Inspiratory muscle dysfunction in patients with severe obstructive sleep apnoea.

Repetitive inspiratory effort against an obstructed airway and intermittent hypoxia may be deleterious to the inspiratory muscles in patients with obstructive sleep apnoea (OSA). We investigated muscular dysfunction by comparing the strength, endurance and fatigability of inspiratory muscles and knee extensors in patients with newly diagnosed severe OSA compared with matched controls. The measurements included strength and endurance tests of both muscles, and a fatigue trial with simultaneous surface electromyography of the diaphragm and the vastus lateralis during voluntary contractions and in response to magnetic stimulation. To our knowledge, this is the first investigation to assess peripheral muscle performance in severe OSA patients versus controls. Patients in the OSA group exhibited significantly lower strength and endurance in both muscles than the control group. The fatigue index decreased significantly exclusively in the inspiratory muscles of OSA patients. Magnetic stimulation-evoked compound muscle action potential latencies increased and the amplitudes decreased significantly in the diaphragm, but not in the vastus lateralis after a fatigue test in the OSA group. In conclusion, a significantly lower functional performance was shown for both inspiratory muscles and knee extensors in the OSA group. However, higher fatigability was only seen in the inspiratory muscles of patients with severe OSA.

Physical activity, physical fitness, and osteopenia in postmenopausal Taiwanese women.

BACKGROUND AND PURPOSE: The purpose of this cross-sectional study was to investigate whether physical activity level and physical fitness parameters differ between postmenopausal Taiwanese women with normal and subnormal bone mineral density (BMD). METHODS: Seventy-six postmenopausal women aged from 42 to 65 years participated in this study. Women taking medication that might influence BMD measurements were not included. The BMDs of the lumbar spine (L2-4) and right femoral neck were measured using dual energy x-ray absorptiometry. Thirty-one women with both BMD values within the normal ranges (1.055 +/- 0.092 g/cm2 for the spine and 0.845 +/- 0.088 g/cm2 for the right femoral neck) of premenopausal Chinese women served as the normal density group. Another 43 women with both BMD values more than one standard deviation below the normal value (0.760 +/- 0.089 g/cm2 for the spine and 0.656 +/- 0.052 g/cm2 for the femoral neck) were recruited as the osteopenic group. Physical activity level was assessed with a 7-day recall questionnaire. Physical fitness assessment included tests of flexibility, muscular strength, endurance, body composition, and cardiopulmonary fitness. A multiple linear regression model adjusted for age, body weight, height, and years since menopause was used. RESULTS: The results revealed that energy expenditure and maximal oxygen consumption were significantly lower in the osteopenic group than in the non-osteopenic group (p < 0.05), while flexibility, body composition, muscle strength and muscular endurance did not differ significantly between the two groups (p > 0.05). CONCLUSIONS: These findings indicate that physical activity may play a major role in BMD levels in postmenopausal women in Taiwan. Future studies should emphasize the effect of physical exercise training on BMD in postmenopausal women.

Home-based trunk-strengthening exercise for osteoporotic and osteopenic postmenopausal women without fracture--a pilot study.

OBJECTIVES: To investigate whether a 12-week home-based programme of trunk-strengthening exercise could benefit spinal mobility, function and quality of life for osteoporotic and osteopenic postmenopausal women without fracture. DESIGNS: Randomized controlled clinical trial. SETTING: Department of Physical Therapy in National Taiwan University Hospital. SUBJECTS: Twenty-eight postmenopausal women (mean age 60.3+/-9.3 years) diagnosed with osteoporosis or osteopenia without fracture history were recruited for this study. Subjects were randomly assigned into exercise or control groups, each consisting of 14 subjects. INTERVENTIONS: The 12-week exercise programme included strengthening routines for the trunk extensor and flexor muscles. The subjects performed three sets of 10 repetitions for each of the exercises, with programmes carried out three times per day at home. MAIN OUTCOME MEASUREMENTS: Muscular strength, spinal range of motion (ROM) and motion velocity, Oswestry Disability Questionnaire (ODQ) and quality of life (QOL) were measured before the start and after completion of the exercise programme. RESULTS: Statistically significant improvements were demonstrated in spinal ROM and motion velocity in the sagittal and frontal planes for the exercise group (p<0.05). Further, the strength of the trunk flexors and extensors increased after exercise training (p<0.05). ODQ measure was significantly reduced in the exercise group (p<0.05), while the controls showed no significant change. Subjects in the exercise group showed better satisfaction in some domains of the Short-Form-36 Health Survey quality of life questionnaire (p<0.05). CONCLUSIONS: This 12-week home-based trunk-strengthening exercise programme could improve trunk mobility and strength, and enhance QOL in osteoporotic and osteopenic postmenopausal women without vertebral fracture. Future study should recruit more cases or more severe subjects to verify the results.

