Musculoskeletal Biomechanics of Gradient Walking in Obese Adults

描述(申请人提供)：锻炼与饮食干预相结合仍然是抗击肥胖症流行的最好希望。快步走是一种推荐和流行的运动形式，但负重运动可能是生物力学负荷的来源，增加肌肉骨骼损伤的风险，并与肥胖和大关节(如膝盖)骨关节炎(OA)联系在一起。因此，将快步走作为治疗肥胖症的运动可能在生物力学上是不合理的。然而，令人惊讶的是，人们对肥胖如何影响行走过程中的生物力学负荷知之甚少。现有的步行生物力学数据库不适用于60%以上的美国成年人超重或肥胖，也不适用于上坡或下坡行走。这项研究的长期目标是为肥胖的成年人寻找步行运动处方，在优化热量消耗和心血管刺激的同时，将下肢生物力学负荷降至最低。具体目标1：确定肥胖如何影响行走的生物力学。我们假设肥胖会增加下肢关节负荷，但适度倾斜加上步行速度减慢会降低这些负荷，而沿适度下降度步行则会增加下肢关节负荷。为了验证这些假设，肌肉骨骼生物力学将使用我们的倾斜式双带测力跑步机在水平、三个倾斜和一个适度下降的速度上进行测量。将研究肥胖和正常体重控制的男女受试者。具体目标2：制定更合理的指南，为肥胖成年人开出步行锻炼处方。我们假设，对于肥胖的成年人，在适度倾斜的情况下缓慢行走可以最大限度地减少膝关节负荷，同时优化卡路里消耗和心血管刺激。为了验证这一假设，我们将结合特定目标1的生物力学结果，以及对肥胖和正常体重成年人的步行代谢成本和最大耗氧率的测量。我们将能够确定以最低的生物力学负荷达到推荐的可持续中等有氧强度(最大摄氧量的55-70%，VO2max)的速度和倾斜组合。这项研究的好处将是更知情、更安全和更有效地将步行作为锻炼的处方，以控制体重和心血管健康。我们确定的步行方案在短期(降低急性损伤率)和长期(降低骨关节炎风险)应该是更安全的。 公共卫生相关性：肥胖是美国可预防的死亡的主要原因，并与发病率和死亡率的增加相关，构成了一个重大的健康挑战。快步走是一种推荐和流行的预防和治疗肥胖的运动形式，但可能是生物力学负荷的来源，增加肌肉骨骼损伤的风险，并将肥胖和大关节(如膝盖)骨关节炎联系在一起。这项研究的好处将是更知情、更安全和更有效地将步行作为锻炼的处方，以控制体重和心血管健康。

DESCRIPTION (provided by applicant): Exercise combined with dietary intervention continues to hold the best promise for combating the obesity epidemic. Brisk walking is a recommended and popular form of exercise but weight bearing exercise may be the source of the biomechanical loads that increase the risk of musculoskeletal injury and link obesity and large joint (e.g. knee) osteoarthritis (OA). Thus, prescribing brisk walking as exercise for treating obesity may be biomechanically unsound. However, remarkably little is known about how obesity affects the biomechanical loads involved in walking. The existing walking biomechanics data base does not apply to the 60+% of American adults who are overweight or obese nor to uphill or downhill walking. The long term goal of this research is to derive walking exercise prescriptions for obese adults that minimize lower extremity biomechanical loads while optimizing caloric expenditure and cardiovascular stimulus. Specific Aim 1: Determine how obesity affects the biomechanics of walking. We hypothesize that obesity increases lower extremity joint loads but that moderate inclines combined with decreased walking speed reduce these loads while walking down moderate declines increases lower extremity joint loads. To test these hypotheses, the musculoskeletal biomechanics will be measured across speed on the level, three inclines and one moderate decline using our inclinable, dual-belt force measuring treadmill. Obese and normal weight control subjects of both genders will be studied. Specific Aim 2: Develop more sound guidelines for prescribing walking exercise for obese adults. We hypothesize that for obese adults, slow walking up a moderate incline minimizes knee joint loads while optimizing caloric expenditure and cardiovascular stimulus. To test this hypothesis, we will combine our biomechanical results from Specific Aim 1 with measurements of the metabolic cost of walking and maximal oxygen consumption rates of obese and normal weight adults. We will be able to identify speed and incline combinations that achieve the recommended sustainable moderate aerobic intensity (55-70% of maximal oxygen uptake, VO2max) with the lowest biomechanical loads. The benefits of this research will be more informed, safer and more effective prescriptions of walking as exercise for weight management and cardiovascular health. The walking regimens that we determine should be safer in the shorter term (reduced rates of acute injuries) and longer term (reduced risk of OA). PUBLIC HEALTH RELEVANCE: Obesity is a chief contributor to preventable deaths in the United States and poses a major health challenge associated with increased morbidity and mortality. Brisk walking is a recommended and popular form of exercise for obesity prevention and treatment but may be the source of the biomechanical loads that increase the risk of musculoskeletal injury and link obesity and large joint (e.g. knee) osteoarthritis. The benefits of this research will be more informed, safer and more effective prescriptions of walking as exercise for weight management and cardiovascular health.