Walking net V ˙ O2 rises with advancing age in older women: where to go from here?

PURPOSE: Walking net V ˙ O2 tends to increase with advancing age; however, factors contributing to this relationship have not been widely described. The implications of such findings could inform targeted strategies to promote independent mobility in older adults. Herein, we evaluated the relationship between net V ˙ O2 and age at two submaximal workloads while exploring potential moderators of this relationship. METHODS: Secondary analyses were performed on 35 older (65 ± 3 years) women who completed a battery of physical assessments including fixed-speed, non-graded and graded (+ 2.5%) treadmill walking with indirect calorimetry to determine net V ˙ O2. Maximal oxygen uptake ( V ˙ O2max), knee extensor maximal isometric voluntary contraction (MVC), peak rate of torque development (RTD), and plantar flexor range-of-motion (PFROM) were also measured. RESULTS: Bivariate correlations showed non-graded (r = 0.403, p = 0.017) and graded (r = 0.413, p = 0.014) net V ˙ O2 were positively related to age. Notably, these relationships strengthened after adjusting for V ˙ O2max. Regression modeling showed age, RTD:MVC ratio (composite of muscle performance), and PFROM together explained 49% and 34% of the variance in non-graded and graded net V ˙ O2, respectively. Further analyses suggested knee extensor MVC moderates the relationship between non-graded net V ˙ O2 and age, accounting for 9% of the variance [ΔR2 = 0.090, F (1,31) = 4.13, p = 0.05]. CONCLUSION: These data support the premise that, in older women, walking net V ˙ O2 rises with advancing age, and additionally, the RTD:MVC ratio and PFROM are independent correlates of non-graded net V ˙ O2. Exercise interventions with a high degree of training specificity including explosive, velocity-based elements may promote independent mobility in older women.

Optimal neuromuscular electrical stimulation parameters after spinal cord injury.

PURPOSE: To examine the interrelationship of pulse duration and pulse frequency on torque production and muscle fatigue in both impaired and non-impaired skeletal muscle of men and women. METHODS: Individuals with [n = 14 (6 females), 38 ± 13 yr; 175 ± 11 cm; 76 ± 20 kg] and without [n = 14 (6 females), 29 ± 8 yr; 175 ± 9 cm; 74 ± 14 kg] spinal cord injury (SCI) participated. Muscle torque was recorded during a series of NMES-induced isometric muscle contractions using different combinations of pulse durations and frequencies. Additionally, two different muscle fatigue protocols (20 and 50 Hz/200µs) were utilized to elicit repeat isometric muscle contractions (1s on and 1s off × 3 min). RESULTS: There was a statistically significant linear trend for pulse charge (the product of pulse frequency and pulse duration) on isometric torque production in participants without (p < 0.001, η2 = 0.79), and in participants with SCI (p < 0.001, η2 = 0.66), with higher total pulse charge generating higher torque values. Participants with SCI had significantly greater muscle fatigue for both muscle fatigue protocols (p < 0.05). CONCLUSIONS: NMES protocols should consider using longer pulse durations with lower frequencies to maximize force production for individuals with SCI. However, because mechanisms of muscle fatigue may be different for impaired muscle when compared to non-impaired muscle, further studies on protocols to offset fatigue are warranted.

Lifting Techniques: Why Are We Not Using Evidence To Optimize Movement?

