Biomedical subjects

Ilkka Vuori

Publications and source records attributed to Ilkka Vuori.

At least 19 recordsLinked to original sources

PubMed2006

Nationwide decline in incidence of hip fracture.

UNLABELLED: This epidemiologic study determined the trend in the number and incidence (per 100,000 persons) of hip fracture among older adults in Finland, an EU country with a well-defined white population of 5.2 million, between 1970 and 2004. The results show that the alarming rise in the fracture incidence from early 1970s until late 1990s has been now followed by declining fracture rates. Reasons for this are largely unknown, but a cohort effect toward a healthier aging population and increased average body weight and improved functional ability among elderly Finns could partly explain the phenomenon. INTRODUCTION: Although osteoporotic fractures of older adults are said to be a major public health concern in modern societies with aging populations, fresh nationwide information on their secular trends is limited. MATERIALS AND METHODS: This epidemiologic study determined the current trend in the number and incidence (per 100,000 persons) of hip fracture among older adults in Finland, an EU country with a well-defined white population of 5.2 million, by taking into account all persons >or= 50 years of age who were admitted to our hospitals for primary treatment of such fracture in 1970-2004. RESULTS: The number of hip fractures among >or= 50-year-old Finns rose very constantly between 1970 (1857 fractures) and 1997 (7122 fractures), but since then, the rise has leveled off (7083 fractures in 2004). After this and because of a continuous rise in population at risk, the crude incidence of hip fracture (showing a clear rise in 1970-1997) decreased between 1997 and 2004, from 438 (per 100,000 persons) in 1997 to 374 in 2004. Concerning the age-adjusted fracture incidence, findings were similar. Until 1997, the age-adjusted incidence of hip fracture clearly increased in both women and men, but thereafter, this incidence declined in both sexes: in women, from 494 in 1997 to 412 in 2004, and in men, from 238 in 1997 to 223 in 2004. CONCLUSIONS: The rise in the incidence of hip fracture in Finland from the early 1970s until the late 1990s has been followed by declining fracture rates. Exact reasons for this are unknown, but a cohort effect toward a healthier aging population and increased average body weight and improved functional ability among elderly Finns cannot be ruled out.

Aged↗

PubMed2006

[Not Available].

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Journal Article↗

PubMed2005

Blood leukocyte count is a risk factor for intima-media thickening and subclinical carotid atherosclerosis in middle-aged men.

Leukocytosis is known to predict future cardiovascular events even in subjects without coronary heart disease (CHD), but its association with early atherosclerotic changes has remained less certain. The aim of the present study was to investigate how the blood leukocyte count compares with several other risk factors for CHD in determining carotid artery intima-media thickness (IMT) and subclinical carotid atherosclerosis in a population sample. Both carotid arteries were investigated with high-resolution B-mode ultrasound in a community-based sample of 219 randomly selected men aged 50-59 years to calculate the mean maximum IMT (MMax IMT) of 12 standard sites. Risk factor assessment included several traditional biochemical risk factors, blood pressure, maximal oxygen consumption and work load on ergometry, life-style habits and hematologic parameters. As genetic determinants, apolipoprotein E and A-IV polymorphisms were studied. According to multivariate regression analysis, age (P<0.0001), blood leukocyte count (P<0.0001) and systolic blood pressure (P<0.042) were the only significant predictors of MMax IMT. MMax IMT increased linearly from the lowest tertile of blood leukocyte count (1.14+/-0.20mm) to the second (1.18+/-0.25 mm) and to the highest tertile (1.25+/-0.27 mm, P=0.019). This difference remained significant after adjustment with age, systolic blood pressure and smoking (P=0.032). Leukocytes seem to have an independent role in the early arterial damage and they may reflect subclinical disease. This implies that leukocyte count is undervalued in the diagnostics and prognostics of carotid atherosclerosis.

Analysis of Variance↗

PubMed2005

Impaired myocardial function in newly onset type 2 diabetes associates with arterial stiffness.

