Voluntary Cycling Research Articles

Effect of subtetanic neuromuscular electrical stimulation on sprint interval exercise.

The study aimed to determine the acute effects of subtetanic neuromuscular electrical stimulation (NMES) combined with active recovery between sprint exercises on blood lactate accumulation, sprint performance, and muscle fatigue. Sixteen healthy young individuals [23(4) years, 10 males] underwent a 1-min rest followed by sprint interval training consisting of four 15-sec maximal sprint exercises with three 5-min active cycling sessions. Participants engaged in voluntary cycling at 40% of peak oxygen consumption, with or without NMES (VOLES or VOL; interventions). Blood lactate concentration ([La]b) was assessed at the end of the rest and each intervention periods. Mean power was assessed during each sprint exercise session. Maximum voluntary contraction (MVC) of the knee extensor was measured before and after sprint interval training to evaluate muscle fatigue. The [La]b was significantly higher in VOLES than in VOL (main effect, P=0.037). Mean power did not differ between conditions (main effect and interaction, P>0.050). MVC after sprint interval exercise was significantly lower in VOLES than in VOL (interaction, P<0.001). Subtetanic NMES combined with voluntary cycling enhanced blood lactate accumulation and induced greater voluntary fatigue but resulted in similar peripheral muscle fatigue and sprint exercise performance compared with voluntary cycling without NMES.

FUNCTIONAL ELECTRICAL STIMULATION COMBINED WITH VOLUNTARY CYCLING ACCENTUATES VO2 RESPONSE IN PEOPLE WITH ADVANCED MULTIPLE SCLEROSIS: A PILOT STUDY

INTRODUCTION &amp; AIMS Lower limb muscle weakness and reduced balance due to disease progression in multiple sclerosis (MS) may make robust aerobic exercise difficult. Functional electrical stimulation (FES) cycling combined with voluntary cycling may allow people with advanced MS to enhance the intensity of aerobic exercise. The aim of this study was to investigate the cardiorespiratory, power, and participant perceptions during acute bouts of FES cycling, voluntary cycling, and FES cycling combined with voluntary cycling (FES assist cycling). METHODS Participants with advanced MS (Expanded Disability Status Scale [EDSS] ≥ 6.0) undertook three exercise trials on a leg cycle ergometer. Trial 1: 30 minutes of FES cycling; Trial 2: two 10-minute bouts of voluntary cycling separated by 10 minutes rest; and Trial 3: a combination of trials 1 and 2 (FES assist cycling). Outcome measures included VO2, cycle power output, heart rate, exertion, and post-exercise perceptions of fatigue. RESULTS Ten people with advanced MS participated (9 female; age 52.4±9.98 y; EDSS 7.1±0.6). Average VO2 during the 30-minute trials was significantly higher for FES assist cycling compared to voluntary cycling (429.7 ± 111.0 vs 388.5 ± 101.0 mL/min, 95% CI 23.4 to 113.0 mL/min, p=0.01), with a large effect size (Hedges’ g=1.04). Participants reported similar perceptions of exertion at the end of each trial (p=0.14). There was no difference in self-reported fatigue at the end of each trial (p=0.21). CONCLUSION This study found FES assist cycling produced significantly higher VO2 values than voluntary cycling, although the clinical significance of these differences is unknown. Participants performed FES assist cycling at a self-reported levels of exertion consistent with moderate to vigorous intensity, however it was considered light-intensity exercise when expressed by METS. FES assist cycling was no more fatiguing post-exercise than the other modes.

Can Neuromuscular Electrical Stimulation Enhance the Effect of Sprint Interval Training?

The aim of this study was to determine the effects of subtetanic neuromuscular electrical stimulation combined with voluntary exercise between repeated Wingate tests on sprint exercise performance and blood lactate accumulation during sprint interval training. Fifteen healthy young males volunteered. After 1-min baseline, participants underwent the Wingate test twice. They performed a 4-min intervention between tests: neuromuscular electrical stimulation with free-weight cycling or voluntary cycling alone [43.6 (8.0) watts], which matched oxygen consumption with neuromuscular electrical stimulation with free-weight cycling. The blood lactate concentration was assessed at the end of the baseline, at 3-min intervention, and on recovery at 1, 3, 5, and 10 min after the second Wingate test. Peak and mean blood lactate concentration during recovery were significantly greater with neuromuscular electrical stimulation with free-weight cycling than voluntary cycling alone (P>0.036 and P=0.011, respectively). Peak power, mean power, and rate of decline (fatigue index) were not significantly different between conditions in both Wingate tests (condition/interaction all P>0.300, partial η2<0.1). Subtetanic neuromuscular electrical stimulation combined with voluntary exercise indicated similar exercise performance and fatigue levels during Wingate tests, but enhanced blood lactate accumulation compared to oxygen consumption-matched voluntary cycling during sprint interval training.

