Rogers Chris W, Dittmer Keren E
School of Veterinary Science, Massey University, Private Bag 11 222, Palmerston North 4410, New Zealand.
School of Agriculture and Environment, Massey University, Private Bag 11 222, Palmerston North 4410, New Zealand.
Animals (Basel). 2019 Sep 3;9(9):646. doi: 10.3390/ani9090646.
In mammals, play behaviour appears innate and, because of this, may provide insight into the frequency and intensity of load that is required to stimulate positive musculoskeletal development. The objective of this review was to explore the interaction between play and tissue (bone) development at a molecular through to whole-animal level, with specific focus on the horse as a model. The basis of our understanding of the response of bone to loading is the mechanostat theorem. This assumes that at a tissue level, bone attempts to keep localised strain within the physiological range of 1500-2500 microstrain. Loads above this range result in a modelling response to reduce strain, and strain below this threshold results in remodelling to maintain the localised physiological range. In foals, locomotor play is dramatic and vigorous, with cumulative increases in both intensity and complexity. Based on published literature describing locomotor play in foals and the microstrain at different gaits in the horse, it was proposed that locomotor play in foal aligns with the mechanostat theorem in both the magnitude and frequency of load cycles applied. The cumulative increases in the complexity and intensity of locomotor play as the foal develops, in turn, ensure the strain rates associated with play remain above the local physiological range and promote material and architectural changes in the distal limb bones. Thus, spontaneous locomotor play may be vital to ensure optimal bone development in the horse. Modern management systems need to provide appropriate opportunities for foals to perform spontaneous locomotor play to optimise bone development and reduce the risk of future musculoskeletal injury later in life.
在哺乳动物中，玩耍行为似乎是天生的，正因为如此，它可能有助于深入了解刺激肌肉骨骼积极发育所需的负荷频率和强度。本综述的目的是探讨从分子水平到全动物水平玩耍与组织（骨骼）发育之间的相互作用，特别以马作为模型进行研究。我们对骨骼对负荷反应的理解基础是机械稳态理论。该理论假定，在组织层面，骨骼试图将局部应变保持在1500 - 2500微应变的生理范围内。高于此范围的负荷会引发一种塑形反应以降低应变，而低于此阈值的应变则会导致重塑以维持局部生理范围。在马驹中，运动性玩耍剧烈且活跃，其强度和复杂性会不断累积增加。基于已发表的描述马驹运动性玩耍以及马不同步态下微应变的文献，有人提出马驹的运动性玩耍在施加的负荷周期的大小和频率方面都符合机械稳态理论。随着马驹的成长，运动性玩耍的复杂性和强度不断累积增加，反过来又确保与玩耍相关的应变率保持在局部生理范围之上，并促进远端肢体骨骼的物质和结构变化。因此，自发的运动性玩耍对于确保马的骨骼最佳发育可能至关重要。现代管理系统需要为马驹提供适当的机会来进行自发的运动性玩耍，以优化骨骼发育并降低日后生活中发生肌肉骨骼损伤的风险。
