Myths and Methodologies: Standardisation in Human Physiology Research-Should We Control the Controllables?

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting. Researchers may also need to consider standardisation of physical activity, whether it be through familiarisation trials, wash-out periods, or guidance on levels of physical activity to be achieved before trials. In terms of pharmacological agents, the ethical implications of standardisation require researchers to carefully consider how medications, caffeine consumption and oral contraceptive prescriptions may affect the study. For research in females, it should be considered whether standardisation between- or within-participants in regards to menstrual cycle phase is most relevant. The timing of measurements relative to various other daily events is relevant to all physiological research and so it can be important to standardise when measurements are made. This review summarises the areas of standardisation which we hope will be considered useful to anyone involved in human physiology research, including when and how one can apply standardisation to various contexts.

Myths and Methodologies: Standardisation in human physiology research-should we control the controllables?

The premise of research in human physiology is to explore a multifaceted system whilst identifying one or a few outcomes of interest. Therefore, the control of potentially confounding variables requires careful thought regarding the extent of control and complexity of standardisation. One common factor to control prior to testing is diet, as food and fluid provision may deviate from participants' habitual diets, yet a self-report and replication method can be flawed by under-reporting. Researchers may also need to consider standardisation of physical activity, whether it be through familiarisation trials, wash-out periods, or guidance on levels of physical activity to be achieved before trials. In terms of pharmacological agents, the ethical implications of standardisation require researchers to carefully consider how medications, caffeine consumption and oral contraceptive prescriptions may affect the study. For research in females, it should be considered whether standardisation between- or within-participants in regards to menstrual cycle phase is most relevant. The timing of measurements relative to various other daily events is relevant to all physiological research and so it can be important to standardise when measurements are made. This review summarises the areas of standardisation which we hope will be considered useful to anyone involved in human physiology research, including when and how one can apply standardisation to various contexts.

Feasibility study of high-intensity interval training to reduce cardiometabolic disease risks in individuals with acute spinal cord injury.

INTRODUCTION: Individuals ageing with spinal cord injury (SCI) experience an accelerated trajectory of diseases and disorders, such as cardiovascular disease and diabetes, that resemble those experienced with ageing alone. Currently, an evidence-based approach toward managing this problem does not exist and therefore the purpose of this study is to determine the feasibility of conducting a high-intensity exercise intervention in individuals with acute (<6 months postinjury) SCI to improve cardiometabolic health. METHODS AND ANALYSIS: We will conduct a single-centre, two parallel-arm, randomised feasibility study of a high-intensity interval training (HIIT) intervention in individuals with acute SCI. We will enrol 40 individuals (20 intervention, 20 control) with acute SCI attending inpatient rehabilitation at Salisbury District Hospital. Participants will be randomly allocated to the intervention group (HIIT) or control group for 18 weeks. Both groups will participate in standard care throughout the duration of the study. The HIIT group only will also perform supervised HIIT exercise on an arm cycle ergometer three times per week. Over the course of the intervention, most participants will be discharged from the hospital, and at this time, an arm cycle ergometer will be installed in their home and the intervention will transition into outpatient care. We will assess cardiorespiratory fitness, glycaemic control, lipid profile and body habitus as well as qualitative assessments of acceptability at weeks 0, 9 and 18 with the primary outcome being the feasibility of a full Randomised Controlled Trial (RCT). ETHICS AND DISSEMINATION: This study will inform a longer-term, definitive, multicentre RCT to establish the impact of this exercise intervention in maintaining the cardiometabolic health of patients during the acute phase following SCI. Results will be disseminated in different formats including peer-reviewed journal articles, conference presentations and internet media, to a wide audience including clinicians, researchers and individuals with SCI. TRIAL REGISTRATION NUMBER: ISRCTN57514022.

Prior arm-crank exercise has no effect on postprandial lipaemia in nondisabled adults.