AIM: The aim of this study was to evaluate myocardial function using pulsed and color-coded tissue Doppler imaging (TDI) and vascular wall elasticity using whole-body impedance cardiography (ICG) in patients with newly diagnosed Type 2 diabetes mellitus (DM2), and to compare the measurements with those of healthy controls. METHODS: Systolic (SBP) and diastolic (DBP) blood pressure and glycosylated hemoglobin (HbA1c) were measured in 49 men (mean age 52.3+/-5.6 years, duration of DM2 1.8 years), and 15 healthy male control subjects (48.3+/-7.4 years). Mitral annular peak systolic (Svm), early (Evm), and late (Avm) diastolic velocities as well as myocardial peak systolic (Sv), early (Ev) and late diastolic (Av) velocity from middle segments of the anterior, inferior and lateral wall and the inferior septum were measured by TDI. ICG at rest was used to measure cardiac index (CI) and pulse wave velocity (PWV). RESULTS: The patients had higher body mass index (BMI 29.1+/-3.7 vs. 25.2+/-2.4 kg/m(2), p=0.000) and SBP (142+/-15 vs. 120+/-7 mmHg, p=0.005) than the controls, CI was comparable (2.8+/-0.5 vs. 2.8+/-0.6l/min/m(2)). The patients had lower age adjusted myocardial Sv (3.8+/-1.1 vs. 4.8+/-1.1cm/s, p=0.002) and Ev (4.6+/-1.6 vs. 6.2+/-1.7 cm/s, p=0.011), and also mitral annulus peak early diastolic velocity (Evm 7.8+/-1.9 vs. 10.4+/-2.6 cm/s, p=0.001). In diabetic patients PWV (14.2+/-2.7 vs. 10.0+/-1.7 m/s, p=0.002) was higher. Age (r=-0.39, p=0.001), BMI (r=-0.44, p=0.000) and PWV (r=-0.52, p=0.000) correlated significantly with Evm. PWV correlated with age (r=0.50, p=0.000), SBP (r=0.67, p=0.000), and HBA1c (r=0.36, p=0.010). In stepwise regression analysis, PWV (beta=-0.39, p=0.000) was the major determinant of Evm. CONCLUSION: Myocardial function is impaired in asymptomatic patients with newly detected DM2 consistent with diabetic heart muscle disease. Arterial stiffness is strongly related to myocardial dynamics, and both may have the same pathophysiologic background.

Analysis of Variance↗

PubMed2005

Serum TRACP 5b is a useful marker for monitoring alendronate treatment: comparison with other markers of bone turnover.

UNLABELLED: We studied clinical performance of serum TRACP 5b and other bone turnover markers, including S-CTX, U-DPD, S-PINP, S-BALP, and S-OC, for monitoring alendronate treatment. TRACP 5b had higher clinical sensitivity, area under the ROC curve, and signal-to-noise ratio than the other markers. INTRODUCTION: The purpose of this study was to compare the clinical performance of serum TRACP 5b (S-TRACP5b) with that of other markers of bone turnover in the monitoring of alendronate treatment. MATERIALS AND METHODS: This double-blinded study included 148 healthy postmenopausal women that were randomly assigned into two groups: one receiving 5 mg alendronate daily (n=75) and the other receiving placebo (n=73) for 12 months. All individuals in both groups received calcium and vitamin D daily. The bone resorption markers S-TRACP5b, serum C-terminal cross-linked telopeptides of type I collagen (S-CTX), and total urinary deoxypyridinoline (U-DPD), and the serum markers of bone formation procollagen I N-terminal propeptide (S-PINP), bone-specific alkaline phosphatase (S-BALP), and total osteocalcin (S-OC) were assessed at baseline and at 3, 6, and 12 months after initiation of treatment. Lumbar spine BMD (LBMD) was measured at baseline and 12 months. RESULTS: Compared with the placebo group, LBMD increased, and all bone markers decreased significantly more in the alendronate group (p<0.001 for each parameter). The decrease of S-TRACP5b after first 3 months of alendronate treatment correlated significantly with the changes of all other markers except S-OC, the best correlation being with S-CTX (r=0.60, p<0.0001). The changes of LBMD at 12 months only correlated significantly with the changes of S-TRACP5b (r=-0.32, p=0.005) and S-CTX (r=-0.24, p=0.037) at 3 months. Based on clinical sensitivity, receiver operating characteristic (ROC) curves, and signal-to-noise ratio, S-TRACP5b, S-CTX, and S-PINP were the best markers for monitoring alendronate treatment. Clinical sensitivity, area under the ROC curve, and signal-to-noise ratio were higher for S-TRACP5b than for the other markers. CONCLUSION: These results show that S-TRACP5b, S-CTX, and S-PINP are useful markers for monitoring alendronate treatment.

