[1] According to the Johns Hopkins Bloomberg School of Public Health, 66% of the American population is either overweight or obese and this number is predicted to increase to 75% by 2015.
[2] Obesity is linked to health problems such as decreased insulin sensitivity and diabetes,[3] cardiovascular disease,[4] cancer,[5] sleep apnea,[6] and joint pain such as osteoarthritis.
Humans expend energy through their basal metabolic rate, the thermic effect of food, non-exercise activity thermogenesis (NEAT), and exercise.
[8] While many treatments for obesity are presented to the public, exercise in the form of walking is an easy, relatively safe activity.
[9] Knee osteoarthritis and other joint pain are common complaints amongst obese individuals and are often a reason as to why exercise prescriptions such as walking are not continued after prescribed.
[18] That same study looked at mean angular velocities at the hip and ankle and found no difference between obese and lean individuals.
[18] In 1996, Messier and colleagues observed the differences in ground reaction forces between obese and lean older adults with osteoarthritis.
[11] Absolute peak in the anteroposterior and mediolateral directions were also greater for the obese group but the difference was erased when scaled to body weight.
Browning and Kram have also found that stance-phase sagittal-plane net muscle moments are greater in obese adults when compared to lean individuals.
This is observed in a study by Foster et al. in 1995 when they took 11 obese women and calculated their energy expenditure before and after weight loss.
One possible suggested strategy to maximize energy expenditure while reducing lower joint extremity is to have obese people walk at a slow speed with an incline.
[25] Other strategies to consider are slow walking for extended periods of time and training underwater to reduce loads on joints and increase lean body mass.
The uses of DEXA and X-rays have improved the placement of these biomechanical markers, but variability still remains and should be taken into account when analyzing scientific findings.