Maximal Arm-cranking Exercise Research Articles

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.

Cardiovascular response to peak voluntary exercise in males with cervical spinal cord injury

Context/Objective: Traumatic damage to the cervical spinal cord is usually associated with a disruption of the autonomic nervous system (ANS) and impaired cardiovascular control both during and following exercise. The magnitude of the cardiovascular dysfunction remains unclear. The aim of the current study was to compare cardiovascular responses to peak voluntary exercise in individuals with tetraplegia and able-bodied participants.Design: A case-control study.Subjects: Twenty males with cervical spinal cord injury (SCI) as the Tetra group and 27 able-bodied males as the Control group were included in the study.Outcome Measures: Blood pressure (BP) response one minute after the peak exercise, peak heart rate (HRpeak), and peak oxygen consumption (VO2peak) on an arm crank ergometer were measured. In the second part of the study, 17 individuals of the Control group completed the Tetra group's workload protocol with the same parameters recorded.Results: There was no increase in BP in response to the exercise in the Tetra group. Able-bodied individuals exhibited significantly increased post-exercise systolic BP after the maximal graded exercise test (123±16%) and after completion of the Tetra group's workload protocol (114±11%) as compared to pre-exercise. The Tetra group VO2peak was 59% and the HRpeak was 73% of the Control group VO2peak and HRpeak, respectively.Conclusions: BP did not increase following maximal arm crank exercise in males with a cervical SCI unlike the increases observed in the Control group. Some males in the Tetra group appeared to be at risk of severe hypotension following high intensity exercise, which can limit the ability to progressive increase and maintain high intensity exercise.

The influence of a fast ramp rate on peak cardiopulmonary parameters during arm crank ergometry

The influence of a very fast ramp rate on cardiopulmonary variables at ventilatory threshold and peak exercise during a maximal arm crank exercise test has not been extensively studied. Considering that short arm crank tests could be sufficient to achieve maximal oxygen consumption (VO₂), it would be of practical interest to explore this possibility. Thus, this study aimed to analyse the influence of a fast ramp rate (20 W min⁻¹) on the cardiopulmonary responses of healthy individuals during a maximal arm crank ergometry test. Seventeen healthy individuals performed maximal cardiopulmonary exercise tests (Ultima CardiO2; Medical Graphics Corporation, St Louis, USA) in arm ergometer (Angio, LODE, Groningen, The Netherlands) following two protocols in random order: fast protocol (increment: 2 w/6 s) and slow protocol (increment: 1 w/6 s). The fast protocol was repeated 60-90 days after the 1st test to evaluate protocol reproducibility. Both protocols elicited the same peak VO₂ (fast: 23.51 ± 6.00 versus slow: 23.28 ± 7.77 ml kg⁻¹ min⁻¹; P = 0.12) but peak power load in the fast ramp protocol was higher than the one in the slow ramp protocol (119 ± 43 versus. 102 ± 39 W, P < 0.001). There was no other difference in ventilatory threshold and peak exercise variables when 1st and 2nd fast protocols were compared. Fast protocol seems to be useful when healthy young individuals perform arm cardiopulmonary exercise test. The usefulness of this protocol in other populations remains to be evaluated.

Muscle deoxygenation of upper-limb muscles during progressive arm-cranking exercise

The purpose of this study was to determine which upper-limb muscle exhibits the greatest change in muscle deoxygenation during arm-cranking exercise (ACE). We hypothesized that the biceps brachii (BB) would show the greatest change in muscle deoxygenation during progressive ACE to exhaustion relative to triceps brachii (TR), brachioradialis (BR), and anterior deltoid (AD). Healthy young men (n = 11; age = 27 +/- 1 y; mean +/- SEM) performed an incremental ACE test to exhaustion. Near-infrared spectroscopy (NIRS) was used to monitor the relative concentration changes in oxy- (O2Hb), deoxy- (HHb), and total hemoglobin (Hbtot), as well as tissue oxygenation index (TOI) in each of the 4 muscles. During submaximal arm exercise, we found that changes to NIRS-derived measurements were not different between the 4 muscles studied (p > 0.05). At maximal exercise HHb was significantly higher in the BB compared with AD (p < 0.05). Relative to the other 3 muscles, BB exhibited the greatest decrease in O2Hb and TOI (p < 0.05). Our investigation provides two new and important findings: (i) during submaximal ACE the BB, TR, BR, and AD exhibit similar changes in muscle deoxygenation and (ii) during maximal ACE the BB exhibits the greatest change in intramuscular O2 status.