Acid Phosphatase↗

PubMed2004

The association of the apolipoprotein E gene promoter polymorphisms and haplotypes with serum lipid and lipoprotein concentrations.

BACKGROUND: Apolipoprotein E (ApoE) is known to modulate lipoprotein transport and metabolism. The common APOE epsilon2/epsilon3/epsilon4 polymorphism explains part of the variation in plasma cholesterol levels. Polymorphisms of the APOE gene regulatory region are suggested to be involved in explaining variation of lipoprotein levels within the APOE epsilon2/epsilon3/epsilon4 genotypes. OBJECTIVES: To study the associations of the APOE gene promoter polymorphisms -219G/T and +113G/C and their haplotypes with serum lipid and lipoprotein concentrations, especially within the most common APOE epsilon3/epsilon3 genotype group. SUBJECTS AND METHODS: From 219 middle-aged Finnish men, APOE genotypes were determined and haplotypes estimated. Plasma lipoproteins were isolated by ultracentrifugation and their lipids were measured. RESULTS: The studied APOE promoter polymorphisms and haplotypes associated with certain lipid variables independently of the APOE epsilon2/epsilon3/epsilon4 genotype. Within the APOE epsilon3/epsilon3 group, both -219G/G and +113G/G genotypes associated statistically significantly with higher levels of very low-density lipoprotein (VLDL) cholesterol, apoB and triglycerides, and tended to associate with lower HDL-cholesterol concentrations than the other genotypes. Compared with the -219T/+113C/epsilon3 haplotype, the more common -219G/+113G/epsilon3 haplotype was found more frequently among the group having high (over median) VLDL-cholesterol and triglyceride concentrations (OR 2.6, p<0.001 and OR=2.1, p=0.009, respectively). CONCLUSIONS: In addition to the APOE epsilon2/epsilon3/epsilon4 polymorphism, the promoter polymorphisms -219G/T and +113G/C as well as their haplotype modulate lipid and lipoprotein concentrations in middle-aged Finnish men.

Adult↗

PubMed2004

Characteristics of leisure time physical activity associated with risk of decline in perceived health--a 10-year follow-up of middle-aged and elderly men and women.

BACKGROUND: Leisure time physical activity (LTPA) has been found to prevent several diseases, but little is known about its protective effect against decline in perceived health. The purpose of the present study is to analyze the protective effect of LTPA against the risk of decline in perceived health in a cohort of 19- to 63-year-old Finnish men (n = 1205) and women (n = 1148) with good perceived health. METHODS: The incidence rate of decline in perceived health was monitored by self-administered questionnaire data from March 1980 through March 1985 through December 1990. LTPA was assessed by (1) a single-item self-assessment of global LTPA; (2) a compiled intensity-frequency measure of LTPA; (3) a total energy expenditure index of LTPA; and (4) three indexes of LTPA (i.e., commuting, fitness, and sport). The association between LTPA and risk of decline in perceived health was assessed using the Cox proportional hazard regression model. RESULTS: Among men, the multivariate analyses revealed an increased risk of decline in perceived health with no weekly vigorous global LTPA (RR = 1.49; 95% CI 1.12-1.98) and with no monthly sport activity (RR = 1.62; 95% CI 1.12-2.35). Among women, the results only showed an increased risk of decline in perceived health with fitness activity at less than once a week (RR = 1.62; 95% CI 1.06-2.48). The total energy expenditure of weekly LTPA and the index of commuting were not associated with the risk of decline in perceived health. CONCLUSIONS: Although energy expenditure of weekly LTPA did not prove to be a protective factor against the risk of decline in perceived health, global level, intensity, and type of weekly LTPA did. Physical activity interventions may need to emphasize the amount, intensity, and type of weekly LTPA, rather than energy expenditure of weekly LTPA, for promoting overall public health among middle-aged and older men and women with good perceived health.

Adult↗

PubMed2004

Determinants of changes in bone mass and femoral neck structure, and physical performance after menopause: a 9-year follow-up of initially peri-menopausal women.

