Rachele M. Pojednic

Longitudinal Decline of Neuromuscular Activation and Power in Healthy Older Adults

BACKGROUND Weakness contributes to the decline of physical function that occurs with aging. Contradictory findings have been reported as to whether neuromuscular activation is impaired with aging, and the extent to which it contributes to weakness. The present study uses a longitudinal design to assess how potential age-related change of neuromuscular activation affects strength, power, and mobility function. METHODS Participants included 16 healthy older adults who were healthy and high functioning at baseline. Strength was measured by leg press one repetition maximum. Power production was measured during a maximal effort rapid leg press movement with resistance set to 70% of the one repetition maximum. During the same movement, neuromuscular activation was quantified as the rate of rise of the quadriceps surface electromyogram (rate of electromyogram rise). Thigh muscle cross-sectional area was measured by computed tomography. Mobility function was assessed by the Short Physical Performance Battery. RESULTS The time between baseline and follow-up testing was almost 3 years. Between these time points, rate of electromyogram rise decreased 28% (p = .004) and power decreased 16.5% (p = .01). There was a trend for reduced anterior thigh muscle cross-sectional area (3%, p = .05), but no change in posterior thigh muscle cross-sectional area (p = .84), one repetition maximum strength (p = .72), or Short Physical Performance Battery score (p = .17). Loss of power was strongly associated with reduction in the rate of electromyogram rise (R (2) = .61, p < .001), but not with reduction of anterior thigh muscle cross-sectional area (p = .83). CONCLUSIONS The present findings suggest that voluntary neuromuscular activation declines with advancing age, contributes to a reduction in power production, and precedes the decline of mobility function.

The specific contributions of force and velocity to muscle power in older adults

The purpose of this study is to examine the relative importance of the force-based and velocity-based measures of muscle performance to explain inter-individual differences in power production capability and functional task performance. Participants included seventy-nine men and women: middle-aged healthy adults (MH: 40-55years), older healthy adults (OH: 70-85years), and older adults with mobility limitations (OML: 70-85years). Muscle power at 180°/s, isometric maximal torque, and maximal contraction velocity at 40% 1RM were measured during unilateral leg extension. The Short Physical Performance Battery (SPPB) was used to differentiate between healthy and mobility limited older adults. Functional task performance was assessed using multiple chair rise and stair climb tests. Leg extensor force (torque), but not maximal contraction velocity, was significantly associated with muscle power in MH. Both torque and velocity were significantly associated with muscle power in OH. Maximal velocity, but not torque, was associated with power in OML. Maximal velocity demonstrated an association with multiple chair rise time and stair climb time in OML, but not MH or OH. It is concluded that movement velocity is an increasingly important determinant of maximal power output with advancing age. Furthermore, movement velocity is also a critical component of functional task performance with aging and may contribute to functional deficits. These findings help to explain why the rate-dependent variable power has emerged as a critical component of both assessment and rehabilitation of muscular performance and physical function in older adults.

The Emerging Biomolecular Role of Vitamin D in Skeletal Muscle

In this review, we summarize current evidence for a direct effect of vitamin D on skeletal muscle. A number of studies identify the receptor for 1,25-dihydroxyvitamin-D3 (vitamin D receptor (VDR)) and the enzyme CYP27B1 (1-&agr;-hydroxylase) in muscle. We hypothesize that vitamin D acts on myocytes via the VDR, and we examine proposed effects on myocyte proliferation, differentiation, growth, and inflammation.

Including lifestyle medicine in undergraduate medical curricula

Purpose Currently, there is no model to integrate the discipline of lifestyle medicine (LM) into undergraduate medical education. Furthermore, there are no guidelines, validated assessment tools, or evaluation or implementation plans in place. Background The World Health Organization predicts that by 2020, two-thirds of disease worldwide will be the result of poor lifestyle choices. Fewer than 50% of US primary care physicians routinely provide specific guidance on nutrition, physical activity, or weight control. Methods We are establishing a plan to integrate LM into medical school education in collaboration with the investing stakeholders, including medical school deans and students, medical curriculum developers and researchers, medical societies, governing bodies, and policy institutes. Three planning and strategy meetings are being held to address key areas of focus – with a particular interest in nutrition, physical activity, student self-care, and behavior change – to develop specific implementation guidelines and landmarks. Results After the first two meetings, the proposed areas of focus were determined to be: 1) supporting of deans and key personnel, 2) creation of federal and state policy commitments, 3) use of assessment as a driver of LM, 4) provision of high-quality evidence-based curricular material on an easily navigated site, and 5) engaging student interest. Implementation strategies for each focus area will be addressed in an upcoming planning meeting in early 2015. Conclusion This initiative is expected to have important public health implications by efficiently promoting the prevention and treatment of non-communicable chronic disease with a scalable and sustainable model to educate physicians in training and practice.