Lifting something off the ground is an essential task and lifting is a documented risk factor for low back pain (LBP). The standard lifting techniques are stoop (lifting with your back), squat (lifting with your legs), and semi-squat (midway between stoop and squat). Most clinicians believe the squat technique is optimal; however, training on squat lifting does not prevent LBP and utilizing greater lumbar flexion (i.e. stoop) when lifting is not a risk factor for LBP. The disconnect between what occurs in clinical practice and what the evidence suggests has resulted in ongoing debate. Clinicians must ask the right questions in order to apply the evidence appropriately. A proposed clinical framework of calm tissue down, build tissue up, improve work capacity can be used to determine which lifting technique is optimal for a patient at any given time. When applying this clinical framework, clinicians should consider metabolic, biomechanical, physical stress tolerance, and pain factors in order to address the movement system. For example, stoop lifting is more metabolically efficient and less challenging to the cardiopulmonary system. There may be few biomechanical differences in spinal postures and gross loads on the lumbar spine between stoop, squat, and semi-squat lifting; however, each lift has distinct kinematic patterns that affects muscle activation patterns, and ultimately the movement system. Clinicians must find the optimal dosage of physical stress to address all aspects of the movement system to minimize the risk of injury. There is no universal consensus on the optimal lifting technique which will satisfy every situation; however, there may be a lifting technique that optimizes movement to achieve a specific outcome. The calm tissue down, build tissue up, improve work capacity framework offers an approach to determine the best lifting technique for an individual patient at any give time. LEVEL OF EVIDENCE: 5.

Effects of functional electrical stimulation on muscle health after spinal cord injury.

Spinal cord injury is a devastating condition interrupting voluntary movement and motor control. In response to unloading, skeletal muscle undergoes numerous adaptations, including rapid and profound atrophy, intramuscular fat accumulation, impaired muscular glucose metabolism and decreased force generation and muscle performance. Functional electrical stimulation (FES) involves electrically stimulating affected muscles to contract in a coordinated manner to create a functional movement or task. Effects of FES-cycling, rowing and resistance training on muscle health are described here. Briefly, FES-cycling and resistance training may slow muscle atrophy or facilitate muscle hypertrophy, and all modalities benefit muscle composition and performance to some extent. These interventions show promise as future rehabilitative tools after spinal cord injury.

Influence of muscle fatigue on contractile twitch characteristics in persons with parkinson's disease and older adults: A pilot study.

INTRODUCTION: It is widely accepted that pathophysiological changes to the central nervous system of persons with Parkinson's disease (PD) result in negative effects on motor function. However, less information is known regarding the pathology of PD on skeletal muscle. The purpose of this study was to determine the effect of a fatiguing isometric knee extension protocol on muscle mechanics using evoked twitch contractions in persons with PD and in non-impaired older adults (OLD). METHODS: Evoked twitch contractions were examined during a fatiguing protocol in PD (66 ± 9 yr, n = 8) and OLD (65 ± 10 yr, n = 5). Participants performed 5-sec maximal isometric voluntary contractions of the quadriceps femoris with 5-sec rest for 3-min. Every 30-sec during rest intervals, a maximal transcutaneous electrical stimulus was administered to the quadriceps femoris to quantify evoked peak twitch torque (pTT), peak relaxation rate (pRR), and peak rate of torque development (pRTD). RESULTS: A large effect of voluntary fatigue (%decline) was observed (g = 1.58). There were no significant differences in pTT (p = 0.09; 95% CI:-3.6, 0.28) or pRR (p = 0.11; 95% CI:-31, 3.6). However, the slope decline of pRTD in OLD (-35.4 ± 24.7) was greater than PD (-11.5 ± 11.4; p = 0.03), indicating that skeletal muscle in persons with PD is less fatigable compared to non-impaired older adults. CONCLUSION: The rate, not the maximum capacity, of torque generation of the muscle during a fatiguing knee extension protocol was affected by PD. Future studies are warranted to identify the mechanism(s) responsible for the observed differences in skeletal muscle contractile characteristics and potential myofiber distribution variation in PD.

The impact of varying interphase interval on neuromuscular electrical stimulation-induced quadriceps femoris muscle performance and perceived discomfort.

