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This longitudinal study investigated the ultrasound appearance of the patellar tendon attachment to the tibia throughout puberty in young tennis players with and without Osgood-Schlatter disease (OSD). Twenty-eight competitive players (17 boys), aged 10.6-15.3 years, had bilateral ultrasound imaging of the patellar tendon attachment to the tibia at baseline and 1 year later. On each occasion, anthropometric measurements, pubertal status and injury history were recorded. Ultrasound appearance of the patellar tendon attachment was categorized into three stages: cartilage attachment, insertional cartilage and mature attachment. Stage 1 appearance, a large anechoic region with or without ossicles and irregularity of the apophysis that are classically associated with OSD, was found in eight players, seven of them were pain free. A majority (62%) of the patellar tendons in stage 1 at baseline progressed toward stage 2 or stage 3 1 year later. Likewise the patellar tendon attachment in most athletes with cartilage insertion showed progression to a mature enthesis over 1 year. The imaging appearance that is classically interpreted as OSD was common in asymptomatic knees. This ultrasonographic description of the patellar tendon attachment to the tibia during growth provides a reference for the assessment of bone tendon attachments in adolescents.

Tendon injuries (tendinopathy) are prevalent across the population, affecting active and inactive individuals and manual workers. The aetiology of tendinopathy is not known. However, extrinsic factors such as load are known to affect the prevalence. More recently, intrinsic factors have been shown to also affect tendons; genes, biomechanics, and strength have been shown to influence tendon disease. One intrinsic factor that appears to have an association with tendinopathy is body composition; more specifically central adiposity. Several studies have reported this association, and several studies have found the association when reporting other aspects of tendinopathy.This paper will detail what is known about the association between tendinopathy and body composition, examine the strength of the association by evaluating studies in the area and speculate on potential mechanisms for the association.The association between tendon health and adiposity, especially central adiposity, warrants further investigation.There may be an interaction between adiposity and tendon pathology. Adiposity may be a key intrinsic risk factor that is translated into tendon disease in the presence of additional intrinsic (e.g., diabetes) and extrinsic factors (e.g., load).

We investigated the effect of playing regular golf and HRT on lumbar and thoracic vertebral bone parameters (measured by QCT) in 72 post-menopausal women. The main finding of this study was that there was positive interaction between golf and HRT on vertebral body CSA and BMC at the thoracic 12 and lumbar 2 vertebra but not the third and seventh thoracic vertebras. Identifying specific exercises that load the spine sufficiently to be osteogenic is an important component of primary osteoporosis prevention. The aim of this study was to determine if in postmenopausal women regular participation in golf resulted in greater paravertebral muscle mass and improved vertebral bone strength. Forty-seven postmenopausal women who played golf regularly were compared to 25 controls. Bone parameters at the mid-vertebral body were determined by QCT at spinal levels T3, T7, T12 and L2 (cross-sectional area (CSA), total volumetric BMD (vBMD), trabecular vBMD of the central 50% of total CSA, BMC and cortical rim thickness). At T7 and L2, CSA of trunk muscles was determined. There was a positive interaction between golf and HRT for vertebral CSA and BMC at T12 and L2, but not at T3 or T7 (p ranging < 0.02 to 0.07). Current HRT use was associated with a 10–15% greater total and trabecular vBMD at all measured vertebral levels. Paravertebral muscle CSA did not differ between groups. Vertebral CSA was the bone parameter significantly related to muscle CSA. These findings provide preliminary evidence that playing golf may improve lower spine bone strength in postmenopausal women who are using HRT.

We examined the combined effects of exercise and calcium on BMC accrual in pre- and early-pubertal boys. Exercise and calcium together resulted in a 2% greater increase in femur BMC than either factor alone and a 3% greater increase in BMC at the tibia-fibula compared with the placebo group. Increasing dietary calcium seems to be important for optimizing the osteogenic effects of exercise.Understanding the relationship between exercise and calcium during growth is important given that the greatest benefits derived from these factors are achieved during the first two decades of life. We conducted a blinded randomized-controlled exercise-calcium intervention in pre- and early-pubertal boys to test the following hypotheses. (1) At the loaded sites (femur and tibia-fibula), exercise and calcium will produce greater skeletal benefits than either exercise or calcium alone. (2) At nonloaded sites (humerus and radius-ulna), there will be an effect of calcium supplementation.Eighty-eight pre- and early-pubertal boys were randomly assigned to one of four study groups: moderate impact exercise with or without calcium (Ca) (Ex+Ca and Ex+placebo, respectively) or low impact exercise with or without Ca (No-Ex+Ca and No-Ex+Placebo, respectively). The intervention involved 20 minutes of either moderate- or low-impact exercise performed three times a week and/or the addition of Ca-fortified foods using milk minerals (392+/-29 mg/day) or nonfortified foods over 8.5 months. Analysis of covariance was used to determine the main and combined effects of exercise and calcium on BMC after adjusting for baseline BMC.At baseline, no differences were reported between the groups for height, weight, BMC, or bone length. The increase in femur BMC in the Ex+Ca group was approximately 2% greater than the increase in the Ex+placebo, No-Ex+Ca, or No-Ex+Placebo groups (all p0.03). At the tibia-fibula, the increase in BMC in the Ex+Ca group was approximately 3% greater than the No-Ex+placebo group (p0.02) and 2% greater than the Ex+Placebo and the No-Ex+Ca groups (not significant). No effect of any group was detected at the humerus, ulna-radius, or lumbar spine for BMC, height, bone area, or volume.In this group of normally active boys with adequate calcium intakes, additional exercise and calcium supplementation resulted in a 2-3% greater increase in BMC than controls at the loaded sites. These findings strengthen the evidence base for public health campaigns to address both exercise and dietary changes in children for optimizing the attainment of peak BMC.

