Exercise Loading and Bone Structure

This cross-sectional study of athletes investigates the influence of sport-specific, long-term physical oading on the bone structure and geometry

Background 

Intensive and regular physical loading is a natural way to make bones strong and thus partly contribute to preventing fragility fractures. Athletes, in turn, represent convenient natural experimental groups with a specific, long-term and intensive loading history, not achievable by other way.

Aim 

This study investigated the associations of sport-specific loading with the proximal femur structure and strength.

 
Methods 

Three-dimensional cortical geometry of the proximal femora in 91 adult female athletes competing in different sports (aerobics, volleyball, swimming, racket sports, soccer, orienteering, weightlifting, cycling, speed skating, cross-country skiing and hurdling) and 20 habitually physically active women were determined using data from magnetic resonance imaging (MRI). Also dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) were done. The sports were categorized into high-impact, odd-impact, repetitive impact, high magnitude, and repetitive nonimpact loadings. Besides assessing various structural and geometric traits from the MR images of bones, finite element models (FEM) for each participant have been created and these models are being evaluated in different loading conditional and simulations.

Results 

Compared to high-impact exercises, established to be osteogenic, also moderate magnitude, odd impacts from unusual directions have similar ability to thicken those cortical regions at the femoral neck which have been vulnerable to fracture. Since the odd-impact exercises are mechanically less demanding to the body, this type of exercise can provide a reasonable basis for devising feasible, targeted bone training against hip fragility. In fact, all types of impact loading, including endurance running causing repetitive impacts, were associated with a stronger proximal femur in a simulated fall situation.

 
Contact 

Harri Sievänen, Research Director 
harri.sievanen(a)ukkinstituutti.fi 

Publications 

Five-year follow-up results of aerobic and impact training on bone mineral density in early breast cancer patients – PubMed (nih.gov) 

Effectiveness of a 12-month Exercise Intervention on Physical Activity and Quality of Life of Breast Cancer Survivors; Five-year Results of the BREX-study – PubMed (nih.gov) 

Niinimäki S, Narra N, Härkönen L, Abe S, Nikander R, Hyttinen J, Knüsel C, Sievänen H. The relationship between loading history and proximal femoral diaphysis cross-sectional geometry.Am J Hum Biol. 2017;29(4).

Abe S, Narra N, Nikander R, Hyttinen J, Kouhia R, Sievänen H. Exercise loading history and femoral neck strength in a sideways fall: A three-dimensional finite element modeling study.Bone. 2016;92:9-17.

Narra N, Nikander R, Viik J, Hyttinen J, Sievänen H. Femoral neck cross-sectional geometry and exercise loading.Clin Physiol Funct Imaging. 2013;33:258-66.

Nikander R, Kannus P, Rantalainen T, Uusi-Rasi K, Heinonen A, Sievänen H. Cross-sectional geometry of weight-bearing tibia in female athletes subjected to different exercise loadings.Osteoporos Int. 2010;21(10):1687-94.

Nikander R, Kannus P, Dastidar P, Hannula M, Harrison L, Cervinka T, Narra NG, Aktour R, Arola T, Eskola H, Soimakallio S, Heinonen A, Hyttinen J, Sievänen H. Targeted exercises against hip fragility. Osteoporos Int. 2009;20(8):1321-8.