Changes in motor control and muscle performance after a short-term body mass reduction program in obese subjects

Two hundred and thirty obese subjects (age: 18-77 yr, BMI: 31.1-65.8 kg/m2) were studied before and after a 3-week body mass reduction (BMR) program, coupling restricted energy diet (1200-1500 kcal/day) with low intensity exercise prescription. It involved 5 days per week (consisting of one-hour dynamic aerobic standing and floor exercise plus 30 min of cycloergometer exercise at 60 W or, alternatively, 4 km outdoor leisure walking on flat terrain) and psychological counseling. One-leg standing balance test (OLSB) and stair climbing test (SCT) were employed to assess motor control and maximal lower limb muscle power, respectively. The BMR program induced a significant weight loss (4.1%; p<0.001), a higher reduction of body mass index (BMI) being observed in males than in females (p<0.001). OLSB performance time increased by 20.5% (p<0.001) after treatment, the improvement being evident in both genders. A 20.8% reduction in SCT time (p<0.05) was also observed and corresponded to a 13.2% increase (p<0.001) in average absolute muscle power and 15.0% increase (p<0.001) in specific muscle power (i.e. the power output per kg of body mass), with no differences between genders. In conclusion, in spite of the moderate reduction of body mass after restricted energy diet and low intensity physical conditioning, significant improvements in motor control and performance, likely to ameliorate the execution of simple daily activities, were observed in obese subjects.