Training of the respiratory muscles in individuals with tetraplegia

An experimental cross-sectional design. To evaluate whether training of the innervated respiratory muscles in individuals with a (partial) cervical spinal cord injury will improve the strength and endurance capacity of these muscles and the exercise performance in these individuals. Department of Physiology and Pulmonary diseases, Nijmegen, The Netherlands. In this study nine individuals with tetraplegia (C3 C7) performed a target flow endurance training of the inspiratory muscles, twice a day for 15 min. First, the subjects performed a 'sham' training for 6 weeks with no appreciable resistance, after that they performed a 'real' training for 6 weeks with a resistance of 70% of the maximal endurance capacity of the inspiratory muscles. The training was evaluated at 0, 6 and 12 weeks by the following tests: (1) the slow Inspiratory Vital Capacity (IVC) and the Forced Inspiratory and Expiratory Volumes over 1 s (FIV1 and FEV1); (2) the Maximal Inspiratory Mouth Pressure (Pimax) and the Endurance Pressure (Pendu) and (3) a maximal arm-cranking exercise test. After the sham training, the Pendu was increased from 3.98 to 4.71 kPa with a P-value of 0.05. The sham training had no influence on any of the other variables. The real training had no effect on the IVC, FIV1, FEV1 and Pimax, however, increased the Pendu from 4.71 to 6.16 kPa (P=0.01), representing the respiratory muscle-endurance capacity. The oxygen consumption (VO2 peak) in the maximal exercise test improved from 0.87 to 0.98 l/min (P = 0.05). The results of the study indicate that training of the respiratory muscles results in an enhanced endurance capacity of these muscles and a concomitant increase in the aerobic exercise performance.

Oxygen uptake during arm cranking with and without leg electrical stimulation in able bodied individuals

Ten able bodied subjects (AB) volunteered to be tested with a Respond II neuromuscular stimulator applied to the lower extremities during submaximal arm crank exercise (ACE) to determine its effect on heart rate (min−1) and VO2 in ml·min−1 ·kg−1. One to two hours after a maximal ACE test, subjects performed four 9‐minute submaximal bouts of ACE; two at 25% and two at 70% of VO2peak. Each work rate was performed with and without, a randomly ordered, electrical stimulation (ES) of the quadriceps and hamstring muscle groups respectively. Electrical stimulation intensity was determined by a subject's maximal tolerance. Data, from four submaximum tests were analyzed with a two 2×2 repeated measures analysis of variance. The main effects were work rate (25% VO2peak and 70% VO2peak) and electrical stimulation (STIM) no stimulation (NOSTIM). No statistical differences was found between the STIM and NOSTIM in VO2 or heart rate at either 25% VO2peak (11.0 ml·min−1·kg−1 vs. 11.2 ml·min−1·kg−1; and 89 min−1 vs. 88 min−1 respectively) or 70% VO2peak (22.8 ml·min−1·kg−1 vs. 22.8 ml·min−1·kg−1; 128 min−1 vs. 127 min−1 respectively). There was a difference in VO2 and heart rate for the main effect of work rate 25%VO2peak or 70%VO2peak (11.1 ml·min−1 ·kg−1 vs. 22.8 ml‐min−1 ·kg−1; 88 min−1 vs. 127 min−1). The results of this study may have been affected by the low level of ES intensity used, due to human subjects' ES guidelines, and use of the lower limbs for stability with increasing intensity of work rate.