Functional electrical stimulation combined with voluntary cycling accentuates VO2 response in people with severe multiple sclerosis: A pilot study

BackgroundLower limb muscle weakness and reduced balance due to disease progression in multiple sclerosis (MS) may make robust aerobic exercise difficult. Functional electrical stimulation (FES) cycling combined with voluntary cycling may allow people with severe MS to enhance the intensity of aerobic exercise. The aim of this study was to investigate the cardiorespiratory, power, and participant-reported perceptions during acute bouts of FES cycling, voluntary cycling, and FES cycling combined with voluntary cycling (FES assist cycling). MethodsParticipants with severe MS (Expanded Disability Status Scale [EDSS] ≥ 6.0) undertook three exercise trials on a leg cycle ergometer. Trial 1 involved 30 min of FES cycling; Trial 2 involved two 10-minute bouts of voluntary cycling separated by 10 min rest; and Trial 3 was a combination of trials 1 and 2 (FES assist cycling). Outcome measures included VO2 (volume of oxygen consumption), cycle power output, heart rate, RPE, and post-exercise perceptions of pain and fatigue. ResultsTen people with severe MS participated (9 female; age 52.4 ± 9.98 y; EDSS 7.1 ± 0.6). The average VO2 during the 30-minute trials was significantly higher for FES assist cycling compared to voluntary cycling (429.7 ± 111.0 vs 388.5 ± 101.0 mL/min, 95% CI 23.4 to 113.0 mL/min, p = 0.01), with a large effect size (Hedges' g = 1.04). Participants reported similar rates of perceived exertion at the end of FES cycling (13 ± 2), voluntary cycling (14 ± 2), and FES assist cycling (15 ± 1); p = 0.14. Self-reported pain was higher during both FES cycling (5.4 vs 0.3; 95% CI 3.4 to 6.7, p = 0.01, Hedges’ g = 2.07) and FES assist cycling (4.2 vs. 0.3; 95% CI 2.3 to 5.5, p = 0.01, Hedges’ g = 1.71) than voluntary cycling, both with large effect sizes. There was no difference in self-reported fatigue at the end of each trial (p = 0.21). ConclusionThis study found FES assist cycling produced significantly higher VO2 values than voluntary cycling, although the clinical significance of these differences is unknown. Participants performed FES assist cycling at a self-reported RPE consistent with moderate to vigorous intensity, however it was considered light-intensity exercise when expressed by METS. FES assist cycling was no more fatiguing post-exercise than the other modes.

Assisted Cycle Therapy (ACT) Improved Self-Efficacy and Exercise Perception in Middle-Age Adults with Down Syndrome.

Alzheimer's disease is prevalent in persons with Down syndrome (DS) as early as their 30s and presents as decreased social interaction, coordination, and physical activity. Therefore, changing attitudes and beliefs about exercise is key to increasing motivation for physical activity especially in middle-age adults with DS. The aim of this study was to examine the effects of Assisted Cycle Therapy (ACT) on self-efficacy and exercise perception in middle-age adults with Down syndrome (DS) following an exercise intervention three times a week for 8 weeks. Twelve participants were in the ACT group in which a motor assisted their cycling to be performed at least 30% faster than voluntary cycling (VC), 10 participants were in the voluntary cycling group, and two participants were in the no cycling (NC) group. The results showed that both exercise groups (i.e., ACT and VC) improved in their self-efficacy after the 8-week intervention. In addition, exercise perception improved following ACT, but not VC or NC. Our results are discussed with respect to their future implications for exercise in the DS population. The results can be attributed to differences in effort required by each intervention group as well as the neurotrophic factors that occur when muscle contractions create synaptic connections resulting in improvement in cognition and feelings of satisfaction.

Subtetanic neuromuscular electrical stimulation can maintain Wingate test performance but augment blood lactate accumulation.

