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Biomedical subjects

A Heinonen

Publications and source records attributed to A Heinonen.

At least 19 recordsLinked to original sources
PubMed2006

A multi-component exercise regimen to prevent functional decline and bone fragility in home-dwelling elderly women: randomized, controlled trial.

SUMMARY: This study showed that combination of strength, balance, agility and jumping training prevented functional decline and bone fragility in home-dwelling elderly women. The finding supports the idea that it is possible to maintain good physical functioning by multi-component exercise program and thus postpone the age-related functional problems. INTRODUCTION: This 1-year randomized, controlled exercise intervention trial assessed the effects of two different training programs and their combination on physical functioning and bone in home-dwelling elderly women. METHODS: One hundred and forty-nine healthy women aged 70-78 years were randomly assigned into: group 1-resistance training (RES), group 2-balance-jumping training (BAL), group 3-combination of resistance and balance-jumping training (COMB), and group 4-controls (CON). Self-rated physical functioning, leg extensor force, dynamic balance, and bone mass and structure were measured. RESULTS: Self-rated physical functioning improved in the COMB group, but was reduced in the CON group; the mean inter-group difference was 10% (95% CI: 0-22%). Mean increase in the leg extensor force was higher in the RES (14%; 4-25%) and COMB (13%; 3-25%) compared with the CON groups. Dynamic balance improved in the BAL (6%; 1-11%) and in the COMB (8%; 3-12%) groups. There were no inter-group differences in BMC at the proximal femur. In those COMB women who trained at least twice a week, the tibial shaft structure weakened 2% (0-4%) less than those in the CON group. CONCLUSIONS: Strength, balance, agility, and jumping training (especially in combination) prevented functional decline in home-dwelling elderly women. In addition, positive effects seen in the structure of the loaded tibia indicated that exercise may also play a role in preventing bone fragility.

Activities of Daily Living↗
PubMed2006

Long-term recreational gymnastics provides a clear benefit in age-related functional decline and bone loss. A prospective 6-year study.

INTRODUCTION: Bone fragility and decreased functional performance are risk factors for osteoporotic fractures. The influence of long-term recreational gymnastics on the maintenance of bone rigidity and physical performance was evaluated. METHODS: One hundred and seven gymnasts and 110 referents (93% of the original sample) participated in this 6-year prospective study. Analysis of covariance (ANCOVA) was used to estimate the between-group differences and changes by time, and regression analyses to find predictors for changes. RESULTS: In both groups agility and leg extensor power decreased by over 3% and 10%, respectively, but the original between-group differences, favoring the gymnasts, persisted. Proximal femur bone mineral content (BMC) decreased approximately 0.5% per year in both groups, and femoral neck section modulus decreased. Trabecular density of the distal tibia declined only marginally, and cortical area of the tibial midshaft remained unchanged, while cortical density decreased about 2% in both groups. After adjustment by age, height, weight, change in weight, and follow-up time, antiresorptive medication and high calcium intake accounted most for the maintenance of bone rigidity. CONCLUSIONS: In spite of similar rates of decline in bone characteristics and physical performance, the recreational gymnasts' overall physical condition was comparable to the level that their less active referents had shown approximately 5 years earlier.

Aged↗
PubMed2005

Ground reaction forces associated with an effective elementary school based jumping intervention.

BACKGROUND: Mechanical loading during childhood plays a critical role in normal growth and development of the skeleton. Ground reaction forces (GRFs) may provide a surrogate measure for the strain experienced by bone on landing and at take off. However, there appear to be no paediatric studies that assess GRFs across a variety of loading activities. OBJECTIVES: To measure biomechanical variables in commonly performed childhood activities used in an elementary physical education intervention study which augmented bone health in boys and girls. METHODS: Maximal GFR, maximal rates of force, and time to maximum force were measured for 12 different jumping activities on a force platform. The jumps measured were drop jumps from 10, 30, and 50 cm, all followed by a plyometric jump, submaximal and maximal jumping jacks, alternating feet jump, counter movement jumps, and side to side jumps over 10 and 20 cm foam barriers. The subjects were 70 children (36 boys and 34 girls), 8.3-11.7 years old. RESULTS: Subjects ranged in height from 128.4 to 172.6 cm and had a mass of 25.0-57.0 kg. Mean (SD) for vertical jump was 24.2 (5.5) cm and 135.2 (16.6) cm for standing long jump. The children engaged in loaded physical activity 5.7 (5.3) hours a week, on average. The highest mean maximal GRFs, normalised for body weight (BW), were generated from the plyometric portion of the drop jumps and the counter movement jump (about 5 times BW) compared with 3.5 times BW for jumping jacks. Similarly, the highest rates of change in force were 514 times BW/s for the drop jump from 10 cm and 493 times BW/s for the counter movement jump. CONCLUSIONS: Simple jumps requiring minimal equipment produce GRFs of 3.5-5 times BW and rates of force of around 500 times BW/s. As children appear to attenuate higher impact forces when jumping from increased heights, it cannot be assumed that merely increasing the height of the jump will necessarily "progress" the exercise intervention.

