One minute of stair climbing and descending reduces postprandial insulin and glucose with 3-min improving insulin resistance following a mixed meal in young adults: A Randomized Controlled Crossover Trial.

Background: Glycemic markers, including postprandial glucose, insulin, and insulin resistance, are strong predictors of morbidity and mortality in individuals with and without diabetes. Stair-climbing and -descending (SCD) at a comfortable pace for 3 minutes after a sugary beverage (300 kilocalories; 100% carbohydrate) lowers insulin, with insulin sensitivity improving in 10 minutes. If similar benefits are seen following consumption of a mixed meal is unknown. We hypothesize SCD will improve these markers in a dose-response manner following a mixed meal. Methods: In a randomized, controlled, crossover trial, young adults (N = 31) performed SCD for 0 (seated control), 1, 3, and 10 minutes after a mixed meal (650 kilocalories; 53% carbohydrates, 33% fat, and 14% protein). Differences in glucose, insulin, and insulin sensitivity (ISI) from baseline to 30 min were analyzed using a mixed-effects ANOVA. Results: A significant fixed-effect was found for change in glucose [F(2.551,67.17) = 4.724,p = 0.007)], insulin [F(2.692,74.49) = 11.28,p < 0.001)], and ISI [F(2.127,56.00) = 5.848,p = 0.004)]. Compared to the seated control (0 minutes), changes in glucose were lower after 1 minute (-14.0 (-7.2)mg/dL,p < 0.001), 3 minutes (-18.4 (-7.0)mg/dL,p = 0.0007), and 10 minutes (-10.0 (-8.1)mg/dL,p = 0.039); changes in insulin were lower after 1 minute (-1.8 (-0.9)µIU/mL,p = 0.0011), 3 minutes (-2.8 (-0.9)µIU/mL,p < 0.001), and 10 minutes (-1.1 (-0.9)µIU/mL,p = 0.033); and changes in ISI were significantly higher after 3 minutes (2.4 (1.5),p < 0.001) and 10 minutes (1.3 (1.6),p = 0.014) but not 1 minute (1.2 (1.5),p = 0.059). Conclusion: Postprandial glucose and insulin improved with 1 minute, and insulin resistance improved with 3 minutes, of SCD at a self-selected, comfortable pace, after consumption of a mixed meal in apparently healthy young adults. Protocol: Trial registration: ClinicalTrials.gov Identifier: NCT04232475.

Three minutes of moderate-intensity stair walking improves glucose and insulin but not insulin sensitivity or total antioxidant capacity.

BACKGROUND AND AIMS: This study examined the effect of moderate intensity stair stepping exercise on the glycemic response, and antioxidant capacity (TAC) during an oral glucose tolerance test (OGTT). METHODS AND RESULTS: Thirty participants (women = 12) completed 4 OGTTs during rest or stair walking bouts of 1, 3, and 10 min in a randomized order. Blood was collected at baseline and 30 min during the OGTTs and analyzed for glucose, insulin, TAC, and lactate. Glucose concentrations were decreased following the 10 min (-22.69 (-34.66 to -10.72) mg/dL, p < 0.002) and 3 min (-15.37 (-25.05 to -5.69) mg/dL, p < 0.004) bouts but not the 1 min bout (-6.18 (-19.54 to 7.18) mg/dL, p = 0.352). Insulin concentrations were decreased following the 10 min (-6.11 (-8.86 to -3.36 µIU/dL), p < 0.001) and 3 min (-2.589 (-4.54 to -0.63) µIU/dL, p < 0.012) bouts but not the 1 min bout (-0.37 (-1.87 to 1.13) µIU/dL, p = 0.616). Insulin sensitivity index values showed a significant increase in the 10-min trial (1.81 (0.03-3.58), p < 0.048), but not during the 3 min (0.65 (-0.66 to 1.96) p = 0.317) or 1 min trial (0.13 (-1.58 to 1.84) p = 0.878). There was no omnibus effect for trial in TAC (p = 0.132, η2 = 0.07). There was no interaction between trial and time for blood lactate (p = 0.621, η2 = 0.02). CONCLUSION: This study provides evidence bouts as short as 3 min decrease postprandial blood glucose and insulin levels but longer bouts are needed to affect insulin sensitivity.

Substrate metabolism during recovery from circuit resistance exercise in persons with spinal cord injury.

