Belinda Ruth Beck

Tibial stress injuries: An aetiological review for the purposes of guiding management

In the last 30 years, few advances have been made in the management of tibial stress injuries such as tibial stress fracture and medial tibial stress syndrome (MTSS). Tibial overuse injuries are a recognised complication of the chronic, intensive, weight-bearing training commonly practised by athletic and military populations. Generally, the most effective treatment is considered to be rest, often for prolonged periods. This is a course of action that will significantly disrupt an active lifestyle, and sometimes end activity-related careers entirely.There is now considerable knowledge of the nature of tibial stress injuries, such that presently accepted management practices can be critically evaluated and supplemented. Most recent investigations suggest that tibial stress injuries are a consequence of the repetitive tibial strain imposed by loading during chronic weight-bearing activity. Evidence is presented in this article for an association between repeated tibial bending and stress injury as a function of: (i) strain-related modelling (in the case of MTSS), and (ii) a strain-related positive feedback mechanism of remodelling (in the case of stress fracture). Factors that influence the bending response of the tibia to loading are reviewed. Finally, a guide for injury prevention and management based on research observations is presented.

Eight Months of Regular In‐School Jumping Improves Indices of Bone Strength in Adolescent Boys and Girls: The POWER PE Study

The POWER PE study was an 8‐mo, randomized, controlled, school‐based exercise intervention designed to apply known principles of effective bone loading to practical opportunities to improve life‐long musculoskeletal outcomes. A total of 99 adolescents (46 boys and 53 girls) with a mean age of 13.8 ± 0.4 yr (peri‐ to postpubertal) volunteered to participate. Intervention subjects performed 10 min of jumping activity in place of regular physical education (PE) warm up. Control subjects performed usual PE warm‐up activities. Bone mass (DXA and QUS) was assessed at baseline and follow‐up along with anthropometry, maturity, muscle power, and estimates of physical activity and dietary calcium. Geometric properties (such as femoral neck [FN] moment of inertia) were calculated from DXA measures. Boys in the intervention group experienced improvements in calcaneal broadband ultrasound attenuation (BUA) (+5.0%) and fat mass (−10.5%), whereas controls did not (+1.4% and –0.8%, respectively). Girls in the intervention group improved FN BMC (+13.9%) and lumbar spine (LS) BMAD (+5.2%) more than controls (+4.9% and +1.5%, respectively). Between‐group comparisons of change showed intervention effects only for whole body (WB) BMC (+10.6% versus +6.3%) for boys. Boys in the intervention group gained more lean tissue mass, trochanter (TR) BMC, LS BMC, and WB BMC and lost more fat mass than girls in the intervention group (p < 0.05). Ten minutes of jumping activity twice a week for 8 mo during adolescence seems to improve bone accrual in a sex‐specific manner. Boys increased WB bone mass and BUA, and reduced fat mass, whereas girls improved bone mass at the hip and spine.

Medial tibial stress syndrome. The location of muscles in the leg in relation to symptoms.

The legs of fifty cadavera were dissected to identify accurately the structures that attach to the tibia at the site of symptoms of medial tibial stress syndrome and that could potentially contribute to this condition. The origins of the soleus, the flexor digitorum longus, and the tibialis posterior muscles as well as that of the deep crural fascia were measured. The average sites of attachment and the ranges of attachment were determined for each structure. The soleus, the flexor digitorum longus, and the deep crural fascia were found to attach most frequently at the site where symptoms of medial tibial stress syndrome occur, while in no specimen was the tibialis posterior found to attach at this site. The data support recent reports that the soleus is probably the major contributor to traction-induced medial tibial stress syndrome. The data also contradict the contention that the tibialis posterior may contribute to this particular condition.

Bone Health Across the Lifespan—Exercising Our Options

BECK, B. R., and C. M. Snow. Bone health across the lifespan—exercising our options. Exerc. Sport Sci. Rev., Vol. 31, No. 3, pp. 117–122, 2003. Exercise is frequently extolled as an osteoporosis treatment. In reality, the use of exercise as an osteoporosis intervention lies more in its ability to: 1) maximize peak bone mass attained in youth; 2) maintain bone mass or reduce age-related bone loss; and 3) preserve muscle strength and postural stability to reduce the risk of falling and fracturing in the later years.

