فواید ورزش شنا

 ورزش شنا یكی از محبوب ترین ورزشها در بین اقشار مختلف مردم است. فردی كه شنا می كند، نه تنها از این طریق احساس راحتی و نشاط می كند بلكه در اثر شنا كردن قابلیتهای جسمانی خود را از قبیل استقامت دستگاه گردش خون و تنفس، قدرت، سرعت و انعطاف پذیری مفاصل شانه و مچ پا افزایش می دهد. ورزش شنا ورزشی است كه از سن نوزادی تا سن كهنسالی میتوان آنرا انجام داد و به طور كلی ورزشی است كه هیجان و اضطراب را كاهش داده، عضلات را قوی و محكم كرده و بدن را نرم و انعطاف پذیر می سازد و باعث می شود كه فرد انرژیی بیشتری برای انجام كارهای روزانه خود كسب كند.

تغییرات فیزیولوژیكی كه در اثر تمرینات استقامتی شنا در بدن بوجود می آید.

تمرینات استقامتی به معنی شنای مداوم در مسافتهای طولانی مثل شنای 400 متر، 600 متر،800 متر،1400 متر و یا حتی مسافتهای بیشتر می باشد. یكی از امتیازهای این نوع تمرین این است كه احتیاج بدن را به دستگاه انتقال اكسیژن افزایش می دهد و در نتیجه سبب تغییرات زیر در بدن می شود.

افزایش بازده قلب، كاهش ضربان قلب، افزایش كیفیت خون از نظر حمل مقدار بیشتری اكسیژن ذخیره شده مقدار بیشتری گلیكوژن در جگر و ماهیچه ها و افزایش تعداد میتوكندریها در تارهای ماهیچه ای.

ماهیچه هایی كه در شنا بكار گرفته می شوند.

در زیر اسامی بعضی از ماهیچه های اصلی كه در مرحله جلو بردن یك شناگر در حركتهای شنا از آنها استفاده می شود ذكر شده است:

1. ماهیچه های پائین برنده دست: ماهیچه پشتی بزرگ، ماهیچه سینه ای بزرگ ماهیچه گرد بزرگ و سرطویل، ماهیچه سه سربازویی. این ماهیچه ها باعث تقویت كشش دست در داخل آب می شوند.

2. ماهیچه های گرداننده داخلی دست: ماهیچه سینه ای بزرگ، ماهیچه پهن پشتی، ماهیچه گرد بزرگ و ماهیچه تحت كتفی این ماهیچه ها قسمت بالایی دست را به طرف داخل میچرخانند. قوی شدن این ماهیچه ها از نظر نگه داشتن آرنج در بالا كه در مرحله اول كشش دست در هر چهار شنا مفید است، ضرورت دارد.

تمرینات سرعتی شنا و تغییرات فیزیولوژیكی حاصل از آن:

تمرینهایی با حداكثر سرعت و فعالیت در مسافتهای كوتاه را تمرینهای سرعتی گویند برای مثال 10 بار و هر بار 25 متر و یا 50 متر شنا با حداكثر سرعت.

این نوع تمرینها سبب افزایش قدرت انقباض ماهیچه( به جهت افزایش هماهنگی میان دستگاه عصبی یا ماهیچه ای) و همچنین افزایش قدرت و مقدارATP-PC ( آدنوزین تری فسفات و فسفات كرآتین) در ماهیچه می شود كه خود سبب می شود كه قدرت شناگر برای انجام تمرینهای سرعتی افزایش یابد.

Want your children to learn how to swim, but don't want to pay $50 or more for a two weeks session? By following these simple instructions, you can teach most children to be beginner swimmers in about two weeks.

Teaching your children to swim is a wonderful summertime activity that allows you some quality time with them. However, before you begin, make sure that you are comfortable with the water. If you are afraid of the water, even if you know how to swim, you may not be the right teacher for your children. Also, any time you are around the water, make sure there are some floatation devices and a first aid kit. A little preparation can ensure a fun and productive swimming lesson for both student and teacher.

Conquering Fear

Most children have a natural fear of putting their faces in the water. This fear makes sense for two obvious reasons: 1. Water gets in their eyes, up their noses, and in their ears. 2. They can't breathe. It is natural that they are afraid. Your job as their teacher is to help them conquer this fear. Unfortunately, some adults try to force children to put their faces in the water. Then, they are surprised when the child hates the water and refuses to get in the pool. Imagine this, someone asks you to put a plastic bag filled with goo over your head. You don't understand why and the last thing you want to do is have goo in your eyes, ears, and nose. Plus, you are worried you won't be able to breathe. Since the person is bigger than you, he forces the bag over your head. How do you feel? Now, he explains that it is all part of a very fun game, but you have to be able to put the bag on your head. How do you feel now? Do you trust him? Do you even want to play the game? Most people would answer no. The way to help children get over their fear of the water is not to force them and never, never, never throw them into the deep end and expect them to swim, even if that is the way you were taught. True, some people actually learned to swim this way, but very few of them enjoyed the experience. They were just thankful they didn't drown. Leaning to swim should be fun; it shouldn't be terrifying.

So if you don't force children to put their faces in the water, what do you do when they refuse? Be very patient. When children are no longer afraid, they will put their faces in the water. It will take some children one day, some children one week, and others much longer. Usually, you can help them conquer their fears by following these steps:

1.     Begin by making the bathtub a fun place to be, fill it with toys, bath crayons, plastic containers, and fun soaps. Leave out the bubbles, since your goal is to get them to put their faces in the water. Then, get down beside the tub and play with your children before you bathe them. Encourage them to use plastic containers to dump water over their hands, toes, and shoulders. If they dump water over their heads, clap for them and then dry their faces with a towel. Try to get them to bend over and blow bubbles for you in the water.

2.     When it is time to bathe them, let a little water drip onto their faces, but have a towel handy so they can wipe it off.

3.     When you believe they are getting comfortable with the water, move outside to a baby pool. Let them run around in the pool as it fills. If they will let you, spray them with the hose as the pool fills. You may want to take some of the toys from the house and transfer them to the baby pool. Also, include something that will stay on the bottom. For older children, coins work well. For younger children, diving eggs, or diving rings are available at dollar stores. Throw the eggs or rings in the pool and let the children race to see who can collect them all.

4.     Now, it is time to try the big pool. Make sure the pool you select has steps. First, hold your children and let them play in your arms. Let them kick and pretend to be motorboats. Tell them motorboats go faster if they have bubbles. Encourage them to blow bubbles. Then, take the rings or eggs and put them on the second step. Gradually, move them down until the children have to put their faces in the water to get the toys. Again, not all children will move at the same speed, so be patient. Hint: Teaching more than one child at a time sometimes helps, too. Often, they will not put their face in the water for you, but they will do it for each other.