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Exercise and Bone Health

Exercise and Bone Health. Patty Trela, PT, DPT, CMPT University Of Utah Health Care Orthopaedic Center Utah Physical Therapy Spring Conference 2009. Objectives. Prescribe exercise that can increase/maintain bone density

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Exercise and Bone Health

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  1. Exercise and Bone Health Patty Trela, PT, DPT, CMPT University Of Utah Health Care Orthopaedic Center Utah Physical Therapy Spring Conference 2009

  2. Objectives • Prescribe exercise that can increase/maintain bone density • Prescribe exercise for bone health, deformity, prevention, falls prevention • Identify physical activity exercise precautions for those with osteoporosis

  3. Exercise: 4 reasons to prescribe (prevention and treatment) • To affect bone mass, structure, and morphology (size and shape) • To prevent falls and fractures • To prevent deformity • To recover function and reduce pain after fracture

  4. Goal 1: Preserve Bone MassImprove Structure, Size, and Shape • Cortical • Long, parallel, compact • Makes up 80% of our bone • Trabecular • Sponge-like • Has 80% more metabolic turnover than cortical • Makes up 20% of our bone • Effected by a greater degree by osteoporosis

  5. Exercise Affect on Bone • Mechanical Loading “speaks” to bone cells • Strain= the deformation of bone tissue in response to load • Deformation/bending cause biomechanical signals that influence bone cell function and keep osteocytes vital • Osteocytes function as strain transducers and they communicate with bone where formation and resorption occur

  6. Optimal Strain for Bone Building • Not a linear relationship • To maintain bone, low magnitude strains work (turkey ulnas: 4 cycles/day) • To build bone, strains need to be: unusual, novel, not customary in distribution • High magnitude and High rates

  7. Not prolonged exercise because mechanoreceptors in bone desensitize rapidly (turkey ulnas 36 cycles per day; 2 min out of 24 hours) Lanyon LE. Bone 1996;18:37S-43S Skerry TM, Suva LJ. Cell Biochem Funct 2003;21:223-229 hours)

  8. Any is good..on Bedrest, bone loss of about 1%/wk, regain at about 1%/month; markers of bone resorption increase after 24 hrs. • Krolner B, Toft B Clin Sci 1983;64:537-40LeBlanc et al. J Bone Miner REs 1990;5:842-50Baecker et al. J app Physiol 2003;95:977-982 • High impact (jumping) is best studied...Children about 2-4% gain Premenopausal women about 1-3% gain

  9. High Impact Exercise • 9 months, 2x/wk; non-impact ex + 20 min high-impact jump training • Increased bone acquisition • premenarcheal female - increased BMD L-spine and femoral neck • postmenarcheal female - no increase BMD Heinonen A et al. Osteoporos Int (2000) 11:1010-10-17

  10. If adults can’t jump, exercise will only maintain bone mass (refill remodeling space?), not increase it • Weight bearing: meta-analysis showed about 1% maintenance of bone per year in pre and postmenopausal women. Wolff et al. Osteoporo Int 1999;9:1-12 • Progressive resistive/strength training: systematic review and meta-analysis showed about 1% maintenance of bone.

  11. High Impact exercise improved bone density (lumbar spine and upper femur) in premenopausal women • 12 months, 3x/wk; 60min ex with 40 min high impact; combined supervised and home program Vainionpaa A et al. Osteoporos Int (2005) 16: 191-197 • Intensity of physical training • Acceleration level equal to running is sufficient to create a positive change at the hip. Vainionpaa A et al. Osteoporos Int (2006) 17: 455-463

  12. Trunk extension strengthening for 6 months beginning 2 months post lung transplant preserved lumbar bone ( Mitchell et al. Transplantation 2003;76:557-562) • Lumbar Extension Machine Training in lung transplant patients: • Exercise group gained 9.2% lumbar BMD • Conrol group lost another 5% lumbar BMD ( Mitchell et al. Transplantation 2003;76:557-562)

  13. Astronaut Bone Density • calcaneous - tremendous variability of loss • radius/ulna - little change in density • 6 month flight • 23% decline in bone loss in femoral neck • 20% decline in load to failure

  14. 2007 Bone recovery Assessment • DEXA in Astronauts • 50% restoration of bone in 9 months • Bone recovery is slow • Problem with repeat fliers – Mars??