Spinal performance and functional impairment in postmenopausal women with osteoporosis and osteopenia without vertebral fracture.

Previous studies have paid much attention to the impact on functional impairment or quality of life from vertebral fractures secondary to osteoporosis, but little research has addressed the function of osteoporotic women without fractures. The purposes of this study were: (1) to describe spinal performance and functional impairment in postmenopausal women with osteoporosis and osteopenia without vertebral fracture, and (2) to investigate the relationship between them. Thirty postmenopausal women diagnosed as having osteoporosis or osteopenia were recruited who fulfilled the following criteria: (1) menopause for at least 6 months; (2) no vertebral fracture; (3) no medication that would interfere with calcium intake. Measurements included assessment of functional impairment and spinal performance including trunk extension/flexion isokinetic strength, spinal range of motion (ROM) and movement velocity in three planes (sagittal, frontal and transverse). The results showed that spinal ROM and velocity were significantly reduced in the osteoporosis group compared with the osteopenia group ( p<0.05), but no significant difference in trunk strength was shown. Functional impairment level showed a slight difference between the two groups ( p = 0.042). There was a significant correlation between spinal ROM and motion velocity with bone mineral density; however, functional impairment correlated with motion velocity only in the transverse plane (trunk rotation) ( p<0.05). Spinal strength did not show any correlation with other parameters. It was concluded that spinal motion performance declined and functional impairment increased in relation to the severity of bone mineral loss in postmenopausal women without vertebral fracture, but their physical performance was not correlated with functional impairments.

Efficacy of a 24-week aerobic exercise program for osteopenic postmenopausal women.

Osteoporosis is one of the most common skeletal disorders affecting postmenopausal women. The purpose of this study was to investigate whether a 24-week program of aerobic high-impact loading exercise was beneficial for enhancing physical fitness and bone mineral density (BMD) in osteopenic postmenopausal women. Forty-three postmenopausal women aged 48-65 years participated in this study. The BMD of the spine (L2-L4) and right femoral neck of each woman was below 1 SD of the mean of premenopausal women, as examined by dual X-ray absorptiometry. The assignment of subjects into exercise or control group was not randomized but based on each subject's anticipated compliance to the 6-month long exercise program. Twenty-two subjects joined the exercise group and attended the training programs and 21 served as the control group. Exercise programs included treadmill walking at an intensity above 70% of maximal oxygen consumption (VO2max) for 30 minutes, followed by 10 minutes of stepping exercise using a 20-cm-high bench. The program was conducted three times per week for 24 weeks. Physical fitness measurements included testing of flexibility, muscular strength and endurance, body composition, and cardiopulmonary fitness. The results showed that the quadriceps strength, muscular endurance, and VO2max in the exercise group had significant improvements, whereas no improvement was found in any of the physical fitness parameters in the control group. The BMD of the L2-L4 and the femoral neck in the exercise group increased 2.0% (P > 0.05) and 6.8% (P < 0.05) and those in the control group decreased 2.3% (P < 0.05) and 1.5% (P > 0.05), respectively. In conclusion, aerobics combined with high-impact exercise at a moderate intensity was effective in offsetting the decline in BMD in osteopenic postmenopausal women.