The mean score is 60 out of 100 and the standard deviation (in other words, the variation in the scores) is 15 marks (see our statistical guides, Measures of Central Tendency and Standard Deviation, for more information about the mean and standard deviation).
What Are the Six Different Types of Swimming Strokes? Swimming provides all-around, low-impact body conditioning as well as exciting competition. Competitive swim meets allow only four strokes -- butterfly, backstroke, breaststroke and the crawl. Two other strokes -- elementary backstroke and sidestroke -- contribute to swimming longer distances, as different sets of muscles are used. The fastest stroke for most swimmers is the front crawl.
Backstroke is a another stroke which exercise almost identical muscle groups as freestyle, with the major difference being that backstroke is swum on your back so therefore your face is out of the water and there is no need to twist your head to breath as in freestyle.wimming is also considered to be one of only a few physical activities which train nearly all major muscle groups in the entire body. The different swimming strokes highlight different muscle groups though all strokes generally work out all the same major muscles of the body.