INTRODUCTION: Whole body energy expenditure and lipid oxidation (Lox) are upregulated during and after exercise. Persons with spinal cord injury (SCI) generally have a blunted ability to utilize fat during exercise, but it is unknown if their substrate partitioning is affected during recovery from exercise. PURPOSE: To determine the effect of a single session of upper body circuit resistance exercise (CRE) on energy expenditure and Lox during exercise recovery in persons with and without SCI. METHODS: Twenty four persons (3 groups; 7 male and 1 female per group) without paralysis (neurologically intact; N) or with chronic (≥ 1 yr) paraplegia (P) or tetraplegia (T) participated. Energy expenditure and substrate partitioning were assessed via indirect calorimetry before, during, and three times after (up to 120 min after) a single session of CRE, or time-matched seated control (CON). RESULTS: During CRE, all groups experienced a similar relative increase in oxygen consumption (49 ± 13, 55 ± 11, and 48 ± 15% VO2peak for N, P, and T, respectively). The Post0-120 energy expenditure was greater following CRE vs. CON (P < 0.01) and independent of injury characteristics (10.6, 22.6, and 14.3% higher than CON for N, P, and T; P = 0.21). The absolute increase in Lox above CON during recovery was similar for N, P, and T (5.74 ± 2.81, 6.62 ± 3.10, and 4.50 ± 3.91 g, respectively; P = 0.45). CONCLUSIONS: Energy expenditure and lipid utilization was increased similarly following circuit exercise in persons without and with spinal cord injury in a manner independent of level of injury.

A single one-minute, comfortable paced, stair-climbing bout reduces postprandial glucose following a mixed meal.

BACKGROUND AND AIMS: Postprandial blood glucose (PBG) is an independent predictor of disease and mortality risk. To date, the shortest, single, moderate-intensity exercise intervention to reduce PBG is a 1 min bout of stair stepping during an oral glucose tolerance test. Whether this effect translates to real meal consumption is unknown. METHODS AND RESULTS: Subjects (N = 30) participated in a randomized controlled crossover trial performing 0 min (seated control), 1 min, 3 min or 10 min of stair climbing and descending bouts (SCD) at a self-selected pace after consumption of a mixed meal on four separate visits. Compared to control, all SCD reduced PBG at least one timepoint: at 30-min the 3 min (-10.8 (-18.7 to -2.8) mg/dL, p = 0.010) and 10 min (-36.3 (-46.4 to -26.3) mg/dL), p < .001), and at 45-min the 1 min (-7.3 (-13.9 to -0.7) mg/dL, p = 0.030, 3 min (-8.7 (-13.9 to -3.6) mg/dL, p = 0.002 and 10 min SCD (-12.2 (-18.2 to -6.1)mg/dL, p < 0.000) reduced PBG. The area under the curve (AUC) for PBG was lower following the 3 min (-4.4% (-7.5 to -1.4%), p = 0.006) and 10 min (-8.9% (-12.4 to -5.3%), p < 0.001), while the incremental AUC (iAUC) was reduced only following the 10 min (-38.0% (-63.7 to -12.3%), p = 0.005) SCD. All SCD were rated by subjects as very light to light intensity. CONCLUSIONS: Single, subjectively "light" intensity stair climbing and descending bouts as short as 1 min in duration attenuate the postprandial glucose response in normal weight individuals following consumption of a mixed meal. More pronounced effects require longer bouts in a dose-dependent manner.

Validity of Caloric Expenditure Measured from a Wheelchair User Smartwatch.

The objective of this study was to investigate the validity of measured caloric expenditure from a fitness smartwatch designed to measured values in wheelchair users against criterion values from a portable metabolic system. 15 wheelchair users and 15 able-bodied participants completed multiple tasks; wheelchair treadmill routine at 30, 45, and 60 strokes per minute, arm cycle ergometry at 45, 60, and 80 revolutions per minute, and arm cycle ergometry VO2Peak test. There were no interactions for device or task and group (wheelchair users vs. able bodied, p=0.375-0.944) therefore results were pooled across groups for all measures. The smartwatch exhibited poor to moderate caloric expenditure association during wheelchair treadmill routine (ICC<0.39) and arm cycle ergometry (ICC<0.541). Smartwatch underestimated caloric expenditure during the wheelchair treadmill task (Mean differences (Limits of Agreement)) (-2.11 (-8.19-3.96), -3.68 (-12.64-5.28), and -4.51 (-15.05-6.02)) and overestimated during the arm cycle ergometry task (0.89 (-3.10-4.88), 3.40 (-0.31-7.12), and 2.81 (-1.71-7.32)). The smartwatch is currently not well suited to calculate caloric expenditure when performing exercise tasks on a wheelchair treadmill and arm cycle ergometry.

