the role of fat free mass on performance and motivation

Obesity is a growing problem and a lack of physical activity is one of the
contributing factors. In this study we will investigate whether
strength-related exercises (SREs) are beneficial in the treatment of obesity.
Firstly, from a biological perspective, it is known that the obese have a
higher fat-free mass (FFM) than their lean counterparts (Westerterp, 1995).
Consequently, they have more muscle strength, and we hypothesize that they not
only perform better in SREs than their lean counterparts, but that they also
perform better in SREs than in aerobe exercises. Secondly, from a psychological
perspective, we assume that SREs are beneficial as well. They might be highly
rewarding. Obese people will notice that SREs will be easier to comply with,
and their performance will be better. This might lead to a higher intrinsic
motivation, causing long term behavioral changes.
These long term behavioral changes (i.e. more involvement in strength related
exercises), will result in a healthier body composition, i.e. an increased
fat-free mass and decreased fat mass. As fat-free mass increases, energy
expenditure will also increase, leading to long term positive effects on energy
balance and metabolic risks.

In this study we address the following assumptions:
A) Are overweight young adults (18-28 years) relatively better in SREs than
aerobic related exertion (ARE) compared to their lean counterparts, and
B) do overweight young adults (18-22 years) have a more positive attitude
towards SRE than ARE compared to their lean counterparts.
Study design: Non invasive, observational study

non invasive, cross sectional

Day 1:
Intake: After having received the subject information, participants that have
expressed their interest (by responding to the advertisment) and were found
eligible, will be invited to visit our laboratories. Before the start of any
tests, the participant will also be informed orally and will be asked to sign
the informed consent and to fill out the medical screening questionnaire. The
participant will be asked to refrain from any high intensity physical exercise
24 hours prior to the testing and to come to the laboratory in a fasted state
(overnight fast).
Height and weight of the participant will be measured. Body composition will be
assessed using underwater weighing.
Subsequently, subjects are asked to eat a light breakfast, and to fill out a
physical activity questionnaire.
One hour after having eaten a light breakfast, cardiovascular fitness will be
assessed with a maximal exercise test on a bicycle ergometer. Approximately one
hour after VO2max testing, subjects will perform a familiarization session with
the exercise equipment to estimate one-repetition maximum (1RM) strength.
During the familiarization session, proper lifting technique will be
demonstrated for leg press, leg extension, and chest press exercises.
At the end of the testing day 1, participants will be provided with activity
monitors, which they will be asked to wear for 7 consecutive days. They will be
asked to maintain their habitual physical activity pattern.

Day 2 ( at least 8 days after day 1).
On day 2, first, the actual 1RM testing will take place. Subsequently, the
subjects will be asked to both perform a series of standardized strength
exercise activities and standardized aerobic exercise activities. After each
exercise activity (both the strength and aerobic), a questionnaire will be
filled out to measure social cognitive determinants. The duration of this
session will depend on the fitness level of the participants, but should not
exceed 3 hours.

The laboratory tests are necessary to determine participants aerobic fitness
and strength. The exercise activities on day 2 are necessary to create a
standardized setting for filling out the questionnaires, as the questionnaires
contain questions about the just performed exercise protocol.

Risks for the participants are minimal since no invasive procedures are
included. The exercise protocols can be easily performed by healthy subjects.
To make sure subjects are allowed to perform maximal exertion tests, potential
participants will be screened using a medical screening questionnaire. The
maximal exertion tests will be conducted by an experienced operator and a
direct line with the hospital is always available. In addition, a medical
doctor will be stand-by during these tests.