Objectives: Determine the effects of varying frequency, phase duration, and interphase interval (IPI) of symmetrical, biphasic pulsed current (SBPC) on quadriceps femoris muscle torque production, perceived discomfort, and muscle fatigue when using neuromuscular electrical stimulation (NMES).Methods: Ten recreationally active able-bodied participants completed this study. Muscle torque was measured during a series of laboratory based, NMES-induced muscle contractions with varying combinations of phase durations (50, 100, 150, or 200 µs) and IPIs (50, 100, 150, or 200 µs) at 25 and 50 Hz. A three-factorial repeated measures experimental design was used. After each contraction, participants rated perceived discomfort on a 10-cm visual analog scale. Subsequently, fatigue tests were conducted using different frequency-IPI combinations.Results: Results of within-subjects ANOVAs revealed no interaction among the three factors: frequency, phase duration and IPI. Significant main effects of phase duration and IPI, but not frequency, on torque production and perceived discomfort were observed. Specifically, significant linear and quadratic trends were observed for the effect of phase duration and IPI on torque production, and the effect of IPI on discomfort, and only a significant linear trend for the effect of phase duration on discomfort. The shorter IPI combined with the longer phase duration produced greater torque with tolerable discomfort. There was no significant effect of IPI on muscle fatigue.Conclusions: Study findings indicated that when administering SBPC on the quadriceps femoris muscle, clinicians should select an IPI of 50 µs and a longer phase duration (e.g. 200 µs) to maximize torque without imposing intolerable discomfort.

Exploring the uptake and implementation of tele-monitored home-exercise programmes in adults with Parkinson's disease: A mixed-methods pilot study.

BACKGROUND: People with Parkinson's disease experience numerous barriers to exercise participation at fitness facilities. Advances in tele-monitoring technologies create alternative channels for managing and supervising exercise programmes in the home. However, the success of these programmes will depend on participants' perceptions of using the technology and their exercise adherence. Thus, this pilot explored the uptake and implementation of two common methods of Internet-exercise training in Parkinson's disease. METHODS: Twenty adults with Parkinson's disease were randomized into either: telecoach-assisted exercise (TAE) or self-regulated exercise (SRE) groups. Both groups received the same eight-week exercise prescription (combined strength and aerobic exercise) and telehealth system that streamed and recorded vital signs and exercise data. TAE participants exercised under a telecoach's supervision via videoconferencing. SRE participants independently managed their exercise training. Quantitative data were described and qualitative data underwent thematic analysis. RESULTS: Quantitative results demonstrated that TAE participants achieved strong attendance (99.2%), whereas SRE participants demonstrated 35.9% lower attendance, 48% less total time exercising, and 74.5% less time exercising at moderate intensity. Qualitatively, TAE participants reported overtly favourable programme experiences and that assistance from a telecoach enhanced their exercise motivation. SRE participants noted several challenges that impeded adherence. CONCLUSION: Findings demonstrate that adults with Parkinson's disease acknowledge benefits of exercising through a telehealth system and are open to utilizing this channel as a means of exercise. However, human-interactive support may be required to overcome unique impediments to participation. Study findings warrant validation in larger trials that can transfer the success of TAE towards more scalable methods of delivery.

Multi-Level Factors Associated with Social Participation among Stroke Survivors: China's Health and Retirement Longitudinal Study (2011-2015).

BACKGROUND: This study aims to examine the impact of individual-level and community-based factors on popular social participation activities of Chinese middle-aged and older adults post-stroke. METHODS: Sub-samples of survivors of stroke (2011: n = 413, 2013: n = 395, 2015: n = 441) recruited by the China Health and Retirement Longitudinal Study (CHARLS) were included in the analysis. Zero-inflated Poisson and multi-level logistic regression models were used to explore factors associated with social participation. RESULTS: More than half of individuals (55.0%) had no social participation and 23.4% participated in multiple social activities. The most popular social activities that individuals participated in were interacting with friends (32.6%) and going to a community club to play table games (22.7%). Multiple individual-level factors were negatively related to social participation (e.g., depressive symptoms and multiple measures of functional limitations) while the allocation of an outdoor exercise facility in the community/village was positively associated with the participation of going to a community club to play table games. CONCLUSION: Stroke survivors are at high risk of limited social participation. Policymakers and other key stakeholders should consider community design among other potential solutions when identifying ways to link at-risk stroke survivors to both opportunities for rehabilitation (e.g., physical function) and social participation.

Effects of High-Intensity Interval Training Versus Moderate-Intensity Training on Cardiometabolic Health Markers in Individuals With Spinal Cord Injury: A Pilot Study.