The aim of this 18 mth RCT was to determine whether calcium-vitamin D, fortified milk enhanced the osteogenic effect of exercise at loaded sites in 180 men aged 61.0 ± 7.4 yrs (mean ± SD) with below average BMD (FN or hip z-score 0,3 to -2.4 SD). They were randomised to one of four groups: (I) Ex + Ca-Vit D. n=45 (2) Ex, n=46 (3) Cal-Vit D, n=45 and (4) control group, n=44. The exercise consisted of high intensity (60 - 85% IRM)progressive resistance training (PRT) and moderate impact weight-bearing exercise 3 daysl wk. Men assigned to Ca-Vit D fortified milk consumed 400 ml/d oflow fat milk providing an additional 1000 mg/d of calcium and 800 IUld of vitamin D,. Total body, FN, hip and LS (L,-L,) BMD, LM and FM (DXA, Lunar Prodigy), diet, physical activity, and muscle strength were assessed at baseline, 12 and 18 months. There were no differences between groups at baseline. Mean (±SD) baseline dietary Ca and vitamin D intakes were 1002 ± 397 mg/d and 42 ± 80 IUld. A total of 172 men (95%) completed the study and exercise attendance averaged 63% and fortified milk compliance averaged 90%. GEE analysis revealed a group-by-time interaction for FN BMD (unadjusted or adjusted for changes in weight), and a trend for LS BMD (p

In this 2-year randomized controlled study of 167 men >50 years of age, supplementation with calcium-vitamin D3-fortified milk providing an additional 1000 mg of calcium and 800 IU of vitamin D3 per day was effective for suppressing PTH and stopping or slowing bone loss at several clinically important skeletal sites at risk for fracture. Introduction: Low dietary calcium and inadequate vitamin D stores have long been implicated in age-related bone loss and osteoporosis. The aim of this study was to assess the effects of calcium and vitamin D3 fortified milk on BMD in community living men >50 years of age. Materials and Methods: This was a 2-year randomized controlled study in which 167 men (mean age ± SD, 61.9 ± 7.7 years) were assigned to receive either 400 ml/day of reduced fat (∼1%) ultra-high temperature (UHT) milk containing 1000 mg of calcium plus 800 IU of vitamin D3 or to a control group receiving no additional milk. Primary endpoints were changes in BMD, serum 25(OH)D, and PTH. Results: One hundred forty-nine men completed the study. Baseline characteristics between the groups were not different; mean dietary calcium and serum 25(OH)D levels were 941 ± 387 mg/day and 77 ± 23 nM, respectively. After 2 years, the mean percent change in BMD was 0.9-1.6% less in the milk supplementation compared with control group at the femoral neck, total hip, and ultradistal radius (range, p < 0.08 to p < 0.001 after adjusting for covariates). There was a greater increase in lumbar spine BMD in the milk supplementation group after 12 and 18 months (0.8-1.0%, p ≤ 0.05), but the between-group difference was not significant after 2 years (0.7%; 95% CI, −0.3, 1.7). Serum 25(OH)D increased and PTH decreased in the milk supplementation relative to control group after the first year (31% and −18%, respectively; both p < 0.001), and these differences remained after 2 years. Body weight remained unchanged in both groups at the completion of the study. Conclusions: Supplementing the diet of men >50 years of age with reduced-fat calcium- and vitamin D3-enriched milk may represent a simple, nutritionally sound and cost-effective strategy to reduce age-related bone loss at several skeletal sites at risk for fracture in the elderly.

Overuse injury to the patellar tendon (patellar tendinopathy) is a major reason for interrupted training and competition for elite athletes. In both sexes, the prevalence of unilateral and bilateral tendinopathy has been shown to differ. It has been proposed that bilateral pathology may have a different aetiology from unilateral pathology. Investigation of risk factors that may be unique to unilateral and bilateral patellar tendinopathy in female athletes may reveal insights into the aetiology of this condition.To examine whether anthropometry, body composition, or muscle strength distinguished elite female basketball players with unilateral or bilateral patellar tendinopathy.Body composition, anthropometry, and muscle strength were compared in elite female basketball players with unilateral (n = 8), bilateral (n = 7), or no (n = 24) patellar tendinopathy. Body composition was analysed using a dual energy x ray absorptiometer. Anthropometric measures were assessed using standard techniques. Knee extensor strength was measured at 180 degrees /s using an isokinetic dynamometer. z scores were calculated for the unilateral and bilateral groups (using the no tendinopathy group as controls). z scores were tested against zero.The tibia length to stature ratio was approximately 1.3 (1.3) SDs above zero in both the affected and non-affected legs in the unilateral group (p0.05). The waist to hip ratio was 0.66 (0.78) SD above zero in the unilateral group (p0.05). In the unilateral group, leg lean to total lean ratio was 0.42 (0.55) SD above zero (p0.07), the trunk lean to total lean ratio was 0.63 (0.68) SD below zero (p0.05), and leg fat relative to total fat was 0.47 (0.65) SD below zero (p0.09). In the unilateral group, the leg with pathology was 0.78 (1.03) SD weaker during eccentric contractions (p0.07).Unilateral patellar tendinopathy has identifiable risk factors whereas bilateral patellar tendinopathy may not. This suggests that the aetiology of these conditions may be different. However, interpretation must respect the limitation of small subject numbers.

As muscles become larger and stronger during growth and in response to increased loading, bones should adapt by adding mass, size, and strength. In this unilateral model, we tested the hypothesis that (1) the relationship between muscle size and bone mass and geometry (nonplaying arm) would not change during different stages of puberty and (2) exercise would not alter the relationship between muscle and bone, that is, additional loading would result in a similar unit increment in both muscle and bone mass, bone size, and bending strength during growth. We studied 47 competitive female tennis players aged 8-17 years. Total, cortical, and medullary cross-sectional areas, muscle area, and the polar second moment of area (I(p)) were calculated in the playing and nonplaying arms using magnetic resonance imaging (MRI); BMC was assessed by DXA. Growth effects: In the nonplaying arm in pre-, peri- and post-pubertal players, muscle area was linearly associated BMC, total and cortical area, and I(p) (r = 0.56-0.81, P0.09 to0.001), independent of age. No detectable differences were found between pubertal groups for the slope of the relationship between muscle and bone traits. Post-pubertal players, however, had a higher BMC and cortical area relative to muscle area (i.e., higher intercept) than pre- and peri-pubertal players (P0.05 to0.01), independent of age; pre- and peri-pubertal players had a greater medullary area relative to muscle area than post-pubertal players (P0.05 to0.01). Exercise effects: Comparison of the side-to-side differences revealed that muscle and bone traits were 6-13% greater in the playing arm in pre-pubertal players, and did not increase with advancing maturation. In all players, the percent (and absolute) side-to-side differences in muscle area were positively correlated with the percent (and absolute) differences in BMC, total and cortical area, and I(p) (r = 0.36-0.40, P0.05 to0.001). However, the side-to-side differences in muscle area only accounted for 11.8-15.9% of the variance of the differences in bone mass, bone size, and bending strength. This suggests that other factors associated with loading distinct from muscle size itself contributed to the bones adaptive response during growth. Therefore, the unifying hypothesis that larger muscles induced by exercise led to a proportional increase in bone mass, bone size, and bending strength appears to be simplistic and denies the influence of other factors in the development of bone mass and bone shape.

