Mehrsheed Sinaki

Stronger Back Muscles Reduce the Incidence of Vertebral Fractures: A Prospective 10 Year Follow-up of Postmenopausal Women

The long-term protective effect of stronger back muscles on the spine was determined in 50 healthy white postmenopausal women, aged 58-75 years, 8 years after they had completed a 2 year randomized, controlled trial. Twenty-seven subjects had performed progressive, resistive back-strengthening exercises for 2 years and 23 had served as controls. Bone mineral density, spine radiographs, back extensor strength, biochemical marker values, and level of physical activity were obtained for all subjects at baseline, 2 years, and 10 years. Mean back extensor strength (BES) in the back-exercise (BE) group was 39.4 kg at baseline, 66.8 kg at 2 years (after 2 years of prescribed exercises), and 32.9 kg at 10 years (8 years after cessation of the prescribed exercises). Mean BES in the control (C) group was 36.9 kg at baseline, 49.0 kg at 2 years, and 26.9 kg at 10 years. The difference between the two groups was still statistically significant at 10 year follow-up (p = 0.001). The difference in bone mineral density, which was not significant between the two groups at baseline and 2 year follow-up, was significant at 10 year follow-up (p = 0.0004). The incidence of vertebral compression fracture was 14 fractures in 322 vertebral bodies examined (4.3%) in the C group and 6 fractures in 378 vertebral bodies examined (1.6%) in the BE group (chi-square test, p = 0.0290). The relative risk for compression fracture was 2.7 times greater in the C group than in the BE group. To our knowledge, this is the first study reported in the literature demonstrating the long-term effect of strong back muscles on the reduction of vertebral fractures in estrogen-deficient women.

Relationship between bone mineral density of spine and strength of back extensors in healthy postmenopausal women

We determined the bone mineral density of the lumbar spine and the strength of back extensors in 68 healthy postmenopausal Caucasian women. Bone mineral density of the second to fourth lumbar vertebrae was measured by dual-photon absorptiometry, and back extensor strength was determined with use of a strain-gauge dynamometer. The bone mineral density percentile ranged from 2 to 99%, and back extensor strength ranged from 37 to 145 lb. Statistical analysis demonstrated a significant positive correlation (P = 0.004) between bone mineral density and back extensor strength, even when bone mineral density was corrected for age. Bone mineral density was also significantly positively correlated with body weight (P = 0.003), height (P = 0.001), and arm span (P = 0.008). These data suggest that the strength of back muscles may contribute to the bone mineral density of vertebral bodies.

Efficacy of Nonloading Exercises in Prevention of Vertebral Bone Loss in Postmenopausal Women: A Controlled Trial

A considerable increase in muscle strength and bone mass can be achieved in young adults through athletic exercise programs. We studied a less demanding nonloading exercise program for the back extensor muscles in postmenopausal women who were not on estrogen therapy. We randomly assigned 65 healthy Caucasian women without evidence of or risk factors for osteoporosis into an exercise group and a control group. The strength of the back extensor muscles and bone mineral density of the lumbar spine were measured at baseline and every 6 months for 2 years. In addition, a physical activity score was determined. Compliance was assessed by regular interviews and review of diaries. During the 2-year study, the mean rates of bone loss in the two groups were not statistically different. The strength of the back extensor muscles increased in both groups but significantly more ( P – 0.002) in the exercise group. We conclude that postmenopausal bone loss is unaffected by a modest exercise program despite an increase in muscle strength. Nonloading muscle exercise may be ineffective in retarding vertebral bone loss in ambulatory, healthy postmenopausal women.

Balance characteristics of persons with osteoporosis

OBJECTIVE People affected by osteoporosis are at particular risk for bone fractures caused by falls. Preventive intervention depends on first describing the risk factors for falls present in this population as a group and as individuals. In this preliminary study, balance characteristics of women with and without osteoporosis were measured with computerized dynamic posturography (CDP). DESIGN A case control design was selected to compare the balance characteristics of each group of patients with osteoporosis. SETTING Testing was performed in the vestibular assessment area of our multispecialty clinic. SUBJECTS Patient groups were selected from within our case load. Ten women with osteoporosis were compared with six women with osteoporosis and kyphosis (Cobb angle more than 54 degrees) and with five age-matched normal subjects. INTERVENTIONS Because this was an observational study, no interventions were used. MAIN OUTCOME MEASURE Averaged results from all trials of sensory organization tests 5 and 6, with use of sway amplitude and balance strategy scores, were used to compare the performance of each patient group. RESULTS Both groups with osteoporosis had different balance control strategies than the group without osteoporosis. Specifically, those with osteoporosis had greater use of hip strategies for maintaining balance than did the normal group. Those with kyphosis also had greater postural sway than either of the other two groups. CONCLUSION Results of this study suggest that there are differences in balance control strategies and sway amplitude between patients with and those without osteoporosis. Further study is recommended in which CDP is used to clarify and confirm these differences. Individual CDP results can be used to optimize habilitative management of these patients.

