Study design: Determination of differences in the cardiorespiratory responses of tetraplegic subjects with incomplete and complete lesions during treadmill gait and endurance exercise provided by neuromuscular electrical stimulation (NMES). Differences between rest and exercise phases were also examined. Objectives: To compare the cardiorespiratory responses in tetraplegic individuals during endurance exercise in the sitting position and treadmill gait with 30-50% body weight relief, both provided by NMES. Setting: Rehabilitation Ambulatory at University Hospital, Brazil. Methods: A total of 31 tetraplegic subjects were evaluated. Individuals were separated into two groups: gait group and endurance exercise group. In the gait group (n ¼ 17), the exercise protocol consisted of three different phases: 8 min of rest, 10 min of treadmill walking using NMES and 10 min of recovery. In the endurance exercise group (n ¼ 14), the cardiorespiratory test consisted of 8 min of rest, 15 min of quadriceps endurance exercise in the sitting position by NMES and 10 min of recovery. Oxygen uptake (VO 2 ), carbon dioxide production (VCO 2 ), respiratory exchange ratio (RER), pulmonary ventilation (V E ) and heart rate (HR) were measured. Results: All parameters increased considerably in the gait group from rest to the walking phase, although individuals with incomplete lesions presented a more pronounced increase than those with complete lesion. In the gait group, for incomplete tetraplegics, the mean VO 2 peak was 0.81670.314 l/min, corresponding to 11.4173.11 ml/kg/min; the mean value for VCO 2 was 0.66070.24 l/min, mean HR was 124.54728.72 bpm and mean V E was 28.3876.28 l/min. In the endurance exercise group, for incomplete tetraplegics, the mean VO 2 peak was 0.24670.07 l/ min, corresponding to 3.8470.92 ml/kg/min; the mean value for VCO 2 was 0.20570.06 l/min, mean HR was 71.45715.51 bpm and mean V E was 11.8372.72 l/min. In the endurance exercise group, smaller differences were observed in all variables from rest to the exercise phase, compared with the large increases observed in the gait group. Conclusions: These preliminary results have shown that gait training probably improves physical capacity in tetraplegic individuals more than the endurance exercise. www.nature.com/sc injured subjects, increases the ability to perform daily activities and reduces medical complications. Neuromuscular electrical stimulation (NMES) in spinal cord injured subjects allows the activation of paralyzed muscles through electrical stimulation of intact periphery motoneurons. 3 Thus, NMES has been used extensively in order to provide walking function 4 and to study the action of the spinal cord in the control of movement, using the concept of task-oriented training, which suggests that sensory input can produce the basic motor pattern. 5 Gait training on the treadmill provides a constant rate of movement and rhythm, which stimulates the reciprocal coordination of the lower limbs. 6 Moreover, NMES activates the large muscle mass, increases str...

Quadriplegic subjects present extensive muscle mass paralysis which is responsible for the dramatic decrease in bone mass, increasing the risk of bone fractures. There has been much effort to find an efficient treatment to prevent or reverse this significant bone loss. We used 21 male subjects, mean age 31.95 ± 8.01 years, with chronic quadriplegia, between C4 and C8, to evaluate the effect of treadmill gait training using neuromuscular electrical stimulation, with 30-50% weight relief, on bone mass, comparing individual dual-energy X-ray absorptiometry responses and biochemical markers of bone metabolism. Subjects were divided into gait (N = 11) and control (N = 10) groups. The gait group underwent gait training for 6 months, twice a week, for 20 min, while the control group did not perform gait. Bone mineral density (BMD) of lumbar spine, femoral neck, trochanteric area, and total femur, and biochemical markers (osteocalcin, bone alkaline phosphatase, pyridinoline, and deoxypyridinoline) were measured at the beginning of the study and 6 months later. In the gait group, 81.8% of the subjects presented a significant increase in bone formation and 66.7% also presented a significant decrease of bone resorption markers, whereas 30% of the controls did not present any change in markers and 20% presented an increase in bone formation. Marker results did not always agree with BMD data. Indeed, many individuals with increased bone formation presented a decrease in BMD. Most individuals in the gait group presented an increase in bone formation markers and a decrease in bone resorption markers, suggesting that gait training, even with 30-50% body weight support, was efficient in improving the bone mass of chronic quadriplegics. Correspondence

This work assessed the influence of treadmill gait training with neuromuscular electrical stimulation (NMES) on the metabolic and cardiorespiratory responses in quadriplegic subjects. The gait group (GG) (n=11) performed 6 months of treadmill training with 30-50% body weight support and with the help of physiotherapists, twice a week, allotting 20 min for each session. The control group (CG) (n=10), during the 6 months of training, did not perform any activity using NMES, performing instead conventional physiotherapy. Metabolic and cardiorespiratory responses (O(2) uptake [VO(2)], CO(2) production [VCO(2)], pulmonary ventilation (V(E)), heart rate [HR], and blood pressure [BP]) were measured on inclusion and after 6 months. For the GG, differences were found in all parameters after training (P<0.05), except for HR and diastolic BP. During gait, VO(2) (L/min) increased by 36%, VCO(2) (L/min) increased by 42.97%, V(E) (L/min) increased by 30.48%, and systolic BP (mm Hg) increased by 4.8%. For the CG, only VO(2) and VCO(2) (L/min) significantly increased at rest (30.82 and 16.39%, respectively) and during knee-extension exercise (26.29 and 17.37%, respectively). Treadmill gait with NMES was, therefore, more efficient toward increasing the aerobic capacity due to yielding higher metabolic and cardiovascular stresses.

Blood pressure pattern was analyzed in 12 complete quadriplegics with chronic lesions after three months of treadmill gait training. Before training, blood pressure values were obtained at rest, during treadmill walking and during the recovery phase. Gait training was performed for 20 min twice a week for three months. Treadmill gait was achieved using neuromuscular electrical stimulation, assisted by partial body weight relief (30-50%). After training, blood pressure was evaluated at rest, during gait and during recovery phase. Before and after training, mean systolic blood pressures and heart rates increased significantly during gait compared to rest (94.16 ± 5.15 to 105 ± 5.22 mmHg and 74.27 ± 10.09 to 106.23 ± 17.31 bpm, respectively), and blood pressure decreased significantly in the recovery phase (86.66 ± 9.84 and 57.5 ± 8.66 mmHg, respectively). After three months of training, systolic blood pressure became higher at rest (94.16 ± 5.15 mmHg before training and 100 ± 8.52 mmHg after training; P < 0.05) and during gait exercise (105 ± 5.22 mmHg before and 110 ± 7.38 mmHg after training; P < 0.05) when compared to the initial values, with no changes in heart rate. No changes occurred in blood pressure during the recovery phase, with the lower values being maintained. A drop in systolic pressure from 105 ± 5.22 to 86.66 ± 9.84 mmHg before training and from 110 ± 7.38 to 90 ± 7.38 mmHg after training was noticed immediately after exercise, thus resulting in hypotensive symptoms when chronic quadriplegics reach the sitting position from the upright position. CorrespondenceA. Cliquet Jr.