TRAINING OF THE RESPIRATORY MUSCLES IN INDIVIDUALS WITH TETRAPLEGIA 233

The purpose of this study was to evaluate whether training of the innervated respiratory muscles in people with a cervical spinal cord injury will improve the strength and endurance capacity of these muscles and the exercise performance in these people. Nine individuals with tetraplegia performed an endurance training of the inspiratory muscles, twice a day for 15 min. First, the subjects trained for 6 wk with no appreciable resistance (NR), after that they trained for 6 wk with a resistance (R) of 70% of their individual maximal endurance capacity of the inspiratory muscles. The training was evaluated using the following tests: 1) a lung function test, in which the vital capacity and the forced inspiratory and expiratory volumes over 1 sec were measured; 2) a ventilation test, in which the maximal inspiratory and expiratory mouth pressure (Pimax and Pemax) and the endurance pressure (Piendu) were measured; 3) a maximal arm-cranking exercise test. Both NR and R-training had no effect on the lung function parameters, in addition, NR had no effect on ventilation nor on exercise parameters. However, after R-training Piendu increased from 35.3 ± 11.2 mmHg to 46.2± 11.8 mmHg (p=0.01), representing the endurance capacity, whereas Pimax and Pemax, representing the strength, remained unchanged. R also increased the ratio between the Pimax and the Piendu from 58.3 ± 18.6% to 77.3 ± 23.3% (p=0.02). The oxygen uptake(˙VO2 peak) at maximal exercise improved from 0.87 ± 0.49 l·min-1 to 0.98 ± 0.44 l·min-1. The results of the study indicate that training of the respiratory muscles results in an enhanced endurance capacity of these muscles and a concomittant increase in exercise performance.

Effect of maximal arm exercise on skin blood flux in the paralyzed lower limbs in persons with spinal cord injury.

The purpose of the present study was to examine the effect of maximal arm exercise on the skin blood circulation of the paralyzed lower limbs in persons with spinal cord injury (PSCI). Eight male PSCI with complete lesions located between T3 and L1 performed graded maximal arm-cranking exercise (MACE) to exhaustion. The skin blood flux at the thigh (SBFT) and that at the calf (SBFC) were monitored using laser-Doppler flowmeter at rest and for 15 s immediately after the MACE. The subject's mean peak oxygen uptake and peak heart rate was 1.41 +/- 0.22 l.min-1 and 171.6 +/- 19.2 beats.min-1, respectively. No PSCI showed any increase in either SBFT or SBFC after the MACE, when compared with the values at rest. These results suggest that the blood circulation of the skin in the paralyzed lower limbs in PSCI is unaffected by the MACE.

Autonomic functions and orthostatic responses 24 h after acute intense exercise in paraplegic subjects

We tested the hypothesis that a bout of graded exercise designed to elicit maximal effort would increase the sensitivity of autonomically mediated baroreflexes and enhance blood pressure (BP) stability in subjects prone to postural hypotension. Therefore, we measured heart rate (HR), BP, forearm vascular resistance (FVR), and vasoactive hormone responses before and during 15 min of 70 degrees head-up tilt (HUT) in 10 paraplegic subjects (21-65 yr) on two occasions: 1) 24 h after maximal arm-crank exercise (postexercise) and 2) without exercise (control). During HUT, HR increased 30 beats/min in both postexercise and control, but the reduction in systolic BP (SBP) during control (-12.0 +/- 4.6 mmHg) was larger (P = 0.017) than that during HUT after exercise (-0.3 +/- 4.3 mmHg). The postexercise increase in FVR from supine to HUT of 17.0 +/- 2.4 to 24.8 +/- 3.2 peripheral resistance units (PRU) was greater (P = 0.042) than the increase observed during control (18.3 +/- 3.7 to 19.5 +/- 3.1 PRU). The gain of the carotid-cardiac baroreflex was also increased (P = 0.049) after exercise. Responses in norepinephrine, vasopressin, and plasma renin-angiotensin induced by HUT were similar for control and postexercise, and there was no difference in either leg compliance or plasma volume between the two conditions. Additionally, HR and SBP responses to phases II and IV of the Valsalva maneuver, indexes of integrated baroreflex sensitivity, were increased (P < 0.05) after maximal exercise compared with control. Thus acute intense exercise eliminated orthostatic hypotension in paraplegics, was associated with increased FVR and baroreflex sensitivity, and was independent of blood volume changes.