Today, elite young gymnasts undertake training programs of progressive volume and intensity from an early age. For example, talented young female gymnasts often commence training at age 5 or 6 and train more than 20 to 30 hours per week year-round throughout childhood and adolescence. Despite the "normal" short stature of top-level gymnasts and the obvious health benefits of physical activity during growth, there is concern that elite level or those gymnasts involved in heavy training regimens may be at risk for adverse effects on growth and maturation. This concern has been the source of much debate in the literature and is complicated by the difficulties in distinguishing between the genetic predisposition to short stature and late or delayed maturation, and the effect of environmental factors such as nutrition and exercise that may influence growth and maturation. The effect of gymnastics training on growth and maturation is often reported as averaged data: an approach that does not identify individual growth patterns. Finding no difference between groups is not proof that there is "in fact" no difference. Accepting the null hypothesis without the appropriate critical review of both the methodological and statistical power to detect differences is a flawed endeavor. We believe there is compelling "circumstantial" evidence to build a case that preparation for advanced gymnastics competition may place some children and youth at risk of reduced growth and delayed maturation.

The increasingly dominant performance of smaller-sized female gymnasts and increased magnitude of training beginning at an early age have prompted public and medical concerns, especially from an auxological perspective. The objective of this review is to determine if gymnastics training inhibits growth of females.An extensive research of MedLine (PubMed interface) along with cross-referencing was conducted using the Text and MeSH words "gymnastics" in combination with "growth," "maturation," "body height," "body weight," and "growth plate." Our analysis is limited to English articles only.All published studies that included data related to the research questions were included.Although data from three historical cohort studies indicate that female gymnasts are short even before they begin training, clinical reports and cohort studies do suggest that some female gymnasts experience attenuated growth during training followed by catch-up growth during periods of reduced training or retirement. There is conflicting evidence whether the "catch-up" is complete. There were no studies reporting prevalence or incidence of inadequate growth. Three cohort studies provide evidence of reduced growth but training was not partitioned from other confounding factors in the gymnastics environment. Although there is a paucity of studies examining the link of dietary practices with diminished growth in female gymnasts, a review of related dietary literature indicates the potential for insufficient energy and nutrient intake among female gymnasts.Elite level or heavily involved female gymnasts may experience attenuated growth during their years of training and competition followed by catch-up growth during reduced training schedules or the months following retirement. However, a cause-effect relation between gymnastics training and inadequate growth of females has not been demonstrated.

There has never been, and will never be, a randomized double-blind placebo-controlled trial demonstrating that exercise in youth, adulthood or old age reduces fragility or osteoporosis-related fractures in old age. The next level of evidence, a randomized, controlled but unblinded study with fractures as an end-point is feasible but has never been done. The basis for the belief that exercise reduces fractures is derived from lower levels of 'evidence', namely, retrospective and prospective observation cohort studies and case-control studies. These studies are at best hypothesis generating, never hypothesis testing. They are all subject to many systematic biases and should be interpreted with extreme scepticism. Surrogate measures of anti-fracture efficacy are the next level of evidence, such as the demonstration of a reduction in risk factors for falls, a reduction in falls, a reduction in fractures due to falls, an increase in peak bone size and mass, prevention of bone loss in midlife and restoration of bone mass and structure in old age.

Background—To minimise injury risk and maximise gymnastics performance, coaches, parents, and health professionals working with young gymnasts need to understand and practise safe gymnastics. Aims—To (a) identify the various injury counter measures specific to gymnastics, (b) critically review the literature describing each injury prevention measure, and (c) assess, using available risk factor and injury data, the weight of evidence to support each of these counter measures. Specific recommendations for further research and implementation strategies to prevent injury and improve safety are also given. Methods—The relevant literature was identified through the use of Medline (1966 to May 1998) and SPORT Discus (1975 to May 1998) searches, hand searching of journals and reference lists, and discussions with key Australian gymnastics organisations. Results—The key gymnastics injury counter measures identified in this review include coaching (physical preparation, education, spotting, and performance technique), equipment, and the health support system (medical screening, treatment, and rehabilitation). Categorisation of the type of evidence for the effectiveness of each of these counter measures in preventing injury showed that most of it is based on informal opinion/anecdotal evidence, uncontrolled data based studies, and several prospective epidemiological studies. There is no evidence from formally controlled trials or specific evaluation studies of counter measures for gymnastics. Conclusions—Although gymnastics is a sport associated with young participants and frequent high volume, high impact training, there is a paucity of information on injury risk factors and the effectiveness of injury practices. Further controlled trials are needed to examine the extent to which injury prevention counter measures can prevent or reduce the occurrence of injury and re-injury. Particular attention should be devoted to improving training facilities, the design and testing of apparatus and personal equipment used by gymnasts, and coaching and the role of spotting in preventing injury.

Physical activity has been proposed as one strategy to enhance bone mineral acquisition during growth. The aim of this study was to determine whether frequent impact loading associated with gymnastics training confers a skeletal benefit on pre- and peripubertal male gymnasts. We measured broadband ultrasonic attenuation (BUA, dB/MHz) at the calcaneus (CBUA); ultrasound velocity (m/s) at the calcaneus (CVOS), distal radius (RVOS) and phalanx (PVOS); serum osteocalcin (OC); total alkaline phosphatase (ALP) and insulin-like growth factor-I (IGF-I) every 3-4 months over an 18-month period in elite male gymnasts and matched normoactive controls (pubertal stage

Cross-sectional studies of elite athletes suggest that growth is an opportune time for exercise to increase areal bone mineral density (BMD). However, as the exercise undertaken by athletes is beyond the reach of most individuals, these studies provide little basis for making recommendations regarding the role of exercise in musculoskeletal health in the community. To determine whether moderate exercise increases bone mass, size, areal, and volumetric BMD, two socioeconomically equivalent schools were randomly allocated to be the source of an exercise group or controls. Twenty boys (mean age 10.4 years, range 8.4–11.8) allocated to 8 months of 30-minute sessions of weight-bearing physical education lessons three times weekly were compared with 20 controls matched for age, standing and sitting height, weight, and baseline areal BMD. Areal BMD, measured using dual-energy X-ray absorptiometry, increased in both groups at all sites, except at the head and arms. The increase in areal BMD in the exercise group was twice that in controls; lumbar spine (0.61 ± 0.11 vs. 0.26 ± 0.09%/month), legs (0.76 ± 0.07 vs. 0.34 ± 0.08%/month), and total body (0.32 ± 0.04 vs. 0.17 ± 0.06%/month) (all p < 0.05). In the exercise group, femoral midshaft cortical thickness increased by 0.97 ± 0.32%/month due to a 0.93 ± 0.33%/month decrease in endocortical (medullary) diameter (both p < 0.05). There was no periosteal expansion so that volumetric BMD increased by 1.14 ± 0.33%/month, (p < 0.05). Cortical thickness and volumetric BMD did not change in controls. Femoral midshaft section modulus increased by 2.34 ± 2.35 cm3 in the exercise group, and 3.04 ± 1.14 cm3 in controls (p < 0.05). The growing skeleton is sensitive to exercise. Moderate and readily accessible weight-bearing exercise undertaken before puberty may increase femoral volumetric BMD by increasing cortical thickness. Although endocortical apposition may be a less effective means of increasing bone strength than periosteal apposition, both mechanisms will result in higher cortical thickness that is likely to offset bone fragility conferred by menopause-related and age-related endocortical bone resorption.

