Bone mineral density accounts for 70% of bone strength Normal Bone Osteoporotic Bone http://www.nof.org/osteoporosis/bonehealth.htm

Types of Bone Neiman pg 617 Bone is a spongy protein matrix in which crystals of calcium and phosphorus salts are embedded. Once produced, bone does not remain as a fixed structure. From birth until death, bone tissue is continually being formed, broken down and re-formed in a process called re-modeling. During puberty, rapid increases in bone growth and density occur, with peak bone density achieved between the ages of 20-30. About 90% of the adult bone mineral content is deposited by the end of adolescence, and this process is affected by both genetic and lifestyle factors.

Types of Bone cortical (compact)-outer, dense shell around bones; thick shafts of long bones ACE CES Manual-pg 362 The human skeleton is composed of two types of bone: cortical (compact) and trabecular (spongy). Cortical bone forms a dense shell around all bones and constitutes the thick shafts of long bones, while trabecular bone is found in the vertebrae and in the ends of long bones. Trabecular bone forms a lattice-like network, which greatly increases its surface area for metabolic activity. As a result, trabecular bone undergoes far more remodeling cycles during an individuals lifetime than cortical bone.

Types of Bone Trabecular (spongy)-found in vertebrae and ends of long bones; forms a lattice-like network increasing its surface area for metabolic activity ACE CES Manual-pg 362 The human skeleton is composed of two types of bone: cortical (compact) and trabecular (spongy). Cortical bone forms a dense shell around all bones and constitutes the thick shafts of long bones, while trabecular bone is found in the vertebrae and in the ends of long bones. Trabecular bone forms a lattice-like network, which greatly increases its surface area for metabolic activity. As a result, trabecular bone undergoes far more remodeling cycles during an individuals lifetime than cortical bone.

Insert fig 15.26 (b) Neiman pg 616

Dowager’s Hump

Remodeling Cycle Bone Resorption (bone removal) Bone Formation ACE-Clinical Ex Specialist Manual==pg 362 A remodeling cycle consists of a bone resorption (bone removal) stage which is followed by a period of new bone formation. Through this coupled process, bone is constantly renewed. During growth and young adulthood, the rate of bone formation is faster than the rate of bone resorption, leading to a gain in bone mineral. This is called bone modeling. During puberty, rapid increases in bone growth and density occur, with peak bone density achieved b/t the ages of 20-30. About 90% of adult bone mineral content is deposited by the end of adolescence, a process affected by both genetic and lifestyle factors. The period b/t ages 9-20 is critical in building bone density. Following growth, the continual process of bone resorption occurs at a slightly faster rate than bone formation, causing a steady, gradual decline in the amount of bone mineral in the skeleton of about 1%/yr These age-related decrements are not as pronounced in men, primarily b/c men reach a higher peak bone density and do not undergo rapid postmenopausal bone loss as women do. Bone resorption is rapid during the first 5 yrs following menopause and may account for 3-5% loss of overall bone mass/yr. During the course of their lifetimes, women lose ~50% of trabecular bone and 30% of cortical and men lose ~ 30 and 20% respectively. Bone Formation

Remodeling Cycle Osteoclast Osteoblasts ACE-Clinical Ex Specialist Manual==pg 362 A remodeling cycle consists of a bone resorption (bone removal) stage which is followed by a period of new bone formation. Through this coupled process, bone is constantly renewed. During growth and young adulthood, the rate of bone formation is faster than the rate of bone resorption, leading to a gain in bone mineral. This is called bone modeling. During puberty, rapid increases in bone growth and density occur, with peak bone density achieved b/t the ages of 20-30. About 90% of adult bone mineral content is deposited by the end of adolescence, a process affected by both genetic and lifestyle factors. The period b/t ages 9-20 is critical in building bone density. Following growth, the continual process of bone resorption occurs at a slightly faster rate than bone formation, causing a steady, gradual decline in the amount of bone mineral in the skeleton of about 1%/yr These age-related decrements are not as pronounced in men, primarily b/c men reach a higher peak bone density and do not undergo rapid postmenopausal bone loss as women do. Bone resorption is rapid during the first 5 yrs following menopause and may account for 3-5% loss of overall bone mass/yr. During the course of their lifetimes, women lose ~50% of trabecular bone and 30% of cortical and men lose ~ 30 and 20% respectively. Osteoblasts

From: Geriatric Consultant Resources LLC http://www.gcrweb.com/OsteoDSS/clinical/path/pages/path-bone-rem.html

Remodeling Cycle Osteoclast: Bone Resorption ACE-Clinical Ex Specialist Manual==pg 362 A remodeling cycle consists of a bone resorption (bone removal) stage which is followed by a period of new bone formation. Through this coupled process, bone is constantly renewed. During growth and young adulthood, the rate of bone formation is faster than the rate of bone resorption, leading to a gain in bone mineral. This is called bone modeling. During puberty, rapid increases in bone growth and density occur, with peak bone density achieved b/t the ages of 20-30. About 90% of adult bone mineral content is deposited by the end of adolescence, a process affected by both genetic and lifestyle factors. The period b/t ages 9-20 is critical in building bone density. Following growth, the continual process of bone resorption occurs at a slightly faster rate than bone formation, causing a steady, gradual decline in the amount of bone mineral in the skeleton of about 1%/yr These age-related decrements are not as pronounced in men, primarily b/c men reach a higher peak bone density and do not undergo rapid postmenopausal bone loss as women do. Bone resorption is rapid during the first 5 yrs following menopause and may account for 3-5% loss of overall bone mass/yr. During the course of their lifetimes, women lose ~50% of trabecular bone and 30% of cortical and men lose ~ 30 and 20% respectively. Osteoblasts: Bone Formation

