Final answer:
The nurse should instruct the patient on producing muscle tension without changing muscle length, focusing on static position maintenance rather than movement during the isometric exercises.
Step-by-step explanation:
When instructing a patient on performing isometric exercises, a nurse should include guidance that emphasizes the importance of producing muscle tension without changing the length of the muscle or the angle of the joint. Isometric contractions involve sarcomere shortening and an increase in muscle tension but do not involve moving a load since the force produced is not sufficient to overcome the resistance.
For example, when attempting to lift an immovable object like a heavy hand weight, there will be activation and shortening of the sarcomere and increasing muscle tension, but the joint angle, such as the elbow's, will remain unchanged. This is because the focus of isometric exercises is to maintain a static position rather than produce movement. Such exercises are commonly used to enhance muscle strength, maintain posture, and stabilize bones and joints.
Instruction on isometric exercises includes not only the exercise itself but also the correct frequency and duration to safely build strength without the risk of injury. Proper breathing techniques should also be included in the instructions to ensure the patient does not hold their breath during these exercises, which could lead to a dangerous increase in blood pressure.