Arm Crank Exercise Research Articles

Effect of Cold Exposure and Exercise on Carbohydrate and Lipid Metabolism in Persons with Cervical Spinal Cord Injury

ObjectiveRates of retiring for Oita International Wheelchair Marathon in the last decade were higher with the lower atmospheric temperature below 22°C. The tendency was stronger in persons with cervical spinal cord injury (CSCI) than the other classes (unpublished data), which may be associated with deteriorated lipid utilization and a faster depletion of glycogen in a whole body. Our purpose was to examine whether serum profile of lipid in CSCI during cold stress and exercise was different from able‐body persons (AB) or varied dependent on the injury level.Methods[Protocol1] Nine CSCI and 11 AB wore a water‐perfused suit and took a supine position then 33‐°C water was perfused into the suit. After 10‐min measurement of thermoneutral condition, 25‐°C water was perfused for 20min (CS), then perfused 33‐°C water for 60min, while monitoring esophageal (Tes) and mean skin temperatures (Tsk). Blood samples were taken before, just after, 60‐ and 120min after CS. [Protocol2] Six of each CSCI and AB did a 30‐min arm crank exercise at 50% VO2peak then took a sitting position for 60min as a recovery. Blood samples were taken before, just after and an hour after exercise. [Protocol3] Bloods were sampled from 5 CSCI and 9 thoracic and lumbar SCI (LSCI), who completed a half marathon, before, just after and an hour after the race. Plasma concentrations of adrenaline ([Ad]p), noradrenaline ([Nor]p), and glucose ([Glc]p), and serum concentrations of insulin ([Ins]s), free fatty acid ([FFA]s), and total ketone bodies ([tKB]s) were assessed in all protocols.Results[Protocol1] Tsk decreased by ~2 °C during CS and Tes decreased by ~0.2 °C after CS with no significant differences between groups. VO2 was similar between groups and remained unchanged throughout the study. Respiratory quotient was significantly decreased in AB after CS but remained unchanged in CSCI. [Ad]p and [Nor]p were lower in CSCI than AB and [Nor]p significantly increased only in AB during recovery. [Glc]p before, immediately and one hour after CS was higher in CSCI but it decreased to the same level as AB 2 hours later. [FFA]s did not differ between groups and decreased after CS in only AB. [tKB]s significantly increased after CS in both groups, but the increase started from 1‐hour recovery in CSCI. [Protocol2] [Ad]p and [Nor]p increased just after exercise in AB but not in CSCI. [Glc]p remained unchanged in both groups but [Ins]s started to decrease just after exercise in CSCI, earlier than AB. [tKB]s increased from the baseline an hour after exercise in CSCI but not in AB, while [FFA]s did not differ between groups. [Protocol3] [Ad]p and [Nor]p was lower in CSCI than LSCI and increased just after the race only in LSCI and returned to the baseline at an hour after the race. [FFA]s increased just after the race in CSCI and remained the higher level at an hour after race, then [tKB]s increased an hour after the race only in CSCI. Both lipid profiles remained unchanged throughout the study in LSCI.ConclusionIt is suggested that lipolysis and ketogenesis are likely to enhance in CSCI during cold or exercise. Lipid and glucose metabolisms vary dependent on the injury level with SCI.Support or Funding InformationThis work was funded by Nachikatsuura Research foundation and Kyoten, Wakayama Med. Univ.

Assessment of Exercise Stroke Volume and Its Prediction From Oxygen Pulse in Paralympic Athletes With Locomotor Impairments: Cardiac Long-Term Adaptations Are Possible.

