Bone Geometry, Strength, and Muscle Size in Runners with a History of Stress Fracture

School of Kinesiology, Laboratory of Musculoskeletal Health, University of Minnesota, Minneapolis, MN 55455, USA.
Medicine and science in sports and exercise (Impact Factor: 3.98). 11/2009; 41(12):2145-50. DOI: 10.1249/MSS.0b013e3181a9e772
Source: PubMed


Our primary aim was to explore differences in estimates of tibial bone strength, in female runners with and without a history of stress fractures. Our secondary aim was to explore differences in bone geometry, volumetric density, and muscle size that may explain bone strength outcomes.
A total of 39 competitive distance runners aged 18-35 yr, with (SFX, n = 19) or without (NSFX, n = 20) a history of stress fracture were recruited for this cross-sectional study. Peripheral quantitative computed tomography (XCT 3000; Orthometrix, White Plains, NY) was used to assess volumetric bone mineral density (vBMD, mg x mm(-3)), bone area (ToA, mm(2)), and estimated compressive bone strength (bone strength index (BSI) = ToA x total volumetric density (ToD(2))) at the distal tibia (4%). Total (ToA, mm(2)) and cortical (CoA, mm(2)) bone area, cortical vBMD, and estimated bending strength (strength-strain index (SSIp), mm(3)) were measured at the 15%, 25%, 33%, 45%, 50%, and 66% sites. Muscle cross-sectional area (MCSA) was measured at the 50% and 66% sites.
Participants in the SFX group had significantly smaller (7%-8%) CoA at the 45%, 50%, and 66% sites (P <or= 0.05 for all), significantly lower SSIp (9%-10%) at the 50% and 66% sites, and smaller MCSA (7%-8%) at the 66% site. The remaining bone parameters including vBMD were not significantly different between groups. After adjusting for MCSA, there were no differences between groups for any measured bone outcomes.
These findings suggest that cortical bone strength, cortical area, and MCSA are all lower in runners with a history of stress fracture. However, the lower strength was appropriate for the smaller muscle size, suggesting that interventions to reduce stress fracture risk might be aimed at improving muscle size and strength.

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Available from: Steven D Stovitz, Oct 04, 2015
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    • "According to Crossley et al. and Franklyn et al., the cross sectional area (CSA) of the tibial cortex is less in male athletes with a history of tibial stress injury than uninjured male athletes (Crossley et al., 1999; Franklyn et al., 2008). Popp et al. and Schnackenburg et al. reported similar findings in female runners (Popp et al., 2009; Schnackenburg et al., 2011). Franklyn et al. also indicated geometric measures related to bone strength, specifically the second moment of area and section modulus in "
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    ABSTRACT: Combinations of smaller bone geometry and greater applied loads may contribute to tibial stress fracture. We examined tibial bone stress, accounting for geometry and applied loads, in runners with stress fracture. 23 runners with a history of tibial stress fracture & 23 matched controls ran over a force platform while 3-D kinematic and kinetic data were collected. An elliptical model of the distal 1/3 tibia cross section was used to estimate stress at 4 locations (anterior, posterior, medial and lateral). Inner and outer radii for the model were obtained from 2 planar x-ray images. Bone stress differences were assessed using two-factor ANOVA (α=0.05). Key contributors to observed stress differences between groups were examined using stepwise regression. Runners with tibial stress fracture experienced greater anterior tension and posterior compression at the distal tibia. Location, but not group, differences in shear stress were observed. Stepwise regression revealed that anterior-posterior outer diameter of the tibia and the sagittal plane bending moment explained >80% of the variance in anterior and posterior bone stress. Runners with tibial stress fracture displayed greater stress anteriorly and posteriorly at the distal tibia. Elevated tibial stress was associated with smaller bone geometry and greater bending moments about the medial-lateral axis of the tibia. Future research needs to identify key running mechanics associated with the sagittal plane bending moment at the distal tibia as well as to identify ways to improve bone geometry in runners in order to better guide preventative and rehabilitative efforts. Copyright © 2015 Elsevier Ltd. All rights reserved.
    Clinical biomechanics (Bristol, Avon) 08/2015; DOI:10.1016/j.clinbiomech.2015.07.012 · 1.97 Impact Factor
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    • "However, a meta-analysis study has shown that there is an association between low bone density and fractures, in children.19 Several studies have reported that fractures occurring during youth might be associated with a reduction in bone gain during puberty, and it might be associated with subsequent low-peak bone mass,20 genetic factors,21 and physical inactivity, and muscle, loss secondary to fractures.22 It is likely that the greater bone strength (mainly determined by bone mass) is, the lower is the incidence of fractures during practice. "
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    ABSTRACT: The objectives of this study were to reveal the proportion of Shorinji Kempo athletes who had suffered fractures related to sports activities, and to evaluate bone mass, bone turnover, nutritional status, and physical function in these athletes. A medical examination was carried out for 16 Shorinji Kempo collegiate athletes. Seven athletes (43.8%) had experienced a sports-related traumatic fracture during Shorinji Kempo practice. Four athletes (25.0%) had a lower speed of sound (% young adult mean < 100%), and five athletes (31.3%) had higher levels of urinary cross-linked N-terminal telopeptides of type 1 collagen (a bone turnover marker) than the age-adjusted standard values. All the athletes had a lower daily calcium intake than the adequate intake, 12 (75.0%) had a lower daily vitamin D intake, and 15 (93.8%) had a lower daily vitamin K intake. Significant positive correlations were found between the vertical jump height, and the daily energy, and protein intakes. Results suggest that fractures are a common injury in Shorinji Kempo athletes, and that some Shorinji Kempo athletes need to improve their bone mass, bone metabolism, and nutritional status in order to strengthen bone and improve physical function.
    Open Access Journal of Sports Medicine 09/2012; 3:107-14. DOI:10.2147/OAJSM.S34010
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    • "Studies have focused on muscle and kinetic parameters and their possible relationships with the incidence of tibia stress fractures in groups with a recent history of injury, rather than examining the pre-fracture period. Moreover, most studies have given priority to long-distance runners (1,8,11,12) and have made no comparisons with other sports that also result in fractures. Therefore, studying the muscle and kinetic characterization of vertical ground reaction forces among triathlon athletes and long-distance runners, and comparing them with non-athletic individuals who are not subjected to high training loads, is important for developing possible strategies to prevent overuse injuries in these two sports. "
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    ABSTRACT: To analyze and compare the vertical component of ground reaction forces and isokinetic muscle parameters for plantar flexion and dorsiflexion of the ankle between long-distance runners, triathletes, and nonathletes. Seventy-five males with a mean age of 30.26 (±6.5) years were divided into three groups: a triathlete group (n=26), a long-distance runner group (n = 23), and a non-athlete control group. The kinetic parameters were measured during running using a force platform, and the isokinetic parameters were measured using an isokinetic dynamometer. The non-athlete control group and the triathlete group exhibited smaller vertical forces, a greater ground contact time, and a greater application of force during maximum vertical acceleration than the long-distance runner group. The total work (180º/s) was greater in eccentric dorsiflexion and concentric plantar flexion for the non-athlete control group and the triathlete group than the long-distance runner group. The peak torque (60º/s) was greater in eccentric plantar flexion and concentric dorsiflexion for the control group than the athlete groups. The athlete groups exhibited less muscle strength and resistance than the control group, and the triathletes exhibited less impact and better endurance performance than the runners.
    Clinics (São Paulo, Brazil) 09/2012; 67(9):1023-8. DOI:10.6061/clinics/2012(09)07 · 1.19 Impact Factor
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