Background: Recent studies in nondisabled individuals have demonstrated that low-volume high-intensity interval training (HIIT) can improve cardiometabolic health similar to moderate-intensity training (MIT) despite requiring 20% of the overall time commitment. To date, there have been no studies assessing the effects of HIIT for improving cardiometabolic health in individuals with SCI. Objectives: The primary purpose of this pilot study was to compare the effects of 6 weeks of low-volume HIIT vs MIT using arm crank ergometer exercise to improve body composition, cardiovascular fitness, glucose tolerance, blood lipids, and blood pressure in a cohort of individuals with longstanding SCI. Methods: Participants were randomized to 6 weeks of HIIT or MIT arm crank exercise training. Aerobic capacity, muscular strength, blood lipids, glucose tolerance, blood pressure, and body composition were assessed at baseline and 6 weeks post training. Results: Seven individuals (6 male, 1 female; n = 3 in MIT and n = 4 in HIIT; mean age 51.3 ± 10.5 years) with longstanding SCI completed the study. The preliminary findings from this pilot study demonstrated that individuals with SCI randomized to either 6 weeks of HIIT or MIT displayed improvements in (a) insulin sensitivity, (b) cardiovascular fitness, and (c) muscular strength (p < .05). However, MIT led to greater improvements in arm fat percent and chest press strength compared to HIIT (p < .05). Conclusion: No differences between MIT and HIIT were observed. Both conditions led to improvements in insulin sensitivity, aerobic capacity, muscle strength, and blood lipids in individuals with SCI. Future larger cohort studies are needed to determine if the shorter amount of time required from HIIT is preferable to current MIT exercise recommendations.

Sustainability of exercise intervention outcomes among people with disabilities: a secondary review.

BACKGROUND: This review explored the sustainability of health and physical activity-based outcomes following exercise trials that were conducted for people with disabilities, and characterised the influence of technology and behaviour change strategies. METHODS: A total of 132 studies were screened from an existing database. RESULTS: Only 22 studies featured follow-up periods and met eligibility criteria. At follow-up, studies typically reported at least one significant health outcome that was maintained (n = 18/21; 86%). However, significant health outcomes accounted for only 32% of the total volume of outcomes that were measured at follow-up. For physical activity-based outcomes, six studies (n = 6/8; 75%) reported that intervention gains were maintained throughout follow-up. The incorporation of technology or behaviour change strategies appeared to be linked with sustainable intervention effects. CONCLUSIONS: Overall, some evidence demonstrated that post-intervention effects were sustainable. However, the strength of the evidence was weak and several existing gaps in knowledge were identified. Moreover, most studies did not focus on sustainability, but instead emphasised short-term effects of exercise participation on health and physical activity outcomes. Study findings call for greater research and programme efforts to maintain health, function, and physical activity behaviour after supports provided by research studies are removed. Implications for rehabilitation Short-term exercise programmes may require additional strategies designed specifically to enhance the sustainability of exercise outcomes and physical activity participation. Incorporating technology within exercise interventions may enhance the likelihood of sustaining health and function outcomes. Exercise programmes framed within behaviour change theory can equip individuals with the appropriate strategies necessary to maintain their physical activity participation.

Characteristics of Adults With Neurologic Disability Recruited for Exercise Trials: A Secondary Analysis.

This review examined demographic and clinical characteristics of participants from exercise trials in 3 neurologic disability conditions (multiple sclerosis, spinal cord injury, and traumatic brain injury) and compared these data with population-based statistics. The authors included 75 published studies from 2006 to 2016: 53 studies for multiple sclerosis (n = 2,034), 14 for spinal cord injury (n = 302), and 8 for traumatic brain injury (n = 272). Pooled data resembled some heterogeneous aspects of population data sets. However, many characteristics were not reported; samples were small and predominantly White, and 48.1% of the people screened were excluded. Thus, findings from these studies may not be translatable across the range of people with these three conditions, which warrant efforts to target the inclusion of underrepresented subgroups in future exercise trials.

A high-protein diet or combination exercise training to improve metabolic health in individuals with long-standing spinal cord injury: a pilot randomized study.