The determinants of cardiac output (CO) during exercise, i.e., stroke volume (SV) and heart rate (HR), could differ in Paralympic athletes (PAthl) with spinal cord injury (SCI) with respect to PAthl with locomotor impairments caused by different health conditions (HCs). The purposes of the present study were the comparisons of two groups of PAthl, one with SCI and the other with either amputation (AMP) or post poliomyelitis syndrome (PM), assessing the (1) peak cardiorespiratory responses and determinants (SV and HR) of CO during maximal and submaximal arm cranking exercise (ACE), respectively; (2) correlations between peak oxygen uptake (VO2peak) and the highest SV obtained during submaximal exercise; and (3) correlations between oxygen pulse (O2 pulse, ratio between VO2 and HR) and both SV and O2 arterio-venous difference [(a-v)O2diff]. Each athlete (19 PAthl with SCI, 9 with AMP, and 5 with PM) completed a continuous incremental cardiopulmonary ACE test to volitional fatigue to assess peak responses. In a different session, CO was indirectly measured through carbon dioxide (CO2) rebreathing method at sub-maximal exercise intensities approximating 30, 50, and 70% of the VO2peak. There were no significant differences between the PAthl groups in age, anthropometry, and VO2peak. However, peak HR was significantly lower, and peak O2 pulse was significantly higher in PAthl with AMP/PM compared to those with SCI. During sub-maximal exercise, PAthl with AMP/PM displayed significantly higher SV values (154.8 ± 17.60 ml) than PAthl with SCI (117.1 ± 24.66 ml). SV correlated significantly with VO2peak in both PAthl with SCI (R2 = 0.796) and AMP/PM (R2 = 0.824). O2 pulse correlated significantly with SV in both PAthl with SCI (R2 = 0.888) and AMP/PM (R2 = 0.932) and in the overall sample (R2 = 0.896). No significant correlations were observed between O2 pulse and (a-v)O2diff. It was concluded that in PAthl with different HCs: (1) significant differences, as a consequence of the different HC, exist in the determinants of CO at maximal and submaximal ACE; (2) SV is a significant determinant of VO2peak, suggesting cardiac adaptations possible also in PAthl with SCI; and (3) SV can be predicted from O2 pulse measurements during submaximal exercise in both groups of PAthl.

Influence of Acute Arm-cranking Exercise with Electrical Muscle Stimulation on Vascular Endothelial Function

Influence of Acute Arm-cranking Exercise with Electrical Muscle Stimulation on Vascular Endothelial Function

The effect of arm-crank exercise training on power output, spirometric and cardiac function and level of autonomy in persons with tetraplegia

Studies on the effects of exercise training in persons with cervical spinal cord injury (CSCI) are scarce. The aim of this study was to determine the effect of an 8-week stationary arm-crank exercise (ACE) training programme on the level of autonomy, exercise performance, pulmonary functional parameters and resting heart rate variability (HRV) in persons with CSCI. Quadriplegia Index of Function (QIF), arm-crank peak power output (Ppeak), spirometric variables, and HRV indices were measured before and after the training programme in a group of 11 persons with CSCI. ACE training increased Ppeak in both groups (p < 0.05), whereas maximum voluntary ventilation (MVV) and low frequency HRV (LF) improved only in the lower CSCI group (p < 0.05). Moreover, QIF and Ppeak were significantly correlated before (r = 0.88; p < 0.01) and after (r = 0.86; p < 0.01) the training period. However, no significant changes were found in the level of autonomy (QIF) as a result of the intervention. Therefore, stationary ACE training appears to be a feasible and effective method for aerobic exercise in persons with tetraplegia and a short-term intervention is able to significantly improve exercise capacity, cardiac autonomic regulation and respiratory muscle endurance, regardless of the absence of significant immediate changes in the level of autonomy.

The influence of protocol design on the identification of ventilatory thresholds and the attainment of peak physiological responses during synchronous arm crank ergometry in able-bodied participants