The Effect of 8 Mos of Twice-Weekly Low- or Higher Intensity Whole Body Vibration on Risk Factors for Postmenopausal Hip Fracture

Beck BR, Norling TL: The effect of 8 mos of twice-weekly low- or higher intensity whole body vibration on risk factors for postmenopausal hip fracture. Objective:Whole body vibration is a potential therapy for age-related loss of musculoskeletal competence. Vibration has improved bone in animal models, but evidence in humans is limited. Relative efficacy of low- vs. high-intensity whole body vibration is also unknown. Our goal was to observe the effect of brief low- and higher intensity whole body vibration on risk factors for hip fracture in postmenopausal women. Design:We used an 8-mo randomized controlled trial design to examine the influence of twice-weekly low-intensity whole body vibration (15 mins, 30 Hz, 0.3 g) or higher intensity whole body vibration (2 × 3 mins, 12.5 Hz, 1 g) on anthropometrics, bone (whole body, hip, spine, forearm, and heel), muscle (wall squat and chair rise), and balance (tandem walk and single leg stance). Physical activity, daily calcium, and compliance were recorded. Effects were examined by repeated-measures analysis of covariance, controlling for age, height, weight, calcium, physical activity, compliance, and baseline values. Results:Forty-seven women (71.5 ± 9.0 yrs) completed the trial. There were no between-group differences in any measure at 8 mos, but within-group effects were evident. Controls lost bone at the trochanter (−6%, P = 0.03) and lumbar spine (−6.6%, P = 0.02), whereas whole body vibration groups did not. Whole body vibration subjects improved wall squat (up to 120%, P = 0.004) and chair rise performance (up to 10.5%, P = 0.05). Conclusions:Eight mos of twice-weekly whole body vibration may reduce bone loss at the hip and spine and improve lower limb muscle function. These changes may translate to a decreased risk of falls and hip fracture.

Do Capacitively Coupled Electric Fields Accelerate Tibial Stress Fracture Healing.

Background Tibial stress fractures increasingly affect athletes and military recruits, with few known effective management options. Electrical stimulation enhances regular fracture healing, but the effect on stress fractures has not been definitively tested. Hypothesis Capacitively coupled electric field stimulation will accelerate tibial stress fracture healing. Study Design Randomized controlled trial; Level of evidence, 1. Methods Twenty men and 24 women with acute posteromedial tibial stress fractures were referred from local clinicians. Subjects were randomly assigned active or placebo capacitively coupled electric field stimulation to be applied for 15 hours per day until healed, given supplemental calcium, and instructed to rest from provocative training. Healing was confirmed when hopping to 10 cm for 30 seconds could be achieved without pain. Results No difference in time to healing was detected between treatment and placebo groups. Women in the treatment group healed more slowly than did the men (P = .05). Superior treatment compliance was associated with reduced time to healing (P = .003). Rest noncompliance was associated with increased time to healing (P = .05). Conclusion Whole-group analysis did not detect an effect of capacitively coupled electric field stimulation on tibial stress fracture healing; however, greater device use and less weightbearing loading enhanced the effectiveness of the active device. More severe stress fractures healed more quickly with capacitively coupled electric field stimulation. Clinical Relevance Although the use of capacitively coupled electric field stimulation for tibial stress fracture healing may not be efficacious for all, it may be indicated for the more severely injured or elite athlete/recruit whose incentive to return to activity may motivate superior compliance.

Consensus on Exercise Reporting Template (CERT): Modified Delphi Study.

Background Exercise interventions are often incompletely described in reports of clinical trials, hampering evaluation of results and replication and implementation into practice. Objective The aim of this study was to develop a standardized method for reporting exercise programs in clinical trials: the Consensus on Exercise Reporting Template (CERT). Design and Methods Using the EQUATOR Networks methodological framework, 137 exercise experts were invited to participate in a Delphi consensus study. A list of 41 items was identified from a meta-epidemiologic study of 73 systematic reviews of exercise. For each item, participants indicated agreement on an 11-point rating scale. Consensus for item inclusion was defined a priori as greater than 70% agreement of respondents rating an item 7 or above. Three sequential rounds of anonymous online questionnaires and a Delphi workshop were used. Results There were 57 (response rate=42%), 54 (response rate=95%), and 49 (response rate=91%) respondents to rounds 1 through 3, respectively, from 11 countries and a range of disciplines. In round 1, 2 items were excluded; 24 items reached consensus for inclusion (8 items accepted in original format), and 16 items were revised in response to participant suggestions. Of 14 items in round 2, 3 were excluded, 11 reached consensus for inclusion (4 items accepted in original format), and 7 were reworded. Sixteen items were included in round 3, and all items reached greater than 70% consensus for inclusion. Limitations The views of included Delphi panelists may differ from those of experts who declined participation and may not fully represent the views of all exercise experts. Conclusions The CERT, a 16-item checklist developed by an international panel of exercise experts, is designed to improve the reporting of exercise programs in all evaluative study designs and contains 7 categories: materials, provider, delivery, location, dosage, tailoring, and compliance. The CERT will encourage transparency, improve trial interpretation and replication, and facilitate implementation of effective exercise interventions into practice.

