Description: Segment 1 A muscle is dissected and its structure is explained using labels and intertitles. A diagram shows the relationship between the muscle and the nerve. The anatomy of the muscle within the body framework is looked at. The difference between voluntary and involuntary muscles is explained. A person plays the violin and a heart is shown beating. Time start: 00:00:00:00 Time end: 00:04:34:11 Length: 00:04:34:11 Segment 2 The next section is 'The properties of muscles'. Impulses carried in the nerves cause the muscles to contract, and this is demonstrated by stimulating a muscle and nerve with an electric current. The muscle contracts, and a graph of its contractions is shown. A stimulus is applied to a man's arm. A demonstration shows that overwork fatigues muscles a man pulls a weight with his finger, but eventually tires. After rest he can continue to repeatedly pull the weight. A graph shows his movements over time. Time start: 00:04:34:11 Time end: 00:10:20:00 Length: 00:05:45:14 Segment 3 The next section is 'Muscles in action'. A man clenches his arm muscles. Animations show how the different muscle groups work together in the arm. A man's torso is shown to demonstrate the muscles used in breathing. A diagram shows how in exercise and sport, many muscles of the body are used. A basketball player is shown. The film ends with the intertitles explaining that through training and practice, we can teach our muscles to perform delicate tasks. A hurdle race is shown. Time start: 00:10:20:00 Time end: 00:15:06:05 Length: 00:04:46:05