PurposeTo examine the effects of stage duration on power output (PO), oxygen uptake (VO2), and heart rate (HR) at peak level and ventilatory thresholds during synchronous arm crank ergometry.MethodsNineteen healthy participants completed a ramp, 1-min stepwise, and 3-min stepwise graded arm crank exercise test. PO, VO2, and HR at the first and second ventilatory threshold (VT1, VT2) and peak level were compared among the protocols: a repeated measures analysis of variance was performed to test for systematic differences, while intraclass correlation coefficients (ICC) and Bland–Altman plots were calculated to determine relative and absolute agreement.ResultsSystematic differences among the protocols were found for PO at VT1, VT2, and peak level. At peak level, PO differed significantly among all protocols (ramp: 115 ± 37 W; 1-min stepwise: 108 ± 34 W; 3-min stepwise: 94 ± 31 W, p ≤ 0.01). No systematic differences for HR or VO2 were found among the protocols. VT1 and VT2 were identified at 52% and 74% of VO2peak, respectively. The relative agreement among protocols varied (ICC 0.02–0.97), while absolute agreement was low with small-to-large systematic error and large random error.ConclusionsPO at VTs and peak level was significantly higher in short-stage protocols compared with the 3-min stepwise protocol, whereas HR and VO2 showed no differences. Therefore, training zones based on PO determined in short-stage protocols might give an overestimation. Moreover, due to large random error in HR at VTs between the protocols, it is recommended that different protocols should not be used interchangeably within individuals.

A cross-sectional comparison between cardiorespiratory fitness, level of lesion and red blood cell distribution width in adults with chronic spinal cord injury

ObjectivesTo assess; (1) differences in red blood cell distribution width between individuals with chronic (>1year), motor-complete cervical (n=21), upper-thoracic (n=27) and thoracolumbar (n=15) spinal cord injury and, (2) associations between red blood cell distribution width and cardiorespiratory fitness. DesignProspective multi-center, cross-sectional study. MethodsPeak oxygen uptake was determined using an upper-body arm-crank exercise test to volitional exhaustion and red blood cell distribution width was measured using an automated hematology system. ResultsThere were significant (p<0.009) differences between groups classified by level of injury in absolute and relative peak oxygen uptake, peak power output and red blood cell distribution width. A significant (p<0.001) large negative association (r = −0.524) was found between relative peak oxygen uptake and red blood cell distribution width. Unbiased recursive partitioning, while revealing study site specific differences in red blood cell distribution width, identified homogenous subgroups based specifically on cardiorespiratory fitness irrespective of additional demographic and injury characteristics. ConclusionThe strong negative association between cardiorespiratory fitness and red blood cell distribution width in individuals with paraplegia parallel those previously observed in non-disabled individuals. Higher red blood cell distribution width values are an independent risk factor for increased cardiovascular mortality, heart failure, and coronary heart disease and may reflect several underlying exacerbated metabolic responses such as oxidative stress and systemic inflammation. These data emphasize the importance of maintaining a high aerobic capacity following spinal cord injury.

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

BackgroundChronic 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.MethodsEleven 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.DiscussionThis 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 registrationClinicalTrials.gov, ID: NCT03545867. Retrospectively registered on 1 June 2018.

Good association between sprint power and aerobic peak power during asynchronuous arm-crank exercise in people with spinal cord injury

Purpose To (1) investigate the association between sprint power and aerobic power output (POpeakGXT) during a graded peak exercise test (GXT); and (2) validate the prediction models of POpeakGXT based on sprint power and personal and lesion characteristics. Materials and methods Wheelchair users with tetraplegia (N = 35) and paraplegia (N = 58) performed a 30 s-Wingate test and GXT on an asynchronous arm-crank ergometer. Data were split into samples to develop and validate the model. Sprint power (POmeanWingate and POpeakWingate, respectively) and POpeakGXT were determined. Regression analyses were performed to develop POpeakGXT prediction models. Candidate independent variables included POmeanWingate or POpeakWingate, age (years), sex, body mass (kg) or BMI (kg/m2), time since injury (TSI, years) and lesion level (tetraplegia/paraplegia). The best model was validated by comparing the predicted POpeakGXT with measured POpeakGXT. Results The best model (R 2 = 0.76) to predict POpeakGXT included POmeanWingate, BMI and all other independent variables. No significant difference was found between measured (68 ± 35 W) and predicted POpeakGXT (68 ± 30 W, p = 0.97). The ICC was excellent (0.89 with 95% confidence intervals: 0.75–0.95). The 95% limits of agreement for the Bland–Altman plots were wide (−30 to 31 W). Conclusions Strong associations were found between POmeanWingate and POpeakGXT. Although relative agreement was excellent, absolute agreement was low. Implications for rehabilitation There is a strong relationship between peak aerobic power output and sprint power output, both tested on an arm-crank ergometer, in people with spinal cord injury. A prediction model for peak aerobic power output, based on sprint power output and personal and lesion characteristics, showed a high explained variance. The predictive model can give a guideline for choosing the right graded exercise test protocol but should be used with caution.