Remodeling Cycle Estrogen Osteoclast Osteoblasts ACE-Clinical Ex Specialist Manual==pg 362 A remodeling cycle consists of a bone resorption (bone removal) stage which is followed by a period of new bone formation. Through this coupled process, bone is constantly renewed. During growth and young adulthood, the rate of bone formation is faster than the rate of bone resorption, leading to a gain in bone mineral. This is called bone modeling. During puberty, rapid increases in bone growth and density occur, with peak bone density achieved b/t the ages of 20-30. About 90% of adult bone mineral content is deposited by the end of adolescence, a process affected by both genetic and lifestyle factors. The period b/t ages 9-20 is critical in building bone density. Following growth, the continual process of bone resorption occurs at a slightly faster rate than bone formation, causing a steady, gradual decline in the amount of bone mineral in the skeleton of about 1%/yr These age-related decrements are not as pronounced in men, primarily b/c men reach a higher peak bone density and do not undergo rapid postmenopausal bone loss as women do. Bone resorption is rapid during the first 5 yrs following menopause and may account for 3-5% loss of overall bone mass/yr. During the course of their lifetimes, women lose ~50% of trabecular bone and 30% of cortical and men lose ~ 30 and 20% respectively. Osteoblasts

Eating Disorders Amenorrhea Osteoporosis Triad Factor #1: Disordered Eating Most girls with female athlete triad try to lose weight primarily to improve their athletic performance. The disordered eating that accompanies female athlete triad can range from avoiding certain types of food the athlete thinks are "bad" (such as foods containing fat) to serious eating disorders like anorexia nervosa or bulimia nervosa. Triad Factor #2: Amenorrhea Because a girl with female athlete triad is simultaneously exercising intensely and not eating enough calories, when her weight falls too low, she may experience decreases in estrogen, the hormone that helps to regulate the menstrual cycle. As a result, a girl's periods may become irregular or stop altogether. Of course, it is normal for teen girls to occasionally miss periods, especially in their first year of having periods. A missed period does not automatically mean a girl has female athlete triad. A missed period could mean something else is going on, like pregnancy or a medical condition. If you have missed a period and you are sexually active, talk to your doctor. Some girls who participate intensively in sports may never even get their first period because they've been training so hard. Other girls may have had periods, but once they increase their training and change their eating habits, their periods may stop. Triad Factor #3: Osteoporosis Low estrogen levels and poor nutrition, especially low calcium intake, can lead to osteoporosis, the third aspect of the triad. Osteoporosis is a weakening of the bones due to the loss of bone density and improper bone formation. This condition can ruin a female athlete's career because it may lead to stress fractures and other injuries. Usually, the teen years are a time when girls should be building up their bone mass to their highest levels — called peak bone mass. Not getting enough calcium during the teen years can also have a lasting effect on how strong a girl's bones are later in life. Osteoporosis

INCIDENCE OF ANOREXIA & BULIMA Percent of Athletes Specific Sports College HS

AMENORRHEA Athletes Percent of Population (%) General

Active Regular Cycling OSTEOPOROSIS Incidence of Bone Fractures (%) Active Amenorrhic Active Regular Cycling Control Marcus eat al, Ann Int Med 102:158-163, 1985

Exercise and Bone Health Tennis Players Soldiers Epicondylar Width 6.46 vs. 6.41 Epicondylar Width 6.69 vs. 6.59 Ulnar Width 1.86 vs 1.79 Ulnar Width 1.65 vs 1.62

Gravity and Bone Health Space Station crew lost interior bone @ 2.2 -2.7% per month in space outer bone @ 1.6 - 1.7% per month. hipbone strength declined by 2.5% per month of flight. vertebral bone @ 0.8 to 0.9% per month, Space travel http://www.spacedaily.com/news/spacetravel-04h.html

Exercise and Bone Health Calcaneous Bone Loss from Bed rest ACSM Resource Manual, page 200

Exercise and Bone Health Femoral Neck Bone Loss from Bed rest ACSM Resource Manual, page 200

Bone Loss from Bed Rest

Exercise and Bone Health Re-ambulation following bed rest

Exercise and Bone Health Smith, E. et al. Med Sci Sports Exerc 13, 80, 1981.

Exercise and Bone Health Cavanaugh Dj & CE Cann, Bone 9:201-204, 1988.

Exercise and Bone Health Control (n=18) Exercise n=17 9 months n= 14 Detraining (n=6) Exercise (n=11) 18 months 13 months Detraining (n=9) 12 months Dalsky et al., Ann Int Med 108:824, 1988

Exercise and Bone Health Detraining Dalsky et al., Ann Int Med 108:824, 1988

Exercise and Bone Health No change in neck of femur or wrist Pruitt, LA et al, J Bone & Min Res 7:179-185, 1992

BALANCE AND FALLS Hourigan, SR, et al Osteoporosis International DOI 10.1007/s00198-0541-7

Piezeoelectric Effect

Piezeoelectric Effect Muscle + - Bone Growth