Biomechanical Phenomena↗
PubMed2003

Former exercisers of an 18-month intervention display residual aBMD benefits compared with control women 3.5 years post-intervention: a follow-up of a randomized controlled high-impact trial.

Exercise is recommended to enhance bone health but data on the maintenance of the exercise-induced bone benefit is sparse. The purpose of the study was to assess the maintenance of the musculoskeletal benefits obtained in an 18-month intervention of high-impact exercise in premenopausal women (34 former trainees and 31 controls). Physical performance and areal bone mineral density (aBMD, g/cm2) were measured at baseline, after 18 months, and after 5 years. All significant 18-month improvements relative to controls in the trainees' neuromuscular performance (isometric leg press, and vertical jump with and without additional 10% weight of the body mass) had been lost at the 5-year follow-up. However, since the changes in aBMD in both former trainees and controls by time were similar, the exercise-induced aBMD gain (i.e. the mean statistically significant intergroup differences of 1-3% in favor of the trainees) was maintained at the femoral neck, distal femur, patella, proximal tibia, and calcaneus at the 5-year follow-up. At lumbar spine, the difference was 1.7% at both 18-month and at the 5-year follow-ups but the difference was not statistically significant (NS) in the latter follow-up. At the trochanter and unloaded distal radius, the intergroup aBMD differences were NS at both the 18-month and 5-year follow-ups. In conclusion, the bone sites aBMD increased in response to the 18-month intervention, also demonstrated maintenance of this gain 3.5 years after the intervention. In contrast, the exercise-induced improvements in the neuromuscular performance vanished during the post intervention follow-up. These findings suggest the possibility of long-term bone benefits of high-impact training in women.

Adult↗
PubMed2003

Effect of alendronate and exercise on bone and physical performance of postmenopausal women: a randomized controlled trial.

In this randomized, double-blind, placebo-controlled 12-month trial we evaluated effects of weight- bearing jumping exercise and oral alendronate, alone or in combination, on the mass and structure of bone, risk factors for falling (muscle strength and power, postural sway, and dynamic balance), and cardiorespiratory fitness in postmenopausal women. A total of 164 healthy, sedentary, early postmenopausal women were randomly assigned to one of four experimental groups: (1) 5 mg of alendronate daily plus progressive jumping exercise, (2) 5 mg alendronate, (3) placebo plus progressive jumping exercise, or (4) placebo. The primary endpoint was 12-month change in bone mass and geometry (measured with dual-energy X-ray absorptiometry and peripheral computed tomography at several axial and limb sites) and physical performance; the secondary endpoint was change in biochemical markers of bone turnover. The jumping exercise was conducted an average 1.6 +/- 0.9 (mean +/- SD) times a week. Alendronate daily was effective in increasing bone mass at the lumbar spine (alendronate vs placebo 3.5%; 95% CI, 2.2-4.9%) and femoral neck (1.3%; 95% CI, 0.2-2.4%) but did not affect other bone sites. Exercise alone had no effect on bone mass at the lumbar spine or femoral neck; it had neither an additive nor an interactive effect with alendronate at these bone sites. However, at the distal tibia the mean increase of 3.6% (0.3-7.1%) in the section modulus (that is, bone strength) and 3.7% (0.1-7.3%) increase in the ratio of cortical bone to total bone area were statistically significant in the exercise group compared to the nonexercise group, indicating exercise-induced thickening of the bone cortex. Bone turnover was reduced in alendronate groups only. Alendronate had no effect on physical performance while the jumping exercise improved leg extensor power, dynamic balance, and cardiorespiratory fitness. As conclusion Alendronate is effective in increasing bone mass at the lumbar spine and femoral neck, while exercise is effective in increasing the mechanical properties of bone at some of the most loaded bone sites, as well as improving the participants' muscular performance and dynamic balance. Together alendronate and exercise may effectively decrease the risk of osteoporotic fractures.

