Impact of a Motivational Resistance-training Program on Adherence and Body Composition in Elderly

Material and Methods

Participants The study included a total of 47 subjects, (29 females, 18 males) ages 65 to 75 years, recruited from an elderly social club. The participants were divided into two groups: experimental group (n=27; 10 men and 17 female) and control group (n=20; 8 men and 12 female). The sampling was natural and intentional. All subjects originated from Murcia (Spain) and met the following inclusion criteria: had never previously attended classes in fitness academies or were not currently performing regular physical activity, and had no previous experience with resistance-training programmes. Exclusion criteria included any history of neuromuscular, metabolic, hormonal or cardiovascular diseases; not taking any medication that could influence hormonal and neuromuscular metabolism. In addition, the participants were advised to not alter their diet during the study. Participants were informed about the possible risks and discomforts that could arise and were asked to complete a health history questionnaire and sign a consent form. The current study was approved of the Ethics Committee of the Catholic University San Antonio of Murcia (Spain) following the guidelines of the Helsinki Declaration.

Design A quasi-experimental design (2x2) was developed, dividing the participants into two groups; one experimental and one control. In this design, an initial measurement prior to the intervention (pre-test) and a measurement after the intervention (post-test) were conducted. This same research design has been used in previous studies, which has sought to assess the effect of an intervention programme on body composition, motivational variables and resistance-training.

Data Collection and Procedure Motivational variables Behavioural regulation during exercise. The Spanish version of Behavioural Regulation during Exercise Questionnaire was used. This questionnaire allows to evaluate the type of motivational regulation related to physical exercise, and consists in 23 items distributed in three dimensions, based on the established distinction in the SDT between autonomous motivation, controlled motivation and demotivation. Autonomous motivation was calculated using the mean score of intrinsic regulation (e.g. "Because I think that exercise is fun"), integrated regulation (e.g. "Because I believe that physical exercise is consistent with my values") and identified regulation (e.g. "I value the benefits of exercise"). Each of these regulations was composed of 4 items, except for the identified regulations which was composed of 3 items. Controlled motivation was calculated using the mean score of introjected regulation (e.g. "I feel guilty when I don't exercise") and external regulation (e.g. "I feel under pressure from my friends/family to exercise") with 4 items each. Demotivation (e.g. "I don't see why I should have to exercise") was also calculated using 4 items. Previous research in the physical activity and health context demonstrated the internal reliability of the instrument.

Basic psychological needs during exercise. To assess the perceived need satisfaction of the participants, the Spanish adaptation of the Basic Psychological Needs in Exercise Scale was used (BPNES), which is specific for the context of physical activity and health.67 The questionnaire includes 12 items distributed in three dimensions. Four items measure autonomy (e.g. "I exercise according to what I intend to do"), four items measure competence (e.g. "I feel that physical exercise is an activity that I do very well") and the other four items measure relatedness (e.g. "I have a close relationship with the people with whom I exercise"). Previous research in the physical activity and health context demonstrated the internal reliability of the instrument.