Dance Anatomy & Kinesiology

8 Dance Anatomy and Kinesiology

(0.2 liters) of milk, 1 cup of yogurt, or

1 ounce (28 grams) of Swiss cheese. So

one can easily achieve 1,200 milligrams

of calcium by having four of such dairy

options or three dairy options plus

other selections that add up to the

needed additional 300 milligrams (see

table 1.1). To foster goals of staying

lean, low or nonfat varieties of these

dairy products can be selected (for

more specific recommendations, see

Nancy Clark’s Sports Nutrition Guidebook

[1997]). For dancers who cannot toler-

ate or do not like dairy products, one

can see from looking at table 1.1 that

it is difficult to meet recommended

values. In such cases, consultation with

a nutritionist and discussion of supple-

mentation with the dancer’s physician

are recommended.

Stress Fractures

While exercise usually serves as a stimu-

lus for increasing bone density, there

are times when the breakdown of bone

exceeds the repair and remodeling of

bone and a stress fracture occurs. A

stress fracture is a microscopic fractur-

ing of the bone resulting in a thin crack

that is so small, it is not even initially

apparent on an X ray. When a bone

undergoes excessive repetitive submax-

imal stress, it responds with increased

osteoclast activity. These osteoclasts

resorb bone as the first step before

laying down a stronger new matrix. In

the process, they temporarily leave the

bone weaker. If stress is too great, the

outer portion of the bone (cortex) may

crack, creating a stress fracture.

Theoretically, stress fracture risk can

be increased by factors that negatively

impact bone health, and so all of the

factors just discussed relating to bone

density, including being female, a his-

tory of menstrual disturbance, less lean

mass in the lower limb, inadequate

calcium intake, a low-fat diet, and smok-

ing, can heighten stress fracture risk

(Bennell et al., 1996; Clarkson, 1998;

Hershman and Mailly, 1990; Taube and

Wadsworth, 1993). Female athletes have

been reported to have a 1.5 to 3.5 times

TABLE 1.1 Calcium Content of Selected Foods (Approximate)

Serving

size

Calcium

content

(mg) Calories

Dairy products

Low-fat yogurt

Plain

Fruit-flavored

1 cup

1 cup

415

340

145

230

Ricotta cheese (part skim) 1/2 cup 335 170

Low-fat milk 1 cup 300 120

Swiss cheese 1 oz 270 105

Cheddar cheese 1 oz 205 110

American cheese 1 oz 175 105

Low-fat cottage cheese 1/2 cup 70 100

Cream cheese 2 tbsp 20 100

Protein foods

Processed tofu with calcium sulfate 4 oz 145 70

Eggs 2 large 56 160

Cooked lentils 1 cup 50 210

Almonds 12-15 40 90

Peanut butter 2 tbsp 20 190

Hamburger patty 3 oz 10 200

Chicken 3 oz 10 140

Vegetables and fruits

Collard greens 1/2 cup 180 30

Bok choy, cooked 1/2 cup 125 15

Broccoli 1/2 cup 70 20

Orange 1 medium 55 70

Green beans 1/2 cup 30 15

Orange juice 1 cup 27 110

Calcium fortified orange juice 1 cup 300 110

Mashed potatoes 1/2 cup 25 100

Carrots 1/2 cup 24 24

Lettuce 1/4 head 20 27

Apple 1 medium 10 80

Grains

Whole-wheat bread 2 slices 40 130

Cooked rice 1/2 cup 10 80

Bagel (water) 1 3 in. 8 165

Sources: Clark (1997) and U.S. Department of Agriculture (1981).