The effect of an anti-G suit on the maximal performance of individuals with paraplegia.

The purpose of this study was to examine whether lower body positive pressure (LBPP) could improve maximal performance in paraplegic subjects (P). LBPP may diminish venous blood pooling (VBP) below the lesion and, therefore, support the redistribution of blood during exercise. Twelve male P subjects with complete spinal cord-lesions between T6 and T12, and 13 male able-bodied control subjects (C), performed maximal arm-cranking exercise with and without LBPP (52 mmHg) by means of an anti-gravity suit. P and C subjects had a significantly lower maximal heart rate (HRmax) with LBPP than without (P: 176 +/- 10 vs 184 +/- 7 b.min-1; C: 174 +/- 8 vs 177 +/- 8 b.min-1), whereas maximal power output (Wmax) and oxygen uptake (VO2max) remained unchanged. This suggests that LBPP provides P and C with central hemodynamic benefits. These benefits, however, did not result in improvements in Wmax or VO2max, probably due to other limitations in the complex and closely linked oxygen uptake process. During submaximal exercise the circulatory benefits were more pronounced in P than in C, probably due to the decrease of the VBP by LBPP. The results of this study suggest that LBPP appears to offer both P and C groups a central hemodynamic benefit without improving maximal performance.

Cardiac output in paraplegic subjects at high exercise intensities.

The purpose of this investigation was to compare cardiac output (Qc) in paraplegic subjects (P) with wheelchair-confined control subjects (C) at high intensities of arm exercise. At low and moderate exercise intensity Qc was the same at a given oxygen uptake (VO2) in P and C. A group of 11 athletic male P with complete spinal-cord lesions between T6 and T12 and a group of 5 well-matched athletic male C performed maximal arm-cranking exercise and submaximal exercise at 50%, 70% and 80% of each individual's maximal power output (Wmax). Maximal VO2 (VO2max) was significantly lower, VO2max per kilogram body mass was equal and maximal heart rate (fc) was significantly higher in P compared to C. At VO2 of 1.3, 1.5 and 1.7 l.min-1, and for P 65%-90% of the VO2max, Qc was not significantly different between the groups, although, Qc in P was achieved with a significantly lower stroke volume (SV) and a significantly higher fc. Although the SV was lower in P, it followed the same pattern as SV in C during incremental exercise, i.e. an increase in SV until about 45% Wmax and thereafter a stable SV. The similar Qc at a given VO2 in both groups indicated that, even at high exercise intensities, circulation in P can be considered isokinetic with a complete compensation by fc for a lower SV.

Cardiovascular responses in paraplegic subjects during arm exercise.

The purpose of this study was to examine cardiovascular responses during arm exercise in paraplegics compared to a well-matched control group. A group of 11 male paraplegics (P) with complete spinal cord-lesions between T6 and T12 and 11 male control subjects (C), matched for physical activity, sport participation and age performed maximal arm-cranking exercise and submaximal exercise at 20%, 40% and 60% of the maximal load for each individual. Cardiac output (Qc) was determined by the CO2 rebreathing method. Maximal oxygen uptake was significantly lower and maximal heart rate (fc) was significantly higher in P compared to C. At the same oxygen uptakes no significant differences were observed in Qc between P and C; however, stroke volume (SV) was significantly lower and fc significantly higher in P than in C. The lower SV in P could be explained by an impaired redistribution of blood and, therefore, a reduced ventricular filling pressure, due to pooling of venous blood caused by inactivity of the skeletal muscle pump in the legs and lack of sympathetic vasoconstriction below the lesion. In conclusion, in P maximal performance appears to have been limited by a smaller active muscle mass and a lower SV despite the higher fc,max. During submaximal exercise, however, this lower SV was compensated for by a higher fc and, thus at the same submaximal oxygen uptake, Qc was similar to that in the control group.