This prospective study set out to determine factors that underlie changes in bone characteristics and physical performance during postmenopausal years. Of 101 peri-menopausal women that originally participated in a randomized, controlled exercise intervention trial, 80 attended the follow-up measurements 9 years later. At follow-up, bone mineral content (BMC) of the lumbar spine, femoral neck and distal radius, as well as the maximal isometric muscle strength of leg extensors and arm flexors, and maximal oxygen uptake, were measured with the same protocols and devices as at the baseline. In addition, the hip structure analysis (HSA) was used to assess changes in the structure and strength at the narrowest section of the femoral neck. Changes in physical fitness or bone characteristics were independent of the original exercise intervention. In general, physical fitness declined with age from 5% to 30% and bone characteristics from 3% to 10%, except for the lumbar spine BMC and the periosteal diameter of the femoral neck, where no changes were observed. The use of hormone therapy (HRT) was the major factor accounting for the maintenance of BMC. Use of HRT alone explained 44% of the variability in the change at the femoral neck BMC, but it was not associated with changes in physical fitness. Change in the body weight was the only factor associated with the change in physical fitness: better maintenance in body weight predicted better maintenance of physical fitness. In conclusion, our results indicate that HRT helps to maintain bone mass and structure, which are important factors in prevention of fragility fractures in later life. However, HRT had no effect on physical fitness, which is highly associated with the risk of falling, the most important cause of fractures.

Accidental Falls↗

PubMed2004

Effect of discontinuation of alendronate treatment and exercise on bone mass and physical fitness: 15-month follow-up of a randomized, controlled trial.

The purpose of this study was to evaluate the remaining effects of 12-month intervention of alendronate and exercise on selected risk factors of fragility fractures in 15-month follow-up after withdrawal of intervention among early postmenopausal women. The trial consisted four experimental groups: (1) 5 mg of alendronate daily + exercise (Al+Ex+), (2) 5 mg alendronate daily (Al+Ex-), (3) placebo + exercise (Al-Ex+), and (4) placebo (Al-Ex-). At the follow-up measurements, bone mass and physical fitness of 102 women (mean age 53.5 +/- 2.5 years) out of initial 150 subjects could be evaluated. Alendronate increased bone mass significantly [mean; 95% confidence interval (CI)] during the intervention at the lumbar spine (3.9%; 2.2% to 5.7%) and femoral neck (2.1%; 0.9% to 3.4%). After withdrawal of alendronate, bone loss resumed to the rate comparable to that evident in the placebo group. Despite the declining bone mass, the between-group mean difference (3.2%; 1.0% to 5.4%) remained at the lumbar spine. However, the benefits at the femoral neck had disappeared 15 months after the withdrawal of alendronate. The 12-month exercise training resulted in significant increases in muscle power, dynamic balance, and aerobic capacity with no benefits on bone mass. Fifteen months later, these performance variables had declined among both the exercisers and nonexercisers. Although the between-group differences were no longer statistically significant, muscle power, dynamic balance, and aerobic capacity of those who exercised still remained above the pretraining levels. In conclusion, 12-month treatment with alendronate prevented postmenopausal bone loss, and residual effect was seen 15 months after withdrawal of the drug at the lumbar spine. Similarly, exercise improved muscle power, agility, and aerobic capacity during the intervention, but the improvement was lost after the cessation of the exercise program. Based on these results, it was evident that to maintain the benefits of alendronate or exercise, therapy should be continued.

Alendronate↗

PubMed2004

Acute cardiovascular complications due to physical exercise in male teenagers.

Five sudden cardiac deaths in male adolescents (age 14-18 years) were detected in a 5-year period in Croatia. Two of them had been engaged in physical exercise at school, one as a professional soccer player, one in recreational swimming, and the fifth had just finished secondary school and was working at the site. All of them were autopsied and in three congenital cardiovascular diseases was found. Two had hypoplastic coronary arteries. The third had hypertrophic cardiomyopathy with interventricular wall of 40 mm. The fourth had normal heart findings including coronaries, but had bilateral pneumonia with a possible altitude (non-cardiogenic) pulmonary edema. The fifth had a chronic myopericarditis with an aneurysm of the left ventricle. All of them had not reported definite symptoms at exertion. According to this data, the death rate in adolescent males in Croatia during or after recreational physical exercise was 1/100,000 per year or 5/500,000 in five years. Thorough preparticipation medical examination including indicated laboratory tests and avoidance of heavy exertion at the time of respiratory infection might have helped to avoid some of the lethal events.

