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We mentioned on Monday how violent crimes have been one of the challenges surrounding the 2016 Olympic Games in Rio de Janeiro, Brazil. Now, the International Olympics Committee is calling for better security at the Rio events. One reason why: four U.S. Olympics swimmers, including medalist Ryan Lochte, were robbed over the weekend.
Lochte told NBC that armed men who were posing as police officers stopped the swimmers' taxi and then took their money at gun point. The swimmers were otherwise unharmed and Rio de Janeiro's police say they're investigating.
Security is not the only concerned of the athletes, though. Besides the physical conditioning they've sharpened for years, there are mental games at the Olympic Games.
DR. SANJAY GUPTA, cnn CHIEF MEDICAL CORRESPONDENT: It's the moment every top athlete for and hopes to achieve, if they don't choke under pressure.
So, just what goes on here in the brain that can keep you from doing your best and how can you stop it from happening.
The body of a highly trained athlete knows exactly what to do. Those skills are stored in muscle memory and over here, an area of the brain the Striatum. It's sort of the brain's autopilot. The key to winning is to keep the brain's thinking part, that Prefrontal Cortex area from interfering. Now, to do that, to be in that zone, means being calmed and focused.
Meditation in yoga helps slow the heart rate and calm the mind. They also turn down that thinking part of the brain.
Visualization is a tried and true approach. Feel like you're catching a basketball so that when it really happens, you've already gone through the motions. Many top athletes have learned to see the positive in pressure and then use it to their advantage. They train their amygdala, that's the brain's memory and emotion center, to associate the signs of stress to a success. In failure, they certainly don't think of that.
我们周一曾提到过，暴力犯罪是2016巴西里约奥运会面临的其中一个挑战。国际奥委会要求里约奥运会提供更好的安全保障。其中一个原因是，包括奖牌获得者瑞安·罗切特在内的4名美国奥运会游泳选手在上周末遭遇抢劫。
罗切特接受美国全国广播公司的采访时表示，几名持械男子装扮成警察截停了他们乘坐的出租车，用枪指着他们，抢走了他们的钱。4名游泳选手并未受伤，里约热内卢警方表示他们正在进行调查。
但是安全问题不是运动员担心的唯一一个问题。除了多年来要不断提高身体训练以外，运动员在奥运会赛场上还要进行精神意志的比拼。
cnn首席医学记者桑杰·古普塔医生：这是所有顶级运动员为之奋斗并希望实现目标的时刻，前提是他们不会因压力而窒息。
大脑中发生了什么让你不能全力以赴，又是什么使你能避免这种情况的发生？
训练有素的运动员的身体知道具体要怎么做。这些技巧已经储存在肌肉记忆里，就储存在大脑纹状体里。它就像是大脑的自动驾驶仪。获胜的关键是让大脑的思考区域——前额叶皮质区，不去进行干扰。为了做到这点，就要使这个区域保持冷静和专注。
瑜珈中的冥想环节可以减慢心率、使头脑冷静。冥想还可以使大脑的思考区域保持平静。
形象化是一个行之有效的方法。就好像你正在拿着一个篮球，当情况真的发生时，其实你已经完成动作了。许多顶级运动员都会学习看待压力中的积极一面，然后将其转化为自己的优势。他们会训练他们的杏仁体，将压力表现和成功联系到一起，杏仁体是大脑的记忆和情感中心。在失利情况下，他们肯定没有考虑这一点。