Concentration- and time-dependent effect of lactate on physiological adaptation (i.e., glycolytic adaptation and mitochondrial biogenesis) have been reported. Subtetanic neuromuscular electrical stimulation (NMES) with voluntary exercise (VOLES) can increase blood lactate accumulation. However, whether this is also true that VOLES can enhance the blood lactate accumulation during sprint exercise is unknown. Thus, we investigated whether VOLES before the Wingate test can enhance blood lactate accumulation without compromising Wingate exercise performance. Fifteen healthy young males (mean [SD], age: 23 [4] years, body mass index: 22.0 [2.1] kg/m2) volunteered. After resting measurement, participants performed a 3-min intervention: VOLES (NMES with free-weight cycling) or voluntary cycling alone, which matched exercise intensity with VOLES (VOL, 43.6 [8.0] watt). Then, they performed the Wingate test with 30min free-weight cycling recovery. The blood lactate concentration ([La]b) was assessed at the end of resting and intervention, and recovery at 1, 3, 5, 10, 20, and 30min. [La]b during intervention was higher with VOLES than VOL (P = 0.011). The increase in [La]b after the Wingate test was maintained for longer with VOLES than VOL at 10- and 20-min recovery (P = 0.014 and 0.023, respectively). Based on the Wingate test, peak power, mean power, and the rate of decline were not significantly different between VOLES and VOL (P = 0.184, 0.201, and 0.483, respectively). The combination of subtetanic NMES with voluntary exercise before the Wingate test has the potential to enhance blood lactate accumulation. Importantly, this combined approach does not compromise Wingate exercise performance compared to voluntary exercise alone.

Microcirculatory and Metabolic Responses during Voluntary Cycle Ergometer Exercise with a Whole-Body Neuromuscular Electrical Stimulation Device

Vigorous exercise increases blood viscosity and may pose a risk of cardiovascular events in patients with cardiovascular diseases. We recently reported that single-use of novel whole-body neuromuscular electrical stimulation (WB-NMES) can be safely applied in healthy subjects without adversely affecting blood fluidity. We performed a crossover study to explore the effectiveness and safety of a hybrid exercise with ergo-bicycle and WB-NMES; 15 healthy volunteers, aged 23–41 years, participated in this study. No arrhythmias were detected during the hybrid exercise and 20 min recovery, and although blood fluidity was transiently exacerbated immediately after both the exercise programs, in vivo parameters in the sublingual and nailfold microcirculation remained unchanged. There was a significant decrease in blood glucose and increase in lactic acid levels immediately after both exercise programs. Even with the same workload as the cycle ergometer exercise, the oxygen intake during the hybrid exercise remained higher than that during the cycle ergometer exercise alone (p &lt; 0.05, r = 0.79, power = 0.81). Both the hybrid and voluntary cycle ergometer exercises transiently exacerbated blood fluidity ex vivo; however, microvascular flow was not adversely affected in vivo.

Power Reserve at Intolerance in Ramp-Incremental Exercise Is Dependent on Incrementation Rate.

The mechanism(s) of exercise intolerance at V˙O2max remain poorly understood. In health, standard ramp-incremental (RI) exercise is limited by fatigue-induced reductions in maximum voluntary cycling power. Whether neuromuscular fatigue also limits exercise when the RI rate is slow and RI peak power at intolerance is lower than standard RI exercise, is unknown. In twelve healthy participants, maximal voluntary cycling power was measured during a short (~6 s) isokinetic effort at 80 rpm (Piso) at baseline and, using an instantaneous switch from cadence-independent to isokinetic cycling, immediately at the limit of RI exercise with RI rates of 50, 25, and 10 W·min-1 (RI-50, RI-25, and RI-10). Breath-by-breath pulmonary gas exchange was measured throughout. Baseline Piso was not different among RI rates (analysis of variance; P > 0.05). Tolerable duration increased with decreasing RI rate (RI-50, 411 ± 58 s vs RI-25, 732 ± 93 s vs RI-10, 1531 ± 288 s; P < 0.05). At intolerance, V˙O2peak was not different among RI rates (analysis of variance; P > 0.05), but RI peak power decreased with RI rate (RI-50, 361 ± 48 W vs RI-25, 323 ± 39 W vs RI-10, 275 ± 38 W; P < 0.05). Piso at intolerance was 346 ± 43 W, 353 ± 45 W, and 392 ± 69 W for RI-50, RI-25, and RI-10, respectively (P < 0.05 for RI-10 vs RI-50 and RI-25). At intolerance, in RI-50 and RI-25, Piso was not different from RI peak power (P > 0.05), thus there was no "power reserve." In RI-10, Piso was greater than RI peak power at intolerance (P < 0.001), that is, there was a "power reserve." In RI-50 and RI-25, the absence of a power reserve suggests the neuromuscular fatigue-induced reduction in Piso coincided with V˙O2max and limited the exercise. In RI-10, the power reserve suggests neuromuscular fatigue was insufficient to limit the exercise, and additional mechanisms contributed to intolerance at V˙O2max.

