|Saturday, April 18th|
Changes in Neuromuscular Coordination with Jump Training After ACL Reconstruction
Audrey RC Elias, University of Montana - Missoula
11:40 AM - 12:00 PM
Of the nearly 200,000 young athletes who undergo anterior cruciate ligament (ACL) reconstructive surgery every year in the United States, approximately half will be diagnosed with early-onset osteoarthritis within 10-15 years. Chronic impairments in mechanics and neuromuscular coordination are thought to decrease the ability of the knee to attenuate forces and accept weight during high-demand activities such as landing from a jump or hop. Specifically, decreased knee bending and a concomitant increase in co-contraction of the anterior and posterior thigh musculature are thought to increase compressive forces during landing. While brief instruction has been found to elicit a transient improvement in mechanical and neuromuscular behaviors in landing, there has been limited research into the effect of extended jump training in this population. No research has been done into the extent to which co-contraction can be modified with training, thereby ameliorating the risk of early-onset osteoarthritis.
PURPOSE: To determine the effects of a best-practice jump training program on mechanical and neuromuscular behaviors in people with impaired weight acceptance following ACL reconstruction.
METHODS: Twenty-five subjects completed a biomechanical screening evaluation (Wk0) of a single leg land from a 20 cm platform utilizing an 8-camera motion capture system with dual force plates. Peak vertical ground reaction force (VGRF) and peak internal extension moment during landing were both normalized to body weight (BW). They and peak knee bending in degrees served as a measure of performance. Quadriceps and hamstring recruitment were analyzed using surface electromyography (sEMG) and normalized to maximum voluntary isometric contraction. Instantaneous hamstring/quadriceps co-contraction was defined as the ratio of the two muscles multiplied by the sum of their activations with a minimum of 0 and maximum of 1. The instantaneous co-contraction was integrated over the weight acceptance phase of landing to generate a co-contraction index (CoI) with a minimum of 0 and maximum of 100. Fifteen subjects were found to have deficits in mechanical function and were enrolled in an 8-week training program. These subjects underwent twice-weekly jump training sessions, with re-testing utilizing the same protocols at mid-training (Wk4), immediately post-training (Wk8), and two months after training (Wk16). The change in kinematic and kinetic variables as well as CoI were analyzed with paired t-tests with a priori significance set to p=0.05.
RESULTS: As of this writing, 14 subjects had completed Wk4 and Wk8 testing. One subject left the study after Wk4. Six had completed Wk16 testing. CoI decreased significantly with training (mean±SD; Wk0: 38.3±16.1; Wk4: 24.4±14.9 (p=0.003); Wk8: 21.3±11.3 (Wk0-Wk8 p=0.0003)). Peak knee flexion increased significantly with training as well (Wk0: 58.0°±10.9°; Wk4: 68.0°±10.1° (p=0.0004); Wk8: 73.3°±7.9° (Wk4-Wk8: p=0.037; Wk0-Wk8: p
DISCUSSION: All mechanical and neuromuscular variables responded to training as expected. While jump training following ACL reconstruction has been recommended, only one other study has demonstrated its effectiveness in ameliorating mechanical risk factors for re-injury and osteoarthritis in this population. We are unaware of another study demonstrating effectiveness in changing neuromuscular behaviors that can increase compressive loads and thereby increase the risk of osteoarthritis. At this time, extensive jump training following ACL reconstruction is uncommon, with most athletes released to practice based on time from surgery or strength symmetry. These results underscore the need for more extensive rehabilitation to improve long-term outcomes for these young athletes.
Gender Policing in Schools and Mental Health: The Importance of Inclusive Non-Discrimination Ordinances
12:00 PM - 12:20 PM
Objectives: High schools increasingly include sexual orientation, and to a lesser extent gender identity, in non-discrimination policies (GLSEN, 2012). These policies, however, often exclude gender-specific discrimination seen as unrelated to these identities, such as the policing of masculinity or femininity. Such policing may involve peers targeting individuals who are seen as not feminine or masculine “enough.” The current study examined the role of gender-specific discrimination in predicting symptoms of psychological distress.
Methods: Participants were 681 UM students, including 63 LGB-identified individuals, who took part in an online study that examined correlates among different dimensions of identities, stigma, and mental health. Participants were asked if they experienced various forms of discrimination in high school, including being hit or teased by peers or teachers, because they were not seen as masculine or feminine enough. A hierarchical regression was calculated to examine the additive impact of gender-specific discrimination in predicting symptoms of psychological distress, while controlling for global experiences of victimization, as well as ethnicity, gender, and sexual orientation.