  15. Exercise for skeletal healthBirth to young adult • Children, adolescents, young adults: variety of physical activities • Sports: jumping, racket sports, volleyball, basketball, soccer, step aerobics, hockey or speed skating. Nikander et al.JBMR 2005;20:520-528 • Beware of too much exercise leading to amenorrhea in young women

  16. Sedentary former gymnasts • 20-32 y/o female; trained 5-12 yrs; retired between 14-22 y/o • gymnasts had higher BMD than controls at all sites • No decline in BMD with increased duration of retirement • BMD of former gymnasts retained during early adulthood.

  17. Exercise for Skeletal HealthMiddle Adult • People without osteoporosis • Strength training 2-3 times per week; 20-30 min • Weight bearing 3-4 times/week, 30-40 min • Posture Exercises • Balance Exercises • If a Person only has time for one exercise: Strength Training!

  18. Exercise for Skeletal Health:Middle and Older Adulthood • People without osteoporosis: • Strength training 2-3 times per week, 20-30 min • Weight Bearing 3-4 times/week, 30-40 min • Impact is ok (as long as joints can handle it) • Posture exercises • Balance Exercises

  19. Male, Elite, Professional Volleyball Players • Compared to non-active controls, BMD was greater in the hip, spine, dominant arm and whole body BMD was greater. Calbet JAL et al. Osteoporos Int (1999) 10:468-474.

  20. Competitive cyclists • Highly competitive young athlete (31.7 + 3.5yrs) and master male cyclist (51.2 + 5.3yrs), min 10 yrs training with little or no WB exercise. • BMD of spine and total hip was lower in master cyclists • Total body BMD was lower in the master’s cyclists compared to the young-adults.15% master cyclists T-scores were lower than -2.5

  21. Long-term home based resistance training • Post-menopausal women (59-78 yrs) on hormone therapy • reversed bone loss, decreased bone turnover, increased femur BMD and maintained body composition. • UE and LE training groups had similar responses to moderate resistance training, supporting a systemic response. Judge et al 2005

  22. Aerobic high impact loading exercise • 24-week, 3x/wk: osteopenic postmenopausal women (48-65 y/o) • treadmill walking (>70%VO2max) for 30 min, 10 min stepping exercise using a 20 cm-high bench • BMD L2-4 of femoral neck increased 2.3% and 6.8% in exercisers and decreased 2.3% 1.5% in controls, respectively • Moderate intensity aerobics with high-impact exercise was effective in offsetting the decline in BMD. Chein Y et al 2000

  23. Exercise Skeletal Health: Osteoporosis • Any age with osteoporosis • Weight bearing 3-4 times/week, up to 45 min • Supervision/training initially for strength training • Balance exercise • Posture exercises • Instruction in safe exercise/movement

  24. Goal 2: Prescribing Exercise to affect bone • Site specificity • Over-exercise • Amenorrhea • endurance loading and fatigue micro damage • Bone status (normal, low bone density, osteoporosis and fracture history) • Health status and co-morbidity

  25. Prospective Follow-up of Subjects in an Exercise RCT • 50 postmenopausal white women who participated in an exercise RCT 10 years previous • At 10 year follow up, VF incidence in the extensor strengthening group was 1.6% vs. 4.4% in the control (p=0.03) • Women in exercise group were still stronger in extensor muscles although they did not continue specific exercise. Sinaki M et al. Bone 2002;30:836-41

  26. Spine Flexion and Incident Fracture • Vertebral Fracture incidence by type of exercise over 1-6 years, in women with osteoporosis and previous vertebral fracture: • 89% flexion • 67% no exercise • 53% flexion and extension • 16% extension Sinaki et al. Arch Phys Med Rehabil 1984;65:593-96

  27. Goal 3: The Importance of Preventing the First Vertebral Fracture • Vertebral fractures are very common >50 y/o • History of fracture is the strongest risk factor for incident fracture • 2/3 of vertebral fractures do NOT come to clinical attention • Even radiographically-detected vertebral fractures are associated with pain, disability, and premature death

  28. Fractures Predict Fractures • Prior fracture increases risk about 4 fold for another vertebral fracture • Other prior fracture (any site, hip, wrist) increase risk 2 fold for any fracture. Klotzbuecher et al, J Bone Miner REs 2000; 15:721-739.