Countdown before voluntary exercise induces muscle vasodilation with baroreflex-mediated decrease in muscle sympathetic nerve activity in humans.

We examined whether a countdown (CD) before voluntary cycling exercise induced prospective vascular adjustment for the exercise and, if so, whether and how muscle sympathetic nerve activity (MSNA) was involved in the responses. Young men performed voluntary cycling in a semirecumbent position (n = 14) while middle cerebral artery blood flow velocity (VMCA; Doppler ultrasonography), heart rate (HR), arterial pressure (AP; finger photoplethysmography), oxygen consumption rate (V̇o2), oxygen saturation in the thigh muscle (; near-infrared spectrometry), cardiac output (CO; Modelflow method), and total peripheral resistance (TPR) were measured (experiment 1). Another group underwent the same exercise protocol but used only the right leg (n = 10) while MSNA (microneurography) was measured in the peroneal nerve of the left leg (experiment 2). All subjects performed eight trials with a ≥5-min rest between trials. In four trials randomly selected from the eight trials, exercise onset was signaled by a 30-s CD, whereas in the remaining four trials, exercise was started without CD. We found that CD first increased VMCA, HR, CO, and mean AP, and then decreased TPR and increased and V̇o2 (experiment 1; all P < 0.021). Furthermore, the CD-induced increase in mean AP decreased total MSNA and burst frequency (experiment 2; both P < 0.048) through the baroreflex, with decreased TPR and increased (experiment 2; both P < 0.001). The vasodilation and increased V̇o2 continued after the start of exercise. Thus CD before starting exercise induced the muscle vasodilatory response with a concomitant reduction in MSNA through the baroreflex to accelerate aerobic energy production after the start of exercise.NEW & NOTEWORTHY Prospective cardiovascular adjustment occurs before starting voluntary exercise, increasing heart rate and arterial pressure followed by muscle vasodilation; however, the precise mechanisms and significance for this vasodilation remain unknown. We found that during the countdown before starting exercise cerebral blood flow velocity increased, followed by increases in heart rate and arterial pressure, which suppressed MSNA through baroreflex, resulting in thigh muscle vasodilation to increase oxygen consumption rate, which might make it easier to start exercise.

The effects of FES cycling combined with virtual reality racing biofeedback on voluntary function after incomplete SCI: a pilot study

BackgroundFunctional Electrical Stimulation (FES) cycling can benefit health and may lead to neuroplastic changes following incomplete spinal cord injury (SCI). Our theory is that greater neurological recovery occurs when electrical stimulation of peripheral nerves is combined with voluntary effort. In this pilot study, we investigated the effects of a one-month training programme using a novel device, the iCycle, in which voluntary effort is encouraged by virtual reality biofeedback during FES cycling.MethodsEleven participants (C1-T12) with incomplete SCI (5 sub-acute; 6 chronic) were recruited and completed 12-sessions of iCycle training. Function was assessed before and after training using the bilateral International Standards for Neurological Classification of SCI (ISNC-SCI) motor score, Oxford power grading, Modified Ashworth Score, Spinal Cord Independence Measure, the Walking Index for Spinal Cord Injury and 10 m-walk test. Power output (PO) was measured during all training sessions.ResultsTwo of the 6 participants with chronic injuries, and 4 of the 5 participants with sub-acute injuries, showed improvements in ISNC-SCI motor score > 8 points. Median (IQR) improvements were 3.5 (6.8) points for participants with a chronic SCI, and 8.0 (6.0) points for those with sub-acute SCI. Improvements were unrelated to other measured variables (age, time since injury, baseline ISNC-SCI motor score, baseline voluntary PO, time spent training and stimulation amplitude; p > 0.05 for all variables). Five out of 11 participants showed moderate improvements in voluntary cycling PO, which did not correlate with changes in ISNC-SCI motor score. Improvement in PO during cycling was positively correlated with baseline voluntary PO (R2 = 0.50; p < 0.05), but was unrelated to all other variables (p > 0.05). The iCycle was not suitable for participants who were too weak to generate a detectable voluntary torque or whose effort resulted in a negative torque.ConclusionsImproved ISNC-SCI motor scores in chronic participants may be attributable to the iCycle training. In sub-acute participants, early spontaneous recovery and changes due to iCycle training could not be distinguished. The iCycle is an innovative progression from existing FES cycling systems, and positive results should be verified in an adequately powered controlled trial.Trial registrationClinicalTrials.gov, NCT03834324. Registered 06 February 2019 - Retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT03834324. Protocol V03, dated 06.08.2015.

