Final answer:
The claim that holding an isometric contraction for at least 30 seconds is best for building strength is false. Isometric exercises are most beneficial when held for 6-10 seconds to avoid excessive fatigue. A combination of isotonic and isometric contractions should be used in a training program for balanced muscle development.
Step-by-step explanation:
Regarding the statement that to build strength using isometric exercises, it is best to hold the contraction maximally for at least 30 seconds, this is false. An isometric contraction is characterized by the muscle producing tension without changing the angle of a skeletal joint. This means there is an increase in muscle tension, but the muscle length remains unchanged. Such exercises are used to maintain posture and joint stability in everyday life and can also be applied to strength training.
Contrary to the belief that a 30-second hold is necessary, most sources recommend holding an isometric exercise for about 6-10 seconds. This duration can effectively increase muscle and bone mass as well as strength, similar to anaerobic exercise, which also involves high-intensity and short-duration activities. Longer holds may lead to excessive fatigue and a decrease in performance of the exercise, potentially causing more harm than benefit. Therefore, shorter holds repeated several times tend to be preferred for maximizing the benefits of isometric training.
A comprehensive training program that includes a variety of exercises, including isotonic contractions (where muscle length changes) and isometric contractions, is most beneficial. This approach ensures that muscles are exposed to different types of forces and movements, which can lead to more balanced muscle development and a lower risk of injury due to repetitive stress.