  29. Increased bone density with resistive exercise • Sedentary 50-70y/o postmenopausal women • 2x/wk exercised on 5 machines for 1 year at a gym • Significant bone density increases in spine, hip and total body (Nelson and Fiatarone 1994)

  30. Exercise effect on bone only works when regular • Postmenopausal women exercised 3 times/week for 9 months • Stair climbed 30 min each session • Spine bone density increased 4% • Bone density returned to baseline within 9 months for those that stopped exercising Dalsky 1988

  31. Safe Exercise for those with Osteoporosis • Avoid high impact • Avoid trunk/spinal • Forward bending/flexion • Loading twisting/rotation

  32. Posture Training • Prevention of fractures • Prevention of progressive Kyphosis • Progressive resistive exercises for back strengthening • Postural exercises

  33. Fracture Force Risks During Bending and Lifting • Compression loads imposed on the L3 segment by 30 degrees trunk flexion • 1800 N arms at chest • 2610 N arms in front hold 2kg in each hand Schultz et al 1982 • To fracture • An osteoporotic vertebra – 300 to 1200 N Edmonson et al 1997

  34. Bend and lift with spine neutral with all postures and activities

  35. Body Mechanics

  36. Exercise Types Improve Kyphosis • Strengthening trunk extensors, abdominals (via stabilization, not flexion), and posterior scapular muscle groups + stretching. • Modified Yoga • Pilates, “core” exercise should have similar benefit • A caveat: must modify for those with osteoporosis - avoid trunk flexion and loaded rotation

  37. Weight Vest – Tool to increase loading • Size: should fit snug to your body and material should be breathable • Start with 5% of your body weight • Increase by 1-2% every 2-3 weeks • Do this for 6-7 weeks, drop down to a much lower weight • Then repeat the build up (periodization) www.wasatchweightvest.com

  38. Issues • Rehabilitation varies by type of fracture (vertebral, hip, wrist, pelvis, humerus, etc) • Few studies of efficacy and effectiveness of interventions • Patient education re: safe movement and activity modification is crucial, but often neglected, after osteoporotic fractures and vertebroplasty/kyphoplasty procedures.

  39. Role of the Physical Therapist • Examination • Measure impairments in alignment, ROM, muscle strength, balance and mobility • Intervention • Prescribe appropriate exercise • Perform manual therapy as appropriate • Educate regarding fracture prevention • Restore function and manage pain

  40. Outcome Measures that are Practical and Motivating to Patients • Timed Loaded Standing to assess trunk and upper extremity endurance. Shipp et al. Osteoporosis Int 2000;11;11:914-922 • Functional Reach or Berg Balance Scale for Balance Capability. Duncan et al J Gerontol 1990;M192-M197. Berg et al. Physiother Can 1989;41:41:304-311 • Gait Velocity • Six Minute Walk • Osteoporosis Quality if Life Questionaire for Disease Specific Ability. Cook et al. Arthritis Rheum 1993;36:750-756

  41. Flexicurve Measurement

  42. Kyphotic Index (KI) • KI = 100 x (TW) divided by (TL) • Clinical Kyphosis > 13 • The greater the KI • decreased VO2 max • decreased strength bench press

  43. Decreased Kyphosis with Exercise • 2x/wk for 12 weeks and daily HEP • Women, mean age 72 yrs, Kyphosis 57 degrees • Exercise: spine extensor strength; thoracic spine, shoulder, and hip ROM, and postural alignment • High intensity PRE’s, foam roller and stretch straps • Improvements in posture (decreased Kyphosis 5%), extensor muscle strength and physical performance Katzman et al 2007

  44. Exercise for Posture and Body Mechanics • Focus on: • Strengthen spine and hip ext, scapular stabilizers, abdominals and extremities • Lengthen cervical muscles, anterior thorax/shoulder girdle, hips, knees, calf/Achilles complex • Individualized by presentation • Practice various activities: home, work, recreation, and sport (yoga, pilates)

  45. Goal 4: Falls Prevention • >1/3 of US adults > 65 y/o fall each year • >90% of hip fractures in adults are caused by falls in age >65 • Most often by falling to side on to hip • Fracture rates double for each decade 65-85+

  46. Predictors of Injurious Falls in Older Persons • One-Leg Balance - can’t stand on one leg Vella B et al; JAGS, 45(6)-1997, 735-8 • Stand and reach less than 6” - highly predictive

  47. Exercise to decrease fall risk • Neuromuscular risk factors for falls: • poor balance • weak muscles • Kyphosis • reduce proprioception • Other risks modified by exercise • previous fall • Impaired transfer and mobility

  48. Falls prevention • Women with osteoporosis and thoracic hyperkyphosis have: • reduced muscle strength • increased body sway (mediolateral) • gait unsteadiness • increased risk of falls Sinaki et al 2005

  49. Balance/Falls prevention • High-Intensity strength training preserve bone density, improve muscle mass, strength and balance in post-menopausal women. • Strength, balance, agility and jumping training improved balance and prevented functional decline in home-dwelling elderly women • Tai Chi has been shown to be effective in increasing balance in the elderly

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