Alendronate↗
PubMed2003

Associations of hormone replacement therapy with bone structure and physical performance among postmenopausal women.

The purpose of this cohort study was to focus on factors associated with bone mass and structure of lower limbs and physical performance after menopause. Eighty nonsmoking women with a mean age of 62.1 (SD 0.8) years participated in the study. They were classified into two groups by their use of hormone replacement therapy (HRT), either the current users (n = 43) or the never or discontinued users (n = 37). The tibial shaft and distal tibia were scanned with peripheral computed tomography. For the shaft region, the bone mineral content (BMC, g), cortical density (CoD, g/cm(3)), cortical area (CoA, mm(2)), and section modulus (BSI, mm(3)) were determined. For the distal part, the evaluated variables were BMC, total area (ToA), ratio of cortical to total area (CoA/ToA), trabecular density (TrD, g/mm(3)), cortical thickness, BSI, and buckling ratio. Isometric and dynamic muscle strength of the leg extensors, agility and postural sway, and cardiorespiratory capacity (VO(2max)) were measured. Unadjusted values for all bone variables were slightly higher among the HRT users compared to nonusers, with the exception of TrD with no difference. After controlling for body weight, the mean differences (95% confidence interval) remained significant for CoD of the tibial shaft and BSI of the distal tibia, the mean between-group differences being 1.5% (0.4 to 2.5%) and 23.0% (7.1 to 41.3%), respectively. Underlying the greater bending strength, HRT users had thicker cortices and a greater ratio of CoA/ToA. No differences existed between the two study groups for lower limb isometric or dynamic power, cardiorespiratory capacity, or postural balance or sway. HRT may offer protection against bone loss and maintain bone strength, although its ability to improve physical performance is not evident.

Bone Density↗
PubMed2002

Site-specific skeletal response to long-term weight training seems to be attributable to principal loading modality: a pQCT study of female weightlifters.

Physical training may be able to improve bone strength through site-specific changes in the composition, size and structure of the bone without notable increases in volumetric density. To address this possibility specifically, we compared 14 competitive female weightlifters with 14 female physical therapy students. Peripheral quantitative computed tomographic scans (pQCT) were taken from the distal radius, radial shaft, distal femur, and tibial midshaft of the dominant limb. Analysis of covariance (ANCOVA) was used to estimate the intergroup differences, using body weight and age as covariates. Cortical density did not differ between the weightlifters and controls at any site, whereas trabecular density was greater in the weightlifters, the benefit being 10% (P = 0.186) at the distal radius and 11% (P = 0.040) at the distal femur compared with the controls. Weightlifters' cortical cross-sectional area was 38% (P = 0.029) larger at the distal radius, 26% larger (P = 0.001) at the radial shaft, and 9% larger at the tibial midshaft (P = 0.034). Consequently, the weightlifters' forearm bone strength indices were also significantly higher, the intergroup difference being 41% (P = 0.001) at the distal radius and 43% (P = 0.004) at the radial shaft. Thus, the observed intergroup difference at the distal radius was mainly due to enlarged bone, particularly its cortex, rather than higher volumetric bone density. Findings at the radial shaft were similar. In contrast, weightlifters' trabecular tissue at the distal femur was denser but the bone per se was not clearly bigger than that of the controls' (intergroup difference 5%, P = 0.117). We suggest that bones subjected to exceptionally high bending-loading (distal radius and radial shaft) are larger than their normal counterparts while at sites experiencing axial, compressive-loading (e.g., distal femur), a denser trabecular structure (more load-carrying area) may be sufficient and any substantial enlargement in bone size may not be necessary.

Adult↗
PubMed2002

A randomized school-based jumping intervention confers site and maturity-specific benefits on bone structural properties in girls: a hip structural analysis study.