Exercise during growth may contribute to the prevention of osteoporosis by increasing peak bone mineral density (BMD). However, exercise during puberty may be associated with primary amenorrhea and low peak BMD, while exercise after puberty may be associated with secondary amenorrhea and bone loss. As growth before puberty is relatively sex hormone independent, are the prepubertal years the time during which exercise results in higher BMD? Are any benefits retained in adulthood? We measured areal BMD (g/cm2) by dual-energy X-ray absorptiometry in 45 active prepubertal female gymnasts aged 10.4 +/- 0.3 years (mean +/- SEM), 36 retired female gymnasts aged 25.0 +/- 0.9 years, and 50 controls. The results were expressed as a standardized deviation (SD) or Z score adjusted for bone age in prepubertal gymnasts and chronological age in retired gymnasts. In the cross-sectional analyses, areal BMD in the active prepubertal gymnasts was 0.7-1.9 SD higher at the weight-bearing sites than the predicted mean in controls (p < 0.01). The Z scores increased as the duration of training increased (r = 0.32-0.48, p ranging between

Pre- and early puberty may be the most opportune time to strengthen the female skeleton, but there are few longitudinal data to support this claim. Competitive female premenarcheal (pre/peri, n = 13) and postmenarcheal (post, n = 32) tennis players aged 10 to 17 years were followed over 12 months. The osteogenic response to loading was studied by comparing the playing and nonplaying humeri for dual-energy X-ray absorptiometry (DXA) bone mineral content (BMC) and magnetic resonance imaging (MRI) total bone area (ToA), medullary area (MedA), cortical area (CoA), and muscle area (MCSA) at the humerus. Over 12 months, growth-induced gains (nonplaying arm) in BMC, ToA, and CoA were greater in pre/peri (10% to 19%, p

Background Adiposity is a modifiable factor that has been implicated in tendinopathy. As tendon pain reduces physical activity levels and can lead to weight gain, associations between tendon pathology and adiposity must be studied in individuals without tendon pain. Therefore, the purpose of this study was to determine whether fat distribution was associated with asymptomatic Achilles tendon pathology. Methods The Achilles tendons of 298 individuals were categorised as normal or pathological using diagnostic ultrasound. Fat distribution was determined using anthropometry (waist circumference, waist hip ratio [WHR]) and dual-energy x-ray absorptiometry. Results Asymptomatic Achilles tendon pathology was more evident in men (13%) than women (5%) (p = 0.007). Men with tendon pathology were older (50.9 ± 10.4, 36.3 ± 11.3, p < 0.001), had greater WHR (0.926 ± 0.091, 0.875 ± 0.065, p = 0.039), higher android/gynoid fat mass ratio (0.616 ± 0.186, 0.519 ± 0.142, p = 0.014) and higher upper-body/lower body fat mass ratio (2.346 ± 0.630, 2.022 ± 0.467, p = 0.013). Men older than 40 years with a waist circumference >83 cm had the greatest prevalence of tendon pathology (33%). Women with tendon pathology were older (47.4 ± 10.0, 36.0 ± 10.3, p = 0.008), had less total fat (17196 ± 3173 g, 21626 ± 7882 g, p = 0.009), trunk fat (7367 ± 1662 g, 10087 ± 4152 g, p = 0.003) and android fat (1117 ± 324 g, 1616 ± 811 g, p = 0.005). They had lower central/peripheral fat mass ratios (0.711 ± 0.321 g, 0.922 ± 0.194 g, p = 0.004) than women with normal tendons. Women with tendon pathology were more often menopausal (63%, 13%, p = 0.002). Conclusions Men with Achilles tendon pathology were older and had a central fat distribution. Women with tendon pathology were older and had a peripheral fat distribution. An interaction between age and waist circumference was observed among men.

Adolescent athletes may be at risk of restricted growth and delayed maturation when intense training is combined with insufficient energy intake. Because catch-up growth commonly occurs when training is reduced or ceases, final adult stature may not be compromised. However, in athletes who have long-term, clinically delayed maturation, catch-up growth may be incomplete. By charting individual growth patterns, physicians, coaches, and athletic trainers can detect vulnerable periods when the training intensity should be reduced and energy intake may need to be increased.

Objective Tendon injuries have been reported to occur more frequently in individuals with increased adiposity. Treatment also appears to have poorer outcomes among these individuals. Our objective was to examine the extent and consistency of associations between adiposity and tendinopathy. Methods A systematic review of observational studies was conducted. Eight electronic databases were searched (Allied and Complementary Medicine, Biological Abstracts, CINAHL, Current Contents, EMBase, Medline, SPORTDiscus, and Web of Science) and citation tracking was performed on included reports. Studies were included if they compared adiposity between subjects with and without tendon injury or examined adiposity as a predictor of conservative treatment success. Results Four longitudinal cohorts, 14 cross-sectional studies, 8 case–control studies, and 2 interventional studies (28 in total) met the inclusion criteria, providing a total of 19,949 individuals. Forty-two subpopulations were identified, 18 of which showed elevated adiposity to be associated with tendon injury (43%). Sensitivity analyses indicated a clustering of positive findings among studies that included clinical patients (81% positive) and among case–control studies (77% positive). Conclusion Elevated adiposity is frequently associated with tendon injury. Published reports suggest that elevated adiposity is a risk factor for tendon injury, although this association appears to vary depending on aspects of study design and measurement. Adiposity is of particular interest in tendon research because, unlike a number of other reported risk factors for tendon injury, it is somewhat preventable and modifiable. Further research is required to determine if reducing adiposity will reduce the risk of tendon injury or improve the results of treatment.

