Osteoporosis Prevention in Sedentary Adolescent Females

描述（由申请人提供）：缺乏身体活动对健康有严重的影响，并已达到流行病的程度。在我们最近完成的干预研究中，我们研究了青少年体育活动行为改变的机制，在一个控制的运动干预。虽然在改善身体健康和身体活动方面取得了成功，但该研究发现，没有任何建议的行为改变的心理社会中介支持。目前提出的研究扩展了我们的研究结果，通过测试一种新的生物行为模型的身体活动行为从最近的理论和实证工作。本研究将测试以下假设：主要假设：1。在基线时对一轮运动有更积极情感反应的青少年，随着时间的推移，更有可能维持或增加他们的身体活动水平。 2.具有更大内在动机的青少年（即，运动享受）将更有可能随着时间的推移维持或增加他们的身体活动水平。 3.急性运动相关情感和内在动机之间存在相互作用，因此，在那些内在动机低的人中，随着时间的推移，急性运动诱导情感和身体活动参与之间的联系会更强。 次要假设：4。通过脑电图确定，左额叶大脑激活程度高于右额叶的青少年，更有可能对一轮运动产生积极的情感转变。5.青少年在锻炼时感到有能力，从锻炼中获得社会联系感和/或体验与锻炼相关的自主性，将更有内在动力去锻炼。120名女性和120名男性青少年将完成静息EEG，以评估大脑活动的不对称性，并将分别在中等强度和高强度水平下执行2项30分钟的运动任务。对运动的情感反应和运动的内在动机将使用标准化问卷进行评估。为期一年的随访将检查自基线测试以来身体活动参与的变化。

DESCRIPTION (provided by applicant): Physical inactivity has dramatic health consequences and is reaching epidemic proportions. In our recently completed intervention study, we examined the mechanisms of adolescent physical activity behavior change in a controlled exercise intervention. Though successful in terms of improving physical fitness and physical activity, the study found no support for any of the proposed psychosocial mediators of behavior change. The currently proposed study extends our findings to date by testing a novel biobehavioral model of physical activity behavior drawn from recent theoretical and empirical work. The study will test the following hypotheses: Primary Hypotheses: 1. Adolescents with a more positive affective response to a bout of exercise at baseline will be more likely to sustain or increase their level of physical activity over time. 2. Adolescents with greater intrinsic motivation to exercise (i.e., exercise enjoyment) at baseline will be more likely to sustain or increase their level of physical activity over time. 3. There will be an interaction between acute exercise-associated affect and intrinsic motivation, such that among those with low intrinsic motivation there will be a stronger association between acute exercise induced affect and physical activity participation over time. Secondary Hypotheses: 4. Adolescents with greater left frontal brain activation relative to right, as determined via EEG, will be more likely to respond to a bout of exercise with a positive affective shift. 5. Adolescents who feel competent when exercising, derive a sense of social connectedness from exercising and/or experience autonomy related to exercise will be more intrinsically motivated to exercise. 120 female and 120 male adolescents will complete a resting EEG to assess brain activity asymmetry, and will perform 2 30-minute exercise tasks at moderate and hard levels of intensity, respectively. Affective response to exercise and intrinsic motivation to exercise will be assessed using standardized questionnaires. A one-year follow-up will examine changes in physical activity participation since the baseline testing.