevention strategies. A better understanding of the effects of anticipation on landing neuromechanics may benefit training interventions. Objective: To determine the effects of anticipation on lower extremity neuromechanics during a single-legged land-and-cut task. Design: Controlled laboratory study. Setting: University biomechanics laboratory. Participants: Eighteen female National Collegiate Athletic Association Division I collegiate soccer players (age = 19.7 ± 0.8 years, height = 167.3 ± 6.0 cm, mass = 66.1 ± 2.1 kg). Intervention(s): Participants performed a single-legged land-and-cut task under anticipated and unanticipated conditions. Main Outcome Measure(s): Three-dimensional initial contact angles, peak joint angles, and peak internal joint moments and peak vertical ground reaction forces and sagittal-plane energy absorption of the 3 lower extremity joints; muscle activation of selected hip- and knee-joint muscles. Results: Unanticipated cuts resulted in less knee flexion at initial contact and greater ankle toe-in displacement. Unanticipated cuts were also characterized by greater internal hip-abductor and external-rotator moments and smaller internal knee-extensor and external-rotator moments. Muscle-activation profiles during unanticipated cuts were associated with greater activation of the gluteus maximus during the precontact and landing phases. Conclusions: Performing a cutting task under unanticipated conditions changed lower extremity neuromechanics compared with anticipated conditions. Most of the observed changes in lower extremity neuromechanics indicated the adoption of a hip-focused strategy during the unanticipated condition

Military connections

There is a long tradition of research on children from military families, which has focused on observations that these children often exhibit both internalizing and externalizing problem behaviors. One of the emphases over that last several decades as the military moves to an all-volunteer force, is a recognition that the military is no longer largely staffed by single males. An emphasis on military families has been exhibited at many different levels. This research compared university students with and without a parental history of military service on extroversion, self-esteem, and attachment style. The hypothesis regarding higher rates of extroversion among children from military families follows from an analysis that extraversion would be a highly desirable trait among service personnel. I also assumed that individuals with a military connection would score higher on self-esteem due to findings that the long-term impact of frequent relocation is high self-esteem. Finally, my hypotheses regarding attachment came from suggestions in the clinical literature that parental absences may lead to insecure attachment patterns. Results indicated that individuals from military families did not differ significantly from individuals without a military connection on any of these personality variables. The results of this study may indicate a greater level of attention to the lives of military families that has positively impacted the attachment and self-esteem of children from military families. These results may also indicate that parental military service does not have a long-lasting effect on the personality variables that were studied

The Association of Dorsiflexion Flexibility on Knee Kinematics and Kinetics during a Drop Vertical Jump in Healthy Female Athletes

Purpose While previous studies have examined the association between ankle dorsiflexion flexibility and deleterious landing postures, it is not currently known how landing kinetics are influenced by ankle dorsiflexion flexibility. The purpose of this study was to examine whether ankle dorsiflexion flexibility was associated with landing kinematics and kinetics that have been shown to increase the risk of anterior cruciate ligament (ACL) injury in female athletes. Methods Twenty-three female collegiate soccer players participated in a preseason screening that included the assessment of ankle dorsiflexion flexibility and lower-body kinematics and kinetics during a drop vertical jump task. Results The results demonstrated that females with less ankle dorsiflexion flexibility exhibited greater peak knee abduction moments (r = −.442), greater peak knee abduction angles (r = .355), and less peak knee flexion angles (r = .385) during landing. The range of dorsiflexion flexibility for the current study was between 9° and 23° (mean = 15.0°; SD 3.9°). Conclusion Dorsiflexion flexibility may serve as a useful clinical measure to predict poor landing postures and external forces that have been associated with increased knee injury risk. Rehabilitation specialists can provide interventions aimed at improving dorsiflexion flexibility in order to ameliorate the impact of this modifiable factor on deleterious landing kinematics and kinetics in female athletes

Hip External Rotator Strength Is Associated With Better Dynamic Control of the Lower Extremity During Landing Tasks

Hip external rotator strength is associated with better dynamic control of the lower extremity during landing tasks. J Strength Cond Res 30(1): 282–291, 2016—The purpose of this study was to determine the association between hip strength and lower extremity kinematics and kinetics during unanticipated single-leg landing and cutting tasks in collegiate female soccer players. Twenty-three National Collegiate Athletic Association division I female soccer players were recruited for strength testing and biomechanical analysis. Maximal isometric hip abduction and external rotation strength were measured using a hand-held dynamometer and expressed as muscle torque (force × femoral length) and normalized to body weight. Three-dimensional lower extremity kinematics and kinetics were assessed with motion analysis and force plates, and an inverse dynamics approach was used to calculate net internal joint moments that were normalized to body weight. Greater hip external rotator strength was significantly associated with greater peak hip external rotation moments (r = 0.47; p = 0.021), greater peak knee internal rotation moments (r = 0.41; p = 0.048), greater hip frontal plane excursion (r = 0.49; p = 0.017), and less knee transverse plane excursion (r = -0.56; p = 0.004) during unanticipated single-leg landing and cutting tasks. In addition, a statistical trend was detected between hip external rotator strength and peak hip frontal plane moments (r = 0.39; p = 0.06). The results suggest that females with greater hip external rotator strength demonstrate better dynamic control of the lower extremity during unanticipated single-leg landing and cutting tasks and provide further support for the link between hip strength and lower extremity landing mechanics

Trophic Interactions: the Relative Importance of Dreissena Filtration and Daphnia Grazing on Phytoplankton Abundance and Water Clarity

A series of controlled laboratory experiments were performed (n=4) to determine the effects of Dreissena filtration and Daphnia grazing on phytoplankton abundance and water clarity. Dreissena consumed significantly more phytoplankton than Daphnia at 48 and 72 hours in vessels containing a single herbivore (Daphnia or Dreissena). Dreissena reduced phytoplankton abundance by 39% overall, while Daphnia reduced 19% of the phytoplankton. However, an additive effect was not observed in vessels containing both herbivores. Phosphorus cycling by Daphnia and cycling and retention by Dreissena changed the dynamics of the vessels significantly. Ultimately, it is likely that Dreissena will increase water clarity to a greater extent than Daphnia due to the differences in phosphorus cycling exhibited by both herbivores

From National Populism to National Corporatism: The Case of Bolivia (1952-1970)

Analyzes the experience of Bolivia with an experiment in a populist resolution of its socioeconomic problems from 1952 to 1970. Objectives of national populist ideology; Factors that lead to the failure of Movimiento Nacionalista Revolucionario in Bolivia to achieve its revolutionary goals: Resurgence of private sector in mining and petroleum

UMA COVID-19_News_President Updates_Message on Directive from Chancellor Malloy for Online Instruction Beginning March 23

Screenshot of University of Maine at Augusta\u27s news webpage with a communication from Chancellor Dannel Malloy regarding the University of Maine System transition to remote learning in response to the COVID-19 pandemic