Adolescent↗

PubMed2003

The impact of somatic health problems on insomnia in middle age.

OBJECTIVE: The objective of this study is to assess the impact on insomnia symptoms of somatic diseases, psychological factors, living habits and life events during the previous year. BACKGROUND: Although health problems are a significant cause of insomnia, psychosocial factors are considered to be even more important. The relative impact of these and other factors on insomnia calls for further evaluation. METHODS: A questionnaire study in a randomly selected middle-aged population in Finland (N=626, 264 men and 362 women). RESULTS: In our study, 9.8% of men and 17.0% of women reported the occurrence of insomnia at least once a week during the previous 3 months. Insomniacs perceived their health as 'poor' or 'rather poor' more often than others and depression, allergic rhinitis, asthma, hypertension and heart symptoms such as arrhythmias were more common among them. Insomnia was not a side-effect of the treatment of these diseases; lack of medical treatment was associated with a higher incidence of insomnia. Work-related factors such as 'moving to a poorer job or to poorer working conditions' during the past year increased the possibility of insomnia, while moving house seemed to have a positive effect. When comparing these associations in logistic regression models, nervousness and tension were, however, the factors most significantly associated with insomnia. CONCLUSIONS: Psychosocial factors appeared to be more significantly associated with prolonged insomnia than somatic health problems.

Adult↗

PubMed2003

Effect of long-term impact-loading on mass, size, and estimated strength of humerus and radius of female racquet-sports players: a peripheral quantitative computed tomography study between young and old starters and controls.

Bone characteristics of the humeral shaft and distal radius were measured from 64 female tennis and squash players and their 27 age-, height-, and weight-matched controls with peripheral quantitative tomography (pQCT) and dual energy X-ray absorptiometry (DXA). The players were divided into two groups according to the starting age of their tennis or squash training (either before or after menarche) to examine the possible differences in the loading-induced changes in bone structure and volumetric density. The following pQCT variables were used: bone mineral content, total cross-sectional area of bone (TotA), cross-sectional area of the marrow cavity (CavA) and that of the cortical bone (CoA), cortical wall thickness (CWT), volumetric density of the cortical bone (CoD) and trabecular bone (TrD), and torsional bone strength index for the shaft (BSIt) and compressional bone strength index for the bone end (BSIc). These bone strength indices were compared with the DXA-derived areal bone mineral density (aBMD) to assess how well the latter represents the effect of mechanical loading on apparent bone strength. At the humeral shaft, the loaded arm's greater bone mineral content (an average 19% side-to-side difference in young starters and 9% in old starters), was caused by an enlarged cortex (CoA; side-to-side differences 20% and 9%, respectively). The loaded humerus seemed to have grown periosteally (the CavA did not differ between the sites), leading to 26% and 11% side-to-side BSIt differences in the young and old starters, respectively. CoD was equal between the arms (-1% difference in both player groups). The side-to-side differences in the young starters' bone mineral content, CoA, TotA, CWT, and BSIt were 8-22% higher than those of the controls and 8-14% higher than those of the old starters. Old starters' bone mineral content, CoA, and BSIt side-to-side differences were 6-7% greater than those in the controls. The DXA-derived side-to-side aBMD difference was 7% greater in young starters compared with that of the old starters and 14% compared with that in controls, whereas the difference between old starters and controls was 6%, in favor of the former. All these between-group differences were statistically significant. At the distal radius, the player groups differed significantly from controls in the side-to-side bone mineral content, TrD, and aBMD differences only: the young starters' bone mineral content difference was 9% greater, TrD and aBMD differences were 5% greater than those in the controls, and the old starters' TrD and aBMD differences were both 7% greater than those in the controls. In summary, in both of the female player groups, the structural adaptation of the humeral shaft to long-term loading seemed to be achieved through periosteal enlargement of the bone cortex, although this adaptation was clearly better in the young starters. Exercise-induced cortical enlargement was not so clear at the distal radius (a trabecular bone site), and the study suggested that at long bone ends, the trabecular density could be a modifiable factor to built a stronger bone structure. Conventional DXA-based aBMD measurement detected the intergroup differences in the exercise-induced bone gains, although, because it measured two dimensions of bone only, it seemed to underestimate the effect of exercise on the apparent bone strength, especially if the playing had been started during the growing years.