Effect of acute watermelon juice supplementation on post-submaximal exercise heart rate recovery, blood lactate, blood pressure, blood glucose and muscle soreness in healthy non-athletic men and women.

The objective of this study was to determine the effects of a single pre-exercise dose of watermelon juice on submaximal post-exercise heart rate (HR) recovery, blood lactate (BL), blood pressure (BP), blood glucose (BG), and muscle soreness in healthy adults. In a randomised crossover design, 27 healthy non-athletic participants (13 males/14 females) consumed 355 mL of watermelon juice, Gatorade, sugar water, or water. HR and BL were significantly higher post-exercise, and both watermelon juice and sugar water increased postprandial BG. However, there were no significant differences among the supplements in HR recovery, BL, or post-exercise muscle soreness. Watermelon juice prevented increased post-exercise systolic and diastolic BP in females, but not in males. More research is warranted to examine the effect of sex on the efficacy of watermelon consumption for controlling BP.

Cardiometabolic Challenges Provided by Variable Assisted Exoskeletal Versus Overground Walking in Chronic Motor-incomplete Paraplegia: A Case Series.

BACKGROUND AND PURPOSE: People with spinal cord injury (SCI) experience secondary complications including low levels of cardiometabolic activity and associated health risks. It is unknown whether overground bionic ambulation (OBA) enhances cardiometabolic challenge during walking in those with motor-incomplete SCI, thereby providing additional therapeutic benefits. CASE DESCRIPTIONS: One man and one woman with chronic motor-incomplete paraplegia due to SCI. INTERVENTION: Assessment of functional walking capacity with the 10-m and 6-minute walk tests. Participants underwent cardiometabolic measurements including heart rate (HR), oxygen consumption ((Equation is included in full-text article.)O2), energy expenditure (EE), and substrate utilization patterns during OBA and overground walking for 6 minutes each. OUTCOMES: The female participant had low functional walking capacity (walking speed = 0.23 m/s; 6-minute walk = 230 ft). She had higher cardiorespiratory responses during OBA versus overground walking (Δ(Equation is included in full-text article.)O2 = -3.6 mL/kg/min, ΔEE = 12 kcal) despite similar mean HR values (ΔHR = -1 beats per minute). She was able to sustain continuous walking only during the OBA trial. The male participant had greater walking capacity (walking speed = 0.33 m/s, 6 minutes = 386ft) and lower responses during OBA versus overground walking (Δ(Equation is included in full-text article.)O2 = -6.0 mL/kg/min, ΔEE = -18 kcal, ΔHR = -6 beats per minute). He was able to walk continuously in both conditions. DISCUSSION: The participant with lower walking capacity experienced a higher cardiometabolic challenge and was able to sustain exercise efforts for longer period with OBA versus overground walking. Therefore, OBA presents a superior alternative to overground training for cardiometabolic conditioning and associated health benefits in this participant. For the participant with higher walking capacity, OBA represented a lower challenge and appears to be an inferior cardiometabolic training option to overground walking. The cardiometabolic response to OBA differs depending on functional capacity; OBA warrants study as an approach to cardiometabolic training for individuals with motor-incomplete SCI who have limited lower extremity function.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A259).

Aging impairs regulation of ryanodine receptors from extensor digitorum longus but not soleus muscles.

INTRODUCTION: Because impaired excitation-contraction coupling and reduced sarcoplasmic reticulum (SR) Ca2+ release may contribute to the age-associated decline in skeletal muscle strength, we investigated the effect of aging on regulation of the skeletal muscle isoform of the ryanodine receptor (RyR1) by physiological channel ligands. METHODS: [3 H]Ryanodine binding to membranes from 8- and 26-month-old Fischer 344 extensor digitorum longus (EDL) and soleus muscles was used to investigate the effects of age on RyR1 modulation by Ca2+ and calmodulin (CaM). RESULTS: Aging reduced maximal Ca2+ -stimulated binding to EDL membranes. In 0.3 µM Ca2+ , age reduced binding and CaM increased binding to EDL membranes. In 300 µM Ca2+ , CaM reduced binding, but the age effect was not significant. Aging did not affect Ca2+ or CaM regulation of soleus RyR1. DISCUSSION: In aged fast-twitch muscle, impaired RyR1 Ca2+ regulation may contribute to lower SR Ca2+ release and reduced muscle function. Muscle Nerve 57: 1022-1025, 2018.