Bone strength benefits after long-term retirement from elite gymnastics in terms of bone geometry and volumetric BMD were studied by comparing retired female gymnasts to moderately active age-matched women. In a cross-sectional study, 30 retired female gymnasts were compared with 30 age-matched moderately active controls. Bone geometric and densitometric parameters were measured by pQCT at the distal epiphyses and shafts of the tibia, femur, radius, and humerus. Muscle cross-sectional areas were assessed from the shaft scans. Independent t-tests were conducted on bone and muscle variables to detect differences between the two groups. The gymnasts had retired for a mean of 6.1 +/- 0.4 yr and were engaged in

Pre- and early puberty seem to be the most opportune times for exercise to improve bone strength in girls, but few studies have addressed this issue in boys. This study investigated the site-, surface-, and maturity-specific exercise-induced changes in bone mass and geometry in young boys. The osteogenic effects of loading were analyzed by comparing the playing and nonplaying humeri of 43 male pre-, peri-, and postpubertal competitive tennis players 10-19 yr of age. Total bone area, medullary area, and cortical area were determined at the mid (40-50%) and distal humerus (60-70%) of both arms using MRI. Humeral bone mass (BMC) was derived from a whole body DXA scan. In prepubertal boys, BMC was 17% greater in the playing compared with nonplaying arm (p < 0.001), which was accompanied by a 12-21% greater cortical area, because of greater periosteal expansion than medullary expansion at the midhumerus and periosteal expansion associated with medullary contraction at the distal humerus. Compared with prepuberty, the side-to-side differences in BMC (27%) and cortical area (20-33%) were greater in peripuberty (p < 0.01). No differences were found between peri- and postpuberty despite longer playing history in the postpubertal players. The osteogenic response to loading was greater in peri- compared with prepubertal boys, which is in contrast with our previous findings in girls and may be caused by differences in training history. This suggests that the window of opportunity to improve bone mass and size through exercise may be longer in boys than in girls.

Female gymnasts frequently present with overt signs of hypoestrogenism, such as late menarche or menstrual dysfunction. The objective was to investigate the impact of history of amenorrhoea on the exercise-induced skeletal benefits in bone geometry and volumetric density in retired elite gymnasts.24 retired artistic gymnasts, aged 17-36 years, who had been training for at least 15 h/week at the peak of their career and had been retired for 3-18 years were recruited. They had not been engaged in more than 2 h/week of regular physical activity since retirement. Former gymnasts who reported history of amenorrhoea ('AME', n=12: either primary or secondary amenorrhoea) were compared with former gymnasts ('NO-AME', n=12) and controls ('C', n=26) who did not report history of amenorrhoea. Bone mineral content (BMC), total bone area (ToA) and total volumetric density (ToD) were measured by pQCT at the radius and tibia (4% and 66%). Trabecular volumetric density (TrD) and bone strength index (BSI) were measured at the 4% sites. Cortical area (CoA), cortical thickness (CoTh), medullary area (MedA), cortical volumetric density (CoD), stress-strain index (SSI) and muscle and fat area were measured at the 66% sites. Spinal BMC, areal BMD and bone mineral apparent density (BMAD) were measured by DXA.Menarcheal age was delayed in AME when compared to NO-AME (16.4+/-0.5 years vs. 13.3+/-0.4 years, p0.001). No differences were detected between AME and C for height-adjusted spinal BMC, aBMD and BMAD, TrD and BSI at the distal radius and tibia, CoA at the proximal radius, whereas these parameters were greater in NO-AME than C (p0.05-0.005). AME had lower TrD and BSI at the distal radius, and lower spinal BMAD than NO-AME (p0.05) but they had greater ToA at the distal radius (p0.05).Greater spinal BMC, aBMD and BMAD as well as trabecular volumetric density and bone strength in the peripheral skeleton were found in former gymnasts without a history of menstrual dysfunction but not in those who reported either primary or secondary amenorrhoea. History of amenorrhoea may have compromised some of the skeletal benefits associated with high-impact gymnastics training.

BACKGROUND: The influence of adiposity on upper-limb bone strength has rarely been studied in children, despite the high incidence of forearm fractures in this population. OBJECTIVE: The objective was to compare the influence of muscle and fat tissues on bone strength between the upper and lower limbs in prepubertal children. DESIGN: Bone mineral content, total bone cross-sectional area, cortical bone area (CoA), cortical thickness (CoTh) at the radius and tibia (4% and 66%, respectively), trabecular density (TrD), bone strength index (4% sites), cortical density (CoD), stress-strain index, and muscle and fat areas (66% sites) were measured by using peripheral quantitative computed tomography in 427 children (206 boys) aged 7-10 y. RESULTS: Overweight children (n = 93) had greater values for bone variables (0.3-1.3 SD; P < 0.0001) than did their normal-weight peers, except for CoD 66% and CoTh 4%. The between-group differences were 21-87% greater at the tibia than at the radius. After adjustment for muscle cross-sectional area, TrD 4%, bone mineral content, CoA, and CoTh 66% at the tibia remained greater in overweight children, whereas at the distal radius total bone cross-sectional area and CoTh were smaller in overweight children (P < 0.05). Overweight children had a greater fat-muscle ratio than did normal-weight children, particularly in the forearm (92 +/- 28% compared with 57 +/- 17%). Fat-muscle ratio correlated negatively with all bone variables, except for TrD and CoD, after adjustment for body weight (r = -0.17 to -0.54; P < 0.0001). CONCLUSIONS: Overweight children had stronger bones than did their normal-weight peers, largely because of greater muscle size. However, the overweight children had a high proportion of fat relative to muscle in the forearm, which is associated with reduced bone strength.

Background/Aim: The study investigated the relationship between indices of adiposity measured by peripheral quantitative computed tomography (pQCT) and dual-energy X-ray absorptiometry (DXA) in pre-pubertal children. Subjects and methods: DXA-derived per cent body fat (%BF) was measured in 284 boys and 288 girls, aged 7–10 years. Cross-sections of the forearm (n=427) and lower leg (n=560) were obtained by pQCT to measure total cross-sectional area of the limb (Total CSA), Muscle CSA, Fat CSA, %Fat CSA (Fat CSA/Total CSA×100) and muscle density. Results: Peripheral QCT-derived %Fat CSA in the forearm and lower leg correlated strongly with DXA-derived %BF (r=0.83–0.89, p < 0.01) in both boys and girls. However, forearm and lower leg %Fat CSA were higher than whole body %BF by 5% and 10%, respectively. A better prediction of whole-body %BF was achieved by including %Fat CSA, muscle density and height into a hierarchical regression model. Using sex-specific regression equations, 87.7% of the boys and 83.7% of the girls had a predicted %BF within 3% units of the %BF obtained by DXA. Conclusion: In pre-pubertal children, pQCT measures of adiposity are strongly associated with whole-body per cent body fat. This reproducible method could be an alternative technique to estimate body composition in this population.