We compared the effects of an 8-week iso-caloric high-protein (HP) diet versus a combined exercise regimen (Comb-Ex) in individuals with long-standing spinal cord injury (SCI). Effects on metabolic profiles, markers of inflammation, and signaling proteins associated with glucose transporter 4 (GLUT-4) translocation in muscles were evaluated. Eleven participants with SCI completed the study (HP diet: n = 5; Comb-Ex: n = 6; 46 ± 8 years; C5-T12 levels; American Spinal Injury Association Impairment Scale A or B). The Comb-Ex regimen included upper body resistance training (RT) and neuromuscular electrical stimulation-induced-RT for paralytic quadriceps muscles, interspersed with high-intensity (80-90% VO2 peak) arm cranking exercises 3 days/week. The HP diet included ~30% total energy as protein (carbohydrate to protein ratio <1.5, ~30% energy from fat). Oral glucose tolerance tests and muscle biopsies of the vastus lateralis (VL) and deltoid muscles were performed before and after the trial. Fasting plasma glucose levels decreased in the Comb-Ex (P < 0.05) group compared to the HP-diet group. A decrease in areas under the curve for insulin and TNF-α concentrations was observed for all participants regardless of group assignment (time effect, P < 0.05). Although both groups exhibited a quantitative increase in insulin sensitivity as measured by the Matsuda Index, the change was clinically meaningful only in the HP diet group (HP diet: pre, 4.6; post, 11.6 vs. Comb-Ex: pre, 3.3; post, 4.6). No changes were observed in proteins associated with GLUT-4 translocation in VL or deltoid muscles. Our results suggest that the HP-diet and Comb-Ex regimen may improve insulin sensitivity and decrease TNF-α concentrations in individuals with SCI.

Paralytic and nonparalytic muscle adaptations to exercise training versus high-protein diet in individuals with long-standing spinal cord injury.

This study compares the effects of an 8-wk isocaloric high-protein (HP) diet versus a combination exercise (Comb-Ex) regimen on paralytic vastus lateralis (VL) and nonparalytic deltoid muscle in individuals with long-standing spinal cord injury (SCI). Fiber-type distribution, cross-sectional area (CSA), levels of translation initiation signaling proteins (Erk-1/2, Akt, p70S6K1, 4EBP1, RPS6, and FAK), and lean thigh mass were analyzed at baseline and after the 8-wk interventions. A total of 11 participants (C5-T12 levels, 21.8 ± 6.3 yr postinjury; 6 Comb-Ex and 5 HP diet) completed the study. Comb-Ex training occurred 3 days/wk and consisted of upper body resistance training (RT) in addition to neuromuscular electrical stimulation (NMES)-induced-RT for paralytic VL muscle. Strength training was combined with high-intensity arm-cranking exercises (1-min intervals at 85-90%, V̇o2peak) for improving cardiovascular endurance. For the HP diet intervention, protein and fat each comprised 30%, and carbohydrate comprised 40% of total energy. Clinical tests and muscle biopsies were performed 24 h before and after the last exercise or diet session. The Comb-Ex intervention increased Type IIa myofiber distribution and CSA in VL muscle and Type I and IIa myofiber CSA in deltoid muscle. In addition, Comb-Ex increased lean thigh mass, V̇o2peak, and upper body strength ( P < 0.05). These results suggest that exercise training is required to promote favorable changes in paralytic and nonparalytic muscles in individuals with long-standing SCI, and adequate dietary protein consumption alone may not be sufficient to ameliorate debilitating effects of paralysis. NEW & NOTEWORTHY This study is the first to directly compare the effects of an isocaloric high-protein diet and combination exercise training on clinical and molecular changes in paralytic and nonparalytic muscles of individuals with long-standing spinal cord injury. Our results demonstrated that muscle growth and fiber-type alterations can best be achieved when the paralyzed muscle is sufficiently loaded via neuromuscular electrical stimulation-induced resistance training.

Human neuromuscular aging: Sex differences revealed at the myocellular level.