Correlation of back extensor strength with thoracic kyphosis and lumbar lordosis in estrogen-deficient women.

Aging and osteoporosis have been associated with skeletal changes. Back extensor strengthening exercises are highly recommended for management of back pain, especially back pain related to osteoporosis. To our knowledge, the correlation of thoracic kyphosis, lumbar lordosis, and sacral inclination with back extensor strength, physical activity, and bone mineral density has not been critically studied in healthy, active, estrogen-deficient women. In a study of 65 such women (ages 48-65 yr), back extensor strength, bone mineral density, and physical activity score were evaluated and measured. These factors were then correlated with radiographic factors: (1) vertebral body ratios (anterior/posterior height) calculated for each vertebra from T-4 through L-5; (2) kyphosis index determined by adding the anterior heights of each vertebral body, T-4 through T-12, and then dividing the total by the corresponding sum of the posterior heights of each vertebral body; (3) thoracic kyphosis; (4) lumbar lordosis; and (5) sacral inclination. Back extensor strength had a significant negative correlation with thoracic kyphosis (r = -0.30, P = 0.019) and a positive correlation with lumbar lordosis (r = 0.26, P = 0.048) and sacral inclination (r = 0.34, P = 0.009). However, bone mineral density and physical activity score did not show any significant correlations with the radiographic factors. The results indicate that the stronger the back extensor, the smaller the thoracic kyphosis and the larger the lumbar lordosis and sacral inclination. We conclude that back extensor strength is an important determinant of posture in healthy women. However, prescribing back extensor strengthening exercises alone may also increase lumbar lordosis, which is not desirable.

Significant reduction in risk of falls and back pain in osteoporotic-kyphotic women through a Spinal Proprioceptive Extension Exercise Dynamic (SPEED) program.

OBJECTIVE To determine the outcome of intervention with a spinal weighted kypho-orthosis (WKO) and a spinal proprioceptive extension exercise dynamic (SPEED) program on the risk of falls in ambulatory community-dwelling persons older than 60 years with osteoporosis-kyphosis at risk for falls. SUBJECTS AND METHODS The study had 3 stages. At stage 1 (baseline), the 12 women in the kyphotic group were compared with 13 healthy controls to assess the risk of falls and balance disorder in the kyphotic group. At stage 2, the 12 kyphotic women began the SPEED program with a WKO (2 supervised sessions in an outpatient clinic and a 4-week, daily home-based training program). At stage 3, baseline and follow-up data of the kyphotic group were compared to determine the effect of intervention. RESULTS At baseline, there were significant differences between the osteoporotic-kyphotic group and the control group in balance (P=.002), gait (P<.05), and strength (P<.05). After a 4-week intervention, comparison of the kyphotic groups baseline and follow-up results showed a significant change in balance (P=.003) and several gait parameters (P<.05). Mean back extensor strength improved significantly from baseline (144.0-46.5 N) to follow-up (198.6+/-55.2 N; P<.001). Lower extremity muscle strength was not changed significantly, except for improved left ankle plantar flexors (P=.02). Back pain decreased significantly (P=.001). CONCLUSION Balance, gait, and risk of falls improved significantly with the 4-week SPEED program.

Effect of Back-Strengthening Exercise on Posture in Healthy Women 49 to 65 Years of Age

OBJECTIVE To evaluate the effect of back-strengthening exercise on posture in 60 healthy estrogen-deficient women. DESIGN The 60 study subjects were randomly assigned to either an exercise or a control group, and various factors were assessed at time of enrollment in the study and at 2-year follow-up. MATERIAL AND METHODS The 32 women in the exercise group were instructed in progressive back-strengthening exercises, whereas the 28 women in the control group had no exercise prescription and were asked to continue their usual physical and dietary activities. At baseline and 2-year follow-up examinations, back extensor strength was measured with a strain-gauge dynamometer, and lateral roentgenograms of the thoracic and lumbar areas of the spine were obtained to measure the angles of thoracic kyphosis, lumbar lordosis, and sacral inclination. The changes in radiographic measurements and back extensor strength were analyzed statistically. RESULTS Back extensor strength increased significantly in both the exercise and the control groups, but no radiographic measurements were significantly different between these groups. The significant increase in back extensor strength in both groups of healthy women suggested that the original grouping did not accurately reflect the amount of exercise. Thus, the 60 subjects were reclassified for comparison on the basis of increase in back extensor strength--27 with more than or equal to the mean increase of 21.1 kg and 33 with less than 21.1 kg. Furthermore, each of these groups of subjects was subdivided on the basis of degree of thoracic kyphosis. Among the subjects with substantial thoracic kyphosis, those with a significant increase in back extensor strength had a significant decrease in thoracic kyphosis (-2.8 +/- 4.2 degrees; P = 0.041), whereas those with a small increase in strength had a nonsignificant increase in thoracic kyphosis (1.8 +/- 5.3 degrees). The increase in back extensor strength did not seem to affect mild degrees of kyphosis. CONCLUSION Increasing the back extensor strength in healthy estrogen-deficient women helps decrease thoracic kyphosis.