Results: Gender-specific harassment predicted symptoms of psychological distress above and beyond a model that accounts for age, gender, ethnicity, sexual orientation, and gender non-specific victimization (change in R2 = .069, p < .001), contributing to an overall model that predicted 18.3% of the variance in psychological distress scores.
Conclusion: Individuals targeted on the basis of their gender expression in schools are especially psychologically impacted. Gender-based discrimination that occurred at school accounted for nearly twice as much variance in psychological distress, relative to global experiences of victimization. These findings suggest that gender inclusive education, and policy changes, are needed in school settings.
Hindcasting Climatic Water Balance Scenarios in the Clearwater Refugium
12:20 PM - 12:40 PM
Strategies for Mitigating Vitamin A Deficiency in Mekelle, Ethiopia
Erika Strehl, University of Montana - Missoula
12:40 PM - 1:00 PM
The fourth United Nations Millennium Development Goal (MDG) is to reduce worldwide child mortality by two-thirds. In the impoverished African country of Ethiopia, child mortality has declined from 123 per 1,000 in 2004/2005 to 88 per 1,000 in 2011/2012 (World Bank, 2013). Yet the rate remains alarmingly high. Micronutrient deficiencies (including iron, zinc, and vitamin A) are contributing to the worldwide child mortality rate. Vitamin A deficiency is one of the most common micronutrient. Between 250,000 and 500,000 children with vitamin A deficiency become blind each year. Within 12 months of becoming blind, half of these children die (World Health Organization (WHO), n.d.).
The WHO supports three types of solutions to eliminate vitamin A deficiency; supplementation, dietary diversification, and food fortification. Worldwide, supplementation is the most common practice for providing micronutrients to communities. However, this practice is successful in mainly urban communities and excludes 45% of children around the world. Supplementation programs alone are not fiscally sustainable (Golden Rice Project, 2012). A study by Mekelle University public health faculty concluded vitamin A capsules are a short-term life saving intervention and a transition towards sustainable food-based interventions is needed. Additionally, an intervention to serve the diets of low-income individuals as well as the urban population is crucial (Kidane, Abegaz, Mulugeta, Singh, 2013).
In order to fulfill the practicum requirement for the graduate program in public health, Erika Strehl traveled to Mekelle, Ethiopia in June 2014. The objective of this project was to investigate strategies used for mitigating vitamin A deficiency within the Mekelle community. Specific learning objectives included identifying organizations working toward eliminating vitamin A deficiency, classifying the type of project (supplementation, food fortification, dietary diversification), exploring the current and potential barriers within these projects, identifying the gaps in education and supplementation, and identifying communities not receiving education or supplementation.
Supplementation of Vitamin A is provided by the Health Extension Workers (HEW), which is a recent program established by the Ethiopian government. The HEW’s are the primary distributors for vitamin A and iron supplements. Infants receive a vitamin A supplement every six months at the Health Post and it is the responsibility of the mother return every six months. Each year thousands of HEW’s are trained to treat various medical problems such as burns, cuts, maternal health, and malnutrition.
Food fortification in Mekelle is in the initial stages of implementation, Ethiopia is one of four countries in Africa without a legal food fortification program (Head, Getachew, 2014). The Ministry of Health has appointed a task force to investigate the use of food fortification and potentially propose a legislation to legalize food fortification. A Fulbright Scholar (Ms. Head) collaborated with the Chemistry department at Mekelle University to create technology for food fortification. Currently, there is a lack of locally available technology to fortify food and what is available is currently imported from other countries, which is accompanied by high import duties and a value added tax (VAT) of 15%. Producing the technology in Ethiopia would alleviate the financial burden of importation. Ms. Head worked with local manufacturers to design and build equipment that would be replicable and cost effective.
For the past fourteen years Mums for Mums, a local non-governmental organization, has educated women on the importance of dietary diversification. Mums for Mums assists homeless women to learn income generating and life skills to become self-reliant. Food preparation training is accompanied by nutrition demonstrations, which focuses on locally available and highly nutritional food, such as the sweet potato. One cup of the boiled sweet potato everyday satisfies the requirement for vitamin A. Women are instructed how to incorporate the sweet potato into meals to provide a balanced diet for their families. The sweet potato is widely available in Ethiopia and not expensive (Asmelash, personal communication, June 2014).
Mekelle currently satisfies the three suggested strategies from the WHO, yet these programs work in isolation from each other. There is a lack of communication and information sharing between the aforementioned programs. With a heavy reliance on supplementation, a shift towards preventive strategies such as nutrition education is a crucial element needed to decrease the prevalence of vitamin a deficiency.