Assisted Cycling Therapy (ACT) Improves Adaptive Behaviors in Adolescents with Down Syndrome

The aim of this research study was to examine the effects of Assisted Cycling Therapy (ACT) on adaptive/maladaptive behaviors, depression, and self-efficacy in adolescents with Down syndrome (DS). The participants were counterbalanced to either intervention groups of 1) Assisted Cycling Therapy (ACT), in which the participants’ voluntary pedaling rates were augmented with a motor to ensure the maintenance of 80 rpm or greater 2) Voluntary Cycling (VC), in which participants cycled at their self-selected pedaling rate or 3) No Cycling (NC), in which the participants sat and watched a video. The ACT and VC groups exercised 3 days a week for 8 weeks for 30 min. Adaptive behavior was measured by the Vineland Adaptive Behavior Scale (VABS) II to analyze the changes in daily living skills and maladaptive behaviors, depression was measured by the Children’s Depressive Inventory, and exercise perception and self-efficacy were measured by the PASE scale, pre and post interventions. The result of this study revealed that social coping skills (p = .001) and depression (p = .022) improved more after participating in ACT than VC or NC interventions. In addition, externalizing maladaptive behaviors (p = .023) improved pre and post ACT and VC interventions but not NC. Our results are discussed with respect to neurological mechanisms associated with our interventions and their effect on functioning in adolescents with DS.

Acute Effects of Assisted Cycling Therapy on Post-Stroke Motor Function: A Pilot Study.

Background Stroke is the most common cause of long-term disability in the United States (US). Assisted Cycling Therapy (ACT) at cadences of about 80 rpm has been associated with improvements in motor and clinical function in other clinical populations. The acute effects of ACT on motor function of persons with stroke have not been investigated. Objectives The primary purpose of this cross-over trial was to compare the effects of ACT, voluntary cycling (VC), and no cycling (NC) on upper (Box and Blocks Test) and lower extremity motor function (Lower Extremity Motor Coordination Test) in adults with chronic stroke (age: 60 ± 16 years; months since stroke: 96 ± 85). The secondary purpose was to examine average cycling cadence and ratings of perceived exertion as predictors of change in motor function following the exercise session. Methods Twenty-two participants (female = 6, male = 16) completed one 20-min session each of ACT (mean cadence = 79.5 rpm, VC (mean cadence = 51.5 rpm), and NC on separate days in quasi-counterbalanced fashion). Results Main effects of intervention did not differ between ACT and VC. Within-intervention analyses revealed significant (p < 0.05) pre- to posttest changes in all outcome measures for ACT but only in the Lower Extremity Motor Coordination Test on the non-paretic side for VC. Trend analyses revealed a positive relationship between average ACT cadences and improvements in upper and lower extremity motor function (p < 0.05). A positive relationship between average VC cadences and lower extremity function was also revealed (p < 0.05). Conclusion ACT and VC produced similar acute improvements in paretic and non-paretic lower extremity motor function whereas changes in upper extremity motor function were more limited. Faster cycling cadences seem to be associated with greater acute effects.

An increase in prefrontal oxygenation at the start of voluntary cycling exercise was observed independently of exercise effort and muscle mass.

