Abstract

Objective：

Muscle strength is a major component influencing sports performance，especially for swim event.So it is important for swimming athletes to develop their specific strength qualities.Basing on the new stress theory，focusing the synthesizing adaptation of skeletal muscle protein，a systematic study was carries out to observer the hormones changing and HSP70 response on the body response.It was from a new angel in this study that the causes of strength training-induced the strength qualities development.

Subject and Methods

The research included human body test and animal test.

There are two part of human body test：（1）The Relationship of Exercise Loads and Serum Hormones Change of Elite Swimming Athletes in Different Training Phase. Ten elite Swimming Athletes of Chinese nation swimming team，including 5 males and 5 females，engaged in the train.Test indexes：BLa，T，C，T/C and IGF-Ⅰ.（2）Study on the Changes of Swimming Athletes Body Composition and Strength quality in Strength Training phase. Six Swimming Athletes of Chinese nation swimming team，including 4 males and 2 females，engaged in the train.Test indexes：T，C，T/C，IGF-Ⅰ，isokinetic strength of shoulder joint and knee joint，and body component.

The purpose of animal test was to establish the strength training models of rats，re-search the rats body stress response to strength training from whole body phase，system-atic phase and cell phase，which can be divided 2 parts：（1）Changes of Rats body function and Serum T，C and IGF -Ⅰin Strength Training. Forty Sprague -Dawley （SD）rats were randomly as-sighed to control group（CG）and exercise group which was further divided into swimming without load group（FG），swimming with loading 5% body weight group（5% G），swimming with loading 10% BW group（5% G）and swim-ming with loading 15% BW group（15% G）.There were 8 rats in each group.Exercise groups were trained in a basin with water.The train lasted 4 weeks，and 6 days a week. The time，which all the groups with load swam，is 38 minutes.And the 38 mins training period was divided 5 stages，which contented 6 mins，and the interval was 2 mins：5% G with 5% BW load attaching to rats tail root trained 4 weeks；10% G with 5% load in the first week，and 10% load in last 3 weeks；15% G with 5% load in the first week，10% load in the second week and 15% in last 2 weeks.The time that the rats of FG swam is 90 minutes.Test indexes：Rats exercise station，body weight，value of the most loads，rel-ative strength ratio，weight of rats'thigh quadriceps muscle，protein content of rats'thigh quadriceps muscle，T，C，IGF-Ⅰ.（2）Changes of Rats Skeletal Muscle Hsp70 Express and Lipox in Strength Training.Test indexes：MDA content，SOD level，Hsp70 content of rats'thigh quadriceps muscle.

Conclusion

（1）In strength training，the muscle strength and power increased obviously.And body weight increased，which caused by the increase of the muscle weight，and embod-ied in skeletal muscle selective hyperplasia，which had no obvious effect on the skeletal muscle protein.

（2）Body serum anabolism hormones including T and IGF -1 increased in ade-quate strength training，which depended on the exercise intensity，while decreased in o-ver-load strength training.And IGF-Ⅰlevel didn't change obviously compared with T，which seem to indicate that the effect of IGF-Ⅰresponse to sports stress was low than T.

（3）Body serum catabolism hormone（C）increased in strength training，and set-tled in a high level in over-load strength training，which indicated that the alters of ser-um C could reflect the body adaptation to the stress.

（4）In strength training，the ratio of anabolism hormones and catabolism hormone increases，this means anabolism dominating in the body，while catabolism hormone will dominate in over-load strength training.

（5）In strength training，rats'skeletal muscle Hsp70 increased.The improvement of Hsp70 level depended on the exercise intensity，and there was a platform stage in the improvement of Hsp70 level.And rats skeletal muscle Hsp70 express decreased in over-load strength training.The reason need more research.

（6）Rats'skeletal muscle MDA content increased significantly in strength training， which induced by exercise intensity，while SOD level s didn't change obviously.It sug-gests：In over-load strength training，skeletal muscles'lipox level increases acutely，and anti-oxidation enzyme's decrease may be a important reason.

（7）There was a negative correlation between skeletal muscle Hsp70 express and lipox，which increased when exercise intensity increased. It suggests that the tissue Hsp70 express increases with sports stress intensity increases，and control the lipox de-gree in a meek condition before the end of platform stage.The Hsp70 express decreases and lipox increases significantly when exercise intensity exceeds the limit intensity of platform stage.

In conclusion，the research constructs a relationship between strength training and skeletal muscle adaptation：In strength training，the secreting hormones secreting changes and anabolism will dominate in the body. Cooperating with the special metabolizing products of skeletal muscle cell（such as leucine and isoleucine）and self-defending mechanism（HSP70），which promotes skeletal muscle protein including constructive pro-tein and enzyme protein synthesized adaptation. The skeletal muscle fibers become thick，and sport function（strength）of them increases.

Key Words：Swim event，the Strength Training，Sports Stress，Adaptation，Whole Body Response，Regulation of Hormones，Heat Shock Protein 70，Lipid Peroxidation