Exercise and Sports Science Australia (ESSA) position statement on exercise prescription for the prevention and management of osteoporosis

TL;DR: Evidence from animal and human trials indicates that bone responds positively to impact activities and high intensity progressive resistance training, and the optimisation of muscle strength, balance and mobility minimises the risk of falls.

About: This article is published in Journal of Science and Medicine in Sport.The article was published on 2017-05-01 and is currently open access. It has received 208 citations till now. The article focuses on the topics: Exercise prescription & Osteoporosis.

Summary

Introduction

• Osteoporotic fractures are associated with substantial morbidity and mortality, also known as Objective.
• The aim of the current position statement is to provide health practitioners with specific, evidence-based guidelines for safe and effective exercise prescription for the prevention or management of osteoporosis, accommodating a range of potential comorbidities.
• Evidence from animal and human trials indicates that bone responds positively to impact activities and high intensity progressive resistance training, also known as Results.
• It is important that all exercise programs be accompanied by sufficient calcium and vitamin D, and address issues of comorbidity and safety.
• Loaded spine flexion is not recommended, and impact activities may require modification in the presence of osteoarthritis or frailty.

Background

• According to the WHO, a DXAderived BMD T-score (standard deviation, SD) of 2.5 or more below the mean for young adult Caucasian women constitutes a diagnosis of osteoporosis.
• While the precise dose of exercise to promote positive skeletal adaptations throughout life remains to be determined, current evidence indicates that the effects of exercise on bone are modality-, dose- and intensity-dependent.
• The goal of the current position statement is to provide specific exercise recommendations for the prevention and/or management of osteoporosis and fragility/low trauma fractures, within the limits of existing evidence.
• In older women, the skeletal response to high impact activities is less consistent, with some but not all trials reporting positive effects 45, 46 .
• Human data are confounded by an inability to control many variables that exert profound influence on bone; including genes, certain diseases, medications, diet and exercise history.

Exercise prescription – Recommendations (Summarised in Table 1)

• An exercise program of moderate to high-impact weight-bearing activities, high intensity PRT and balance training forms the basis of the current recommendations.
• While frail individuals would theoretically benefit from a similar program of osteogenic exercise, limitations in clinical or functional capacity may necessitate a more conservative approach, with a particular focus on optimising muscle function and enhancing balance to reduce the risk of falling 13, 53 .
• Thus, an exercise prescription should take account of an individual’s BMD and functional and clinical risk factors for falls and fracture.
• For some, a period of moderate advancing to high-intensity PRT may also be required to condition the musculoskeletal system before introducing impact exercises.
• The authors define “high risk” of low trauma fracture as having osteoporosis (T- score less than -2.5 SD), previous fracture, and/or multiple risk factors for fracture.

Special considerations

• Individuals with the lowest bone mass and/or the lowest levels of previous exercise exposure are likely to exhibit the greatest response to increased exercise loading 71 .
• Increasing muscle strength and balance will reduce fall risk and are therefore recommended for such individuals.
• Table 2 provides specific modifications to exercise recommendations for persons with common comorbidities, including osteoarthritis, frailty/neuromuscular impairment, and/or cardiopulmonary disease.
• The clinical community has traditionally discouraged repetitive impact exercise for individuals with hip or knee osteoarthritis (OA).
• A recent study has shown that progressive high impact exercise training can benefit bone without adversely affecting knee joint cartilage of mildly osteoarthritic postmenopausal women 72 .

Contraindications to exercise

• As with any exercise recommendation, certain caveats apply.
• Individuals with known vertebral osteoporosis/kyphosis should avoid deep forward flexion activities, particularly when lifting a load or carrying an object (e.g. rowing, lifting weights with a flexed spine, yoga, Pilates, bowling, sit-ups, house and yard work), in order to avoid vertebral wedge fractures.
• High-risk individuals should receive training in safe lifting and postural techniques to avoid dangerous or excessive loading during common daily tasks or recreational activities.
• Exercise prescription for individuals with pain, kyphosis and/or poor balance must be individualised and supervised.
• Finally, exercise recommendations for the prevention or management of osteoporosis must be undertaken within the boundaries of exercise restrictions for comorbid conditions.

Gaps in the literature

• There are two main gaps in the literature.
• It is not possible to provide definitive guidelines for the precise amount, intensity and duration of every exercise that will stimulate optimal gains in bone for every individual.
• It has been estimated that to power the definitive exercise intervention trial for a hip fracture endpoint in women, a sample size of over 7000 individuals at high risk of low trauma fracture would be required, which would take many years to recruit at a prohibitive financial cost 76 .
• The number would be far greater for a sample of men.
• Nevertheless, insufficient direct experimental evidence limits the ability to draw definitive conclusions with regards to the influence of exercise on fracture incidence.