Absence of cardiovascular drift during prolonged arm-crank exercise in individuals with spinal cord injury.

Observational study OBJECTIVE: To investigate the effects of prolonged arm-crank exercise on cardiovascular drift (CVdrift) in spinal cord injury (SCI). This is a community-based supervision study METHODS: Ten participants with motor -complete or incomplete SCI (lesion level T7-L1), and 10 able-bodied (AB) participants matched for age performed a 40-min arm-crank exercise at an intensity of 50% of peak oxygen uptake (VO2). During the exercise, there were no significant differences between the groups in VO2, tissue O2 saturation in the biceps brachii (active muscle), and chest and arm skin temperature (all P > 0.05). In the AB, heart rate (HR) increased within the first 15 min of the exercise and continued to increase until the end of the exercise; however, in the SCI, HR increased within first 15 min of the exercise and then remained constant until the end of exercise. After 10 min of exercise, thigh skin temperature had increased more in the SCI than in the AB (P < 0.05). Thigh skin blood flow (SkBF) continued to increase after 10 min of exercise in the AB but remained almost stable in the SCI. Relative changes in the thigh SkBF were associated with changes in HR during exercise between the values at 10 min and 40 min in the pooled data (R2 = 0.706, P < 0.001). CVdrift during the prolonged arm-crank exercise was not observed in individuals with SCI. This might be partially explained by different responses in cutaneous circulation within the inactive muscles of these participants.

Influence Of Arm cranking Exercise With Electrical Stimulation On The Vascular Endothelial Function

PURPOSE: Arm-cranking exercise may not result in reduction in ba-PWV. Electrical muscle stimulation (EMS) has been shown to be able to increase the blood flow and the peripheral circulation. Arm-cranking exercises with EMS may therefore be able to increase the arterial function. However, less is known about the effect of submaximal arm-cranking exercise with EMS on the vascular endothelial function. METHODS: Eight healthy adult men were studied under two experimental trials (arm-cranking exercise with EMS; A+E trial,arm-cranking exercise without EMS; A trial). In the A+E trial, submaximal arm-cranking exercise at 50%VO2 max with both lower leg and thigh muscles were sequentially stimulated at 4-Hz for 20min. Before and after each trial, the brachial systolic and diastolic blood pressure (SBP / DBP) were measured in the supine position. The vascular endothelial function of the right brachial artery was also assessed by flow-mediated dilation (FMD). RESULTS: In the A+E trial, the FMD increased immediately after (9.7 ± 0.8%) and 30 min after (8.4 ± 0.7%) compared with rest (6.0 ± 0.7%). The FMD in the A trial, increased immediately after (8.0 ± 1.2%) compared with rest (6.4 ± 0.4%), however, no significant differences were found in 30min after (6.4 ± 1.0%). Immediately after and 30 min after each trial, significant differences in the FMD were found between the A+E and A trials (p < 0.05). The SBP and DBP were not significantly different between the both trials. CONCLUSIONS: Acute arm-cranking exercise with EMS increases the vascular endothelial function. These results suggest that chronic arm-cranking with EMS might be useful for reduction the risk of cardiovascular disease.

Influence of arm-cranking exercise with electrical muscle stimulation on arterial stiffness

Influence of arm-cranking exercise with electrical muscle stimulation on arterial stiffness

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.