Reducing Glycemic Indicators with Moderate Intensity Stepping of Varied, Short Durations in People with Pre-Diabetes.

Investigate the effects of short duration stair climbing/descending at a self-selected pace on post-prandial glucose responses in adults. Thirty participants (10 female) completed 4 oral glucose tolerance tests on separate days. Following glucose consumption, participants underwent seated rest (control) or walked up/down 21 stairs at a self-selected comfortable pace for 10, 3, and 1min in randomized order. Blood glucose was measured by capillary sampling from finger sticks every 15min until values for all trials converged. Area under the curve (AUC) was calculated by trapezoidal rule. In addition, cardiometabolic measurements were taken during stair exercise with a mobile metabolic cart. Results are presented as mean (SD) unless stated otherwise. All stair-climbing trials reduced peak (30min) postprandial blood glucose levels compared to the control [(1 min = 12(31), p = 0.026; 3 min = -15(25), p = 0.003; 10 min = 35(32) mg/dL, p < 0.001]. At 45min, there were significant reductions only for the 3 and 10 min trials [13(29) and 23(31) mg/dL, p = 0.023 and < 0.001 respectively], but not the 1 min trial [6(33) mg/dL, p = 0.317]. There were significant differences in AUC compared to the control only for the 3 and 10min trials [502 (1141) and 866 (1123) mg/dL·min-1, p = 0.023 and < 0.000] but not for the 1min trial [353 (1265) mg/dL·min-1, p = 0.110]. Median (interquartile range) RPEs reported for the 1, 3, and 10min trials were 1.0 (1.5), 2.0(2), and 3.0 (2.0) respectively, while VO2 was n/a, 54(12), and 59(13)% of peak, respectively. Total metabolic cost was 1.4 (0.5), 4.0 (1.0), and 11.9 (2.1) L O2, respectively. A single 1min bout of low-moderate intensity stair stepping can significantly lower peak glucose concentration, with longer bouts being more effective.

Model Programs to Address Obesity and Cardiometabolic Disease: Interventions for Suboptimal Nutrition and Sedentary Lifestyles.

Problems posed by obesity-related endocrine diseases embody a national health crisis. Caloric excess and sedentary lifestyle from which they develop also pose significant challenges for rehabilitation providers. Almost two thirds of the U.S. population are currently overweight or obese, a number that has increased by >10% within the last decade and is expected to grow. An overweight body habitus is strongly associated with clinical hazards, including cardiometabolic syndrome, diabetes hypertension, and coronary artery disease. The component health risks of the cardiometabolic syndrome include coalescing of risk factors that predict a health calamity unless effective interventions can be developed and widely adopted. Obesity by itself is now considered an American Diabetes Association-qualified disability, but it is also disturbingly prevalent in other physical disability groupings of adults and children. This monograph describes successes of the Diabetes Prevention Program (DPP), a National Institutes of Health multisite randomized controlled trial that reported significant weight reduction and a 58% decreased incidence of type-2 diabetes accompanying 1 year of structured lifestyle intervention. This treatment benefit (1) exceeded that of metformin pharmacotherapy, (2) was so powerful that the trial was closed before reaching endpoints, and (3) was judged cost-effective for the patient and society. The DPP roadmap incorporating physical activity, diet, and behavioral approaches has been widely adapted to specific community, faith, racial, ethnic, school, and national populations with excellent outcomes success. The lockstep physical activity approach, activity prescription, and long-term success of the program are described and compared with other programs to illustrate effective countermeasures for the pandemics of obesity and obesity-related cardioendocrine disease. We will illustrate adaptation of the DPP for a cohort of persons with disability from spinal cord injury and the benefits observed.

Effects of prandial challenge on triglyceridemia, glycemia, and pro-inflammatory activity in persons with chronic paraplegia.

