The benefits of isometric training

I recently came across an article on the effects of exercise training on blood pressure. I found the idea interesting since the antihypertensive action of exercise is well known and the usual recommendation is aerobic training of various intensities. However the current guidelines for blood pressure control are based on rather old data, where more modern exercise modes like interval training and isometric exercise training had not been considered. 

The findings of the study were somewhat surprising. As expected, aerobic exercise training, dynamic resistance training, combined training, high-intensity interval training and isometric exercise training do reduce blood pressure. What was unexpected was that the most effective exercise mode was isometric exercise training.

The authors of the study argue that their findings provide a framework that would allow the proposal of new exercise recommendations aiming at preventing and/or treating hypertension. Their findings are summarised in the infographic below.

First let us define what is meant by isometric. Isometric exercises are static. The muscles do contract but do not change their length. The joints involved do not move. The body is supposed to be stable. Isometric exercises can be done with weights but also using just one's body weight. In this sense they are extremely simple, neither necessitating specific equipment nor taking up much space. And they are of rather short duration.

The paper I mentioned being a scientific, public health-oriented, one does not offer specific exercise recommendations. For those of you who would be interested in more specific recommendations here are my favourite two. 

The first is the plank. One starts by assuming a position with the elbows directly beneath the shoulders and the body forming a straight line from head to heels. One must engage the core muscles and  hold this position, keeping the back flat and avoiding sagging or arching. One must remember to breathe steadily throughout the exercise. The duration should be one that challenges one's endurance, gradually increasing the time as strength improves.  Variations, such as side planks or plank with leg lifts, do also exist.

The second is the wall-sit exercise. One begins by standing with the back against the wall and the feet about shoulder-width apart. Then one lowers the body into a seated position, sliding down the wall until the knees form a 90-degree angle. One must ensure that one's back is pressed against the wall and the thighs are parallel to the ground. The position is held, engaging one's quadriceps, hamstrings, and glutes. This is an effective isometric exercise that targets the lower body, particularly the quadriceps, and helps build muscular endurance over time. For those who would like variations of the wall-sit exercise, here is a link to a page from Inspire US Foundation. (And, in case you are wondering, they also have a page on an interesting plank variation).

A proper isometric training program usually involves four two-minute contractions, separated by one- to four-minute rest intervals. Beginners should not go for such durations and should adapt the contraction times to their possibilities, increasing them progressively as they become more proficient. One sees that the plank and wall-sit set can be done in less than half an hour. Isometric training can be done three times per week and can be incorporated into a training program involving exercises of other type.