EVALUATION OF A TRAINING-PROGRAM FOR PERSONS WITH SCI PARAPLEGIA USING THE PARASTEP(R)1 AMBULATION SYSTEM .5. LOWER-EXTREMITY BLOOD-FLOW AND HYPEREMIC RESPONSES TO OCCLUSION ARE AUGMENTED BY AMBULATION TRAINING

Objective: To test whether 12 weeks of exercise conditioning using fun ctional neuromuscular stimulation (FNS) ambulation alters the resting lower extremity blood flow and hyperemic responses to vascular occlusi on in subjects with paraplegia, and to determine whether an associatio n exists between limb how and lower extremity fat-free mass. Design: P retest, posttest. Setting: Academic medical center. Participants: Subj ects with chronic neurologically complete paraplegia. Intervention: Th irty-two sessions of microprocessor-controlled ambulation using electr ically stimulated contractions of lower extremity muscles and a rollin g walker. Outcome Measures: Subjects underwent quantitative Doppler ul trasound examination of the common femoral artery (CFA) before and aft er training. End-diastolic arterial images and arterial flow-velocity profiles obtained at rest and after 5 minutes of suprasystolic thigh o cclusion were computer-digitized for analysis of heart rate (HR), CFA peak systolic velocity (PSV), CFA cross-sectional area (CSA), how velo city integral (FVI), pulse volume (PV), and CFA (arterial) inflow volu me (AIV). Results: Significant effects of training on CSA (p <.0001), FVI (p <.05), computed PV (p <.001), and computed AIV (p <.01) were ob served. Resting HR was lower following training (p <.05). The change f or resting PSV approached but did not reach significance (p =.083). An alysis of postocclusion PV and AN showed significant effects for condi tioning status (p values <.01), postcompression time (p values <.0001) , and their interaction (p values <.01). At 1 minute after occlusion, the posttraining AIV response was 78.2% greater in absolute magnitude and 17.4% more robust when expressed as a percentage change from its r esting value than before training. Significant correlations were found between thigh fat free mass and both AIV and PV (p values <.05). Conc lusion: Exercise training using PNS ambulation increases the resting l ower extremity AIV in individuals with paraplegia and augments the hyp eremic response to vascular occlusion. Improved posttraining blood how is attributable both to vascular structural changes and upregulation of vascular flow control mechanisms. Limb mass is associated with the volume of arterial blood flow. (C) 1997 by the American Congress of Re habilitation Medicine and the American Academy of Physical Medicine an d Rehabilitation.