CONTEXT/OBJECTIVE: Exaggerated postprandial lipemia has been reported after spinal cord injury (SCI). We examined metabolite and accompanying pro-inflammatory biomarker responses to repeat feeding of typical high-fat meals in individuals with chronic paraplegia. DESIGN: Descriptive trial. METHODS: Metabolites (triglycerides, glucose, and insulin) and inflammatory biomarkers (interleukin-6 and high-sensitivity C-reactive protein (hsCRP)) were measured under fasting conditions in 11 recreationally active individuals with chronic (>1 year) paraplegia. Subjects received high-fat meals at time point 0 and again at minute 240. Antecubital venous blood was obtained at time points -30 (fasting), 0 (first meal), 30, 60, 90, 120, 240 (second meal), 360, and 480 minutes. Correlations were examined among the study variables. Exploratory subgroup analysis was performed for subjects with levels of postprandial glucose greater than >200 mg/dl. RESULTS: Triglycerides showed a significant rise 4 hours after eating. Basal inflammatory markers were elevated, and did not undergo additional change during the testing. Additionally, subjects with excessive postprandial glucose responses showed higher hsCRP levels than those having typical glucose responses both for fasting (11.8 ± 6.5 vs. 2.9 ± 2.7 mg/l, P = 0.064) and postprandial (11.1 ± 4.9 vs. 3.7 ± 3.8 mg/l, P = 0.018) values. CONCLUSIONS: Despite elevations in metabolic response markers, inflammatory markers did not change significantly after consumption of population-representative (i.e. hypercaloric) mixed-nutrient meals. Levels of fasting CRP in the high-risk range are consistent with other reports in persons with SCI and continue to pose concern for their cardiovascular disease risk. The possible association between postprandial metabolic responses and inflammatory states warrants further investigation to identify individual component risks for this secondary health hazard.

Reference fitness values in the untrained spinal cord injury population.

OBJECTIVE: Establish reference values of cardiorespiratory fitness applicable to the general, untrained spinal cord injury (SCI) population. DESIGN: Data were retroactively obtained from 12 studies (May 2004 to May 2012). SETTING: An institution-affiliated applied physiology research laboratory. PARTICIPANTS: A total of 153 men and 26 women (age, 18-55y) with chronic SCI (N=179) were included. Participants were not involved in training activities for 1 or more months before testing and were able to complete a progressive resistance exercise test to determine peak oxygen consumption (Vo2peak). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Percentile ranking (poor<20%; fair; 20%-40%; average, 40%-60%; good, 60%-80%; excellent, 80%-100%) used to establish reference values. RESULTS: Reference cardiorespiratory fitness values based on functional classification as paraplegic or tetraplegic were established (paraplegic: median, 16.0mL·kg(-1)·min(-1); range, 1.4-35.2mL·kg(-1)·min(-1); tetraplegic: median, 8.8mL·kg(-1)·min(-1); range, 1.5-21.5mL·kg(-1)·min(-1)) for untrained men and women. For the primary outcome measure (Vo2peak), persons with paraplegia had significantly higher values than did persons with tetraplegia (P<.001). Although men had higher values than did women, these differences did not reach significance (P=.256). Regression analysis revealed that motor level of injury was associated with 22.3% of the variability in Vo2peak (P<.001), and an additional 8.7% was associated with body mass index (P<.001). No other measure accounted for additional significant variability. CONCLUSIONS: Established reference fitness values will allow investigators/clinicians to stratify the relative fitness of subjects/patients from the general SCI population. Key determinants are motor level of injury and body habitus, yet most variability in aerobic capacity is not associated with standard measures of SCI status or demographic characteristics.

Understanding therapeutic benefits of overground bionic ambulation: exploratory case series in persons with chronic, complete spinal cord injury.

