No abstract

Bed rest and spaceflight reduce exercise fitness. Supine lower body negative pressure (LBNP) treadmill exercise provides integrated cardiovascular and musculoskeletal stimulation similar to that imposed by upright exercise in Earth gravity. We hypothesized that 40 min of supine exercise per day in a LBNP chamber at 1.0-1.2 body wt (58 +/- 2 mmHg LBNP) maintains aerobic fitness and sprint speed during 15 days of 6 degrees head-down bed rest (simulated microgravity). Seven male subjects underwent two such bed-rest studies in random order: one as a control study (no exercise) and one with daily supine LBNP treadmill exercise. After controlled bed-rest, time to exhaustion during an upright treadmill exercise test decreased 10%, peak oxygen consumption during the test decreased 14%, and sprint speed decreased 16% (all P < 0.05). Supine LBNP exercise during bed rest maintained all the above variables at pre-bed-rest levels. Our findings support further evaluation of LBNP exercise as a countermeasure against long-term microgravity-induced deconditioning.

This study compared the Functional Independence Measure (FIM) scores of traumatic (n=12) and vascular (n=12) unilateral lower limb amputees at admission and discharge from a rehabilitation facility. FIM scores that were measured were amputation FIM subscores and total FIM scores. Comorbidity indexes were developed to weight the stump condition and comorbidities seen in both groups. The vascular group was significantly (P<0.01) greater stump comorbidity, but there was no significant difference with respect to length of stay, medical comorbidity score, and amputation and total FIM scores both at admission and discharge between the two groups. Medical comorbidity was significantly (P<0.05) correlated with amputation and total FIM scores at discharge for traumatic amputees with r = -0.64 and r = -0.66, respectively. Stump comorbidity was significantly (P<0.05) correlated with total FIM at discharge with r = -0.64 for vascular amputees. Medical comorbidity was a good predictor of discharge FIM scores for traumatic amputees, whereas stump comorbidity predicted discharge FIM scores for vascular amputees, although not as well. In conclusion, inpatient traumatic amputees may be younger than vascular amputees, but traumatic amputees may not necessarily be healthier or do better functionally at discharge than vascular amputees.

This exercise countermeasure protocol may help prevent microgravity-induced deconditioning during long-duration space flight.