This cross-sectional study investigated the imaging appearance of the previous termpatellarnext term tendon attachment to the tibia in young male and female tennis players of different ages and pubertal status. Forty-four competitive young players, who had been playing tennis at least for 2 years, were recruited from a tennis school and local tennis clubs. All subjects had bilateral ultrasound imaging of the previous termpatellarnext term tendon attachment to the tibia. Standard anthropometric measurements, pubertal status and injury history were recorded. Ultrasound appearance of the previous termpatellarnext term tendon attachment was categorised into three stages: cartilage attachment, insertional cartilage and mature attachment. Cartilage attachment was more prevalent in boys (32%) and extended further into puberty (until Tanner stage 4) compared to girls (6% and Tanner stage 1). Tendons with Osgood–Schlatter Disease symptoms (n = 3) did not have a cartilage attachment. Imaging appearance commonly seen in young active athletes, consistent with a clinical diagnosis of OSD, was more common in boys and in the pre- and peri-pubertal stages.

To review systematically studies examining the association between sedentary lifestyle and low back pain (LBP) using a comprehensive definition of sedentary behaviour including prolonged sitting both at work and during leisure time. Journal articles published between 1998 and 2006 were obtained by searching computerized bibliographical databases. Quality assessment of studies employing a cohort or case–control design was performed to assess the strength of the evidence. Using pre-determined keywords, we identified 1,778 titles of which 1,391 were considered irrelevant. Then, 20 of the remaining 387 publications were scrutinized for full review after an examination of all the 387 abstracts. Finally, 15 studies (10 prospective cohorts and 5 case–controls) were included in the methodological quality assessment, of which 8 (6 cohorts and 2 case–controls; 53%) were classified as high-quality studies. One high-quality cohort study reported a positive association, between LBP and sitting at work only; all other studies reported no significant associations. Hence, there was limited evidence to demonstrate that sedentary behaviour is a risk factor for developing LBP. The present review confirms that sedentary lifestyle by itself is not associated with LBP.

We examined the independent and combined effects of a multi-component exercise program and calcium-vitamin-D(3)-fortified milk on bone mineral density (BMD) in older men. Exercise resulted in a 1.8% net gain in femoral neck BMD, but additional calcium-vitamin D(3) did not enhance the response in this group of older well-nourished men.This 12-month randomised controlled trial assessed whether calcium-vitamin-D(3)-fortified milk could enhance the effects of a multi-component exercise program on BMD in older men.Men (n = 180) aged 50-79 years were randomised into: (1) exercise + fortified milk; (2) exercise; (3) fortified milk; or (4) controls. Exercise consisted of high intensity progressive resistance training with weight-bearing impact exercise. Men assigned to fortified milk consumed 400 mL/day of low fat milk providing an additional 1,000 mg/day calcium and 800 IU/day vitamin D(3). Femoral neck (FN), total hip, lumbar spine and trochanter BMD and body composition (DXA), muscle strength 25-hydroxyvitamin D and parathyroid hormone (PTH) were assessed.There were no exercise-by-fortified milk interactions at any skeletal site. Exercise resulted in a 1.8% net gain in FN BMD relative to no-exercise (p0.001); lean mass (0.6 kg, p0.05) and muscle strength (20-52%, p0.001) also increased in response to exercise. For lumbar spine BMD, there was a net 1.4-1.5% increase in all treatment groups relative to controls (all p0.01). There were no main effects of fortified milk at any skeletal site.A multi-component community-based exercise program was effective for increasing FN BMD in older men, but additional calcium-vitamin D(3) did not enhance the osteogenic response.

In a previous 2-y randomized controlled trial, we showed that calcium- and vitamin D3-fortified milk stopped or slowed bone loss at several clinically relevant skeletal sites in older men.The present study aimed to determine whether the skeletal benefits of the fortified milk were sustained after withdrawal of the supplementation.One hundred nine men50 y old who had completed a 2-y fortified milk trial were followed for an additional 18 mo, during which no fortified milk was provided. Bone mineral density (BMD) of the total hip, femoral neck, lumbar spine, and forearm was measured by using dual-energy X-ray absorptiometry.Comparison of the mean changes from baseline between the groups (adjusted for baseline age, BMD, total calcium intake, and change in weight) showed that the net beneficial effects of fortified milk on femoral neck and ultradistal radius BMD at the end of the intervention (1.8% and 1.5%, respectively; P0.01 for both) were sustained at 18-mo follow-up (P0.05 for both). The nonsignificant between-group differences at the total hip (0.8%; P = 0.17) also persisted at follow-up (0.7%; P = 0.10), but there were no lasting benefits at the lumbar spine. The average total dietary calcium intake in the milk supplementation group at follow-up approximated recommended amounts for Australian men50 y old (1000 mg/d) but did not differ significantly from that in the control subjects (1021 versus 890 mg/d).Supplementation with calcium- and vitamin D3-fortified milk for 2 y may provide some sustained benefits for BMD in older men after withdrawal of supplementation.

Peripheral quantitative computed tomography (pQCT) has mainly been used as a research tool in children. To evaluate the clinical utility of pQCT and formulate recommendations for its use in children, the International Society of Clinical Densitometry (ISCD) convened a task force to review the literature and propose areas of consensus and future research. The types of pQCT technology available, the clinical application of pQCT for bone health assessment in children, the important elements to be included in a pQCT report, and quality control monitoring techniques were evaluated. The review revealed a lack of standardization of pQCT techniques, and a paucity of data regarding differences between pQCT manufacturers, models and software versions and their impact in pediatric assessment. Measurement sites varied across studies. Adequate reference data, a critical element for interpretation of pQCT results, were entirely lacking, although some comparative data on healthy children were available. The elements of the pQCT clinical report and quality control procedures are similar to those recommended for dual-energy X-ray absorptiometry. Future research is needed to establish evidence-based criteria for the selection of the measurement site, scan acquisition and analysis parameters, and outcome measures. Reference data that sufficiently characterize the normal range of variability in the population also need to be established.