We compared 7-month changes in bone structural properties in pre- and early-pubertal girls randomized to exercise intervention (10-minute, 3 times per week, jumping program) or control groups. Girls were classified as prepubertal (PRE; Tanner breast stage 1; n = 43 for intervention [I] and n = 25 for control [C]) or early-pubertal (EARLY; Tanner stages 2 and 3; n = 43 for I and n = 63 for C). Mean +/- SD age was 10.0 +/- 0.6 and 10.5 +/- 0.6 for the PRE and EARLY groups, respectively. Proximal femur scans were analyzed using a hip structural analysis (HSA) program to assess bone mineral density (BMD), subperiosteal width, and cross-sectional area and to estimate cortical thickness, endosteal diameter, and section modulus at the femoral neck (FN), intertrochanter (IT), and femoral shaft (FS) regions. There were no differences between intervention and control groups for baseline height, weight, calcium intake, or physical activity or for change over 7 months (p > 0.05). We used analysis of covariance (ANCOVA) to examine group differences in changes of bone structure, adjusting for baseline weight, height change, Tanner breast stage, and physical activity. There were no differences in change for bone structure in the PRE girls. The more mature girls (EARLY) in the intervention group showed significantly greater gains in FN (+2.6%, p = 0.03) and IT (+1.7%, p = 0.02) BMD. Underpinning these changes were increased bone cross-sectional area and reduced endosteal expansion. Changes in subperiosteal dimensions did not differ. Structural changes improved section modulus (bending strength) at the FN (+4.0%, p = 0.04), but not at the IT region. There were no differences at the primarily cortical FS. These data provide insight into geometric changes that underpin exercise-associated gain in bone strength in early-pubertal girls.

Biomechanical Phenomena↗
PubMed2001

Mineral mass, size, and estimated mechanical strength of triple jumpers' lower limb.

This study was designed to examine the anticipated strong influence of extreme impact loading on the mineral mass, size, and gross structural properties of triple jumpers' lower limb bones. We compared the bone data obtained with peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA) from 8 Finnish triple jumpers with corresponding data from gender-, age-, height-, and weight-matched nonathletic peers. The volumetric (trabecular) density was significantly higher in the jumpers than in controls (from an average 18% difference at the distal tibia to a 41% difference at the proximal tibia), whereas the cortical density did not differ between groups. The DXA-derived areal bone mineral density of the femoral neck and lumbar spine was 31% higher in the jumpers than in controls, compared with a 16% difference between groups at the less-loaded distal radius. The lower limb bones were comparable in size between groups except at the distal femur where a significant 4%-6% difference was observed in favor of the triple jumpers. Mean tibial cortical wall thickness and area were substantially greater in the triple jumpers; the mean group difference ranged from about 20% at the shaft sites, to over 50% at the distal tibia. Given the apparently stronger cortices in the triple jumpers, the section moduli (bone strength index) of their femoral necks and tibiae were 19%-31% higher compared with the control group. Our findings indicate the ability of extreme impact loading to considerably improve bone's mechanical competence. Adaptation to loading seems to occur in a site-specific fashion by gross geometric changes, structural or architectural changes, or by their combination. The loading effect was best seen as enlarged bone cortices, probably after the trabecular density had reached its ceiling.

Absorptiometry, Photon↗
PubMed2001

Muscle cross-sectional area is associated with specific site of bone in prepubertal girls: a quantitative magnetic resonance imaging study.

It is well established that forces applied to bone are the result of muscle contraction. However, data regarding the contribution of muscle cross-sectional area (because muscle area is proportional to muscle strength) to cortical bone area before puberty are controversial. We tested the hypothesis that muscle cross-sectional area is associated with total cortical bone area, and whether there is a region-specific relationship between these parameters in prepubertal and early pubertal girls. Seventeen healthy (9-11 years, Tanner stages I-II) white girls participated in the study. We measured bone loading characteristics (maximal ground reaction forces; GRFs) for a drop jump (50 cm) and side-to-side jump (over a 20-cm-high fence) on a multicomponent force platform. Muscle cross-sectional area and bone cortical area (square centimeters) of the proximal third of the left and right lower leg was measured with a 1.5 T magnetic resonance system using a quadrature head coil. The sequence was T(1) weighted, with spin-echo in transverse (tibial) planes and 3 mm sections with no gap (ten slices). The tibial cross-sectional areas were subdivided into three anatomical sectors (SI-SIII), with the tibial centroid as origin. SI extended from the medial tibial border to the most anterior edge, SII extended from the anterior edge laterally to the interosseous border, and SIII extended posteromedially from the interosseous border to the medial tibial border. The nonparametric bone and muscle volume correlations demonstrated that the total muscle cross-sectional area correlated significantly with the total cortical area in both legs (left leg: r(s) = 0.59, p = 0.020; right leg: r(s) = 0.57, p = 0.016). Significant correlations were also found between left and right muscle area and cortical area in SII (r(s) = 0.68, p = 0.003, 0.67, and 0.003, respectively). There was no significant association between the muscle area and cortical area in SI or SIII. In addition, there was a significant correlation between GRFs of the side-to-side jump and total cortical area (left leg: r = 0.75, p < 0.01; right leg: r = 0.78, p < 0.01). Thus, we found that muscle area was most highly associated with bone cortical area in SII, the anterolateral sector of the tibia, which emphasizes the specific interplay of muscles and bone in the lower limb. This relationship was present in a regional, site-specific fashion.