Summary

• For the healthy individual whose goal is to prevent osteoporosis, lifelong exercise including regular, brief, weight-bearing, high-impact exercise and high intensity PRT is recommended.
• Adequate calcium and vitamin D will complement exercise programs for musculoskeletal health and function.
• For the high-risk individual with established osteoporosis and increased risk of fracture, falls prevention programs with a focus on balance and mobility training and high intensity PRT are essential.
• Ongoing supervision is required for individuals at high risk of low trauma fracture and those unaccustomed to high intensity exercise.
• Correct technique, particularly for exercises loading the spine, is imperative to avoid increasing the risk of vertebral fracture.

Frequently asked questions

Q1. What are the main causes of falls?

As falls are a major cause of fracture, gait, balance, mobility, transfer ability, range of motion, muscle strength (particularly of the trunk, elbow, hip and knee extensors) and vision should also be considered. 

Q2. What is the purpose of a PRT program for low-risk individuals?

Progressively challenging balance, posture and mobility exercises should be a greater focus than for low-risk individuals, to prevent falls. 

Q3. What is the role of exercise in preventing falls in older adults?

As kyphotic posture is associated with impaired balance in the elderly with osteoporosis 57 , back extension exercise may indirectly reduce falls risk. 

Q4. What is the role of exercise in preventing fractures in the elderly?

In light of the strong association between falls and osteoporotic fractures, any exercise programdesigned to prevent fractures in the elderly, particularly those with known risk factors for falling, should include activities to optimise muscle function, balance and gait stability. 

Q5. What is the role of exercise in the prevention and management of low bone mass?

As bone is a dynamic tissue with the capacity to adapt to changing load requirements, exercise iswidely recognised as a vital physical stimulus for the development and maintenance of optimal bone strength throughout life. 

Q6. How many people would be required to recruit for a definitive exercise intervention trial?

It has been estimated that to power the definitive exercise intervention trial for a hip fracture endpoint in women, a sample size of over 7000 individuals at high risk of low trauma fracture would be required, which would take many years to recruit at a prohibitive financial cost 76 . 

Q7. What are the commonly affected bones?

Osteoporotic fracture can occur at virtually any skeletal site; however, the bones most frequently affected are the spine, hip, wrist, humerus and pelvis. 

Q8. What are some of the benefits of combining PRT and high impact activities?

Some exercise programs that have combined both high intensity PRT and moderate-to-high impact activities such as running, jumping, skipping and high impact aerobics have improved multiple musculoskeletal outcomes for both older women and men, including BMD, and muscle mass, strength and function 48, 49 . 

Q9. How many studies have reported benefits of exercise to BMD in adulthood?

Many trials have reported relatively modest benefits of exercise to BMD in adulthood - preventing loss or promoting gains in the order of only 1-3% following exerciseinterventions of between 24 and 104 weeks 32 . 

Q10. How do you improve bone health in children and adolescents?

RCTs and meta-analyses indicate that exercise training involving certain forms of weight-bearing impact exercise, such as hopping and jumping, and/or progressive resistance training (PRT), alone or in combination (multi-modal programs), can improve the bone health of children and adolescents 28 , pre29 and postmenopausal women 30 , and older men 31 . 

Q11. What are the caveats for avoiding deep forward flexion activities?

Individuals with known vertebralosteoporosis/kyphosis should avoid deep forward flexion activities, particularly when lifting a load or carrying an object (e.g. rowing, lifting weights with a flexed spine, yoga, Pilates, bowling, sit-ups, house and yard work), in order to avoid vertebral wedge fractures. 

Q12. What are the caveats for high-impact activities and exercises?

high-impact activities and exercises that require rapid and/or loaded twisting, and explosive or abrupt actions (e.g., golf, racquet sports) may be contraindicated for some individuals at high risk of low trauma fracture, particularly those with vertebral osteoporosis, poor balance, or osteoarthritis. 

Q13. What is the evidence that walking can increase the risk of fracture?

There is also evidence that the inclusion of walking in an exercise program can expose previously sedentary or frail older adults to an increased risk of falling, thereby increasing the risk of fracture 13 . 

Q14. What are the feasible activities to optimise bone health at different stages of life?

More feasible activities to optimise bone health at different stages of life have been examined in randomised controlled trials (RCTs) designed to employ the principles of optimal loading from animal studies. 

Q15. What is the role of exercise in preventing falls in older people?

In most cases, falls prevention programs that are focused on balance and mobility, including Tai Chi or the well-known Otago Home Exercise Program, do not induce the necessary bone strain to stimulate adaptive skeletal benefits in older people 51, 52 , but may play a vital role in neuromuscular conditioning 53 . 

Q16. How many impacts are required to stimulate the response in premenopausal women?

Relatively few impacts (10-50/day, 3 times/week) 42 are required to stimulate the response in premenopausal women, but added benefit may be derived from more frequent exposure (4-7 days/week) 43 .