The strategies to motivation assessment used were based on the principles of the Self-Determination Theory (SDT). SDT includes a meta-theory for framing motivational studies, a formal theory that defines intrinsic and varied extrinsic sources of motivation, their role in cognitive and social development, as well as in individual differences. SDT is a theory of motivation and personality that addresses three universal, innate and basic psychological needs: autonomy, competence and relatedness. During the resistance-training programme, the subjects received verbal motivational strategies, based on previous studies which have proven the beneficial effect they exert on BPN satisfaction and autonomous motivation.