Washington D.C: Obesity diminishes a person's ability to build muscle after engaging in resistance exercise, according to a new study. Nicholas Burd, who led the new research with the division of nutritional sciences graduate student Joseph Beals, said,"Our new study goes further, showing there is an obesity-related impairment in building new muscle proteins in the fed state after a weightlifting session."

Beals and his colleagues recruited nine obese and nine normal-weight 20- to 23-year-old adults for the new study. The participants, who did not engage in a regular exercise program, took a couple of standardized health surveys and were deemed healthy but "insufficiently active" prior to enrollment in the study.After assessing participants' body composition, glucose tolerance and ability to engage in a weighted leg extension exercise, the researchers began infusions of stable-isotope-labelled phenylalanine in all study subjects. This allowed the team to monitor amino acid levels in participants' blood and muscles throughout the experiment. The team took muscle biopsies from one leg of each of the study subjects, who then performed four sets of 10-12 repetitions of the resistance exercise with the opposite leg.