Age-related muscle loss (sarcopenia) is a major clinical problem affecting both men and women - accompanied by muscle weakness, dysfunction, disability, and impaired quality of life. Current definitions of sarcopenia do not fully encompass the age-related changes in skeletal muscle. We therefore examined the influence of aging and sex on elements of skeletal muscle health using a thorough histopathological analysis of myocellular aging and assessments of neuromuscular performance. Two-hundred and twenty-one untrained males and females were separated into four age cohorts [mean age 25 y (n = 47), 37 y (n = 79), 61 y (n = 51), and 72 y (n = 44)]. Total (-12%), leg (-17%), and arm (-21%) lean mass were lower in both 61 y and 72 y than in 25 y or 37 y (P < 0.05). Knee extensor strength (-34%) and power (-43%) were lower (P < 0.05) in the older two groups, and explosive sit-to-stand power was lower by 37 y (P < 0.05). At the histological/myocellular level, type IIx atrophy was noted by 37 y and type IIa atrophy by 61 y (P < 0.05). These effects were driven by females, noted by substantial and progressive type IIa and IIx atrophy across age. Aged female muscle displayed greater within-type myofiber size heterogeneity and marked type I myofiber grouping (~5-fold greater) compared to males. These findings suggest the predominant mechanisms leading to whole muscle atrophy differ between aging males and females: myofiber atrophy in females vs. myofiber loss in males. Future studies will be important to better understand the mechanisms underlying sex differences in myocellular aging and optimize exercise prescriptions and adjunctive treatments to mitigate or reverse age-related changes.

Effects of aging and Parkinson's disease on motor unit remodeling: influence of resistance exercise training.

Aging muscle atrophy is in part a neurodegenerative process revealed by denervation/reinnervation events leading to motor unit remodeling (i.e., myofiber type grouping). However, this process and its physiological relevance are poorly understood, as is the wide-ranging heterogeneity among aging humans. Here, we attempted to address 1) the relation between myofiber type grouping and molecular regulators of neuromuscular junction (NMJ) stability; 2) the impact of motor unit remodeling on recruitment during submaximal contractions; 3) the prevalence and impact of motor unit remodeling in Parkinson's disease (PD), an age-related neurodegenerative disease; and 4) the influence of resistance exercise training (RT) on regulators of motor unit remodeling. We compared type I myofiber grouping, molecular regulators of NMJ stability, and the relative motor unit activation (MUA) requirement during a submaximal sit-to-stand task among untrained but otherwise healthy young (YA; 26 yr, n = 27) and older (OA; 66 yr, n = 91) adults and OA with PD (PD; 67 yr, n = 19). We tested the effects of RT on these outcomes in OA and PD. PD displayed more motor unit remodeling, alterations in NMJ stability regulation, and a higher relative MUA requirement than OA, suggesting PD-specific effects. The molecular and physiological outcomes tracked with the severity of type I myofiber grouping. Together these findings suggest that age-related motor unit remodeling, manifested by type I myofiber grouping, 1) reduces MUA efficiency to meet submaximal contraction demand, 2) is associated with disruptions in NMJ stability, 3) is further impacted by PD, and 4) may be improved by RT in severe cases. NEW & NOTEWORTHY Because the physiological consequences of varying amounts of myofiber type grouping are unknown, the current study aims to characterize the molecular and physiological correlates of motor unit remodeling. Furthermore, because exercise training has demonstrated neuromuscular benefits in aged humans and improved innervation status and neuromuscular junction integrity in animals, we provide an exploratory analysis of the effects of high-intensity resistance training on markers of neuromuscular degeneration in both Parkinson's disease (PD) and age-matched older adults.

Quantification and characterization of grouped type I myofibers in human aging.