Effect of gender, age, and anthropometry on axial and appendicular muscle strength.

Sinaki M, Nwaogwugwu NC, Phillips BE, Mokri M: Effect of gender, age, and anthropometry on axial and appendicular muscle strength. Am J Phys Med Rehabil 2001;80:330–338. ObjectiveTo assess age and gender differences in muscle strength. DesignThe strength of back extensors, upper limbs (grip), and lower limbs (knee extensors) was measured. Anthropometric measurements and body mass index also were assessed. ResultsGroup comparisons were made for each decade. Back extensor strength (BES) in subjects aged 20 to 89 yr ranged from 93 to 832 N in men and from 71 to 440 N in women. BES peaked in the fourth decade for men and in the fifth decade for women. When the two genders were compared, muscle strength in women was less than that in men at all ages. At different decades, women’s BES ranged from 54% to 76% compared with that of men’s BES. There was a 64% loss of BES in men from the peak in their fourth decade (556 N) to the lowest level in their ninth decade (201 N). Women experienced a 50.4% loss from the peak in their fifth decade (306 N) to the lowest level in their ninth decade (152 N). ConclusionsMen had a greater loss of BES than women with increasing age. In both genders, there was more loss of BES than appendicular muscle strength. Reduction in BES in women coincided with increased body mass index in older age. In women, there was a negative correlation between body weight and level of physical activity, whereas this finding was not evident in men. Background factors related to a higher incidence of back pain, falls, and fractures, especially in women, may be a reduction in muscle strength, along with increasing age and body mass index. This cross-sectional study showed that physiologic reduction of muscle strength, which began early in life, later stopped and that muscle strength even improved, despite the aging process. Therefore, initiating strengthening exercises at any age is encouraged to prevent the impact of several age-related musculoskeletal challenges.

Muscle strength in Osteoporotic versus normal women

Strong back muscles contribute to good posture and skeletal support. Osteoporosis, being a metabolic bone disease, should not affect muscle strength. In this study we were interested in comparing the back extensor strength (BES) of osteoporotic and normal women. Fifty-five women ages 40–85 years who had a documented diagnosis of osteoporosis and were referred for initiation of proper exercise programs were included in our study after meeting the inclusion criteria. They all had evaluation of their posture, back and upper extremity strength, and physical activity score through our Rehabilitation of Osteoporosis Program -Exercise (ROPE). In addition, to avoid the interference of pain on application of maximal effort, we did not include subjects with acute back pain or those who experienced back pain with maximal effort during the testing trial. BES for osteoporotic women ranged from 16 to 65 lb (mean ± SD, 36.5±15.5) for ages 40–59 years, 9 to 55 lb (mean ± SD, 29.9±10.6) for ages 60–69 years, 6 to 52 lb (mean ± SD, 24.3±10.2) for ages 70–79 years, and 17 to 27 lb (mean ± SD, 21.2±4.2) for ages 80 years or older. Comparison of these data with the BES of 25 normal women, with statistical adjustment for age, demonstrated that the osteoporotic women had significantly lower BES than the normal women. A longitudinal study of a larger group of women would be of great interest for clarifying whether the weakness of back extensors precedes and, indeed, contributes to compression fractures of the spine.

Reducing the risk of falls through proprioceptive dynamic posture training in osteoporotic women with kyphotic posturing: A randomized pilot study

Sinaki M, Lynn SG: Reducing the risk of falls through proprioceptive dynamic posture training in osteoporotic women with kyphotic posturing: A randomized pilot study. Am J Phys Med Rehabil 2002;81:241–246. Objective To assess the effect of a proprioceptive dynamic posture training program on balance in osteoporotic women with kyphotic posture. Design Subjects were randomly assigned to either a proprioceptive dynamic posture training program or exercise only group. Anthropometric measurements, muscle strength, level of physical activity, computerized dynamic posturography, and spine radiography were performed at baseline and 1 mo. Results At the 1-mo follow-up, three groups were formed on the basis of the baseline computerized dynamic posturography results. In general, groups 1 and 2 had no significant change at 1 mo, whereas group 3 improved balance significantly at 1 mo. Conclusion The subjects who had abnormal balance and used the proprioceptive dynamic posture training program had the most significant improvement in balance. Improved balance could reduce the risk of falls.