Peak oxygen uptake measured during a perceptually-regulated exercise test is reliable in community-based manual wheelchair users

ABSTRACTThis study compares test-retest reliability and peak exercise responses from ramp-incremented (RAMP) and maximal perceptually-regulated (PRETmax) exercise tests during arm crank exercise in individuals reliant on manual wheelchair propulsion (MWP). Ten untrained participants completed four trials over 2-weeks (two RAMP (0–40 W + 5–10 W · min−1) trials and two PRETmax. PRETmax consisted of five, 2-min stages performed at Ratings of Perceived Exertion (RPE) 11, 13, 15, 17 and 20). Participants freely changed the power output to match the required RPE. Gas exchange variables, heart rate, power output, RPE and affect were determined throughout trials. The V̇O2peak from RAMP (14.8 ± 5.5 ml · kg−1 · min−1) and PRETmax (13.9 ± 5.2 ml · kg−1 · min−1) trials were not different (P = 0.08). Measurement error was 1.7 and 2.2 ml · kg−1 · min−1 and coefficient of variation 5.9% and 8.1% for measuring V̇O2peak from RAMP and PRETmax, respectively. Affect was more positive at RPE 13 (P = 0.02), 15 (P = 0.01) and 17 (P = 0.01) during PRETmax. Findings suggest that PRETmax can be used to measure V̇O2peak in participants reliant on MWP and leads to a more positive affective response compared to RAMP.

Moderate-intensity Arm-cranking Exercise may not Improve Arterial Function in Healthy Adult Men.

Endurance exercises, such as cycling or running, are useful for improving arterial function. However, people suffering from partial paralysis or arthritis are unable to perform these kinds of lower-limb exercises. In the present study, we explored the acute effect of upper-arm exercise on arterial stiffness in healthy men. Fourteen healthy adult men performed two experimental trials. The order of experiments was randomized between a 30-min arm-cranking exercise at 50% V̇O2max (A-trial) and a 30-min leg-cycling exercise at 50% V̇O2max (C-trial). The brachial to ankle pulse wave velocity (baPWV), brachial systolic/diastolic blood pressure and heart rate were obtained with subjects in the supine position. The baseline hemodynamic values were not markedly different between the two trials. Compared with the baseline value, the baPWV was significantly reduced at 30 and 60 min after the C-trial. In the A-trial, however, there were no significant changes in the baPWV throughout the trial. These results indicate that acute 50% V̇O2max arm-cranking exercise induced relatively little change in the baPWV, which was the opposite of the finding observed with leg-cycling exercise. Therefore, in order to improve arterial function via aerobic upper-arm exercises, the exercise mode/intensity or other approaches should be considered.

Home-Based Exercise Enhances Health-Related Quality of Life in Persons With Spinal Cord Injury: A Randomized Controlled Trial

ObjectiveTo assess the influence of a home-based exercise intervention on indices of health-related quality of life (HRQOL) in persons with spinal cord injury (SCI). DesignThis was a randomized controlled trial (HOMEX-SCI; ISRCTN57096451). After baseline laboratory testing and a week of free-living physical activity monitoring, eligible participants were randomly assigned (2:1 allocation ratio) to a home-based moderate-intensity upper-body exercise intervention group (INT, n=13), or a lifestyle maintenance control group (CON, n=8), for 6 weeks. SettingHome-based with short laboratory visits immediately before and after the intervention/control period. ParticipantsInactive participants (N=21) with chronic (>1yr) SCI (injury level <T4). InterventionParticipants assigned to the INT completed 4, 45-minute moderate-intensity (60%-65% peak oxygen uptake) arm-crank exercise sessions per week for 6 weeks. Participants assigned to the control group (CON) were asked to maintain their habitual physical activity behavior. Main Outcome MeasuresSecondary outcome measures were assessed, including physical and mental component scores (PCS and MCS) of health-related quality of life (HRQOL), fatigue, global fatigue (FSS), and shoulder pain index (WUSPI). Cardiorespiratory fitness (CRF), objectively measured habitual moderate-to-vigorous physical activity (MVPA), and exercise self-efficacy (ESE) were also assessed at baseline and follow-up. ResultsChanges in the PCS (P=.017) of the Short Form 36 Health Survey (SF-36), ESE (P=.011), and FSS (P=.036) were significantly different between the 2 groups, with moderate to large effect sizes (d=0.75-1.37). Various HRQOL outcomes demonstrated likely to very likely positive inferences in favor of the INT group following the 6-week exercise intervention. Changes in ESE were significantly (P<.01) associated with changes in PCS (r=0.62), MCS (r=0.71), FSS (r=-0.71), and global fatigue (r=0.57). ConclusionsA 6-week upper-body exercise intervention improved indices of HRQOL in persons with SCI. Improvements were associated with increases in ESE. While this intervention demonstrated a positive effect on perceived physical functioning, future interventions should aim to support social and mental functioning and exercise maintenance.

