做仰卧起坐可以快速炼成六块腹肌？哈佛医学院的医生可不这样认为，做仰卧起坐练腹肌看似有效，实则不然。
医生建议做平板支撑来代替仰卧起坐。平板支撑要用手掌和脚尖把自己撑起来，就像俯卧撑的预备姿势。研究结果称为“核心肌肉锻炼”，在哈佛医学院健康报告里有详细阐述。
仰卧起坐只能锻炼腹部肌肉，平板支撑可以调动你正面、侧面、后背的几个肌肉群。要想锻炼核心肌肉，尤其是六块腹肌，这些肌肉群就都得锻炼到。
哈佛健康脉动的作者总结了报告的要点：“仰卧起坐只能增强几个肌肉群，核心肌肉锻炼通过动作的动态模式可增强我们每天都会用到的整套核心肌肉。
传统的仰卧起坐还有可能对身体造成损伤，比如背部要不停着地。此外，从仰卧到坐起这个过程，大腿到腰椎有组肌肉叫髋部屈肌会受到拉伸，这组肌肉如果太紧绷，太发达就会拉扯到下脊椎，可能造成下背不适或下背疼。
平板支撑不需要任何器械，随便在哪都能做。不妨试试？
Health.com建议先从基础的平板支撑开始：俯卧，双肘弯曲，肩膀和肘关节与地面垂直，双手握拳，双腿与臀部同宽，双肘与肩部同宽，腹肌收紧，脚尖蹬地撑起身体，上臂支撑在地面上，头部到脚跟成一条直线。刚开始的时候坚持一分钟就行了。
随着身体素质的提高，支撑时间可以逐步加长，还可以伸直手臂用手掌撑地。（译自Business Insider，原文如下）
Harvard doctors say this overlooked move is the quickest way to get strong abs
If you think sit-ups are the quickest ticket to 6-pack abs, the physicians at Harvard Medical School have news for you: That classic exercise isn't as efficient as it seems.
Instead of crunches, they suggest doing planks, the exercise that involves holding yourself on your hands and toes in a pre-push-up position. The findings are detailed in aHarvard Medical School health report called "Core Exercises."
As opposed to sit-ups, which target only your abdominal muscles, planks recruit several groups of muscles along your sides, front, and back. If you want a strong core — especially the kind that would give you 6-pack-like definition across your abs — you need to challenge all of these muscles.
"Sit-ups or crunches strengthen just a few muscle groups," write the authors of theHarvard Healthbeat newsletter, which summarizes the report's key takeaways. "Through dynamic patterns of movement, a good core workout helps strengthen the entire set of core muscles you use every day."
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Conventional crunches may also be hard on different parts of your body, including your back, which gets pushed against the floor. Additionally, when you pull your body up into a sit-up position, you're working a group of muscles called the hip flexors which run from your thighs to the lumbar vertebrae in your lower back. When these muscles get too tight or become overly-strengthened,they can yank on your lower spine. This can cause pain or discomfort in your lower back.
And unlike ab-crunch machines, planks don't require a single piece of equipment, so you can do them anywhere.
Ready to give them a try?
The folks at Health.com recommendstarting out by lying face-down with your legs extended and your elbows bent, directly under your shoulders, with your hands clasped. Your feet should be hip-width apart; your elbows should be shoulder-width apart. Next, tighten your abs and tuck your toes to elevate your body, keeping your forearms on the ground. Your body should be in a straight line from your head to your heels. To start, hold it for one minute.
As you get stronger, you can gradually build up to maintain the position for longer periods of time, and extend your arms to hold yourself up on your palms.