INTRODUCTION: Myofiber type grouping is a histological hallmark of age-related motor unit remodeling. Despite the accepted concept that denervation-reinnervation events lead to myofiber type grouping, the completeness of those conversions remains unknown. METHODS: Type I myofiber grouping was assessed in vastus lateralis biopsies from Young (26 ± 4 years; n = 27) and Older (66 ± 4 years; n = 91) adults. Grouped and ungrouped type I myofibers were evaluated for phenotypic differences. RESULTS: Higher type I grouping in Older versus Young was driven by more myofibers per group (i.e., larger group size) (P < 0.05). In Older only, grouped type I myofibers displayed larger cross-sectional area, more myonuclei, lower capillary supply, and more sarco(endo)plasmic reticulum calcium ATPase I (SERCA I) expression (P < 0.05) than ungrouped type I myofibers. DISCUSSION: Grouped type I myofibers retain type II characteristics suggesting that conversion during denervation-reinnervation events is either progressive or incomplete. Muscle Nerve 57: E52-E59, 2018.

Racial Differences in Weight Gain: A 5-Year Longitudinal Study of Persons With Spinal Cord Injury.

OBJECTIVE: To assess racial differences in body mass index (BMI) change over 5 years among people with spinal cord injury (SCI). DESIGN: Multicenter longitudinal study. SETTING: Spinal Cord Injury Model Systems centers. PARTICIPANTS: Individuals (N=437; 313 non-Hispanic white, 81 non-Hispanic black, and 43 Hispanic; 335 men; mean age, 41.3±13.5y) who incurred an SCI from 1974 to 2010 and completed 2 follow-up assessments within 5 years between October 1, 2006 and September 18, 2015 (mean duration of injury, 9.1±9.6y at the start of the 5-year follow-up). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: BMI (in kilograms per meters squared). RESULTS: The mean BMI of 437 participants increased from 26.4±6.3 to 27.0±6.4kg/m2 over 5 years (P=.002). The greatest increase was noted for Hispanics (2.0±5.7kg/m2; P=.02), followed by non-Hispanic whites (0.6±3.9kg/m2; P=.01) and non-Hispanic blacks (0.01±3.7kg/m2; P>.99). The differences in BMI increase across racial groups were significant (P=.03) in those with paraplegia (American Spinal Injury Association Impairment Scale A, B or C), those who were underweight or of normal weight at baseline, and those within 10 years of their injury. Such racial differences remained significant after taking into account demographic and injury characteristics. CONCLUSIONS: Our study findings provide a foundation for future research to explore risk and protective factors that contribute to racial differences in weight gain after SCI, which help alert health care professionals to a high-risk group for obesity prevention and management.

High-Intensity Exercise Acutely Increases Substantia Nigra and Prefrontal Brain Activity in Parkinson's Disease.

BACKGROUND Pathologic alterations in resting-state brain activity patterns exist among individuals with Parkinson's disease (PD). Since physical exercise alters resting-state brain activity in non-PD populations and improves PD symptoms, we assessed the acute effect of exercise on resting-state brain activity in exercise-trained individuals with PD. MATERIAL AND METHODS Resting-state functional magnetic resonance imaging (fMRI) was collected twice for 17 PD participants at the conclusion of an exercise intervention. The acute effect of exercise was examined for PD participants using the amplitude of low frequency fluctuation (ALFF) before and after a single bout of exercise. Correlations of clinical variables (i.e., PDQ-39 quality of life and MDS-UPDRS) with ALFF values were examined for the exercise-trained PD participants. RESULTS An effect of acute exercise was observed as an increased ALFF signal within the right ventromedial prefrontal cortex (PFC), left ventrolateral PFC, and bilaterally within the substantia nigra (SN). Quality of life was positively correlated with ALFF values within the vmPFC and vlPFC. CONCLUSIONS Given the role of the SN and PFC in motor and non-motor symptoms in PD, the acute increases in brain activity within these regions, if repeated frequently over time (i.e., exercise training), may serve as a potential mechanism underlying exercise-induced PD-specific clinical benefits.

Randomized, four-arm, dose-response clinical trial to optimize resistance exercise training for older adults with age-related muscle atrophy.