Simple, novel physical activity maintains proximal femur bone mineral density, and improves muscle strength and balance in sedentary, postmenopausal Caucasian women

SummaryA simple, appealing, physical activity program can be prescribed to reduce the risk of falls in sedentary, postmenopausal, independent-living, Caucasian women. Foot stamping, progressively loaded squats, and in-line dancing positively influence proximal femoral bone mineral density, lower extremity strength, and static and dynamic balance.Introduction Foot stamping, squats exercises, and in-line dancing together create a suitable activity program for sedentary, independent-living older women.MethodsForty-five postmenopausal women not taking medications for bone health were randomly assigned to one of three groups. All groups attended one line dance class per week. Two groups additionally performed progressively loaded squats five times per week. One group also performed four foot stamps, twice daily, five times per week. Broadband ultrasound attenuation (BUA), proximal femur (PF) and lumbar spine (LS) bone mineral density (BMD), squats number, and balance variables were measured.ResultsThere were no differences within or between groups in baseline and follow-up BUA, PF or LS BMD; however, a strong stamp compliance effect was apparent for BUA (r = 0.73) and PF BMD (r = 0.79). Number of squats (p < 0.01) and single leg stance time (p < 0.01) increased, while timed up and go time decreased (p < 0.01) for all participants.ConclusionsLine dancing, particularly in concert with regular squats and foot stamping, is a simple and appealing strategy that may be employed to reduce lower extremity bone loss, and improve lower limb muscle strength and balance, in independent living, otherwise healthy, postmenopausal Caucasian women.

Seasonal change in bone, muscle and fat in professional rugby league players and its relationship to injury: a cohort study

Objectives To examine the anthropometric characteristics of an Australian National Rugby League team and identify the relationship to type and incidence of injuries sustained during a professional season. It was hypothesised that body composition would not change discernibly across a season and that injury would be negatively related to preseason bone and muscle mass. Design A repeated measure, prospective, observational, cohort study. Setting Griffith University, Gold Coast, Australia. Participants 37 professional male Australian National Rugby League players, 24.3 (3.8) years of age were recruited for preseason 1 testing, of whom 25 were retested preseason 2. Primary and secondary outcome measures Primary outcome measures included biometrics; body composition (bone, muscle and fat mass; dual-energy x-ray absorptiometry; XR800, Norland Medical Systems, Inc); bone geometry and strength (peripheral quantitative CT; XCT 3000, Stratec); calcaneal broadband ultrasound attenuation (BUA; QUS-2, Quidel); diet and physical activity history. Secondary outcome measures included player injuries across a single playing season. Results Lean mass decreased progressively throughout the season (pre=81.45(7.76) kg; post=79.89(6.72) kg; p≤0.05), while whole body (WB) bone mineral density (BMD) increased until mid-season (pre=1.235(0.087) g/cm2; mid=1.296(0.093) g/cm2; p≤0.001) then decreased thereafter (post=1.256(0.100); p≤0.001). Start-of-season WB BMD, fat and lean mass, weight and tibial mass measured at the 38% site predicted bone injury incidence, but no other relationship was observed between body composition and injury. Conclusions Significant anthropometric changes were observed in players across a professional rugby league season, including an overall loss of muscle and an initial increase, followed by a decrease in bone mass. Strong relationships between anthropometry and incidence of injury were not observed. Long-term tracking of large rugby league cohorts is indicated to obtain more injury data in order to examine anthropometric relationships with greater statistical power.

The study of skeletal calcium metabolism with 41Ca and 45Ca

The living skeleton can be labeled for life by the administration of radiologically trivial amounts of 41Ca tracer. After initial elimination of tracer from the readily exchangeable calcium pools subsequent skeletal calcium turnover maintains and modulates the urine 41Ca content. Uniquely, bone calcium metabolism may then be studied with tracer in near equilibrium with the bodys calcium and resorbing calcium directly measured by accelerator mass spectrometry (AMS) of excreta. Our experiments with 25 41Ca labeled subjects demonstrate excellent diurnal stability and remarkable response to intervention of the urine signal. Thus the tracer method may prove a competitive means of measuring the effects of antiresorptive osteoporosis treatments, for therapy development or even clinical monitoring. Novel studies of long-term skeletal evolution are also possible. We realize that routinely administered short-lived calcium radiotracers contain 41Ca impurities and that thousands of experimental participants have been historically inadvertently 41Ca labeled. The 41Ca urine index might now rapidly further be characterized by contemporary measurements of these one-time subjects, and with their by now thoroughly skeleton-equilibrated tracer they might be ideal participants in other new experiments. We are also investigating 45Ca AMS. It may prove preferable to label the skeleton with this radiotracer already familiar to bioscientists, but new to AMS.