OBJECTIVE: To explore responses to overground bionic ambulation (OBA) training from an interdisciplinary perspective including key components of neuromuscular activation, exercise conditioning, mobility capacity, and neuropathic pain. DESIGN: Case series. SETTING: Academic research center. PARTICIPANTS: Persons (N=3; 2 men, 1 woman) aged 26 to 38 years with complete spinal cord injury (SCI) (American Spinal Injury Association Impairment Scale grade A) between the levels of T1 and T10 for ≥1 year. INTERVENTION: OBA 3d/wk for 6 weeks. MAIN OUTCOME MEASURES: To obtain a comprehensive understanding of responses to OBA, an array of measures were obtained while walking in the device, including walking speeds and distances, energy expenditure, exercise conditioning effects, and neuromuscular and cortical activity patterns. Changes in spasticity and pain severity related to OBA use were also assessed. RESULTS: With training, participants were able to achieve walking speeds and distances in the OBA device similar to those observed in persons with motor-incomplete SCI (10-m walk speed, .11-.33m/s; 2-min walk distance, 11-33m). The energy expenditure required for OBA was similar to walking in persons without disability (ie, 25%-41% of peak oxygen consumption). Subjects with lower soleus reflex excitability walked longer during training, but there was no change in the level or amount of muscle activity with training. There was no change in cortical activity patterns. Exercise conditioning effects were small or nonexistent. However, all participants reported an average reduction in pain severity over the study period ranging between -1.3 and 1.7 on a 0-to-6 numeric rating scale. CONCLUSIONS: OBA training improved mobility in the OBA device without significant changes in exercise conditioning or in neuromuscular or cortical activity. However, pain severity was reduced and no severe adverse events were encountered during training. OBA therefore opens the possibility to reduce the common consequences of chronic, complete SCI such as reduced functional mobility and neuropathic pain.

Use of functional electrical stimulation cycle ergometers by individuals with spinal cord injury.

PURPOSE: To assess the use of network-connected home-based functional electrical stimulation (FES) cycle ergometers. METHOD: De-identified data on >20,000 FES sessions for 314 users with spinal cord injury were analyzed for usage patterns and energy expenditure. These were compared with authoritative exercise guidelines of 150 minutes of moderate-intensity aerobic activity per week over at least 2 days per week for a total of 1,000 kcals. RESULTS: Seven percent of participants were classified as high- (≥5 days/week), 11% as medium- (2-5 days/week), and 82% as low-frequency users (<2 days/week). CONCLUSION: None of the users satisfied authoritative energy expenditure recommendations for disease prevention with FES cycling alone.

Metabolic responses to 4 different body weight-supported locomotor training approaches in persons with incomplete spinal cord injury.

OBJECTIVE: To describe metabolic responses accompanying 4 different locomotor training (LT) approaches. DESIGN: Single-blind, randomized controlled trial. SETTING: Rehabilitation research laboratory, academic medical center. PARTICIPANTS: Individuals (N=62) with minimal walking function due to chronic motor-incomplete spinal cord injury. INTERVENTION: Participants trained 5 days/week for 12 weeks. Groups were treadmill-based LT with manual assistance (TM), transcutaneous electrical stimulation (TS), and a driven gait orthosis (DGO) and overground (OG) LT with electrical stimulation. MAIN OUTCOME MEASURES: Oxygen uptake (V˙o2), walking velocity and economy, and substrate utilization during subject-selected "slow," "moderate," and "maximal" walking speeds. RESULTS: V˙o2 did not increase from pretraining to posttraining for DGO (.00 ± .18L/min, P=.923). Increases in the other groups depended on walking speed, ranging from .01 ± .18 m/s (P=.860) for TM (slow speed) to .20 ± .29 m/s (P=.017) for TS (maximal speed). All groups increased velocity but to varying degrees (DGO, .01 ± .18 Ln[m/s], P=.829; TM, .07 ± .29 Ln[m/s], P=.371; TS, .33 ± .45 Ln[m/s], P=.013; OG, .52 ±.61 Ln[m/s], P=.007). Changes in walking economy were marginal for DGO and TM (.01 ± .20 Ln[L/m], P=.926, and .00 ± .42 Ln[L/m], P=.981) but significant for TS and OG (.26 ± .33 Ln[L/m], P=.014, and .44 ± .62 Ln[L/m], P=.025). Many participants reached respiratory exchange ratios ≥ 1 at any speed, rendering it impossible to statistically discern differences in substrate utilization. However, after training, fewer participants reached this ceiling for each speed (slow: 9 vs 6, n=32; moderate: 12 vs 8, n=29; and maximal 15 vs 13, n=28). CONCLUSIONS: DGO and TM walking training was less effective in increasing V˙o2 and velocity across participant-selected walking speeds, while TS and OG training was more effective in improving these parameters and also walking economy. Therefore, the latter 2 approaches hold greater promise for improving clinically relevant outcomes such as enhanced endurance, functionality, or in-home/community ambulation.