We have reported using near-infrared spectroscopy that an increase in prefrontal oxygenated-hemoglobin concentration (Oxy-Hb) at the start of cycling exercise has relation to central command, defined as a feedforward signal descending from higher brain centers. The final output of central command evokes the exercise effort-dependent cardiovascular responses. If the prefrontal cortex may output the final signal of central command toward the autonomic nervous system, the prefrontal oxygenation should increase depending on exercise effort. To test the hypothesis, we investigated the effects of exercise intensity and muscle mass on prefrontal oxygenation in 13 subjects. The subjects performed one- or two-legged cycling at various relative intensities for 1min. The prefrontal Oxy-Hb and cardiovascular variables were simultaneously measured during exercise. The increase in cardiac output and the decrease in total peripheral resistance at the start of one- and two-legged cycling were augmented in proportion to exercise intensity and muscle mass recruitment. The prefrontal Oxy-Hb increased at the start of voluntary cycling, while such increase was not developed during passive cycling. Mental imagery of cycling also increased the prefrontal Oxy-Hb, concomitantly with peripheral muscle vasodilatation. However, the increase in prefrontal Oxy-Hb at the start of voluntary cycling seemed independent of exercise intensity and muscle mass recruitment. It is likely that the increased prefrontal activity at the start of cycling exercise is not representative of the final output signal of central command itself toward the autonomic nervous system but may trigger neuronal activity in the caudal brain responsible for the generation of central command.

Countdown before voluntary exercise induces muscle vasodilation with decreased muscle sympathetic nerve activity in humans

We examined whether countdown (CD) before voluntary bicycle ergometer exercise induced cerebro‐cardiovascular responses and, if so, whether these responses to CD were altered by postural change from the semi‐recumbent to supine position. Young men (n=14) performed voluntary cycle exercise in the semi‐recumbent position while middle cerebral artery blood flow velocity (CBF; Doppler ultrasonography), heart rate (HR), blood pressure (finger photoplethysmography), oxygen consumption rate (VO2), oxygen saturation in the right thigh muscle (StO2; near‐infrared spectrometry), cardiac output (CO; cZ method) and total peripheral resistance (TPR) were measured. The subjects repeated 8 trials, intermitted by more than 5‐min rest. In 4 trials randomly selected from 8 trials, the onset of exercise was signaled by a 30‐sec CD, whereas in the remaining 4 trials, exercise was started without CD. We found that CD increased CBF, HR, CO, mean blood pressure, and VO2 sequentially, decreasing TPR with increased StO2. To assess efferent signals causing vasodilation and the effects of posture change from the semi‐recumbent to supine position, other groups of subjects underwent the same exercise protocol but using only right leg in the semi‐recumbent (n=10) or supine (n=8) positions while muscle sympathetic nerve activity (MSNA; microneurography) and StO2 were measured in the left and right leg, respectively. We found that CD decreased MSNA burst frequency and total MSNA (both, P&lt;0.05), which were significantly correlated with the increase in StO2 (both, P&lt;0.001). However, these responses to CD were nearly abolished by the postural change. Thus, CD before starting voluntary exercise induced cerebro‐cardiovascular responses from central system to effector organs in a sequential manner in the semi‐recumbent position, but these responses were minimized while in the supine position.Support or Funding InformationThis study was supported by grants from the Japan Society for the Promotion of Science (24689014 and 15H04680).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

GABAergic Contribution to the Muscle Mechanoreflex‐Mediated Heart Rate Responses at the Onset of Exercise in Humans

It is well stablished that the cardiovascular response to exercise is governed by both central and peripheral mechanisms. However the possible neurotransmitters involved in the autonomic responses during exercise are not fully understood. During exercise, Potts et al. (Neuroscience 2003;119:201–14) showed that electrically evoked muscular contraction inhibits arterial baroreceptors signaling within the nucleus of the tractus solitaries (NTS) via activation of GABAergic receptors in rats, suggesting that skeletal muscle afferents are a potential source synaptic drive to GABAergic neurons within the NTS. However, the extent to which these findings can be extrapolated to humans remains unclear. We reasoned that the GABAergic mechanisms involved in the heart rate (HR) responses at the onset of dynamic exercise is primarily mediated by muscle mechanoreceptors afferents. Therefore, in this study we sought to determine if central GABA mechanisms are involved in the muscle mechanoreflex‐mediated HR responses at the onset of exercise in humans. Twenty‐eight healthy subjects (14 men) aged between 18 to 35 years randomly performed three bouts of 5‐s of passive and active cycling under placebo and following oral administration of diazepam (10 mg), a benzodiazepine that produces an enhancement in GABAA activity. Beat‐to‐beat HR (electrocardiography) and arterial blood pressure (BP ‐ finger photopletysmography) were continuously measured. Electromyography of vastus lateralis was obtained to confirm no electrical activity during passive trials. HR increased from rest under placebo and further increased following administration of diazepam in both passive (Δ12 ± 1 beats min−1 vs. Δ17 ± 1 beats min−1, P &lt; 0.01) and active (Δ14 ± 1 beats min−1 vs. Δ18 ± 1 beats min−1, P &lt; 0.01) cycling. Arterial BP increased from rest similarly during all conditions. Importantly, no sex‐related differences were found in any variables during all experiments. These findings demonstrate for the first time that the central GABAergic mechanisms significantly contribute to the muscle mechanoreflex‐mediated cardiac vagal withdrawal at the onset of exercise in humans.Support or Funding InformationBrazilian National Council of Scientific and Technological Development (CNPq)Foundation for Research Support of Federal District (FAPDF)Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES)This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

