Changes in gas exchange kinetics with training in patients with spinal cord injury

Barstow, Thomas J.; Scremin, A.M. Erika; Mutton, Deborah L.; Kunkel, Charles F.; Cagle, Thomas G.; Whipp, Brian J.

doi:10.1097/00005768-199610000-00003

Cited by 51 publications

(32 citation statements)

References 27 publications

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“…11 This is in contrast to other work in able-bodied subjects in which we utilized a 3-exponential model. 6,27 The reason for not applying a more complex exponential model to the current data lay in the frequently large breath-to-breath noise levels seen in these patients, which in our judgement precluded con®dent assessment of speci®c components of the Vo 2 response.…”

Section: Discussionmentioning

confidence: 93%

“…11 ± 14 Peak Vo 2 is also reduced 13 ± 15 and has been shown to be well correlated with the heart rate achieved. 11 We hypothesized that if the low maximum heart rate was a result of a fundamental alteration in regulation of heart rate in patients with SCI, then we would also expect to see a reduction in peak heart rate during arm exercise similar to that seen with FES leg cycling. This was not the case, however.…”

Section: Discussionmentioning

confidence: 99%

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Peak and kinetic cardiorespiratory responses during arm and leg exercise in patients with spinal cord injury

et al. 2000

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Study design: A paired comparison of the peak and submaximal responses of oxygen uptake and heart rate in patients with spinal cord injury (SCI) performing voluntary arm cycle exercise and functional electrical stimulation (FES) leg cycling exercise. Objectives: To test if the blunted heart rate response and slower rate of adjustment of oxygen uptake seen in patients with SCI performing FES leg cycle exercise are also characteristic of arm exercise in these patients. Methods: Eight paraplegics performed incremental and constant work rate (CWR) exercise with the legs and arms. Mean response times (MRT) for Vo 2 during exercise (on) and in recovery (o ) were calculated from the breath-by-breath Vo 2 pro®le. Results: Peak heart rate was higher during incremental arm exercise, and uncorrelated with that observed during incremental FES leg cycling. For the same increase in Vo 2 , constant work rate arm exercise was associated with faster (and normal) Vo 2 kinetics, greater increase in heart rate, and lower end-exercise blood lactate, compared to FES leg cycling. Conclusions: The consistently higher peak heart rate and Vo 2 , and faster Vo 2 kinetics, for voluntary arm compared to FES leg cycle exercise suggest no intrinsic dysfunction of heart rate control in these paraplegics. Rather, these data suggest that during FES leg cycling the changes seen are due to some characteristic speci®c to the injury, such as reduced muscle mass and/or deconditioning of the remaining muscle.

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Section: Discussionmentioning

confidence: 93%

Section: Discussionmentioning

confidence: 99%

Peak and kinetic cardiorespiratory responses during arm and leg exercise in patients with spinal cord injury

et al. 2000

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“…Interestingly, exercise training could bring about accelerated metabolic adjustment, ie, faster gas exchange kinetics, even in lesion muscles. 28 As well, inactivity, such as from bed-rest, in normal healthy subjects resulted in reduced exercise capacity and slower V . O 2 kinetics.…”

Section: Steadymentioning

confidence: 99%

Kinetics and steady-state of V̇O2 responses to arm exercise in trained spinal cord injury humans