Immediate and 24-h blood pressure-lowering effects of arm crank exercise in patients with traumatic lower-limb amputation: a randomized cross-over study.

This study aimed to investigate the clinic and 24-h postexercise hypotension (PEH) after a moderate-intensity arm crank exercise session in individuals with traumatic lower-limb amputation. Nine men (46±17 years) with unilateral traumatic lower-limb amputation participated in two experimental sessions conducted randomly: an aerobic exercise (EXE: arm crank ergometer, 30 min) or a control session (CON: participants remained seated on the cycle ergometer, 30 min). Clinic and 24-h systolic, diastolic, and mean blood pressure (BP) response were measured after both sessions. The clinical measurements of blood flow and forearm vascular resistance (FVR) were also performed. Compared with the preintervention period, the BP levels did not change in the CON session. However, EXE resulted in a significant hypotensive effect in systolic (-10±0.9 mmHg, P≤0.05), diastolic (-11±1.5 mmHg, P≤0.05), and mean BP (-11±1.2 mmHg, P≤0.05) during the entire postexercise period. The PEH was accompanied by a decreased FVR over the entire postintervention period (P≤0.05). Significant reductions were found for 24-h average systolic, diastolic, and mean BP levels (P=0.03, 0.01, and 0.02, respectively) following EXE compared with the CON session. These results showed, for the first time, that individuals with traumatic lower-limb amputation presented immediate and 24-h PEH after a single bout of arm crank exercise testing. The PEH at the clinic condition was justified, at least in part, by the reduction in peripheral FVR.

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.

Performance comparison of the MOXY and PortaMon near-infrared spectroscopy muscle oximeters at rest and during exercise.

The purpose of the study was to compare muscle oxygenation as measured by two portable, wireless near-infrared spectroscopy (NIRS) devices under resting and dynamic conditions. A recently developed low-cost NIRS device (MOXY) was compared against an established PortaMon system that makes use of the spatially resolved spectroscopy algorithm. The influence of increasing external pressure on tissue oxygen saturation index (TSI) indicated that both devices are stable between 2 and 20mmHg. However, above this pressure, MOXY reports declining TSI values. Analysis of adipose tissue thickness (ATT) and TSI shows a significant, nonlinear difference between devices at rest. The devices report similar TSI (%) values at a low ATT (<7 mm) (PortaMon minus MOXY difference is +1.1±2.8%) with the major subsequent change between the devices occurring between 7 and 10mm; at ATT values >10 mm the difference remains constant (-14.7±2.8%). The most likely explanation for this difference is the small source-detector separation (2.5cm) in the MOXY resulting in lower tissue penetration into muscle in subjects with higher ATT. Interday test-retest reliability of resting TSI was evaluated on five separate occasions, with the PortaMon reporting a lower coefficient of variation (1.8% to 2.5% versus 5.7% to 6.2%). In studies on male subjects with low ATT, decreases in the TSI were strongly correlated during isometric exercise, arterial occlusion, and incremental arm crank exercise. However, the MOXY reports a greater dynamic range, particularly during ischemia induced by isometric contraction or occlusion (Δ74.3% versus Δ43.7%; hyperemia MAX-occlusion MIN). This study shows that in this subject group both MOXY and PortaMon produce physiologically credible TSI measures during rest and exercise. However, the absolute values obtained during exercise are generally not comparable between devices unless corrected by physiological calibration following an arterial occlusion.