A single bout of cycling or running performed in the evening can reduce postprandial lipaemia (PPL) the following morning, although this is currently unknown for upper-body exercise. The aim of this study was to determine if a bout of arm-crank exercise (high-intensity interval [HIIE] or moderate-intensity continuous [MICE]), can attenuate PPL in noninjured individuals. Eleven healthy and recreationally active participants (eight males, three females; age: 27 ± 7 years; body mass index: 23.5 ± 2.5 kg·m-2) volunteered to participate in three trials: HIIE (10 × 60 s at 80% peak power output), MICE (50% peak power output of isocaloric duration), and a no-exercise control condition. Each exercise bout was performed at 18:00, and participants consumed a standardised evening meal at 20:00. Following an overnight fast, a 5-h mixed-macronutrient tolerance test was performed at 08:00. There were no significant differences in triglyceride incremental area under the curve between HIIE (192 ± 94 mmol·L-1 per 300 min), MICE (184 ± 111 mmol·L-1 per 300 min), and the no-exercise condition (175 ± 90 mmol·L-1 per 300 min) (P = 0.46). There were no significant differences in incremental area under the curve for glucose (P = 0.91) or insulin (P = 0.59) between conditions. Upper-body MICE and HIIE performed in the evening do not influence PPL the following morning, in normotriglyceridemic individuals. Clinical Trials Registration: NCT04277091. Novelty: Arm-crank exercise has no effect on PPL when performed the evening prior to a mixed-macronutrient meal test. Upper-body sprint interval exercise should be investigated as a potential solution to reduce PPL.

The welfare of wildlife: an interdisciplinary analysis of harm in the legal and illegal wildlife trades and possible ways forward.

Wildlife trade-both legal and illegal-is an activity that is currently the focus of global attention. Concerns over the loss of biodiversity, partly stemming from overexploitation, and the corona virus pandemic, likely originating from wildlife trade, are urgent matters. These concerns though centre on people. Only sometimes does the discussion focus on the wildlife traded and their welfare. In this article, we make the case as to why welfare is an important component of any discussion or policy about wildlife trade, not only for the interests of the wildlife, but also for the sake of humans. We detail the harm in the trade as well as the current welfare provisions, particularly in relation to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), which guide global transport and trade. There are a number of ways that the current approach to wildlife welfare could be improved, and we propose ways forward in this regard.

European illegal puppy trade and organised crime.

Organised crime groups' involvement in illicit markets is a common focus of law enforcement and governments. Drug, weapon, human and wildlife trafficking (and others) are all illegal activities with link to organised crime. This paper explores the overlooked illicit market of puppies. We detail the state of knowledge about the organisation of the UK puppy trade, which includes irresponsible and illegal breeding of puppies throughout Europe and their often-illegal movement into the UK. In 2017, we conducted an analysis of hundreds of online advertisements in Scotland, 12 expert interviews, a stakeholder survey of 53 participants, and 40 focus groups across Great Britain. Our data suggest an organised illicit market running in parallel to the legal trade. We speculate as to whether at some point along the supply chain organised crime groups are responsible for the suffering and death of the puppies and the economic and emotional damage to 'consumers'. Online monitoring and physical scrutiny at the ports must be improved to reduce non-human animal abuse. People buying puppies must also be made aware that their purchase could be profiting organised crime.

Neither Postabsorptive Resting Nor Postprandial Fat Oxidation Are Related to Peak Fat Oxidation in Men With Chronic Paraplegia.

The peak rate of fat oxidation (PFO) achieved during a graded exercise test is an important indicator of metabolic health. In healthy individuals, there is a significant positive association between PFO and total daily fat oxidation (FO). However, conditions resulting in metabolic dysfunction may cause a disconnect between PFO and non-exercise FO. Ten adult men with chronic thoracic spinal cord injury (SCI) completed a graded arm exercise test. On a separate day following an overnight fast (≥ 10 h), they rested for 60 min before ingesting a liquid mixed meal (600 kcal; 35% fat, 50% carbohydrate, 15% protein). Expired gases were collected and indirect calorimetry data used to determine FO at rest, before and after feeding, and during the graded exercise test. Participants had "good" cardiorespiratory fitness (VO2peak: 19.2 ± 5.2 ml/kg/min) based on normative reference values for SCI. There was a strong positive correlation between PFO (0.30 ± 0.08 g/min) and VO2peak (r = 0.86, p = 0.002). Additionally, postabsorptive FO at rest was significantly and positively correlated with postprandial peak FO (r = 0.77, p = 0.01). However, PFO was not significantly associated with postabsorptive FO at rest (0.08 ± 0.02 g/min; p = 0.97), postprandial peak FO (0.10 ± 0.03 g/min; p = 0.43), or incremental area under the curve postprandial FO (p = 0.22). It may be advantageous to assess both postabsorptive FO at rest and PFO in those with SCI to gain a more complete picture of their metabolic flexibility and long-term metabolic health.

