Pamela J. Barrett

The cardiovascular capacities of adults with Down syndrome: a comparative study

The purpose of this study was to compare the cardiovascular capacities of individuals with Down syndrome (DS) to individuals without Down syndrome who are mentally retarded. Sixteen young adults with DS and 16 individuals without DS (12 males and 4 females, respectively), all with mild/moderate mental retardation, participated in this study. Peak VO2 (absolute and relative), VE (1.min-1), heart rate (HR, b.min-1), and RER (VCO2/VO2) were determined by exercise tests utilizing a treadmill (TM) and Schwinn Air-Dyne ergometer (SAE). The best test result was chosen from the TM and SAE tests and used for statistical comparisons. Cardiac output (Q, 1.min-1) was measured while standing quietly and while walking at 3 mph, 0% grade, using the CO2 rebreathing method for 11 (9 males and 2 females) subjects from each group. Arteriovenous oxygen differences (a-v O2), cardiac index (QI), and stroke volume (SV) were calculated from VO2, Q, HR, and body surface area. Peripheral vascular resistance (PVR), left ventricular work index (LVWI), and left ventricular stroke work index (LVSWI) were calculated from mean arterial pressure, Q, QI, and stroke volume index. Results showed that individuals without DS had statistically significant (P less than 0.01) higher mean peak VO2 (35.6 vs 24.6 ml.kg-1.min-1; 2567 vs 1683 ml.min-1), VE (89.3 vs 59.2 1/min-1), and HR (179 vs 159 b.min-1) than individuals with DS, respectively. No differences in RER were seen between the groups. No differences were seen in cardiovascular parameters measured while quietly standing.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of lower body positive pressure on the exercise capacity of individuals with spinal cord injury.

The purpose of this study was to determine the effect lower body positive pressure (LBPP) has on the cardiovascular/exercise capacities of individuals with spinal cord injury (SCI) during both arm crank exercise (ACE) and wheelchair exercise performed on a treadmill (WCTM). Ten male adults (age = 31.1 +/- 10 yr) with SCI and five male nondisabled (ND) adults (31.2 +/- 10 yr) participated in this study. The ND subjects performed ACE only. For subjects with SCI, significantly higher (P < 0.025) peak VO2 (1042 +/- 212 vs 839 +/- 218 ml.min-1), peak VE (46 +/- 17 vs 35 +/- 9 l.min-1), and work rate (50 +/- 15 vs 40 +/- 13 W) were seen during ACE with LBPP. No significant differences for peak VO2, VE, or work rate were seen for the ND subjects with LBPP during ACE. In addition, significantly higher peak VO2 (960 +/- 322 vs 828 +/- 312 ml.min-1) was recorded with LBPP for the subjects with SCI during WCTM. Cardiac output (Q, l.min-1; CO2 rebreathing method) was measured at 50% peak VO2 for both ND subjects and subjects with SCI during ACE. Subjects with SCI demonstrated significantly higher SV (94 +/- 20 vs 84 +/- 20 ml) with LBPP. No differences were observed in SV at 50% peak VO2 during ACE for the ND subjects with LBPP. The results of this study suggest that for individuals with SCI, LBPP augments exercise capacity by preventing the redistribution of blood to the lower extremities.

Endurance exercise training in Guillain-Barre Syndrome

The purpose of this case study was to determine whether an individual who had residual deficits following an acute incidence of Guillain-Barre Syndrome (GBS) would experience improved physiological adaptations following aerobic endurance training. A 57-year-old man who needed the aid of a crutch for walking three years following an acute bout of GBS participated in this study. Peak work level (watts), oxygen consumption (VO2 mL/min; mL/kg.min), and ventilation (VE, L/min) were determined on a bicycle ergometer (BE), a Schwinn Air-Dyne ergometer (SAE), and an arm crank ergometer (ACE) before and after exercise training. Isokinetic leg strength measured using a dynamometer and total work capacity in watts using BE were also determined before and after training. The subject trained for 16 weeks at an approximate frequency of 3 days/week, an average duration of 30 minutes, and an average intensity of 75% to 80% of pretraining peak HR. A 9% and 11% improvement was seen in peak oxygen consumption for the SAE and BE, respectively. For peak ventilation, a 23% and 11% improvement was seen for the SAE and BE, respectively. For the ACE, a 16% increase in peak ventilation was seen, with no improvement in aerobic capacity. Total work capacity on the BE was improved by 29% following training. Positive improvements were also seen in isokinetic leg strength. This study demonstrated that a man still suffering residual symptoms following an incidence of GBS was able to improve his cardiopulmonary and work capacity and isokinetic strength of his legs following a supervised training program using the SAE. The subject also reported improvements in activities of daily living.

Duurtraining bij patiënten met het syndroom van Guillain Barré

Deze casus betreft een patient met restsymptomen na acute verschijnselen van het syndroom van Guillain Barre. Het doel van deze beschrijving was, na te gaan of de patient, na een periode van aerobe duurtraining, tekenen vertoont van een verbeterde fysiologische adaptatie.