Gas Exchange During Maximal Upper Extremity Exercise

to characterize gas exchange and cardiopulmonary performance during maximal progressive arm crank exercise. Cardiopulmonary variables were measured and arterial blood gases were determined in blood samples obtained from an indwelling radial arterial catheter during arm crank exercise (34 watts/min). Arm crank exercise was compared to maximal leg exercise performed by a different but comparable group of subjects from a previous study. 19 healthy young (mean +/- SEM: 20 +/- 1 yr) black males. Peak arm crank exercise resulted in lower values compared to peak leg exercise for: power (129 +/- 2 vs 253 +/- 10 W), VO2 (2.17 +/- 0.04 vs 3.26 +/- 0.14 L/min); VCO2 (2.9 +/- 0.11 vs 4.32 +/- 0.17 L/min); HR (168 +/- 3 vs 189 +/- 3 beats/min); AT (1.15 +/- 0.05 vs 1.83 +/- 0.07 L/min); and VE (101 +/- 2 vs 144 +/- 8 L/min), respectively. Arm crank exercise (baseline vs peak) elicited an impressive improvement in PaO2 (85 +/- 1 to 97 +/- 1 mm Hg), no change in SaO2 (96 +/- 0.2 to 96 +/- 0.2 percent), no significant increase in P(A-a)O2 (3 +/- 0.7 to 5 +/- 0.9 mm Hg) and an appropriate trending decrease in VD/VT (0.22 +/- 0.01 to 0.17 +/- 0.01). Peak arm crank values were significantly different from peak cycle exercise for PaO2 (82 +/- 2.2 mm Hg), SaO2 (93 +/- 0.4 percent), P(A-a)O2 (21 +/- 1.9 mm Hg) and VD/VT (0.08 +/- 0.01). At comparable levels of VO2 for arm crank and cycle exercise (2.17 +/- 0.04 vs 2.26 +/- 0.08 L/min), significant differences were observed for PaO2 (97 +/- 1.4 vs 81 +/- 1.9 mm Hg); SaO2 (96 +/- 0.2 vs 94 +/- 0.4 percent); P(A-a)O2 (5 +/- 0.9 vs 14 +/- 1.5 mm Hg); and VD/VT (0.17 +/- 0.01 vs 0.08 +/- 0.01), respectively. Maximal arm crank exercise represents a submaximal cardiopulmonary stress compared to maximal leg exercise. The differences in gas exchange observed at peak exercise between arm crank and leg exercise for the most part reflect the lower VO2 achieved. However, the persistence of these gas exchange differences even at a comparable level of VO2 suggests that factors other than VO2 may be operative. These factors may include differences in alveolar ventilation, CO2 production, ventilation-perfusion inequality, diffusion, and control of breathing.

Exercise and hypoxia increase sickling in venous blood from an exercising limb in individuals with Sickle cell trait

The association between sickle cell trait (SCT) and complications related to exercise may be explained if exercise-induced sickling interferes with capillary blood flow and causes tissue ischemia and functional abnormalities. To test this hypothesis, we measured sickling and blood gas values in venous and arterial blood of an exercising limb in subjects with SCT and in controls. The study consisted of 15 subjects with hemoglobin AS (SCT group) and 15 subjects with hemoglobin AA (control group). Each performed two maximal arm crank exercise tests, one at 1,270 meters and one at simulated 4,000 meters. At 1,270 meters, axillary venous sickling increased significantly (p less than 0.05) from (mean +/- SD) 1.0 +/- 1.0% at rest to 2.3 +/- 2.6% during peak exercise. At simulated 4,000 meters, sickling increased significantly (p less than 0.001) from 1.5 +/- 1.2% to 8.5 +/- 7.1%. A wide range of sickling during peak exercise was observed (1% to 25%). One minute after exercise at simulated 4,000 meters, venous sickling remained elevated (7.2 +/- 7.8%) despite high levels of oxygen saturation. Arterial sickling (less than 1%) was present in only two subjects. There was no significant difference in oxygen consumption (29.4 +/- 3 versus 30.7 +/- 4 mL/kg/minute) between the subjects with SCT and the controls, nor was there a correlation between exercise performance and sickling (r less than 0.2). We conclude that exercise at 1,270 meters slightly, albeit significantly, increased sickling in blood from an exercising limb and that simulated 4,000 meters dramatically potentiated this effect. Sickling in the effluent blood of an exercising limb does not appear to measurably affect overall maximal arm crank exercise performance.