Bone and Bones↗
PubMed2001

Results of a 10 week community based strength and balance training programme to reduce fall risk factors: a randomised controlled trial in 65-75 year old women with osteoporosis.

OBJECTIVE: To test the efficacy of a community based 10 week exercise intervention to reduce fall risk factors in women with osteoporosis. METHODS: Static balance was measured by computerised dynamic posturography (Equitest), dynamic balance by timed figure of eight run, and knee extension strength by dynamometry. Subjects were randomised to exercise intervention (twice weekly Osteofit classes for 10 weeks) or control groups. RESULTS: The outcome in 79 participants (39 exercise, 40 control) who were available for measurement 10 weeks after baseline measurement is reported. After confounding factors had been controlled for, the exercise group did not make significant gains compared with their control counterparts, although there were consistent trends toward greater improvement in all three primary outcome measures. Relative to the change in control subjects, the exercise group improved by 2.3% in static balance, 1.9% in dynamic balance, and 13.9% in knee extension strength. CONCLUSIONS: A 10 week community based physical activity intervention did not significantly reduce fall risk factors in women with osteoporosis. However, trends toward improvement in key independent risk factors for falling suggest that a study with greater power may show that these variables can be improved to a level that reaches statistical significance.

Accidental Falls↗
PubMed2001

Good maintenance of exercise-induced bone gain with decreased training of female tennis and squash players: a prospective 5-year follow-up study of young and old starters and controls.

This prospective 5-year follow-up study of 64 adult female racquet sports players and 27 controls assessed the changes in the playing-to-nonplaying arm bone mineral content (BMC) differences to answer three questions: (1) Are training-induced bone gains lost with decreased training? (2) Is the bone response to decreased training different if the playing career has been started before or at puberty rather than after it? (3) Are the possible bone changes related to the changes in training? The players were divided into two groups according to the starting age of their tennis or squash playing. The mean starting age was 10.5 years (SD, 2.2) among the players who had started training before or at menarche (young starters; n = 36) while 26.4 years (SD, 8.0) among those players who had begun training a minimum of 1 year after menarche (old starters; n = 28). At baseline of the 5-year follow-up, the mean age of the young starters was 21.6 years (SD, 7.6) and that of old starters was 39.4 years (SD, 10.5). During the follow-up, the young starters had reduced the average training frequency from 4.7 times a week (2.7) to 1.4 times a week (1.3) and the old starters from 4.0 times a week (1.4) to 2.0 times a week (1.4), respectively. The 5-year follow-up revealed that despite reduced training the exercise-induced bone gain was well maintained in both groups of players regardless of their clearly different starting age of activity and different amount of exercise-induced bone gain. The gain was still 1.3-2.2 times greater in favor of the young starters (at the follow-up, the dominant-to-nondominant arm BMC difference was 22% [8.4] in the humeral shaft of the young starters versus 10% [3.8] in the old starters, and 3.5% [2.4] in controls). In the players, changes in training were only weakly related to changes in the side-to-side BMC difference (r(s) = 0.05-0.34, all NS), and this was true even among the players who had stopped training completely a minimum 1 year before the follow-up. In conclusion, if controlled interventions will confirm our findings that an exercise-induced bone gain can be well maintained with decreased activity and that the maintenance of the bone gain is independent of the starting age of activity, exercise can be recommended for preventing osteoporosis and related fractures.

Adult↗
PubMed2000

High-impact exercise and bones of growing girls: a 9-month controlled trial.