Lifestyle Medicine Education

The actual causes of premature adult deaths, the preponderance of noncommunicable chronic diseases, and their associated costs are related to unhealthy behaviors, such as poor nutrition, physical inactivity, and tobacco use. Although recommended as the first line of prevention and management, providers often do not provide behavioral change counseling in their care. Medical education in lifestyle medicine is, therefore, proposed as a necessary intervention to allow all health providers to learn how to effectively and efficiently counsel their patients toward adopting and sustaining healthier behaviors. Lifestyle medicine curricula, including exercise, nutrition, behavioral change, and self-care, have recently evolved in all levels of medical education, together with implementation initiatives like Exercise is Medicine and the Lifestyle Medicine Education (LMEd) Collaborative. The goal of this review is to summarize the existing literature and to provide knowledge and tools to deans, administrators, faculty members, and students interested in pursuing lifestyle medicine training or establishing and improving an LMEd program within their institution.

Innovation in Diabetes Care: Improving Consumption of Healthy Food through a “Chef Coaching” Program: A Case Report

Nutrition therapy as part of lifestyle care is recommended for people with type 2 diabetes. However, most people with diabetes do not follow this guideline. Changing eating habits involves obtaining knowledge and building practical skills such as shopping, meal preparation, and food storage. Just as fitness coaches use their specific knowledge base in fitness to enhance the effectiveness of their coaching, credentialed chefs trained as health coaches might combine their culinary expertise with coaching in order to improve clients’ food choices and lifestyles. This report documents the case of a 55-year-old white male physician, single and living alone, who was recently diagnosed with type 2 diabetes and reported chronic stress, sedentary behavior, and unhealthy eating habits. He participated in a chef coaching program of 8 weekly one-on-one 30-minute coaching sessions via Skype delivered by a chef trained as a health coach. During the first five meetings, the patients goals were primarily culinary; however, with his success in accomplishing these goals, the patient progressed and expanded his goals to include other lifestyle domains, specifically exercise and work-life balance. At the end of the program, the patient had improved both his nutritional and exercise habits, his confidence in further self-care improvement, and his health parameters such as HgA1c (8.8% to 6.7%; normal <6.5%). We conclude that chef coaching has the potential to help people with diabetes improve their practical culinary skills and implement them so that they eat better and, further, has the potential to help them improve their overall self-care. We intend to further develop chef coaching and assess its potential as we learn from its implementation.

A parallel curriculum in lifestyle medicine.

Less than 50 per cent of US primary care doctors routinely provide guidance to their patients on lifestyle behaviours such as diet, physical activity or weight control, despite the prediction by the World Health Organization that by 2020, two‐thirds of disease worldwide will be the result of poor lifestyle choices. This gap in patient–clinician dialogue is perhaps the result of a lack of structured training in medical school surrounding the components of lifestyle medicine.

Bridging the gap between clinicians and fitness professionals: a challenge to implementing exercise as medicine

Objective Health clubs (HC) and personal trainers (PT) are traditional outlets for the promotion of physical activity (PA) and exercise programming. As physicians are increasingly being called on to write exercise prescriptions for their patients, this study sought to investigate the level of integration between the healthcare and fitness systems. Design An internet study was designed with five domains to understand physicians’: (1) overall perception of HC, (2) appropriateness and recommendation of HC and PT to their patients, (3) attitude regarding specific aspects of HC, (4) support of patient participation in HC sponsored exercise and (5) elements of HC that physicians would like to know for referral. Methods An electronic survey was sent to members of two mailing lists of primary care and sports medicine specialty physicians during 2011–2012. Results On a Likert scale of 1–10 412 physicians reported being familiar with HC (8.9±2.1), indicated a favourable view of HC (7.9±2.2), and believe HC to be an appropriate venue for their patients (7.5±2.3). However, physicians only recommend HC to 41%±28% of their patients and PT for only 21%±21.6% of patients. Physicians ranked expense and convenience as the most problematic elements of HC (8.1±2.1 and 6.3±2.5, respectively). 72% of physicians indicated cost as most concerning when recommending a specific HC. Conclusion HC and PT are a significant implementation system for the promotion of physical activity, yet physicians are concerned with several elements of HC and are not adequately relying on this partnership to promote physical activity to their patients.