Exercise Interventions Targeting Obesity in Persons With Spinal Cord Injury.

Spinal cord injury (SCI) results in an array of cardiometabolic complications, with obesity being the most common component risk of cardiometabolic disease (CMD) in this population. Recent Consortium for Spinal Cord Medicine Clinical Practice Guidelines for CMD in SCI recommend physical exercise as a primary treatment strategy for the management of CMD in SCI. However, the high prevalence of obesity in SCI and the pleiotropic nature of this body habitus warrant strategies for tailoring exercise to specifically target obesity. In general, exercise for obesity management should aim primarily to induce a negative energy balance and secondarily to increase the use of fat as a fuel source. In persons with SCI, reductions in the muscle mass that can be recruited during activity limit the capacity for exercise to induce a calorie deficit. Furthermore, the available musculature exhibits a decreased oxidative capacity, limiting the utilization of fat during exercise. These constraints must be considered when designing exercise interventions for obesity management in SCI. Certain forms of exercise have a greater therapeutic potential in this population partly due to impacts on metabolism during recovery from exercise and at rest. In this article, we propose that exercise for obesity in SCI should target large muscle groups and aim to induce hypertrophy to increase total energy expenditure response to training. Furthermore, although carbohydrate reliance will be high during activity, certain forms of exercise might induce meaningful postexercise shifts in the use of fat as a fuel. General activity in this population is important for many components of health, but low energy cost of daily activities and limitations in upper body volitional exercise mean that exercise interventions targeting utilization and hypertrophy of large muscle groups will likely be required for obesity management.

The Relationship between HIV Duration, Insulin Resistance and Diabetes Risk.

The risk of developing Type 2 Diabetes Mellitus in people living with HIV (PLWH) can be four times greater and can occur at an earlier age and even without the presence of obesity compared to those without HIV. Therefore, the purpose of this analytical cross-sectional study was to determine the relationship between HIV duration and glucose metabolism among PLWH. Eighty-two PLWH were categorized into shorter (≤15 years) or longer HIV duration (≥16 years) and then compared for differences in demographics, physical and clinical characteristics, biomarkers, and dietary intake. Compared to those with shorter HIV duration (n = 34), those with longer HIV duration (n = 48) were on average older (p = 0.02), reported lower consumption of alcohol (p = 0.05), had higher levels of homeostasis model assessment of insulin resistance (HOMA-IR, p = 0.02), were also more likely to be a woman (p = 0.06), and have higher levels of fasting insulin (p = 0.06). When adjusted for age and body weight, the levels of HOMA-IR and fasting insulin were higher (p = 0.02 and p = 0.04) with longer compared to shorter HIV duration, respectively. Longer exposure to HIV infection is associated with impaired insulin sensitivity. Continuing research aimed at the long-term effects of HIV infection and (antiretroviral therapy) is required.

Effect of high-intensity interval training on cardiometabolic component risks in persons with paraplegia: Protocol for a randomized controlled trial.

Individuals with a spinal cord injury (SCI) are at an increased risk of developing cardiovascular disease and present with a multitude of elevated cardiometabolic component risks. Although upper-body exercise appears an effective strategy to improve some of these outcomes, the effectiveness of high-intensity interval training (HIIT) has yet to be determined for this population. Therefore, a randomized controlled trial will be conducted to determine the effectiveness of a 6 week home-based upper-body HIIT intervention on biomarkers of cardiometabolic health in persons with spinal cord injury, in comparison to a control (CON) group. We will recruit 40 individuals with chronic (>1 year post-injury) paraplegia (spinal cord lesion between the second thoracic and second lumbar vertebrae), aged between 18 and 65 years. After baseline testing, participants will be assigned randomly, using a 2:1 allocation, to the home-based exercise intervention (HIIT, n = 26) or control group (CON, n = 14). The HIIT intervention will consist of 30 min of arm crank-based HIIT (60 s intervals at 80-90% peak heart rate) four times per week. Participants in the CON group will be asked to maintain their habitual diet and physical activity patterns over the study period. Baseline and follow-up assessments will be made for determination of body composition, postprandial glycaemic control, fasting blood lipids and systemic inflammation, aerobic capacity, physical activity and energy intake, resting metabolic rate, resting blood pressure, and subjective measures of health and well-being. ClinicalTrials.gov, ID: NCT04397250. Registered on 21 May 2020.

