Just doing the exercise isn't enough. Engage your core muscles during each exercise to receive the most benefits.  To find your core muscles, hold yourself in push-up position for about a minute or two and pay attention to what feels tired. It's usually not your arms. When you drop into a push-up position, or do any core-tightening exercise, tighten your ab muscles during each rep. Those are the muscles we're talking about. To do these exercise properly, breathe in when you're contracting the muscles and breathe out when you're releasing them. o planks. Planks are simple and engage all your core abdominal muscles, making them an excellent exercise for tightening your core. To do one, get in push-up position. Raise your feet to about shoulder height by balancing them on an exercise ball, or a stool. Keep your arms flexed just slightly, not locked, and hold that position with your core muscles engaged for one minute. When you're first starting out, aim for 2-3 sets of these, holding each for about a minute if you can. If that's too hard, hold it for at least 30 seconds, or go as long as you can. Lie on one side and brace yourself on your elbow. Put your legs on top of each other. Place your other arm on top of your hip or reach it up to the ceiling. Tighten your abs, lifting your hips off the floor. Keep your back straight, forming a triangle with the floor. Hold for 30 to 60 seconds, then repeat on the other side. Try to do 3-5 sets of these, on both sides. o burpees. Start in push-up position, your core muscles engaged and your back straight. In one swift motion, jump forward into a squatting position with your feet and stand up. Then drop back into a squat and kick your legs back out into push-up position. You should do this as quickly as you can, comfortably. When you're first starting out, try to do three sets of 15 burpees. If you want more of a challenge, do jumping burpees, or do them while you're holding hand weights. Start in push-up position, your core muscles engaged and you back very straight. With...

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Write a summary of the previous text in Chinese:
将核心锻炼贯穿所有的锻炼动作。 平板支撑。 侧平板式。 立卧撑跳（Burpee）。 登山练习。 仰卧举腿。 俯卧行走。 抓绳练习。 卷腹不宜做得过多，动作必须保证正确。