Each bean contains 0.8 - 2.5 % caffeine. For your information in an average cup of coffee you have 75mg caffeine. One cup of coffee contains around 25 coffee beans, and you are not getting the full coffee bean in coffee, so the caffeine can add up if you eat a lot.
The reason why temperature effects muscles is because of the numerous atoms in the body that react to temperature. When the air, or body temperature is colder the atoms tend to stay closer together, causing less movement...when it is hot, the atoms (molecules) move around more, causing more range of motion. It also allows blood to flow more easily when it is warm than cold.
Temperature can directly affect enzyme activity. Increases in temperature can cause the enzymes to operate at a quicker pace and cause the enzymatic reaction to move along faster, while decreases in temperatures can cause the enzymes to become sluggish and the reaction to slow down.   Temperature can have other effects as well. Enzymes perform their work on what is called a substrate. The substrate may also be affected by temperature. For example, there is an enzyme commonly used in molecular biology called ligase. Ligase joins to pieces of DNA together.