A Single Bout of Upper-Body Exercise Has No Effect on Postprandial Metabolism in Persons with Chronic Paraplegia.

PURPOSE: The acute effects of a single bout of upper-body exercise on postprandial metabolism in persons with spinal cord injury are currently not well understood. The primary aim of this study was to evaluate the effects of a single bout of upper-body high-intensity interval exercise (HIIE) and moderate-intensity continuous exercise (MICE) in comparison with a no-exercise control (REST) condition on postprandial metabolic responses in persons with chronic paraplegia. METHODS: Ten participants (eight males, two females; age, 49 ± 10 yr; time since injury, 22 ± 13 yr) with chronic paraplegia took part in a randomized crossover study, consisting of three trials: HIIE (8 × 60 s at 70% peak power output [PPEAK]), MICE (25 min at 45% PPEAK), and REST, at least 3 d apart. Exercise was performed in the fasted state, and participants consumed a mixed-macronutrient liquid meal 1-h postexercise. Venous blood and expired gas samples were collected at regular intervals for 6-h postmeal consumption. RESULTS: There were no significant differences in postprandial incremental area under the curve for triglycerides (P = 0.59) or glucose (P = 0.56) between conditions. Insulin incremental area under the curve tended to be lower after MICE (135 ± 85 nmol·L-1 per 360 min) compared with REST (162 ± 93 nmol·L-1 per 360 min), but this did not reach statistical significance (P = 0.06, d = 0.30). Participants reported a greater fondness (P = 0.04) and preference for HIIE over MICE. CONCLUSIONS: After an overnight fast, a single bout of upper-body exercise before eating has no effect on postprandial metabolism in persons with chronic paraplegia, irrespective of exercise intensity. This suggests that alternative exercise strategies may be required to stimulate postprandial substrate oxidation for this population.

Effects of Exercise Mode on Postprandial Metabolism in Humans with Chronic Paraplegia.

PURPOSE: The purpose of this study was to assess the acute effects of exercise mode and intensity on postprandial macronutrient metabolism. METHODS: Ten healthy men age 39 ± 10 yr with chronic paraplegia (13.2 ± 8.8 yr, ASIA A-C) completed three isocaloric bouts of upper-body exercise and a resting control. After an overnight fast, participants completed circuit resistance exercise (CRE) first and the following conditions in a randomized order, separated by >48 h: i) control (CON), ~45-min seated rest; ii) moderate-intensity continuous exercise (MICE), ~40-min arm cranking at a resistance equivalent to ~30% peak power output (PPO); and iii) high-intensity interval exercise (HIIE), ~30 min arm cranking with resistance alternating every 2 min between 10% PPO and 70% PPO. After each condition, participants completed a mixed-meal tolerance test consisting of a 2510-kJ liquid meal (35% fat, 50% carbohydrate, 15% protein). Blood and expired gas samples were collected at baseline and regular intervals for 150 min after a meal. RESULTS: An interaction (P < 0.001) was observed, with rates of lipid oxidation elevated above CON in HIIE until 60 min after a meal and in CRE at all postprandial time points up to 150 min after a meal. Postprandial blood glycerol was greater in MICE (P = 0.020) and CRE (P = 0.001) compared with CON. Furthermore, nonesterified fatty acid area under the curve had a moderate-to-strong effect in CRE versus MICE and HIIE (Cohen's d = -0.76 and -0.50, respectively). CONCLUSIONS: In persons with paraplegia, high-intensity exercise increased postprandial energy expenditure independent of the energy cost of exercise. Furthermore, exercise combining resistance and endurance modes (CRE) showed the greater effect on postprandial lipid oxidation.

Development and deployment of an at-home strength and conditioning program to support a phase I trial in persons with chronic spinal cord injury.

