Purpose/Aim: Epidemiological evidence suggests, contrary to popular mythos, that increased exercise/joint activity does not place articular cartilage at increased risk of disease, but instead promotes joint health. One explanation for this might be activity-induced cartilage rehydration; where joint articulation drives restoration of tissue hydration, thickness, and dependent tribomechanical outcomes (e.g., load support, stiffness, and lubricity) lost to joint loading. However, there have been no studies investigating how patterning of intermittent articulation influences the hydration and biomechanical functions of cartilage.

Materials and Methods: Here we leveraged the convergent stationary contact area (cSCA) testing configuration and its unique ability to drive tribological rehydration, to elucidate how intermittency of activity affects the biomechanical functions of bovine stifle cartilage under well-controlled sliding conditions that have been designed to model a typical “day” of human joint activity.

Results: For a fixed volume of “daily” activity (30 min) and sedentary time (60 min), breaking up intermittent activity into longer and less-frequent bouts (corresponding to longer continuous sedentary periods) resulted in the exposure of articular cartilage to markedly greater strains, losses of interstitial pressure, and friction coefficients.

Conclusions: These results demonstrated that the regularity of ex vivo activity regimens, specifically the duration of sedentary bouts, had a dominant effect on the biomechanical functions of articular cartilage. In more practical terms, the results suggest that brief but regular movement patterns (e.g., every hour) may be biomechanically preferred to long and infrequent movement patterns (e.g., a long walk after a sedentary day) when controlling for daily activity volume (e.g., 30 min).

目的/目的：流行病学证据表明，与流行的说法相反，运动/关节活动的增加不会使关节软骨患病的风险增加，反而会促进关节健康。一种解释可能是活动引起的软骨补液。关节关节驱动组织水合作用，厚度和相关的摩擦力学结果（例如，载荷支撑，刚度和润滑性）恢复至关节载荷所致。但是，还没有研究调查间歇性关节的构图如何影响软骨的水合作用和生物力学功能。

材料和方法：在这里，我们利用会聚静态接触面积（cSCA）测试配置及其驱动摩擦水合作用的独特能力，来阐明活动的间歇性如何在设计良好的滑动条件下影响牛膝关节软骨的生物力学功能模拟人类关节活动的典型“一天”。

结果：对于固定的“每日”活动（30分钟）和久坐时间（60分钟），将间歇性活动分解为更长和更少的发作（对应更长的连续久坐时间）导致关节软骨暴露于明显更大的应变，组织压力损失和摩擦系数。

结论：这些结果表明离体活动方案的规律性，特别是久坐发作的持续时间，对关节软骨的生物力学功能起主要作用。用更实际的话说，当控制日常活动量（例如）时，短暂而有规律的运动方式（例如，每小时）比长期和不频繁的运动方式（例如，久坐后长时间走）在生物力学上更可取。 ， 30分钟）。