Adult↗

PubMed2003

Effect of 8-month vertical whole body vibration on bone, muscle performance, and body balance: a randomized controlled study.

Recent animal studies have given evidence that vibration loading may be an efficient and safe way to improve mass and mechanical competence of bone, thus providing great potential for preventing and treating osteoporosis. Randomized controlled trials on the safety and efficacy of the vibration on human skeleton are, however, lacking. This randomized controlled intervention trial was designed to assess the effects of an 8-month whole body vibration intervention on bone, muscular performance, and body balance in young and healthy adults. Fifty-six volunteers (21 men and 35 women; age, 19-38 years) were randomly assigned to the vibration group or control group. The vibration intervention consisted of an 8-month whole body vibration (4 min/day, 3-5 times per week). During the 4-minute vibration program, the platform oscillated in an ascending order from 25 to 45 Hz, corresponding to estimated maximum vertical accelerations from 2 g to 8 g. Mass, structure, and estimated strength of bone at the distal tibia and tibial shaft were assessed by peripheral quantitative computed tomography (pQCT) at baseline and at 8 months. Bone mineral content was measured at the lumbar spine, femoral neck, trochanter, calcaneus, and distal radius using DXA at baseline and after the 8-month intervention. Serum markers of bone turnover were determined at baseline and 3, 6, and 8 months. Five performance tests (vertical jump, isometric extension strength of the lower extremities, grip strength, shuttle run, and postural sway) were performed at baseline and after the 8-month intervention. The 8-month vibration intervention succeeded well and was safe to perform but had no effect on mass, structure, or estimated strength of bone at any skeletal site. Serum markers of bone turnover did not change during the vibration intervention. However, at 8 months, a 7.8% net benefit in the vertical jump height was observed in the vibration group (95% CI, 2.8-13.1%; p = 0.003). On the other performance and balance tests, the vibration intervention had no effect. In conclusion, the studied whole body vibration program had no effect on bones of young, healthy adults, but instead, increased vertical jump height. Future human studies are needed before clinical recommendations for vibration exercise.

Adult↗

PubMed2003

Exercise training improves baroreflex sensitivity in type 2 diabetes.

Type 2 diabetes is a strong risk factor for coronary heart disease and sudden cardiac death. It is associated with reduced baroreflex sensitivity (BRS) and heart rate variability (HRV), which are indicators of increased risk for mortality and morbidity in various patient populations. This study was designed to assess the effects of exercise training on BRS, HRV, and hemodynamics in patients with type 2 diabetes. Subjects (50 men, mean age 53.3 +/- 5.1 years) with type 2 diabetes were randomized into either a control group, in which they received conventional treatment only, or an exercise group, in which they received conventional treatment together with heart rate-controlled endurance training twice a week and supervised muscle strength training twice a week for 12 months. Measurements taken at baseline and follow-up included VO(2max), standard time and frequency domain measures of HRV during 24-h recording, and BRS by the phenylephrine method. Cardiac index, systemic vascular resistance index, stroke index, and pulse wave velocity were measured by whole-body impedance cardiography. Significant improvements in VO(2max) (exercise group: +2.3 ml x kg(-1) x min(-1); P < 0.005 vs. control group), muscle strength, and glycemic control (exercise group: HbA(1c) -0.9%; P < 0.001 vs. control group) were observed in the exercise group. BRS increased in the exercise group, from 6.8 to 8.6 ms/mmHg, and decreased in the control group, from 7.5 to 6.4 ms/mmHg (95% CI for the difference between 0.05 and 4.36 ms/mmHg; P < 0.05). No significant changes in the time or frequency domain measures of HRV or in systemic hemodynamics were observed. We concluded that exercise training improves BRS sensitivity in type 2 diabetes subjects in addition to increasing the exercise capacity and muscle strength and improving glucose control. These beneficial effects in reflectory autonomic regulation and glucose control caused by exercise may be associated with improved prognosis of type 2 diabetes patients.