Impact of Exercise on Cardiometabolic Component Risks in Spinal Cord-injured Humans.

ABSTRACTPurposeSpinal cord injury (SCI) creates a complex pathology, characterized by low levels of habitual physical activity and an increased risk of cardiometabolic disease. This study aimed to assess the effect of a moderate-intensity upper-body exercise training intervention on biomarkers of cardiometabolic component risks, adipose tissue metabolism, and cardiorespiratory fitness in persons with SCI.MethodsTwenty-one inactive men and women with chronic (>1 yr) SCI (all paraplegic injuries) 47 ± 8 yr of age (mean ± SD) were randomly allocated to either a 6-wk prescribed home-based exercise intervention (INT; n = 13) or control group (CON; n = 8). Participants assigned to the exercise group completed 4 × 45-min moderate-intensity (60%–65% peak oxygen uptake (V˙O2peak)) arm-crank exercise sessions per week. At baseline and follow-up, fasted and postload blood samples (collected during oral glucose tolerance tests) were obtained to measure metabolic regulation and biomarkers of cardiovascular disease. Abdominal subcutaneous adipose tissue biopsies were also obtained, and cardiorespiratory fitness was assessed.ResultsCompared with CON, INT significantly decreased (P = 0.04) serum fasting insulin (Δ, 3.1 ± 10.7 pmol·L−1 for CON and −12.7 ± 18.7 pmol·L−1 for INT) and homeostasis model assessment of insulin resistance (HOMA2-IR; Δ, 0.06 ± 0.20 for CON and −0.23 ± 0.36 for INT). The exercise group also increased V˙O2peak (Δ, 3.4 mL·kg−1·min−1; P ≤ 0.001). Adipose tissue metabolism, composite insulin sensitivity index (C-ISIMatsuda), and other cardiovascular disease risk biomarkers were not different between groups.ConclusionsModerate-intensity upper-body exercise improved aspects of metabolic regulation and cardiorespiratory fitness. Changes in fasting insulin and HOMA2-IR, but not C-ISIMatsuda, suggest improved hepatic but not peripheral insulin sensitivity after 6 wk of exercise training in persons with chronic paraplegia.

Experimental Protocol of a Three-minute, All-out Arm Crank Exercise Test in Spinal-cord Injured and Able-bodied Individuals.

Reliable exercise protocols are required to test changes in exercise performance in elite athletes. Performance improvements in these athletes may be small; therefore, sensitive tools are fundamental to exercise physiology. There are currently many exercise tests that allow for the examination of exercise capacity in able-bodied athletes, with protocols mainly for lower-body or whole-body exercise. There is a trend to test athletes in a sport-specific setting that closely resembles the actions that the participants are used to performing. Only a few protocols test short-term, high-intensity exercise capacity in participants with an impairment of the lower body. Most of these protocols are very sport-specific and are not applicable to a wide range of athletes. One well-known test protocol is the 30 s Wingate test, which is well-established in cycling and in arm crank exercise testing. This test analyzes high-intensity exercise performance over a 30 s time duration. In order to monitor exercise performance over a longer duration, a different method was modified for application to the upper body. The 3 min, all-out arm crank ergometer test allows athletes to be tested in a manner specific to 1,500 m wheelchair racing (in terms of exercise duration), as well as to upper body exercises such as rowing or hand-cycling. In order to increase the reliability with identical test conditions, it is crucial to precisely replicate settings such as the resistance (i.e., torque factor) and the position of the participants (i.e., the height of the crank, the distance between the crank and the participant, and the fixation of the participant). Another important issue concerns the beginning of the exercise test. Fixed revolutions per minute are required to standardize the test conditions for the start of the exercise test. This exercise protocol shows the importance of accurate operations to reproduce identical test conditions and settings.