STUDY DESIGN: Nonrandomized clinical trial (NCT02354625). OBJECTIVES: As a part of a Phase I clinical trial to assess the safety of autologous human Schwann cells (ahSC) in persons with chronic spinal cord injury (SCI), participants engaged in a multimodal conditioning program pre- and post-ahSC transplantation. The program included a home-based strength and endurance training program to prevent lack of fitness and posttransplantation detraining from confounding potential ahSC therapeutic effects. This paper describes development, deployment, outcomes, and challenges of the home-based training program. SETTING: University-based laboratory. METHODS: Development phase: two men with paraplegia completed an 8-week laboratory-based 'test' of the home-based program. Deployment phase: the first four (two males, two females) participant cohort of the ahSC trial completed the program at home for 12 weeks pre and 20 weeks post ahSC transplant. RESULTS: Development phase: both participants improved their peak aerobic capacity (VO2peak) (≥17%), peak power output (POpeak) (≥8%), and time to exhaustion (TTE) (≥7%). Deployment phase: pretransplant training minimally increased fitness in the two male participants (≥6% POpeak and ≥9% TTE). The two women had no POpeak changes and slight TTE changes (+2.6 and -1.2%, respectively.) All four participants detrained during the posttransplant recovery period. After posttransplant retraining, all four participants increased TTE (4-24%), three increased VO2peak (≥11%), and two increased POpeak (≥7%). CONCLUSIONS: Home-based strength and condition programs can be effective and successfully included in therapeutic SCI trials. However, development of these programs requires substantial content knowledge and experience.

Physiological responses to moderate intensity continuous and high-intensity interval exercise in persons with paraplegia.

STUDY DESIGN: Randomized crossover. OBJECTIVES: To test differences in the duration and magnitude of physiological response to isocaloric moderate intensity continuous (MICE) and high-intensity interval exercise (HIIE) sessions in persons with spinal cord injury (SCI). SETTING: Academic medical center in Miami, FL, USA. METHODS: Ten adult men (mean ± s.d.; 39 ± 10 year old) with chronic (13.2 ± 8.8 year) paraplegia (T2-T10) completed a graded exercise test. Then, in a randomized order, participants completed MICE and HIIE for a cost of 120 kcal. MICE was performed at 24.6% POpeak. During HIIE, exercise was completed in 2 min work and recovery phases at 70%:10% POpeak. RESULTS: MICE and HIIE were isocaloric (115.9 ± 21.8 and 116.6 ± 35.0 kcal, respectively; p = 0.903), but differed in duration (39.8 ± 4.6 vs 32.2 ± 6.2 min; p < 0.001) and average respiratory exchange ratio (RER; 0.90 ± 0.08 vs 1.01 ± 0.07; p = 0.002). During MICE, a workrate of 24.6 ± 6.7% POpeak elicited a V̇O2 of 53.1 ± 6.5% V̇O2peak (10.1 ± 2.2 ml kg-1 min-1). During HIIE, a workrate at 70% POpeak elicited 88.3 ± 6.7% V̇O2peak (16.9 ± 4.2 ml kg-1 min-1), and 29.4 ± 7.7% of the session was spent at or above 80% V̇O2peak. During HIIE working phase, RER declined from the first to last interval (1.08 ± 0.07 vs 0.98 ± 0.09; p < 0.001), reflecting an initially high but declining glycolytic rate. CONCLUSIONS: Compared with MICE, HIIE imposed a greater physiological stimulus while requiring less time to achieve a target caloric expenditure. Thus, exercise intensity might be an important consideration in the tailoring of exercise prescription to address the cardiometabolic comorbidities of SCI.

Effect of Exercise on Cardiometabolic Risk Factors in Adults With Chronic Spinal Cord Injury: A Systematic Review.

OBJECTIVE: To determine the effects of exercise on individual cardiometabolic syndrome (CMS) risk factors in adults with chronic spinal cord injury (SCI). DATA SOURCES: English language searches of PubMed, Web of Science, EMBASE, and Scopus (January 1, 1970, to July 31, 2019). STUDY SELECTION: Articles were included if they met the following criteria: (1) original articles with statistical analysis, (2) participants were adults with a SCI sustained ≥1 year ago, (3) exercise intervention duration ≥2 weeks, and (4) included any CMS risk factor as an outcome. DATA EXTRACTION: The methodological quality of articles was assessed using the Downs and Black score. DATA SYNTHESIS: Sixty-five studies were included for the final analysis, including 9 studies classified as high quality (≥66.7%), 35 studies classified as fair quality (50%-66.6%), and 21 studies classified as low quality (<50%). Improvements in waist circumference (4/6 studies) and markers of hepatic insulin sensitivity (4/5 studies) were reported following upper body aerobic exercise training, but no improvements in fasting glucose (8/8 studies), lipid profile (6/8 studies), systolic blood pressure (8/9 studies), or diastolic blood pressure (9/9 studies) were observed. Improvements in markers of peripheral insulin sensitivity (5/6 studies) were observed following functional electrical stimulation (FES) cycling. Improvements in lipid profile (4/5 studies) were observed following upper body resistance training (RT) (with or without aerobic exercise). No consistent improvements in CMS risk factors were observed following assisted ambulation, FES hybrid, FES rowing, and FES RT. CONCLUSIONS: Upper body aerobic exercise training (>75% maximum heart rate) appears to improve waist circumference and hepatic insulin sensitivity but appears insufficient for improving fasting glucose, lipid profile, or resting blood pressure. The addition of RT to upper body aerobic exercise may elicit favorable changes in the lipid profile. More high-quality studies are needed to confirm if FES cycling is effective at improving peripheral insulin sensitivity.