Baroreflex↗

PubMed2002

Effect of a vibration exposure on muscular performance and body balance. Randomized cross-over study.

This randomized cross-over study was designed to investigate the effects of a 4-min vibration bout on muscle performance and body balance in young, healthy subjects. Sixteen volunteers (eight men, eight women, age 24-33 years) underwent both the 4-min vibration- and sham-interventions in a randomized order on different days. Six performance tests (stability platform, grip strength, isometric extension strength of lower extremities, tandem-walk, vertical jump and shuttle run) were performed 10 min before (baseline), and 2 and 60 min after the intervention. The effect of vibration on the surface electromyography (EMG) of soleus, gastrocnemius and vastus lateralis muscles was also investigated. The vibration-loading, based on a tilting platform, induced a transient (significant at the 2-min test) 2.5% net benefit in the jump height (P = 0.019), 3.2% benefit in the isometric extension strength of lower extremities (P=0.020) and 15.7% improvement in the body balance (P = 0.049). In the other 2-min or in the 60-min tests, there were no statistically significant differences between the vibration- and sham-interventions. Decreased mean power frequency in EMG of all muscles during the vibration indicated evolving muscle fatigue, while the root mean square voltage of EMG signal increased in calf muscles. We have shown in this study that a single bout of whole body vibration transiently improves muscle performance of lower extremities and body balance in young healthy adults.

Adult↗

PubMed2002

Effect of four-month vertical whole body vibration on performance and balance.

PURPOSE: This randomized controlled study was designed to investigate the effects of a 4-month whole body vibration-intervention on muscle performance and body balance in young, healthy, nonathletic adults. METHODS: Fifty-six volunteers (21 men and 35 women, aged 19-38 yr) were randomized to either the vibration group or control group. The vibration-intervention consisted of a 4-month whole body vibration training (4 min.d(-1), 3-5 times a week) employed by standing on a vertically vibrating platform. Five performance tests (vertical jump, isometric extension strength of the lower extremities, grip strength, shuttle run, and postural sway on a stability platform) were performed initially and at 2 and 4 months. RESULTS: Four-month vibration intervention induced an 8.5% (95% CI, 3.7-13.5%, P=0.001) net improvement in the jump height. Lower-limb extension strength increased after the 2-month vibration-intervention resulting in a 3.7% (95% CI, 0.3-7.2%, P=0.034) net benefit for the vibration. This benefit, however, diminished by the end of the 4-month intervention. In the grip strength, shuttle run, or balance tests, the vibration-intervention showed no effect. CONCLUSION: The 4-month whole body vibration-intervention enhanced jumping power in young adults, suggesting neuromuscular adaptation to the vibration stimulus. On the other hand, the vibration-intervention showed no effect on dynamic or static balance of the subjects. Future studies should focus on comparing the performance-enhancing effects of a whole body vibration to those of conventional resistance training and, as a broader objective, on investigating the possible effects of vibration on structure and strength of bones, and perhaps, incidence of falls of elderly people.

Adult↗

PubMed2002

Effect of long-term impact-loading on mass, size, and estimated strength of humerus and radius of female racquet-sports players: a peripheral quantitative computed tomography study between young and old starters and controls.