The maximum amount of bone a person can obtain during the first two decades of life is an important determinant of bone mass in later life, and an increase in peak bone mass has been associated with decreased risk for osteoporotic fractures. It is known that growth of bone and thus development of peak bone mass are strongly controlled by genetic factors, but information on the role of environmental factors, such as exercise and nutrition, (e.g., exercise) on growing bone is limited. We tested a hypothesis that in growing girls the benefit of mechanical loading on bone mineral mass and bone strength is better before rather than after the menarche. Sixty-four girls (25 premenarcheal, 39 postmenarcheal) carried out a supervised 9-month step-aerobic program (two sessions per week), each session complemented with additional jumps. Sixty-two girls (33 premenarcheal, 29 postmenarcheal) served as controls. Bone mineral content (BMC) at the lumbar spine and proximal femur was measured by dual-energy X-ray absorptiometry (DXA). In addition, the cortical density (CoD, mg/cm3) and cortical cross-sectional area (CoA, mm2) and the density-weighted polar section modulus (BSI, mm3) of the tibial midshaft were determined by peripheral quantitative tomography (pQCT). In the premenarcheal girls, BMC increased statistically significantly more in the trainees than controls at the lumbar spine (p = 0.012) (8.6% vs 5.3%) and femoral neck (p = 0.014) (9.3% vs 5.3%). In the tibial midshaft, the intergroup differences (CoD, CoA and BSI) were not significant. The postmenarcheal girls showed no significant post-training intergroup differences in any of the bone parameters (BMC increased in the lumbar spine 6.0% vs 4.9%; femoral neck 3.4% vs 3.2%; and trochanter 2.6% vs 3.5%). Although a large proportion of bone mineral increase in the growing girls of this study was attributable to growth itself, this 9-month exercise intervention showed that a clear and large additional bone gain could be obtained in exercising premenarcheal girls, but not in exercising postmenarcheal girls. In other words, exercise seemed more beneficial for additional bone mineral acquisition before menarche (i.e., during the growth spurt) rather than after it.

Absorptiometry, Photon↗
PubMed2000

Biomechanical loading in the triple jump.

The triple jump is a demanding field event in which a jumper must tolerate extremely high impact forces while maintaining high horizontal speed. The present study was designed to clarify the mechanical loading characteristics and the role of neuromuscular function in the triple jump. Seven national triple jumpers (4 males, 3 females) volunteered to perform 3-6 jumps. The mean best performances were 14.32+/-0.45 m and 11.90+/-0.28 m for males and females, respectively. The three longest triple jumps for each jumper were selected for final analysis. The mean contact times were 0.139 s (hop), 0.157 s (step) and 0.177 s (jump). The largest ground reaction forces were observed in the step (15.2 times body weight), while the highest peak pressures were recorded under the heel and forefoot. The plantar pressure of the lateral side of the forefoot was highly related to the length of the triple jump (P < 0.05-0.01). In addition, electromyograms of both legs Suggested that mechanical loading places high demands on the neuromuscular system, as characterized by the high rate of activation in the pre-activity phase followed by high eccentric activity. Thus, the high activities of the gastrocnemius, vastus lateralis and hip extensor muscles seem to play an important role in preventing unnecessary yielding of the jumper during the braking phase.

Acceleration↗
PubMed1999

Disproportionate, age-related bone loss in long bone ends: a structural analysis based on dual-energy X-ray absorptiometry.

The width of long bone diaphyses apparently increase with age, a phenomenon that is suggested to have some positive impact on bone strength. On the other hand, these changes in size that are site-specific may cause a deterioration in the local mechanical integrity of the whole bone. Physical activity and calcium intake are known to be able to modify bone mass and size. It is, however, not known whether these lifestyle habits can modify the postulated disproportionate changes in bone size. To address this question, bone mineral content (BMC)-derived estimates of cross-sectional areas (CSA) of femur and radius in 158 premenopausal (mean age 43, standard deviation 2 years) and 134 postmenopausal (63 (2) years), clinically healthy women with contrasting long-term histories in physical activity and calcium intake were determined from dual-energy X-ray absorptiometry (DXA) data. The DXA-obtained BMC correlated strongly with the actual CSA (r = 0.94) determined with peripheral quantitative computed tomography. The ratios between functionally interrelated CSA data (i.e., (radial shaft CSA/distal radius CSA), (trochanter CSA/femoral neck CSA), (femoral shaft CSA/trochanter CSA) and (femoral shaft CSA/femoral neck CSA)) were considered primary outcome variables. Neither physical activity nor calcium intake separately or interactively were associated with any CSA ratio. Age showed no interaction with physical activity or calcium intake but was independently associated with all CSA ratios, except the ratio of femoral shaft CSA to trochanteric CSA. This study indicated clearly that a preferential reduction in the cross-sectional area occupied by bone mineral occurs disproportionately at the long bone ends as compared with diaphyseal sites, and this apparently inherent, age-associated relative loss seems not to be prevented by physical activity or calcium intake. In particular, given the utmost clinical relevance of the proximal femur region, an observed loss in femoral neck CSA of about 10% in contrast to about a 5% loss in trochanteric CSA warrants further investigation regarding its potential role as a predictor for hip fracture. Not only the local differences in bone composition but also the biomechanical aspects are important factors underlying these apparent changes in CSA at the studied skeletal sites.