Differences in Acute Metabolic Responses to Bionic and Nonbionic Ambulation in Spinal Cord Injured Humans and Controls.

OBJECTIVES: To (1) compare energy expenditure during seated rest, standing, and prolonged bionic ambulation or bipedal ambulation in participants with spinal cord injury (SCI) and noninjured controls, respectively, and (2) test effects on postbionic ambulation glycemia in SCI. DESIGN: Two independent group comparison of SCI and controls. SETTING: Academic Medical Center. PARTICIPANTS: Ten participants with chronic SCI (C7-T1, American Spinal Injury Association Impairment Scale A-C) and 10 controls (N=20). INTERVENTIONS: A commercial bionic exoskeleton. MAIN OUTCOME MEASURES: Absolute and relative (to peak) oxygen consumption, perceived exertion, carbohydrate/fat oxidation, energy expenditure, and postbionic ambulation plasma glucose/insulin. RESULTS: Average work intensity accompanying 45 minutes of outdoor bionic ambulation was <40% peak oxygen consumption, with negligible drift after reaching steady state. Rating of perceived exertion (RPE) did not differ between groups and reflected low exertion. Absolute energy costs for bionic ambulation and nonbionic ambulation were not different between groups despite a 565% higher ambulation velocity in controls and 3.3× higher kilocalorie per meter in SCI. Fuel partitioning was similar between groups and the same within groups for carbohydrate and fat oxidation. Nonsignificant (9%) lowering of the area under a glucose tolerance curve following bionic ambulation required 20% less insulin than at rest. CONCLUSION: Work intensity during prolonged bionic ambulation for this bionic exoskeleton is below a threshold for cardiorespiratory conditioning but above seated rest and passive standing. Bionic ambulation metabolism is consistent with low RPE and unchanged fuel partitioning from seated rest. Bionic ambulation did not promote beneficial effects on glycemia in well-conditioned, euglycemic participants. These findings may differ in less fit individuals with SCI or those with impaired glucose tolerance. Observed trends favoring this benefit suggest they are worthy of testing.

Influence of upper-body continuous, resistance or high-intensity interval training (CRIT) on postprandial responses in persons with spinal cord injury: study protocol for a randomised controlled trial.

BACKGROUND: Chronic spinal cord injury (SCI) increases morbidity and mortality associated with cardiometabolic diseases, secondary to increases in central adiposity, hyperlipidaemia and impaired glucose tolerance. While upper-body Moderate Intensity Continuous Training (MICT) improves cardiorespiratory fitness, its effects on cardiometabolic component risks in adults with SCI appear relatively modest. The aim of this study is to assess the acute effects of Continuous Resistance Training (CRT), High Intensity Interval Training (HIIT), MICT and rest (CON) on fasting and postprandial systemic biomarkers and substrate utilisation. METHODS: Eleven healthy, chronic SCI (> 1 year, ASIA A-C) men will be recruited. Following preliminary testing, each will complete four experimental conditions, where they will report to the laboratory following an ~ 10-h overnight fast. A venous blood sample will be drawn and expired gases collected to estimate resting metabolic rate (RMR). In order to ensure an isocaloric exercise challenge, each will complete CRT first, with the remaining three conditions presented in randomised order: (1) CRT, ~ 45 min of resistance manoeuvres (weight lifting) interspersed with low-resistance, high-speed arm-crank exercise; (2) CON, seated rest; (3) MICT, ~ 45 min constant arm-crank exercise at a resistance equivalent to 30-40% peak power output (PPO) and; (4) HIIT, ~ 35 min arm-crank exercise with the resistance alternating every 2 min between 10% PPO and 70% PPO. After each ~ 45-min condition, participants will ingest a 2510-kJ liquid test meal (35% fat, 50% carbohydrate, 15% protein). Venous blood and expired gas samples will be collected at the end of exercise and at regular intervals for 120 min post meal. DISCUSSION: This study should establish the acute effects of different forms of exercise on fasting and postprandial responses in chronic SCI male patients. Measures of glucose clearance, insulin sensitivity, lipid and inflammatory biomarker concentrations will be assessed and changes in whole-body substrate oxidation estimated from expired gases. TRIAL REGISTRATION: ClinicalTrials.gov, ID: NCT03545867 . Retrospectively registered on 1 June 2018.