et al. 2002

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Study design: Cross-sectional study comparing trained spinal cord injured (SCI) subjects (lesion level: L1*T6) with healthy young subjects (CONT). Objective: To investigate the kinetics of response in oxygen uptake (V . O 2 ) in human upperbody skeletal muscles, nine trained SCI subjects underwent submaximal supine arm exercises. Method: The SCI subjects underwent an incremental arm exercise test until exhaustion. The days after this ®rst round of testing, breath-by-breath V . O 2 and beat-by-beat heart rate (HR) on-and o -kinetics were determined during three repetitions of constant exercise at 50% of V . O 2peak . The overall time course of response was determined from the half time (t 1/2 ). Increased capillary blood lactate production (D[La]b) at the onset of exercise was de®ned as the di erence between at rest and at the end of exercise. Cardiac output (Q . ) was measured using the acetylene rebreathing method during the steady state of exercise. In accordance with the Fick principle, the di erence in arterial-venous O 2 content (Ca-v _ O 2 ) was de®ned as V . O 2 /Q . . Results: During the steady state of the submaximal arm exercise, a more signi®cant increase in the steady state of Q . was obtained in the CONT subjects than in the trained SCI subjects: respectively, 14.9+1.4 l/min versus (12.7+0.8 l/min). There was no di erence in the steady state of V . O 2 between the two groups; as a result, SCI subjects had the greater Ca-v _ O 2 . Meanwhile,V . O 2 on-and o -kinetics became much faster in the trained SCI subjects than in the CONT subjects. In addition, t 1/2 HR on-kinetics was not signi®cantly di erent between the SCI and CONT groups. Increased D[La]b was closely related to larger t 1/2 V . O 2 on-kinetics (r=0.624, P50.05). Conclusion: It is concluded that the acceleration of V . O 2 on-and o -kinetics in the trained SCI subjects was observed even though there was no di erence in HR on-and o -kinetics between the SCI and CONT groups and a lower steady state of Q . in the trained SCI subjects. V . O 2 kinetics would therefore be the limiting factor in oxidative phosphorylation in the upper skeletal muscles, thereby providing a lower lactic O 2 -de®cit (ie D[La]b).

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“…4,5 These changes may be associated with functional de®cits at the whole body level, including a reduced aerobic capacity, 6 prolonged exercise gas-exchange kinetics, 7 and reduced insulin-mediated glucose utilization. 5 Functional electrical stimulated (FES) cycle ergometer training has been used to improve some of these whole-body parameters, including maximal oxygen uptake, 8,9 gas-exchange kinetics, 8 and submaximal exercise endurance time 9,10 in individuals with SCI. In healthy individuals, dierences in these measures of exercise peformance have been attributed to dierences in muscle characteristics.…”

Section: Introductionmentioning

confidence: 99%

Histochemical changes in muscle of individuals with spinal cord injury following functional electrical stimulated exercise training

et al. 1999

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Study Design: Longitudinal training. Objectives: To determine the eects of functional electrical stimulated (FES) leg cycle ergometer training on muscle histochemical characteristics in individuals with motor-complete spinal cord injury (SCI). Setting: University of Alberta, Edmonton, Alberta, Canada. Methods: Six individuals with motor-complete SCI (age 31 ± 50 years; 3 ± 25 years postinjury) trained using FES leg cycle ergometry for 30 min, 3 days per week for 8 weeks. Biopsies of the vastus lateralis muscle were obtained pre-and post-training and analyzed for ®bre composition, ®bre size and capillarization. Results: The majority of muscle ®bres were classi®ed as type 2 pre-and post-training. Average ®bre area increased 23% (P50.05) and capillary number increased 39% (P50.05) with training. As a result of these proportional increases, capillarization expressed relative to ®bre area was unchanged with training. Conclusions: FES leg cycle ergometer training results in proportional increases in ®bre area and capillary number in individuals with SCI. Sponsorship: Supported by the Glenrose Rehabilitation Hospital.

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Changes in gas exchange kinetics with training in patients with spinal cord injury

Cited by 51 publications

References 27 publications

Peak and kinetic cardiorespiratory responses during arm and leg exercise in patients with spinal cord injury

Peak and kinetic cardiorespiratory responses during arm and leg exercise in patients with spinal cord injury

Kinetics and steady-state of V̇O2 responses to arm exercise in trained spinal cord injury humans

Histochemical changes in muscle of individuals with spinal cord injury following functional electrical stimulated exercise training

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