The action of low-intensity pulsed ultrasound in bones of osteopenic rats

In this study, the action of low-intensity pulsed ultrasound for 20 min/day, during twenty days, was analyzed in an attempt to revert bone loss in the proximal femur of osteopenic rats. Although the quantitative results of bone mineral content (BMC) demonstrated no significant difference among the groups ( P > 0.05), the histologic investigations have shown the occurrence of recent bone formation not observed in the nontreated group. Moreover, the treated femur presented less microarchitectural deterioration than the nontreated group. These results suggest that the low-intensity ultrasound can interfere in a positive way on osteoporosis.28111411

Energy expenditure during rest and treadmill gait training in quadriplegic subjects

Study design: The analysis of oxygen uptake (VO2) and energy consumption in quadriplegics after 6 months of treadmill gait with neuromuscular electrical stimulation (NMES). Objectives: To compare metabolic responses in quadriplegics after 6 months of treadmill training, with NMES (30-50% body weight relief), with quadriplegics who did not perform gait. Setting: Ambulatory of University Hospital, Brazil. Methods: Quadriplegics were separated into gait and control groups (CGs). On inclusion, all subjects performed VO2 test. In the gait group (GG) (n = 11), the protocol consisted of 8 min of rest, 10 min of treadmill walking using NMES and 10 min of recovery. In the CG (n = 10), testing consisted of 8 min rest, 15 min of quadriceps endurance exercise in sitting position with NMES and 10 min recovery. VO2, carbon dioxide production (VCO2) and energy consumption were measured. The GG performed 6 months of treadmill training, using NMES, for 20 min, twice a week. The CG did not practice any activity with NMES, performing conventional physiotherapy only; the CG was stimulated only during the cardiorespiratory test. Results: All parameters increased significantly for the GG: 36% for VO2 (l/min), 43% for VCO2 (l/min) and 32.5% for energy consumption (J/kg/s). For the CG, during knee extension exercise, VO2 increased without changes in the energy consumption (P<0.05); smaller values were obtained for all parameters when compared to those obtained during gait. Conclusions: Quadriplegic gait was efficient towards increasing VO2 and energy consumption, which can decrease the risk of cardiovascular diseases.431165866

Metabolic and cardiorespiratory responses of tetraplegic subjects during treadmill walking using neuromuscular electrical stimulation and partial body weight support

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 = 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 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 (VO2), carbon dioxide production (VCO2), 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 VO2 peak was 0.81 +/- 70.314 l/ min, corresponding to 11.41 +/- 3.11 ml/kg/min; the mean value for VCO2 was 0.660 +/- 0.24 l/min, mean HR was 124.54 +/- 28.72 bpm and mean V-E was 28.38 +/- 6.28 l/min. In the endurance exercise group, for incomplete tetraplegics, the mean VO2 peak was 0.246 +/- 0.07 l/min, corresponding to 3.84 +/- 0.92 ml/kg/ min; the mean value for VCO2 was 0.205 +/- 0.06 l/min, mean HR was 71.45 +/- 15.51 bpm and mean V-E was 11.83 +/- 2.72 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.43740040

Ação da atividade física sobre as propriedades mecânicas dos fêmures e tíbias de ratas osteopênicas Effects of physical activity on the mechanical properties of osteopenic female rats' femurs and tibiae

Avaliamos as propriedades mecânicas, obtidas através de ensaios de flexo-compressão de fêmures e de flexão em 3 pontos de tíbias, de ratas adultas, ovariectomizadas e submetidas à atividade física. Foram utilizadas 30 ratas divididas em 3 grupos: G1: Controle. G2: Animais ovariectomizados e não submetidos a exercícios. G3: Foram treinados em uma gaiola giratória por cinco dias consecutivos, em seguida submetidos à ovariectomia, permanecendo em repouso por 24 horas. Exercitaram por 30 minutos, 5 dias por semana durante 9 semanas com velocidade de aproximadamente 0,31 m/s. Os valores obtidos de carga e de deformação evidenciaram que os fêmures das ratas ovariectomizadas apresentaram redução estatisticamente significativa nas propriedades mecânicas de carga e de deformação no limite máximo. Os fêmures do grupo ovariectomizado e submetido à prática de exercícios apresentaram valores de carga e de deformação no limite máximo superiores aos do grupo apenas ovariectomizado, no entanto, sem significância estatística. As tíbias não apresentaram alterações significativas em nenhuma das propriedades mecânicas estudadas. A atividade física aplicada por 30 minutos, 5 dias por semana durante 9 semanas a 0,31 m/s não foi suficiente para corrigir as alterações biomecânicas do tecido ósseo provocadas pela ovariectomia.<br>We evaluated the mechanical properties, obtained by means of flexion-compression assays in femurs and flexion assays on three tibial sites of ovariectomized adult female rats submitted to physical activity. Thirty rats were employed and divided into 3 groups: G1: Control. G2: Ovariectomized animals and not submitted to physical activity. G3: Animals trained in a spinning cage for five consecutive days, subsequently submitted to ovariectomy, and allowed to rest during 24 hours. The animals were submitted to physical activity for 30 minutes, 5 days a week, for a period of 9 weeks, at a speed of approximately 0.31 m/s. The values achieved for load and deformation evidenced that ovariectomized rats’ femurs presented with a statistically significant reduction on load and deformation mechanical properties, at the maximum limit. Femurs in the group submitted to ovariectomy and physical activity presented with load and deformation values at maximum limit superior to those for the group submitted only to ovariectomy, however, with no statistical significance. The tibiae didn’t present significant changes in any of the mechanical properties studied. Physical activity applied for 30 minutes, 5 days a week, during 9 weeks at 0.31 m/s was not enough to correct the biomechanical changes of bone tissue yielded by ovariectomy