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- Elam, Cecilia, et al.
(författare)
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Effects of age on muscle power, postural control and functional capacity after short-term immobilization and retraining.
- 2022
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Ingår i: Journal of musculoskeletal & neuronal interactions. - 1108-7161. ; 22:4, s. 486-497
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated the effect of lower limb immobilization and retraining on postural control and muscle power in healthy old and young men.Twenty men, nine old (OM:67.3±4.4 years) and eleven young (YM:24.4±1.6 years) underwent 2 weeks of unilateral whole-leg casting, followed by 4 weeks of retraining. Measures included center of pressure (CoP) sway length and area during single- and double-leg stance, maximal leg extensor muscle power, habitual and maximal 10-m gait speed, sit-to-stand performance, and 2-min step test.After immobilization, leg extension muscle power decreased by 15% in OM (from 2.68±0.60 to 2.29±0.63 W/kg, p<0.05) and 17% in YM (4.37±0.76 to 3.63±0.69 W/kg, p<0.05). Double-leg CoP sway area increased by 45% in OM (218±82 to 317±145 mm2; p<0.05), with no change in YM (p=0.43). Physical function did not change after immobilization but sit-to-stand performance (+20%, p<0.05) and 2-min step test (+28%, p<0.05) increased in OM following retraining. In both groups, all parameters returned to baseline levels after retraining.Two weeks of lower limb immobilization led to decreases in maximal muscle power in both young and old, whereas postural control was impaired selectively in old men. All parameters were restored in both groups after 4 weeks of resistance-based retraining.
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| 2. |
- Williams, Jonathan A., et al.
(författare)
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Time course changes to structural, mechanical and material properties of bone in rats after complete spinal cord injury
- 2022
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Ingår i: Journal of Musculoskeletal Neuronal Interactions. - 1108-7161. ; 22:2, s. 212-234
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Characterise the spatiotemporal trabecular and cortical bone responses to complete spinal cord injury (SCI) in young rats. Methods: 8-week-old male Wistar rats received T9-transection SCI and were euthanised 2-, 6-, 10-or 16-weeks post-surgery. Outcome measures were assessed using micro-computed tomography, mechanical testing, serum markers and Fourier-transform infrared spectroscopy. Results: The trabecular and cortical bone responses to SCI are site-specific. Metaphyseal trabecular BV/TV was 59% lower, characterised by fewer and thinner trabeculae at 2-weeks post-SCI, while epiphyseal BV/TV was 23% lower with maintained connectivity. At later-time points, metaphyseal BV/TV remained unchanged, while epiphyseal BV/TV increased. The total area of metaphyseal and mid-diaphyseal cortical bone were lower from 2-weeks and between 6-and 10-weeks post-SCI, respectively. This suggested that SCI-induced bone changes observed in the rat model were not solely attributable to bone loss, but also to suppressed bone growth. No tissue mineral density differences were observed at any time-point, suggesting that decreased whole-bone mechanical properties were primarily the result of changes to the spatial distribution of bone. Conclusion: Young SCI rat trabecular bone changes resemble those observed clinically in adult and paediatric SCI, while cortical bone changes resemble paediatric SCI only.
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