Bone Adaptation to Impact Loading

Summary

Ageing populations have made osteoporosis and fragility fractures a major public health concern worldwide. Half of all women and 30% of all men will suffer a fracture related to osteoporosis during their lifetime. While medical prevention of this immense problem is impossible at population level, it is necessary to find efficient preventive strategies. Exercise is one of the major prevention approaches because one reason behind the increasing burden of osteoporosis is the modern sedentary lifestyle. However, the optimal type, intensity, frequency, and duration of exercise that best enhances skeletal integrity are still largely unknown.

We conducted a 12-month population-based randomized controlled exercise intervention in 120 premenopausal women. The aim was to investigate the effect of impact exercise on bone mineral density, geometry and metabolism in healthy women with the intention of assessing the intensity and amount of impact loading with a novel accelerometer-based measurement device. Training effects on risk factors of osteoporotic fractures, physical performance and risk factors of cardiovascular diseases were also evaluated.

This study demonstrated that 12 months of regular impact exercise favoured bone formation, increased bone mineral density in weight-bearing bones, especially at the hip, and led to geometric adaptations by increasing periosteal circumference. Bone adaptations had a dose- and intensity-dependent relationship with measured impact loading. Changes in proximal femur were threshold-dependent, indicating the importance of high impacts exceeding acceleration of 4 g as an osteogenic stimulus. The number of impacts needed to achieve this stimulation was 60 per day. Impact exercise also had a favourable effect on physical performance and cardiorespiratory risk factors by increasing maximal oxygen uptake, dynamic leg strength and decreasing low-density lipoproteins and waist circumference. Changes were dose-dependent with impact loading at wide intensity range.

Bone adapts to impact loading through various mechanisms to ensure optimal bone strength. The number of impacts needed to achieve bone stimulation appeared to be 60 per day, comparable to the same number of daily jumps. If done on a regular basis, impact exercise may be an efficient and safe way of preventing osteoporosis.

Conditions

• Osteoporosis

Interventions

BEHAVIORAL

Exercise

Progressive impact exercise

Sponsors & Collaborators

• Oulu Deaconess Institute

  collaborator OTHER

• UKK Institute

  collaborator OTHER

• Finnish Institute of Occupational Health

  collaborator OTHER

• The Finnish Funding Agency for Technology and Innovation (TEKES)

  collaborator OTHER_GOV

• Newtest Ltd

  collaborator UNKNOWN

• CCC Group Ltd.

  collaborator INDUSTRY

• Fastrax Ltd.

  collaborator INDUSTRY

• University of Oulu

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

PREVENTION

Masking

SINGLE

Model

PARALLEL

Eligibility

Min Age

35 Years

Max Age

40 Years

Sex

FEMALE

Healthy Volunteers

No

Timeline & Regulatory

Start

2002-05-31

Primary Completion

2003-06-30

Completion

2003-06-30

Countries

• Finland

Study Locations