Heavy reliance on carbohydrate across a wide range of exercise intensities during voluntary arm ergometry in persons with paraplegia.

CONTEXT/OBJECTIVE: To describe and compare substrate oxidation and partitioning during voluntary arm ergometry in individuals with paraplegia and non-disabled individuals over a wide range of exercise intensities. DESIGN: Cross-sectional study. SETTING: Clinical research facility. PARTICIPANTS: Ten apparently healthy, sedentary men with paraplegia and seven healthy, non-disabled subjects. INTERVENTIONS: Rest and continuous progressive voluntary arm ergometry between 30 and 80% of peak aerobic capacity (VO2peak). OUTCOME MEASURES: Total energy expenditure and whole body rates of fat and carbohydrate oxidation. RESULTS: A maximal whole body fat oxidation (WBFO) rate of 0.13 ± 0.07 g/minute was reached at 41 ± 9% VO2peak for subjects with paraplegia, although carbohydrate became the predominant fuel source during exercise exceeding an intensity of 30-40% VO2peak. Both the maximal WBFO rate (0.06 ± 0.04 g/minute) and the intensity at which it occurred (13 ± 3% VO2peak) were significantly lower for the non-disabled subjects than those with paraplegia. CONCLUSION: Sedentary individuals with paraplegia are more capable of oxidizing fat during voluntary arm ergometry than non-disabled individuals perhaps due to local adaptations of upper body skeletal muscle used for daily locomotion. However, carbohydrate is the predominant fuel source oxidized across a wide range of intensities during voluntary arm ergometry in those with paraplegia, while WBFO is limited and maximally achieved at low exercise intensities compared to that achieved by able-bodied individuals during leg ergometry. These findings may partially explain the diminished rates of fat loss imposed by acute bouts of physical activity in those with paraplegia.

Salsalate Improves Postprandial Glycemic and Some Lipid Responses in Persons With Tetraplegia: A Randomized Clinical Pilot Trial With Crossover Design.

Objectives: To investigate the effects of salsalate on fasting and postprandial (PP) glycemic, lipidemic, and inflammatory responses in persons with tetraplegia. Methods: This study was a randomized, double-blind, cross-over design. It was conducted at a university laboratory. Ten males aged 25 to 50 years with SCI at C5-8 levels for ≥1 year underwent 1 month of placebo and salsalate (4 g/day) treatment. Blood samples were drawn before and 4 hours after breakfast and lunch fast-food meal consumption. Results: Descriptive statistics indicate that fasting and PP glucose values were reduced with salsalate (pre-post mean difference, 4 ± 5 mg/dL and 8 ± 8 mg/dL, respectively) but largely unchanged with placebo (0 ± 6 mg/dL and -0 ± 7 mg/dL, respectively). Insulin responses were generally reciprocal to glucose, however less pronounced. Fasting free fatty acids were significantly reduced with salsalate (191 ± 216 mg/dL, p = .021) but not placebo (-46 ± 116 mg/dL, p = .878). Results for triglycerides were similar (25 ± 34 mg/dL, p =.045, and 7 ± 29 mg/dL, p = .464). Fasting low-density lipoprotein (LDL) levels were higher after salsalate (-10 ± 12 mg/dL, p = .025) but not placebo (2 ± 9 mg/dL, p = .403) treatment. Inflammatory markers were largely unchanged. Conclusion: In this pilot trial, descriptive values indicate that salsalate decreased fasting and PP glucose response to fast-food meal challenge at regular intervals in persons with tetraplegia. Positive effects were also seen for some lipid but not for inflammatory response markers. Given the relatively "healthy" metabolic profiles of the participants, it is possible that salsalate's effects may be greater and more consistent in people with less favorable metabolic milieus.

Evidence-based and heuristic approaches for customization of care in cardiometabolic syndrome after spinal cord injury.