Absorptiometry, Photon↗
PubMed1999

Changes in bone mineral content with decreased training in competitive young adult tennis players and controls: a prospective 4-yr follow-up.

PURPOSE: The purpose of this 4-yr prospective follow-up study of male tennis players was to determine the changes in the playing-to-nonplaying arm differences in bone mineral content (BMC) and answer two questions: 1) Are training induced bone gains lost with decreased training? and 2) Are the possible bone changes related to the changes in training? METHODS: Subjects were 13 former competitive male tennis players and their 13 controls. The players had started their playing career at the mean age of 11 yr. The initial comparisons between the playing and contralateral arms' BMC were done in 1992 (mean age 26 yr), and follow-up was performed 4 yr later. The players were competing at the national top level in the beginning of the study, and all had retired from the top tennis (mean) 2.3+/-0.6 yr before follow-up. Accordingly, they had reduced the average training frequency from 5.2 times a week to 2.6 times a week and the mean hours of training per week from 7.6 to 3.3. RESULTS: The 1996 measurements revealed that on average the players' exercise-induced bone gain in the playing arm had not disappeared with time despite decreased average playing activity and that observed bone changes were not related to changes in training. The side-to-side BMC differences were largest in the humeral shaft (25% in 1992 and 26% 4 yr later) and the proximal humerus (19% and 18%). The radial shaft difference was 14% and the distal radius difference 13% in both 1992 and 1996. In controls, the side-to-side BMC differences were small, less than 5%, and they did not change by time. CONCLUSIONS: In conclusion, this study suggests that bone gain obtained by regular tennis training does not disappear by time despite decreased playing activity. Regular exercise can be valuable for maximizing peak bone mass and thus contributing to prevention of osteoporosis and related fractures later in life.

Adult↗
PubMed1999

Good maintenance of high-impact activity-induced bone gain by voluntary, unsupervised exercises: An 8-month follow-up of a randomized controlled trial.

The purpose of this study was to evaluate whether premenopausal women's voluntary unsupervised aerobic and step training could maintain the skeletal benefits obtained by an 18-month supervised high-impact training, and if so, to what extent. Thirty women of the original 39 study subjects (i. e., persons who completed the preceding 18-month randomized training intervention and who volunteered to continue the training on their own for a further 8 months) and 19 women of the 45 original control subjects (i.e., persons who volunteered to continue as controls) were included. The study group trained an average of twice per week and the training consisted of regular aerobic and step classes provided by local fitness centers. Areal bone mineral density (BMD, g/cm2) was measured from the lumbar spine, femoral neck, trochanter area of the femur, distal femur, patella, proximal tibia, calcaneus, and dominant distal radius at baseline and after 18 and 26 months. During the extended 8-month follow-up, the BMD of the study group increased more at the femoral neck (the intergroup change was +0.9% at 18 months and +2.8% at 26 months, p = 0.004 for the change between 18 and 26 months) and remained at the 18-month level at the distal femur, patella, proximal tibia, and calcaneus. In these sites, the statistically significant changes during the entire 26 months of training were 1.7-4.0% in the training group as compared with the changes of -0.9-1.5% in the control group. In the lumbar spine, BMD decreased from the 18-month level in both groups. In conclusion, the significant BMD increases that were obtained by supervised 18-month high-impact training were effectively maintained with subsequent unsupervised regular aerobic and step classes (twice per week). The finding emphasizes the effectiveness and feasibility of self-controlled aerobic and step exercises in the primary prevention of osteoporosis among healthy premenopausal women.

Adult↗