Interrater and intrarater reliability of ventilatory thresholds determined in individuals with spinal cord injury.

STUDY DESIGN: Cross-sectional. OBJECTIVES: Individualized training regimes are often based on ventilatory thresholds (VTs). The objectives were to study: (1) whether VTs during arm ergometry could be determined in individuals with spinal cord injury (SCI), (2) the intrarater and interrater reliability of VT determination. SETTING: University research laboratory. METHODS: Thirty graded arm crank ergometry exercise tests with 1-min increments of recreationally active individuals (tetraplegia (N = 11), paraplegia (N = 19)) were assessed. Two sports physicians assessed all tests blinded, randomly, in two sessions, for VT1 and VT2, resulting in 240 possible VTs. Power output (PO), heart rate (HR), and oxygen uptake (VO2) at each VT were compared between sessions or raters using paired samples t-tests, Wilcoxon signed-rank tests, intraclass correlation coefficients (ICC, relative agreement), and Bland-Altman plots (random error, absolute agreement). RESULTS: Of the 240 VTs, 217 (90%) could be determined. Of the 23 undetermined VTs, 2 (9%) were VT1 and 21 (91%) were VT2; 7 (30%) among individuals with paraplegia, and 16 (70%) among individuals with tetraplegia. For the successfully determined VTs, there were no systematic differences between sessions or raters. Intrarater and interrater ICCs for PO, HR, and VO2 at each VT were high to very high (0.82-1.00). Random error was small to large within raters, and large between raters. CONCLUSIONS: For VTs that could be determined, relative agreement was high to very high, absolute agreement varied. For some individuals, often with tetraplegia, VT determination was not possible, thus other methods should be considered to prescribe exercise intensity.

Exercise and Health-Related Risks of Physical Deconditioning After Spinal Cord Injury.

A sedentary lifestyle occurring soon after spinal cord injury (SCI) may be in contrast to a preinjury history of active physical engagement and is thereafter associated with profound physical deconditioning sustained throughout the lifespan. This physical deconditioning contributes in varying degrees to lifelong medical complications, including accelerated cardiovascular disease, insulin resistance, osteopenia, and visceral obesity. Unlike persons without disability for whom exercise is readily available and easily accomplished, exercise options for persons with SCI are more limited. Depending on the level of injury, the metabolic responses to acute exercise may also be less robust than those accompanying exercise in persons without disability, the training benefits more difficult to achieve, and the risks of ill-considered exercise both greater and potentially irreversible. For exercise to ultimately promote benefit and not impose additional impairment, an understanding of exercise opportunities and risks if exercise is undertaken by those with SCI is important. The following monograph will thus address common medical challenges experienced by persons with SCI and typical modes and benefits of voluntary exercise conditioning.

Clinician-Focused Overview of Bionic Exoskeleton Use After Spinal Cord Injury.

Spinal cord injury (SCI) resulting in paralysis of lower limbs and trunk restricts daily upright activity, work capacity, and ambulation ability, putting persons with an injury at greater risk of developing a myriad of secondary medical issues. Time spent in the upright posture has been shown to decrease the risk of these complications in SCI. Unfortunately, the majority of ambulation assistive technologies are limited by inefficiencies such as high energy demand, lengthy donning and doffing time, and poor gait pattern precluding widespread use. These limitations spurred the development of bionic exoskeletons. These devices are currently being used in rehabilitation settings for gait retraining, and some have been approved for home use. This overview will address the current state of available devices and their utility.