Publications by authors named "David Russ"

Following injury, older adults exhibit slow recovery of muscle function. Age-related impairment of sarcolemmal membrane repair may contribute to myocyte death, increasing the need for myogenesis and prolonging recovery. Dietary fish oil (FO) is a common nutritional supplement that may alter plasma membrane composition to enhance the response to membrane injury.

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Introduction: Evidence-based practice (EBP) results in high-quality care and decreases unwarranted variation in practice.

Review Of The Literature: Few performance criteria related to EBP are included in physical therapy clinical education (CE) performance measures, despite EBP requirements in Doctor of Physical Therapy education. The purpose of this study was to develop EBP-specific competencies that may be used for Doctor of Physical Therapy students for use throughout CE.

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Osteoporosis is characterized by low bone mass and structural deterioration of bone tissue, which leads to bone fragility (ie, weakness) and an increased risk for fracture. The current standard for assessing bone health and diagnosing osteoporosis is DXA, which quantifies areal BMD, typically at the hip and spine. However, DXA-derived BMD assesses only one component of bone health and is notably limited in evaluating the bone strength, a critical factor in fracture resistance.

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Article Synopsis
  • The study investigates the importance of rate of torque development (RTD) in enhancing physical function among older adults (OAs) compared to younger adults (YAs).
  • It assesses neuromuscular function, voluntary activation (VA), and how these factors relate to various mobility tests in both age groups, finding key differences in RTD indices.
  • Results indicate that while certain measures of RTD are not effective for OAs, others normalized to stimulated torque parameters may help identify central mechanisms behind RTD impairments in this population.
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The voltage-gated potassium channels (Kv) are complex ion channels with distinct roles in neurotransmission, electrical conductivity of the heart, and smooth and striated muscle functions. Previously, we demonstrated that deletion of Kvβ2 in mice results in decreased Pax7 protein levels, hindlimb muscles and body weights, and fiber type switching. In the present study, we tested the hypothesis that Kvβ2 regulates skeletal muscle function in mice.

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There is increasing interest in using motor function tests to identify risk of cognitive impairment in older adults (OA). This study examined associations among grip strength, with and without adjustment for muscle mass, manual dexterity and Trail Making Test (TMT) A and B in 77 OA (73.4 ± 5.

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Article Synopsis
  • Fsp27 is a protein linked to lipid droplet regulation in fat cells, but its role in muscle function was previously unknown.
  • This study found that mice lacking Fsp27 showed significantly reduced muscle endurance and strength compared to normal mice, while glycogen levels remained consistent.
  • The research indicates that Fsp27 is crucial for fat storage in muscles and directly affects muscle performance, highlighting a metabolic paradox where Fsp27-knockout mice have healthy glucose metabolism but poor exercise capacity.
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Background: Nicotinamide phosphoribosyltransferase (Nampt), a key enzyme in NAD salvage pathway is decreased in metabolic diseases, and its precise role in skeletal muscle function is not known. We tested the hypothesis, Nampt activation by P7C3 (3,6-dibromo-α-[(phenylamino)methyl]-9H-carbazol-9-ethanol) ameliorates diabetes and muscle function.

Methods: We assessed the functional, morphometric, biochemical, and molecular effects of P7C3 treatment in skeletal muscle of type 2 diabetic (db/db) mice.

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Background: Older adults display wide individual variability (heterogeneity) in the effects of resistance exercise training on muscle strength. The mechanisms driving this heterogeneity are poorly understood. Understanding of these mechanisms could permit development of more targeted interventions and/or improved identification of individuals likely to respond to resistance training interventions.

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Chronic low back pain (cLBP) rates among younger individuals are rising. Although pain and disability are often less severe, underlying changes in trunk behavior may be responsible for recurrence. We examine the biomarker capacity of a simple Trunk Compliance Index (TCI) to distinguish individuals with and without cLBP.

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The capacity to move is essential for independence and declines with age. Slow movement speed, in particular, is strongly associated with negative health outcomes. Prior research on mobility (herein defined as movement slowness) and aging has largely focused on musculoskeletal mechanisms and processes.

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Background: Sorensen Test time-to-task-failure (TTF) predicts several low back pain (LBP) clinical outcomes, including recurrence. Because the test is described as a measure of trunk extensor (TE) muscle endurance, LBP rehabilitation programs often emphasize endurance training, but the direct role of TE muscle function on Sorensen Test-TTF remains unclear.

Objective: To assess the discriminative and associative properties of multiple markers of isolated TE performance with regard to Sorensen Test-TTF in individuals with recurrent LBP.

