(HealthDay News) -- Gardening is a great form of exercise, but it can also leave you with a painful backache.

(HealthDay News) -- A muscle cramp occurs when a muscle involuntarily tightens and does not release, often leading to intense pain.

TUESDAY, May 8 (HealthDay News) -- Everyone knows teen behavior is highly influenced by their friends, but a new study finds even a friend's parents can influence whether or not a teen drinks alcohol or uses drugs.

TUESDAY, May 8 (HealthDay News) -- Incentives such as gift cards, T-shirts and coupons encourage more people to donate blood, a new study finds.

TUESDAY, May 8 (HealthDay News) -- Women who use an intrauterine device (IUD) as birth control may not have to worry about gaining weight after the device is implanted, new research suggests.

TUESDAY, May 8 (HealthDay News) -- Nearly half of the counties in the United States lack a single obstetrician-gynecologist, a situation that may worsen as medical school graduates gravitate toward metropolitan areas, a new study indicates.

TUESDAY, May 8 (HealthDay News) -- There is a great deal of genetic diversity in cells shed by cancerous tumors into the bloodstream, a new study has found.

TUESDAY, May 8 (HealthDay News) -- Consuming probiotic-rich foods may decrease the risk of diarrhea for patients who are taking antibiotics, a new study suggests.

TUESDAY, May 8 (HealthDay News) -- Sperm cells navigate the complex fluid-filled channels of the female reproductive tract by crawling along walls and swimming around corners, a new study reveals.

TUESDAY, May 8 (HealthDay News) -- Eye color may help predict risk for vitiligo, an autoimmune disease in which the skin loses its pigment, a new study finds.

TUESDAY, May 8 (HealthDay News) -- The United States' progress against the battle of the bulge has been slow, but certain strategies could speed obesity prevention efforts, a new report concludes.

TUESDAY, May 8 (HealthDay News) -- Eating too quickly may raise your risk of diabetes, a small, preliminary study suggests.

TUESDAY, May 8 (HealthDay News) -- Now there's another reason to hate your commute.

TUESDAY, May 8 (HealthDay News) -- Routine screening of women for domestic violence could reduce cases of abuse and injuries, a new analysis indicates.

TUESDAY, May 8 (HealthDay News) -- A five-year study of home births in Oregon found an elevated rate of deaths among babies that had to be transferred to the hospital because something went wrong during the delivery.

Here are some of the latest health and medical news developments, compiled by the editors of HealthDay:

TUESDAY, May 8 (HealthDay News) -- Older women with the irregular heartbeat known as atrial fibrillation face a 14 percent greater risk of stroke than men with the same condition, Canadian researchers report.

TUESDAY, May 8 (HealthDay News) -- Being physically active might lengthen the lives of people with breast and colon cancer, a new study suggests.