An increase in prefrontal oxygenation at the start of voluntary cycling exercise was observed independently of exercise effort and muscle mass

We have reported using near‐infrared spectroscopy that an increase in prefrontal oxygenated‐hemoglobin concentration (Oxy‐Hb) at the start of cycling exercise has relation to central command, defined as a feedforward signal descending from higher brain centers. The final output of central command evokes the cardiovascular responses depending on exercise effort. If the prefrontal cortex may output the final signal of central command toward the autonomic nervous system, the prefrontal oxygenation should increase depending on exercise effort. To test the hypothesis, we investigated the effects of exercise intensity and muscle mass on prefrontal oxygenation by longitudinal comparisons in 13 subjects. The subjects performed one‐ or two‐legged cycling at various relative intensities (20%, 35%, 45%, and 60% of maximal voluntary exercise intensity) for 1 min. The prefrontal Oxy‐Hb and cardiovascular variables were simultaneously measured during exercise. The increase in cardiac output and the decrease in total peripheral resistance at the start of one‐ and two‐legged cycling were augmented (P&lt;0.05) in proportion to exercise intensity and/or muscle mass recruitment. However, the increase in prefrontal Oxy‐Hb seemed independent of exercise intensity. When the rating of perceived exertion was equal, the increase in prefrontal Oxy‐Hb was not different (P&gt;0.05) between one‐and two‐legged cycling. Furthermore, no correlations (P&gt;0.05) were found between the increase in prefrontal Oxy‐Hb and exercise intensity or rating of perceived exertion. It is likely that increased prefrontal oxygenation at the start of cycling exercise does not represent the final output of central command descending to the autonomic nervous system.Support or Funding InformationThis study was funded by Grant‐in‐Aid (15H03061) for Scientific Research (B) from the Japan Society for the Promotion of Science (JSPS).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The cardinal exercise stopper: Muscle fatigue, muscle pain or perception of effort?

The capacity to sustain high-intensity aerobic exercise is essential for endurance performance. Therefore, it is important to understand what is the factor limiting time to exhaustion (TTE) in healthy and fit adults. In Study 1, maximal voluntary cycling power (MVCP) was measured in 11 volunteers before and immediately after a high-intensity TTE test on cycle ergometer. Cadence was 60 rpm in both the MVCP and TTE tests. Despite a 35% loss in MVCP, power produced during the final MVCP test (mean ± SD 469 ± 111 W) was significantly higher than the power required by the TTE test (269 ± 55 W) (P < 0.001). In Study 2, 12 participants performed a cold pressor test (CPT) to the limit of tolerance followed by a high-intensity TTE test on cycle ergometer. Ratings of pain unpleasantness (RPU) during the TTE test were anchored to the unpleasantness of pain experienced during the CPT. On average, the RPU was 9.7 ± 0.4 at completion of the CPT and 5.0 ± 0.9 at exhaustion during the TTE test. The difference between these two ratings of pain unpleasantness was statistically significant (P < 0.001). In both Studies 1 and 2, the slope of the rating of perceived exertion (RPE) during the TTE test correlated significantly with TTE (r = -0.75 and -0.83, P < 0.01). Results of this two-part investigation suggest that perception of effort, rather than severe locomotor muscle fatigue or intolerably unpleasant muscle pain, is the cardinal exercise stopper during high-intensity aerobic exercise.