Component and coalesced health risks of the cardiometabolic syndrome (CMS) are commonly reported in persons with spinal cord injuries (SCIs). These CMS hazards are also co-morbid with physical deconditioning and elevated pro-atherogenic inflammatory cytokines, both of which are common after SCI and worsen the prognosis for all-cause cardiovascular disease. This article describes a systematic procedure for individualized CMS risk assessment after SCI, and emphasizes evidence-based and intuition-centered countermeasures to disease. A unified approach will propose therapeutic lifestyle intervention as a routine plan for aggressive primary prevention in this risk-susceptible population. Customization of dietary and exercise plans then follow, identifying shortfalls in diet and activity patterns, and ways in which these healthy lifestyles can be more substantially embraced by both stakeholders with SCI and their health care providers. In cases where lifestyle intervention utilizing diet and exercise is unsuccessful in countering risks, available pharmacotherapies and a preferred therapeutic agent are proposed according to authoritative standards. The over-arching purpose of the monograph is to create an operational framework in which existing evidence-based approaches or heuristic modeling becomes best practice. In this way persons with SCI can lead more active and healthy lives.

Physiological responses to exergaming after spinal cord injury.

PURPOSE: To investigate whether exergaming satisfies guideline-based intensity standards for exercise conditioning (40%/50% oxygen uptake reserve [VO2R] or heart rate reserve (HRR), or 64%/70% of peak heart rate [HRpeak]) in persons with paraplegia. METHODS: Nine men and women (18-65 years old) with chronic paraplegia (T1-L1, AIS A-C) underwent intensity-graded arm cycle exercise (AE) to evaluate VO2peak and HRpeak. On 2 randomized nonconsecutive days, participants underwent graded exercise using a custom arm cycle ergometer that controls the video display of a Nintendo Gamecube (GameCycle; Three Rivers Holdings LLC, Mesa, AZ) or 15 minutes of incrementally wrist-weighted tennis gameplay against a televised opponent (XaviX Tennis System; SSD Co Ltd, Kusatsu, Japan). RESULTS: GameCycle exergaming (GCE) resistance settings ≥0.88 Nm evoked on average ≥50% VO2R. During XaviX Tennis System exergaming (XTSE) with wrist weights ≥2 lbs, average VO2 reached a plateau of ~40% VO2R. Measurements of HR were highly variable and reached average values ≥50% HRR during GCE at resistance settings ≥0.88 Nm. During XTSE, average HR did not reach threshold levels based on HRR for any wrist weight (20%-35% HRR). CONCLUSIONS: On average, intensity responses to GCE at resistance setting ≥0.88 Nm were sufficient to elicit exercise intensities needed to promote cardiorespiratory fitness in individuals with SCI. The ability of XTSE to elicit cardiorespiratory fitness benefits is most likely limited to individuals with very low fitness levels and may become subminimal with time if used as a conditioning stimulus.

Subjective measures of exercise intensity to gauge substrate partitioning in persons with paraplegia.

BACKGROUND: The Borg Rating of Perceived Exertion (RPE) Scale and talk test (TT) are commonly recommended for persons to gauge exercise intensity. It is not known whether they are suitable to estimate substrate partitioning between carbohydrate and fat in persons with SCI. OBJECTIVE: Investigate substrate partitioning/utilization patterns associated with RPE and TT. METHODS: Twelve participants with chronic paraplegia underwent 2 arm crank exercise tests on nonconsecutive days within 2 weeks. Test 1 was a graded exercise test (GXT) to volitional exhaustion. Test 2 was a 15-minute self-selected steady state (SS) voluntary arm exercise bout simulating a brief, yet typical exercise session. RESULTS: For the GXT, very light intensity exercise (RPE < 9) and TT stage before last positive were associated with highest contribution of fat oxidation (~35%-50%) to total energy expenditure (TEE). Fat oxidation was low at all stages, with the highest rate (0.13 ± 0.07 g/min) occurring at stage 1 (10 W). Corresponding average RPE was 7 ± 2 and the TT was positive for all participants at this stage. For the SS, fuel partitioning throughout exercise was dominated by carbohydrate oxidation (1.47 ± 0.08 g/min), accounting for almost all (~94%) of TEE with only a minute contribution from fat oxidation (0.02 ± 0.004 g/min). A positive TT was associated with an average contribution of fat oxidation of ~10%. CONCLUSIONS: RPE but not the TT appears suitable to predict exercise intensities associated with the highest levels of fat oxidation. However, such intensities are below authoritative intensity thresholds for cardiorespiratory fitness promotion, and therefore the applicability of such a prediction for exercise prescriptions is likely limited to individuals with low exercise tolerance.