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Importance: Low back pain (LBP) is one of the most common reasons for seeking medical care. Manual therapy is a common treatment of LBP, yet few studies have directly compared the effectiveness of thrust (spinal manipulation) vs nonthrust (spinal mobilization) techniques.

Objective: To evaluate the comparative effectiveness of spinal manipulation and spinal mobilization at reducing pain and disability compared with a placebo control group (sham cold laser) in a cohort of young adults with chronic LBP.

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Background: Approximately 35% of individuals > 70 years have mobility limitations. Historically, it was posited lean mass and muscle strength were major contributors to mobility limitations, but recent findings indicate lean mass and muscle strength only moderately explain mobility limitations. One likely reason is that lean mass and muscle strength do not necessarily incorporate measures globally reflective of motor function (defined as the ability to learn, or to demonstrate, the skillful and efficient assumption, maintenance, modification, and control of voluntary postures and movement patterns).

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Optimal health benefits from exercise are achieved by meeting both aerobic and muscle strengthening guidelines, however, most older adults (OAs) do not exercise and the majority of those who do only perform one type of exercise. A pragmatic solution to this problem may be emphasizing a single exercise strategy that maximizes health benefits. The loss of muscle mass and strength at an accelerated rate are hallmarks of aging that, without intervention, eventually lead to physical disability and loss of independence.

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Background: Dietary fish oil (DFO) has been identified as a micronutrient supplement with the potential to improve musculoskeletal health in old age. Few data are available for effects of DFO on muscle contractility, despite the significant negative impact of muscle weakness on age-related health outcomes. Accordingly, the effects of a DFO intervention on the contractile function and proteomic profile of adult and aged in an animal model of aging were investigated.

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Background: Weakness is a risk factor for physical limitations and death in older adults (OAs). We sought to determine whether OAs with clinically meaningful leg extensor weakness exhibit differences in voluntary inactivation (VIA) and measures of corticospinal excitability when compared to young adults (YAs) and OAs without clinically meaningful weakness. We also sought to estimate the relative contribution of indices of neural excitability and thigh lean mass in explaining the between-subject variability in OAs leg extensor strength.

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Age-related declines in physical function lead to decreased independence and higher healthcare costs. Individuals who meet the endurance and resistance exercise recommendations can improve their physical function and overall fitness, even into their ninth decade. However, most older adults do not exercise regularly, and the majority of those who do only perform one type of exercise, and in doing so are not getting the benefits of endurance or resistance exercise.

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Purpose: The goal of this trial was to determine whether low-load blood flow-restricted (BFR) exercise of appendicular muscles induces a cross-transfer of effect to the trunk extensor (TE) muscles, such that low-load TE exercise would enhance TE size and function to a greater extent than standard low-load exercise in people with recurrent low back pain (LBP). We also investigated the direct effects of BFR exercise in the appendicular muscles.

Methods: Thirty-two adults with recurrent, nonspecific LBP were randomized into two groups: Appendicular BFR exercise (BFR exercise) or control exercise (CON exercise).

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Time to task failure (TTF) on the Sørensen test predicts low back pain (LBP), but mechanisms driving TTF may vary in those with and without recurrent LBP. To determine the physiological and psychological predictors of TTF, 48 sex, age, and BMI matched participants (24 Healthy, 24 LBP) completed psychological surveys, maximal strength assessments, and the Sørensen test. A two-way ANOVA revealed no significant effects of group (p = 0.

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Background: Sørensen trunk extension endurance test performance predicts the development of low back pain and is a strong discriminator of those with and without low back pain. Performance may greatly depend on psychological factors, such as kinesiophobia, self-efficacy, and motivation. Virtual reality video games have been used in people with low back pain to encourage physical activity that would otherwise be avoided out of fear of pain or harm.

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Aim: Contusion injury in aging muscle has not been studied in detail, but older adults are at risk for such injuries due to increased risk of falls. As falls in older populations are unlikely to be eliminated, interventions to minimize the negative impact of falls, including contusion injury should be pursued. Dietary fish oil (FO) is a common often supplement in older adults, which is associated with factors that might reduce or worsen the negative impact of contusion.

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Background: Low back pain (LBP) is one of the most common reasons for seeking medical care. Manipulative therapies are a common treatment for LBP. Few studies have compared the effectiveness of different types of manipulative therapies.

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Understanding mechanisms of fatigue of the trunk extensors is important because fatigue is a major factor in predicting incidence of low back pain, but few studies have examined trunk extensor fatigue muscles using differing load types and measured the amplitude and frequency domain of the electromyographic signal to explain these differences. Sixteen healthy participants performed position- and force-matching fatigue tasks in a modified Sørensen test position. Time to task failure was significantly longer during the position-matching task compared to force-matching task (58.

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