Bone characteristics of the humeral shaft and distal radius were measured from 64 female tennis and squash players and their 27 age-, height-, and weight-matched controls with peripheral quantitative tomography (pQCT) and DXA. The players were divided into two groups according to the starting age of their tennis or squash training (either before or after menarche) to examine the possible differences in the loading-induced changes in bone structure and volumetric density. The used pQCT variables were bone mineral content (BMC), total cross-sectional area (TotA) of bone, cross-sectional area of the marrow cavity (CavA) and that of the cortical bone (CoA), cortical wall thickness (CWT), volumetric density of the cortical bone (CoD) and trabecular bone (TrD), and torsional bone strength index (BSIt) for the shaft, and compressional bone strength index (BSIc) for the bone end. These bone strength indices were compared with the DXA-derived areal bone mineral density (aBMD) to assess how well the latter represents the effect of mechanical loading on apparent bone strength. At the humeral shaft, the loaded arm's greater BMC (an average 19% side-to-side difference in young starters and 9% in old starters) was caused by an enlarged cortex (CoA; side-to-side differences 20% and 9%, respectively). The loaded humerus seemed to have grown periosteally (the CavA did not differ between the sites) leading to 26% and 11% side-to-side BSIt difference in the young and old starters, respectively. CoD was equal between the arms (-1% difference in both player groups). The side-to-side differences in the young starters' BMC, CoA, TotA, CWT, and BSIt were 8-22% higher than those of the controls and 8-14% higher than those of the old starters. Old starters' BMC, CoA, and BSIt side-to-side differences were 6-7% greater than those in the controls. The DXA-derived side-to-side aBMD difference was 7% greater in young starters compared with that of the old starters and 14% compared with that in controls, whereas the difference between old starters and controls was 6%, in favor of the former. All these between-group differences were statistically significant. At the distal radius, the player groups differed significantly from controls in the side-to-side BMC, TrD, and aBMD differences only; the young starters' BMC difference was 9% greater, TrD and aBMD differences were 5% greater than those in the controls, and the old starters' TrD and aBMD differences were both 7% greater than those in the controls. In summary, in both of the female player groups the structural adaptation of the humeral shaft to long-term loading seemed to be achievedthrough periosteal enlargement of the bone cortex although this adaptation was clearly better in the young starters. Exercise-induced cortical enlargement was not so clear at the distal radius (a trabecular bone site), and the study suggested that at long bone ends also the TrD could be a modifiable factor to build a stronger bone structure. The conventional DXA-based aBMD measurement detected the intergroup differences in the exercise-induced bone gains, although, measuring two dimensions of bone only, it seemed to underestimate the effect of exercise on the apparent bone strength, especially if the playing had been started during the growing years.

Absorptiometry, Photon↗

PubMed2002

Associations of calcium intake and physical activity with bone density and size in premenopausal and postmenopausal women: a peripheral quantitative computed tomography study.

The purpose of this cross-sectional study was to examine the impact of long-term physical activity (PA) and calcium intake on non-weight-bearing radius and weight-bearing tibia. Altogether, 218 healthy, nonsmoking women, [92 premenopausal women, mean age, 32.6 years (SD, 2.2 years), and 126 postmenopausal women, mean age, 67.3 years (SD, 2.0 years)] participated. The subjects were divided according to their habitual levels of physical activity (PA+ or PA-) and calcium intake (Ca+ or Ca-). The distal end and shaft regions of the radius and tibia were evaluated with peripheral quantitative tomography (pQCT). For the shaft regions, bone mineral content (BMC), cortical cross-sectional area (CoA), cortical density (CoD), and bone strength index, that is, 1-11.9% of the density-weighted section modulus (BSI) were determined. For the distal ends, BMC, total cross-sectional area (ToA), trabecular density (TrD), and BSI were determined. The BMC at the distal radius in the young PA+ group was 6.6% (95% CI, 1- to 11.9%) lower than that of the PA- group. A similar nonsignificant trend was found for the radial shaft. The radial shaft showed a mechanically more competent structure among the older subjects with a BSI 8.5% (95% CI, 1.8-15.6%) higher in the older PA+ group than in the older PA- group. The associations between calcium intake and the radial bone characteristics were systematically positive in both age groups. PA seemed to benefit the distal tibia. In the younger age group the TrD was 6.9% (95% CI, 1.8-12.4%) higher in the PA+ group, and in the elderly the BMC was 5% (95% CI, 0.3-9.9%) higher in the PA+ group than in the PA- group. Note that in the younger age group the ToA was 5.1% (95% CI, 0-9.1%) smaller in the PA+ group than in the PA- group, and in the older age group the ToA was 4.2% (95% CI, -0.3-8.9%) greater in the PA+ group than in the PA- group. The association of PA and bone characteristics at the tibial shaft was positive in both age groups (statistically significant for the older subjects). The tibial shaft BSI of the older PA+ group was 8.6% (95% CI, 2.6-14.9%) better than that of the old PA- group. There was no association between calcium intake and the tibial bone characteristics in either age group. In conclusion, high calcium intake was positively associated with a mechanically competent structure in the radius among both younger and older women, whereas the influence of PA did not become apparent until older ages. PA seemed to benefit particularly the weight-bearing tibia, whereas calcium intake was not associated with the tibia.

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