PURPOSE: The myriad consequences of age-related muscle atrophy include reduced muscular strength, power, and mobility; increased risk of falls, disability, and metabolic disease; and compromised immune function. At its root, aging muscle atrophy results from a loss of myofibers and atrophy of the remaining type II myofibers. The purpose of this trial (NCT02442479) was to titrate the dose of resistance training (RT) in older adults in an effort to maximize muscle regrowth and gains in muscle function. METHODS: A randomized, four-arm efficacy trial in which four, distinct exercise prescriptions varying in intensity, frequency, and contraction mode/rate were evaluated: (1) high-resistance concentric-eccentric training (H) 3d/week (HHH); (2) H training 2d/week (HH); (3) 3d/week mixed model consisting of H training 2d/week separated by 1 bout of low-resistance, high-velocity, concentric only (L) training (HLH); and (4) 2d/week mixed model consisting of H training 1d/week and L training 1d/week (HL). Sixty-four randomized subjects (65.5±3.6y) completed the trial. All participants completed the same 4weeks of pre-training consisting of 3d/week followed by 30weeks of randomized RT. RESULTS: The HLH prescription maximized gains in thigh muscle mass (TMM, primary outcome) and total body lean mass. HLH also showed the greatest gains in knee extension maximum isometric strength, and reduced cardiorespiratory demand during steady-state walking. HHH was the only prescription that led to increased muscle expression of pro-inflammatory cytokine receptors and this was associated with a lesser gain in TMM and total body lean mass compared to HLH. The HL prescription induced minimal muscle regrowth and generally lesser gains in muscle performance vs. the other prescriptions. MAJOR CONCLUSIONS: The HLH prescription offers distinct advantages over the other doses, while the HL program is subpar. Although limited by a relatively small sample size, we conclude from this randomized dose-response trial that older adults benefit greatly from 2d/week high-intensity RT, and may further benefit from inserting an additional weekly bout of low-load, explosive RT. TRIAL REGISTRATION: ClinicalTrials.govNCT02442479.

e-Health-based management of patients receiving oral anticoagulation therapy: results from the observational thrombEVAL study.

Essentials e-Health based health care by an expert centre may advance management of oral anticoagulation. Outcome of patients was compared between an e-health based coagulation service and regular care. Patients in the coagulation service cohort experienced a significantly better clinical outcome. Lower risk for adverse events was related to anticoagulation-specific and non-specific outcome. SUMMARY: Background Management of oral anticoagulation (OAC) therapy is essential to minimize adverse events in patients receiving vitamin K-antagonists (VKAs). Data on the effect of e-health-based anticoagulation management systems on the clinical outcome of OAC patients are limited. Objectives To compare the clinical outcome of OAC patients managed by an e-health-based coagulation service (CS) with that of patients receiving regular medical care (RMC). Methods The prospective multicenter cohort study thrombEVAL (NCT01809015) comprised 1558 individuals receiving RMC and 760 individuals managed by a CS. Independent study monitoring and adjudication of endpoints by an independent review panel were implemented. Results The primary study endpoint (composite of thromboembolism, clinically relevant bleeding and death) occurred in 15.7 per 100 patient-years (py) with RMC and in 7.0 per 100 py with the CS (rate ratio [RR], 2.3; 95% confidence interval [CI], 1.7-3.1). Rates for major and clinically relevant bleeding were higher with RMC than with the CS: 6.8 vs. 2.6 and 10.1 vs. 3.6 per 100 py, respectively. Thromboembolic events showed an RR of 1.5 (95% CI, 0.8-2.6) comparing RMC with the CS. Hospitalization (RR, 2.6; 95% CI, 2.3-3.0) and all-cause mortality (RR, 4.6; 95% CI, 2.8-7.7) were markedly more frequent with RMC. In Cox regression analysis with adjustment for age, sex, cardiovascular risk factors, comorbidities, treatment characteristics and sociodemographic status, hazard ratios (HR) for the primary endpoint (HR, 2.2; 95% CI, 1.5-3.4), clinically relevant bleeding (HR, 3.1; 95% CI, 1.7-5.5), hospitalization (HR, 2.2; 95% CI, 1.8-2.8) and all-cause mortality (HR, 5.6; 95% CI, 2.9-11.0) favored CS treatment. Conclusions In this study, e-health-based management of OAC therapy was associated with a lower frequency of OAC-specific and non-specific adverse events.