Just when the news seems as bad as it can be, researchers find even more. According to a study authored by Dain LaRoche, an Assistant Professor of Kinesiology at UNH, women who are overweight or obese have less of both leg strength and overall leg power than peers of the same age who are at their optimal weight. Those factors, specifically the reduced leg power, increases the risk of injuries that can cause permanent disability and a loss of independence. It has been a long held myth that it is only the underweight seniors who are at risk for injury.

LaRoche’s study began in part because of the prevalence of obesity among Americans and the number of people who are heading into senior citizen status. Over two thirds of American adults are either overweight or obese and the elderly population will more than double by 2030 which increases the number of adults who are over their ideal weight.

Using a number of volunteers, LaRoche measured leg strength and leg power plus walking speed on women who were normal weight as well as those who were overweight. In terms of absolute strength, which is measured differently, there was little difference in the women, regardless of their size, but in terms of lower body strength, there was a 24% decrease in women who were overweight and the numbers were even worse when it came to terms of power. In the study, power was defined as the rate at which speed is applied during a motion or exercise. Power became the more important number to monitor because it was most closely related to actual physical function and increased fall risk. In that measurement, overweight women were nearly 40% less powerful than their thinner peers. Walking speed for the overweight women was also 20% slower.

According to these results, LaRoche cautions adults to maintain normal weight if possible but if they were already overweight, they had two options: to either lose weight or to gain strength. Despite the old thinking, older adults can strength train and make serious gains in their overall physical strength. For most adults, gaining strength may be easier to accomplish than trying to lose weight is.

The news for men is not much better with another study showing that overweight and obese men are at increased risk for osteoarthritis that will lead to the need for a hip replacement. Women are spared this risk, even at increased weight. In the limited study, women were no more likely to need hip or knee replacement because of their weight and/or osteoarthritis.

In the study, nearly 1500 Icelandic people who had had hip and/or knee replacement were compared against 1103 people who did not have either surgery. One of the factors used in the study the body mass index. Women, according to the study, were not affected but overweight men were more likely to need a hip replacement while the risk went up to 70% for obese men.