According to the talk-test method of measuring exercise intensity, a person who is engaging in vigorous physical activity should be
a. able to talk during the activity.
b. able to sing during the activity.
c. unable to hear others talk during the activity.
d. unable to talk during the activity.

D. unable to talk during the activity.

Explanation:

The talk test is a subjective method that is used for the estimation of appropriate cardiorespiratory exercise intensity. This method is used for maintaining the intensity of exercise at which the conversation of the person can be found to be comfortable.

When an exerciser reaches up to the intensity at which he/she barely respond in conversation then the intensity is considered to be safe and appropriate for the improvement of the cardiorespiratory endurance.

According to the able explanation, D is the correct option. The person will be unable to talk due to an increase in the intensity of the exercise.

well say a good goal is to do 150 sit ups in a week! or 90 pull ups a day. even 60 push ups in a month these are all fair goals!