The Engineering of Sport 7 pp 613-621 | Cite as
Exercise History and Remodelling Stress Fracture are Related to Cortical Bone Ultimate Strength (P264)
Abstract
Mechanical load deforms bone tissue first elastically then plastically. The tissue adapts to the load through internal remodelling and external modelling. Large or repetitive loads can induce significant damage and cause large changes in bone shape and density. Remodelling initially causes transient osteoporosis during damage removal. Intense exercise can damage bone material, we hypothesised that exercise history reduces bone ultimate strength and that ultimate strength is reduced in bones with evidence of stress fracture syndrome. Equine humeri from 18 Thoroughbred racehorses were categorised on the basis of periosteal callus (none, mild, moderate, severe). The location of the callus was consistent with stress related modelling at the proximocaudal stress fracture site. Cortical cores from the humeral diaphysis distal to the callus site were monotonically compressed to failure (strain rate: 0.01s−1). The effect of stress fracture callus severity on ultimate strength was assessed using non-parametric tests. The relationships between ultimate strength and exercise history variables were examined with univariate and stepwise linear regression (p<0.05). Cores with mild and moderate callus had 5.0% and 6.6% lower ultimate strength than cores without callus. High speed exercise distances (race, work, and total event distances in the 2–4 months before death) had positive, linear, univariate relationships with ultimate strength (r2>0.23). Average total high speed distance was the only parameter retained in the stepwise model (r2=0.42). Degradation of material properties occurred in cortical diaphyseal bone material of bones with early evidence of stress fracture syndrome at a distant site, and was related to intense exercise. Thus, remodelling events likely associated with stress fracture syndrome are not isolated to the site of stress fracture.
Keywords
Biomechanics Ultimate Strength Stress Fracture Bone CallusPreview
Unable to display preview. Download preview PDF.
6-References
- [D1]Davies, H. M. S. (2006). Estimating peak strains associated with fast exercise in Thoroughbred racehorses. International Conference on Equine Exercise Physiology. Fontainebleau, France, Equine Veterinary Journal. 36: 383–386.Google Scholar
- [EG1]Estberg, L., I.A. Gardner, et al. (1998). ≪A case-crossover study of intensive racing and training schedules and risk of catastrophic musculoskeletal injury and lay-up in California thoroughbred racehorses.≫ Prev Vet Med 33(1–4): 159–70.CrossRefGoogle Scholar
- [FR1]Firth, E. C. and C. W. Rogers (2005). ≪Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. Conclusions.≫ N Z Vet J 53(6): 377–83.Google Scholar
- [GM1]Gustafson, M. B., R. B. Martin, et al. (1996). ≪Calcium buffering is required to maintain bone stiffness in saline solution.≫ J Biomech 29(9): 1191–4.CrossRefGoogle Scholar
- [HG1]Hill, A. E., I. A. Gardner, et al. (2004). ≪Effects of injury to the suspensory apparatus, exercise, and horseshoe characteristics on the risk of lateral condylar fracture and suspensory apparatus failure in forelimbs of thoroughbred racehorses.≫ Am J Vet Res 65(11): 1508–17.CrossRefGoogle Scholar
- [HS1]Hsieh, Y. F. and M. J. Silva (2002). ≪In vivo fatigue loading of the rat ulna induces both bone formation and resorption and leads to time-related changes in bone mechanical properties and density.≫ J Orthop Res 20(4): 764–71.CrossRefGoogle Scholar
- [HL1]Huang, T.H., S. C. Lin, et al. (2003). ≪Effects of different exercise modes on mineralization, structure, and biomechanical properties of growing bone.≫ J Appl Physiol 95(1): 300–7.MathSciNetGoogle Scholar
- [JS1]Joo, Y. I., T. Sone, et al. (2003). ≪Effects of endurance exercise on three-dimensional trabecular bone microarchitecture in young growing rats.≫ Bone 33(4): 485–493.CrossRefGoogle Scholar
- [KE1]Kohrt, W. M., A. A. Ehsani, et al. (1997). Effects of Exercise Involving Predominatly Either Joint-Reaction or Ground-Reaction Forces on Bone Mineral Density in Older Women. 12: 1253–1261.Google Scholar
- [MB1]Martin, R. B., D. B. Burr, et al. (1998). Skeletal Tissue Mechanics. New York, Springer-Verlag New York.Google Scholar
- [MB2]Mori, S. and D. B. Burr (1993). ≪Increased intracortical remodeling following fatigue damage.≫ Bone 14(2): 103–9.CrossRefGoogle Scholar
- [NB1]Nunamaker, D.M., D. M. Butterweck, et al. (1989). ≪Some geometric properties of the third metacarpal bone: a comparison between the thoroughbred and standardbred racehorse.≫ J Biomech 22(2): 129–34.CrossRefGoogle Scholar
- [NB2]Nunamaker, D. M., D. M. Butterweck, et al. (1990). ≪Fatigue fractures in thoroughbred racehorses: relationships with age, peak bone strain, and training.≫ J Orthop Res 8(4): 604–11.CrossRefGoogle Scholar
- [RS1]Raab, D. M., E. L. Smith, et al. (1990). ≪Bone mechanical properties after exercise training in young and old rats.≫ J Appl Physiol 68(1): 130–4.Google Scholar
- [S1]Stover, S. M. (2003). ≪The epidemiology of Thoroughbred racehorse injuries.≫ Clinical Techniques in Equine Practice 2(4): 312–322.CrossRefGoogle Scholar
- [SJ1]Stover, S. M., B. J. Johnson, et al. (1992). ≪An association between complete and incomplete stress fractures of the humerus in racehorses.≫ Equine Vet J 24(4): 260–3.CrossRefGoogle Scholar
- [VP1]Verheyen, K., J. Price, et al. (2006). ≪Exercise distance and speed affect the risk of fracture in racehorses.≫ Bone 39(6): 1322–1330.CrossRefGoogle Scholar
- [VN1]Verheyen, K. L., J. R. Newton, et al. (2006). ≪A case-control study of factors associated with pelvic and tibial stress fractures in Thoroughbred racehorses in training in the UK.≫ Prev Vet Med 74(1): 21–35.CrossRefGoogle Scholar
- [WH1]Warden, S. J., J. A. Hurst, et al. (2005). ≪Bone adaptation to a mechanical loading program significantly increases skeletal fatigue resistance.≫ J Bone Miner Res 20(5): 809–16.CrossRefGoogle Scholar