From cars to bikes \u2013 the feasibility and effect of using e-bikes, longtail bikes and traditional bikes for transportation among parents of children attending kindergarten: design of a randomized cross-over trial

BackgroundThe present study aims to increase bicycling and level of physical activity (PA), and thereby promote health in parents of toddlers, by giving access to different bicycle types. There is a need for greater understanding of e-bikes and their role in the transportation network, and further effects on PA levels and health. Moreover, longtail bikes could meet certain practical needs not fulfilled by e-bikes or traditional bikes, hence increased knowledge regarding their feasibility should be obtained. No previous studies have investigated whether providing an e-bike or a longtail bike over an extended period in a sample of parents of toddlers influence objectively assessed amount of bicycling and total PA level, transportation habits, cardiorespiratory fitness, body composition and blood pressure.MethodsA randomized cross-over trial will be performed, entailing that participants in the intervention group (n = 18) complete the following intervention arms in random order: (i) three months access to an e-bicycle with trailer for child transportation (n = 6), (ii) three months access to a longtail bicycle (n = 6), and (iii) three months access to a regular bicycle with trailer (n = 6), in total nine months. Also, a control group (n = 18) maintaining usual transportation and PA habits will be included. A convenience sample consisting of 36 parents of toddlers residing in Kristiansand municipality, Southern Norway, will be recruited. Total amount of bicycling (distance and time), total level of PA, and transportation habits will be measured at baseline and in connection to each intervention arm. Cardiorespiratory fitness, body composition and blood pressure will be measured at baseline and post-intervention. Main outcome will be bicycling distance and time spent cycling.DiscussionNew knowledge relevant for the timely issues of public health and environmental sustainability will be provided among parents of toddlers, representing a target group of greatest importance. There is a call for research on the influence of e-bikes and longtail bikes on travel behavior and PA levels, and whether voluntary cycling could improve health. If the present study reveals promising results, it should be replicated in larger and more representative samples. Eventually, inclusion in national public health policies should be considered.Trial registrationID NCT03131518, made public 26.04.2017.

SUSTAINABILITY OF THE BRAZILIAN ECONOMY USING THE SYSTEM PUBLIC FUNDS TRANSFERS IN SICONV

Decree No. 6,170/2007 regulated agreements, transfer agreements and terms of decentralized execution signed by federal public administration’s organs and entities with organs or, public or private nonprofit entities for the implementation of programs, projects and activities involving the transfer of resources and decentralization of credits arising from the Union's Fiscal and Social Security Budget; and created the Agreements and Transfer Agreements Management System - SICONV, open to the public, through the Portal of Agreements. SICONV initiated a new era in public management; as it renewed the relationship between Federal Government and its organs; and public and private entities signing agreements, transfer agreements and terms of partnership celebrated with Union’s resources. This initiative automated transfers’ processes, since all procedures are now performed and recorded in this system. SICONV covers all operations of the voluntary transfers life cycle, from the provision of resources to accountability, and it is seamlessly integrated with the main structuring systems of the Federal Government. Thus, SICONV established itself in the Public Administration as a major transformation system that enabled and consolidated changes in many patterns and concepts - currently already established - of how voluntary transfers were executed. Keywords: Information Technology, Government Information Systems, Public Management, Public Administration, Knowledge Management

Variations of ankle-foot orthosis-constrained movements increase ankle range of movement while maintaining power output of recumbent cycling.

Previous research investigated recumbent cycle power output (PO) from the perspective of knee and hip joint biomechanics. However, ankle-foot biomechanics and, in particular, the effect of ankle-foot orthosis (AFO)-constrained movements on cycle PO has not been widely explored. Therefore, the purpose of this study was to determine whether AFOs of a fixed position (FP) and in dorsi-plantarflexion (DPF)-, dorsiflexion (DF)- and plantarflexion (PF)-constrained movements might influence PO during voluntary recumbent cycling exercises. Twenty-five healthy individuals participated in this study. All underwent 1-min cycling at a fixed cadence for each of the AFOs. The peak and average PO of each condition were analyzed. The peak and average PO were 27.2±12.0 W (range 6-60) and 17.2±9.0 W (range 2-36), respectively, during voluntary cycling. There were no significant differences in the peak PO generated by the AFOs (p=0.083). There were also no significant differences in the average PO generated using different AFOs (p=0.063). There were no significant differences in the changes of the hip and knee joint angles with different AFOs (p=0.974 and p=1.00, respectively). However, there was a significant difference in the changes of the ankle joint angle (p<0.00). The present study observed that AFO-constrained movements did not have an influence in altering PO during voluntary recumbent cycling in healthy individuals. This finding might serve as a reference for future rehabilitative cycling protocols.