This methods paper outlines the overall design of a community-based multidisciplinary longitudinal study with the intent to stimulate interest and communication from scientists and practitioners studying the role of physical activity in preventive medicine. In adults, lack of regular exercise is a major risk factor in the development of chronic degenerative diseases and is a major contributor to obesity, and now we have evidence that many of our children are not sufficiently active to prevent early symptoms of chronic disease. The lifestyle of our kids (LOOK) study investigates how early physical activity contributes to health and development, utilizing a longitudinal design and a cohort of eight hundred and thirty 7–8-year-old (grade 2) school children followed to age 11–12 years (grade 6), their average family income being very close to that of Australia. We will test two hypotheses, that (a) the quantity and quality of physical activity undertaken by primary school children will influence their psychological and physical health and development; (b) compared with existing practices in primary schools, a physical education program administered by visiting specialists will enhance health and development, and lead to a more positive perception of physical activity. To test the first hypothesis we will monitor all children longitudinally over the 4 years. To test the second we will involve an intervention group of 430 children who receive two 50 min physical education classes every week from visiting specialists and a control group of 400 who continue with their usual primary school physical education with their class-room teachers. At the end of grades 2, 4, and 6 we will measure several areas of health and development including blood risk factors for chronic disease, cardiovascular structure and function, physical fitness, psychological characteristics and perceptions of physical activity, bone structure and strength, motor control, body composition, nutritional intake, influence of teachers and family, and academic performance.

The long-term effects of calcium and vitamin D supplementation on bone material and structural properties in older men are not known. The aim of this study was to examine the effects of high calcium (1000 mg/day)- and vitamin-D(3) (800 IU/day)-fortified milk on cortical and trabecular volumetric BMD (vBMD) and bone geometry at the axial and appendicular skeleton in men aged over 50 years. One hundred and eleven men who were part of a larger 2-year randomized controlled trial had QCT scans of the mid-femur and lumbar spine (L(1)-L(3)) to assess vBMD, bone geometry and indices of bone strength [polar moment of inertia (I(polar))]. After 2 years, there were no significant differences between the milk supplementation and control group for the change in any mid-femur or L(1)-L(3) bone parameters for all men aged over 50 years. However, the mid-femur skeletal responses to the fortified milk varied according to age, with a split ofor=62 versus62 years being the most significant for discriminating the changes between the two groups. Subsequent analysis revealed that, in the older men (62 years), the expansion in mid-femur medullary area was 2.8% (P0.01) less in the milk supplementation compared to control group, which helped to preserve cortical area in the milk supplementation group (between group difference 1.1%, P0.01). Similarly, for mid-femur cortical vBMD and I(polar), the net loss was 2.3 and 2.8% less in the milk supplementation compared to control group (P0.01 and0.001, respectively). In conclusion, calcium-vitamin-D(3)-fortified milk may represent an effective strategy to maintain bone strength by preventing endocortical bone loss and slowing the loss in cortical vBMD in elderly men.

To investigate the effect of the progression of adolescent onset anorexia nervosa (AN) on bone parameters we followed two cohorts (Disease cohort and recovered cohort) of adolescents for a total of 5.2 years. In the 'Disease' cohort (n = 18), lumbar spine bone density (BMD) was reduced by 0.6 SD after 0.8 years of disease and was reduced a further 1.0 SD after a total 2.5 years of disease (p < 0.001). At the third lumbar vertebra there was bone loss (-3.7%, p < 0.05) resulting in reduced volumetric BMD (-5.1%, p < 0.08). In the 'recovered' cohort, lumbar spine BMD was reduced by 1.9 SD after 1.7 years of disease, and increased by 1.5 SD after 2.7 years of recovery (p < 0.001). At the third lumbar vertebra there was an increase in bone mass (20.5%, p < 0.001) and bone volume (14.1%, p < 0.001), resulting in increased volumetric BMD (6.3%, p < 0.08). Normalisation of lumbar spine BMD may be achieved in patients with adolescent onset AN when the successful recovery of body weight is combined with the return of regular menses.

Combining exercise with calcium supplementation may produce additive or multiplicative effects at loaded sites; thus, we conducted a single blind, prospective, randomized controlled study in pre- and early-pubertal girls to test the following hypotheses. (1) At the loaded sites, exercise and calcium will produce greater benefits than exercise or calcium alone. (2) At non-loaded sites, exercise will have no benefit, whereas calcium with or without exercise will increase bone mass over that in exercise alone or no intervention. Sixty-six girls aged 8.8 +/- 0.1 years were randomly assigned to one of four study groups: moderate-impact exercise with or without calcium or low-impact exercise with or without calcium. All participants exercised for 20 minutes, three times a week and received Ca-fortified (434 +/- 19 mg/day) or non-fortified foods for 8.5 months. Analysis of covariance (ANCOVA) was used to determine interaction and main effects for exercise and calcium on bone mass after adjusting for baseline bone mineral content and growth in limb lengths. An exercise-calcium interaction was detected at the femur (7.1%, p < 0.05). In contrast, there was no exercise-calcium interaction detected at the tibia-fibula; however, there was a main effect of exercise: bone mineral content increased 3% more in the exercise than non-exercise groups (p < 0.05). Bone mineral content increased 2-4% more in the calcium-supplemented groups than the non-supplemented groups at the humerus (12.0% vs. 9.8%, respectively, p < 0.09) and radius-ulna (12.6% vs. 8.6%, respectively, p < 0.01). In conclusion, greater gains in bone mass at loaded sites may be achieved when short bouts of moderate exercise are combined with increased dietary calcium, the former conferring region-specific effects and the latter producing generalized effects.

Exercise during growth results in biologically important increases in bone mineral content (BMC). The aim of this study was to determine whether the effects of loading were site specific and depended on the maturational stage of the region. BMC and humeral dimensions were determined using DXA and magnetic resonance imaging (MRI) of the loaded and nonloaded arms in 47 competitive female tennis players aged 8-17 years. Periosteal (external) cross-sectional area (CSA), cortical area, medullary area, and the polar second moments of area (I(P), mm4) were calculated at the mid and distal sites in the loaded and nonloaded arms. BMC and I(P) of the humerus were 11-14% greater in the loaded arm than in the nonloaded arm in prepubertal players and did not increase further in peri- or postpubertal players despite longer duration of loading (both, p0.01). The higher BMC was the result of a 7-11% greater cortical area in the prepubertal players due to greater periosteal than medullary expansion at the midhumerus and a greater periosteal expansion alone at the distal humerus. Loading late in puberty resulted in medullary contraction. Growth and the effects of loading are region and surface specific, with periosteal apposition before puberty accounting for the increase in the bone's resistance to torsion and endocortical contraction contributing late in puberty conferring little increase in resistance to torsion. Increasing the bone's resistance to torsion is achieved by modifying bone shape and mass, not necessarily bone density.

