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The knee meniscus is a crucial component of the knee that functions to stabilize the joint, distribute load, and maintain congruency. Meniscus tears and degeneration are common, and natural healing is limited. Notably, few children present with meniscus injuries and other related fibrocartilaginous tissues heal regeneratively in immature animals and in the fetus. In this work, we evaluated fetal, juvenile, and adult bovine meniscus properties and repair capacity in vitro. Although no changes in cell behavior (migration and proliferation) were noted with age, drastic alterations in the density and distribution of the major components of meniscus tissue (proteoglycan, collagen, and DNA) occurred with development. Coincident with these marked tissue changes, the in vitro healing capacity of the tissue decreased with age. Fetal and juvenile meniscus formed a robust repair over 8 weeks on both a histological and mechanical basis, despite a lack of vascular supply. In contrast, adult meniscus did not integrate over this period. However, integration was improved significantly with the addition of the growth factor transforming growth factor-beta 3. Finally, to evaluate engineered scaffold integration in the context of aging, we monitored cellular infiltration from native tissue into engineered nanofibrous constructs. Our findings suggest that maturation processes that enable load bearing in the adult limit endogenous healing potential and identify new metrics for the development of tissue-engineered meniscus implants.

The present study examined whether the previously observed benefits of an external focus of attention (i.e., focusing on the movement effect), relative to an internal focus (i.e., focusing on one's body movements) and control conditions, would generalize to tasks requiring maximum force production, such as jumping. In two experiments, participants performed a vertical jump-and-reach task. A Vertec™ measurement device was used to determine jump-and-reach height. Participants performed under three conditions in a within-participant design: External focus (i.e., focus on the rungs of the Vertec that were to be touched), internal focus (i.e., focus on the finger, with which the rungs were to be touched), and control conditions (i.e., focus on jumping as high as possible). Experiment 1 showed that participants' jump-and-reach height was greatest with an external focus. Those results were replicated in Experiment 2. In addition, it was observed that the vertical displacement of the center of mass was greater under the external focus condition, compared to the other two conditions. This suggests that participants jumped higher by producing greater forces when they adopted an external focus. These findings indicate that the previously shown benefits of an external attentional focus generalize to tasks requiring maximal force production

Implicit motor learning is an established motor learning technique that has been largely overlooked outside of academia. It is beneficial to learners in that it allows them to perform undisrupted even in the face of stress and other adverse conditions. This is thought to be due to a reduced ability to 'reinvest' acquired knowledge -something that can cause the performer to 'manually override' what should be an automatic movement. The problem with traditional forms of implicit motor learning is their impracticality in applied settings. To that end, in this paper we attempt to provide a jumping off point for practitioners by briefly outlining the theoretical concepts of implicit learning and the difficulties it faces. From there, we explore alternative techniques that are more practical but impart similar, if not identical, benefits to performance.

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