In their recent article Intensive training in elite young female athletes, Baxter-Jones and Maffulli reviewed 18 studies and concluded “training does not appear to affect growth and maturation.”1 We have two concerns about this conclusion. Firstly, we agree that analyses of cross sectional and cohort data in this population are confounded by sampling bias; gymnasts who are successful at an elite level are likely to be self selected by their small stature and delayed maturation. Furthermore, data from cross sectional …

To determine whether high-volume, high-impact physical training in prepubertal and early pubertal male gymnasts is associated with reduced statural and segmental growth and reduced serum insulin-like growth factor-I (IGF-I) and increased cortisol (C) levels.Height, sitting height, leg length, and segmental lengths (humerus, radius, femur, and tibia) and breadths (biacromial and bi-iliac), diet, serum IGF-I, testosterone, and C were measured in competitive male gymnasts and normoactive children (Tanner stageor = 2) every 3 to 4 months over an 18-month period.At baseline, gymnasts (n = 31) were 0.7 years older than members of the control group (P.05, n = 50) but were no different in terms of biologic maturity. Age-adjusted z scores showed that the gymnasts were shorter than members of the control group (-0.5 +/- 0.2 SD, P.05) because of reduced leg length (-0.8 +/- 0.2 SD, P.001) but not sitting height. Segmental lengths and bi-iliac breadth age-adjusted z scores were also reduced in the gymnasts (P ranging.05 to.001). No difference was detected for serum IGF-I or C. After 18 months of follow-up, no differences were found for rates of change in height, sitting height or leg length, segmental lengths, IGF-I, or C between those gymnasts and control subjects who remained prepubertal and early pubertal (gymnasts n = 18; control group n = 35). However, the magnitudes of baseline differences in anthropometric measures (z scores) persisted throughout the study.Short stature in these competitive male gymnasts was due to a reduced leg length but not sitting height. The lack of a difference in growth rates, IGF-I, and diet over the 18-month period indicates that the short stature reported in male gymnasts is due to selection bias rather than gymnastics training.

The growing years may be the most opportune time in life for exercise to result in large increases in bone density, enough to reduce the risk of fracture late in life. However, it is not known if there is an ‘optimal’ time during growth when the skeleton is most responsive to exercise. Comparing the osteotrophic response to exercise between pre- and peripubertal children is complex because: (i) the development of the skeleton within each stage of puberty is characterised by differing temporal patterns of growth in bone size and mass; (ii) the hormonal regulation of the skeleton is unique to each stage of puberty; and (iii) it is difficult to equate the relative mechanical load placed on the prepubertal compared with the pubertal skeleton. There are sound biological bases for the hypotheses being proposed for both the pre- and peripubertal years being the time when the skeleton is most responsive to exercise; that is, exercise may enhance bone formation in a synergistic fashion in the presence of growth hormone (prepubertal years) or sex steroids (peripubertal years). The paucity of data and the complex methodology make it difficult to draw conclusions as to the most opportune time during growth when exercise may lead to the greatest osteotrophic response. The limited data available support the notion that the prepubertal years may be the most opportune time, due to increases in bone density and periosteal expansion of cortical bone.

There is increasing concern that too much physical activity may lead to osteoarthritis. The continuous stress that physical activity places on the joints can result in microtrauma and degeneration of the articular cartilage. However, the onset of osteoarthritis appears to depend on the frequency, intensity and duration of physical activity. Research has shown that individuals of all ages can tolerate moderate amounts of exercise without adverse consequences or accelerated development of osteoarthritis. However, excessive participation in high impact sports, particularly over a long period of time and at an elite level, can increase the risk of developing osteoarthritis. Participants may also be at risk if they have abnormal joint anatomy or alignment, joint instability, underlying muscle weakness or imbalance, or if they are overweight and engage in significant amounts of exercise. Individuals who have experienced sports injuries to joints, or macrotrauma, may also be at risk of accelerated development of osteoarthritis. Certain types of surgery for the treatment of severe sports injuries, particularly to the knee, also appear to be associated with an increased risk. If surgery to the knee is required, continuous passive motion is an ideal form of rehabilitative treatment, as it promotes healing of the articular cartilage, ligaments and tendons. Moreover, athletes who have undergone surgery should return slowly to sporting activities to ensure they do not place too much stress on their injured joint(s). Further research into the causes of osteoarthritis is required; in particular, prospective and retrospective cohort studies are needed to confirm the association between exposure to risk factors and the development of osteoarthritis.

Does weight-bearing exercise offset bone loss associated with oligomenorrhea? If so, bone mineral density (BMD) will be stable at weight bearing sites but decrease at non-weight-bearing sites with increasing duration of oligomenorrhea. To test this hypothesis, BMD (g/cm2), was measured by dual-energy X-ray absorptiometry in 41 oligomenorrheic ballet dancers aged 17.7 +/- 0.2 years (mean +/- SEM) and 46 age-matched controls with normal menstrual function. BMD correlated negatively with the duration of oligomenorrhea at weight-bearing and non-weight-bearing sites (femoral neck, r = -0.33, p0.05; Ward's triangle, r = -0.29, p = 0.06; trochanter, r = -0.33, p0.05; lumber spine, r = -0.25, p = 0.1; skull, r = -0.29, p = 0.06; arms, r = -0.32, p0.05; ribs, r = -0.30, p = 0.06). The slopes of the regression of BMD on duration of oligomenorrhea were greater at the proximal femur (trochanter, -0.28 +/- 0.13, femoral neck, -0.24 +/- 0.11; Ward's triangle, -0.29 +/- 0.15) than the skull (-0.15 +/- 0.08, p0.05, p0.1, p0.1 respectively). The slopes at the trochanter and femoral neck were also greater than at the ribs (-0.10 +/- 0.05; both p0.1). In the dancers with oligomenorrhea of less than 40 months duration, BMD was higher than the age-predicted mean at weight-bearing sites (except the lumber spine), but not at non-weight-bearing sites (femoral neck, 9.1 +/- 3.4%; Ward's triangle, 10.0 +/- 1.7%; trochanter, 9.4 +/- 4.1%, all p0.05; lumbar spine, -2.1 +/- 2.7%, NS; skull, -2.5 +/- 2.1%, NS; ribs, -3.0 +/- 1.6% NS; arms, -3.9 +/- 1.6%; p0.05). In the dancers with greater than 40 months oligomenorrhea, BMD was no higher than the age predicted mean, at the weight bearing sites, and was lower at non-weight bearing sites (femoral neck, 4.3 +/- 2.3%, NS; Ward's triangle, 3.5 +/- 3.2%, NS; trochanter, 2.1 +/- 2.7%, NS; lumbar spine, -3.8 +/- 2.1%, NS; arms, -7.5 +/- 0.8%, p0.05; skull, -6.2 +/- 1.8%, p0.01; ribs, -5.4 +/- 1.1%, p0.0001). In conclusion, weight-bearing exercise is unlikely to offset the deleterious effects of oligomenorrhea. Bone loss appears to occur at all sites but may begin from a higher level at weight-bearing sites and may proceed more rapidly.