Fortius Health

It’s cardiovascular health Thursday! Let’s talk about how CPR works.

CPR stands for cardiopulmonary resuscitation. The first word, cardiopulmonary, refers to the heart and the lungs. Resuscitation means to revive. This is actually a bit of a misnomer because CPR on its own has a low chance of actually restarting a heart that has stopped. CPR is useful, however, in manually circulating blood while more effective resuscitation techniques are accessed and employed.

Let’s talk about the manual circulation of blood. CPR works because the heart is located directly behind the sternum (breastbone) in the center of your chest. The sternum acts as an anchor for the ribcage and physically protects the heart from trauma, but it also comes in handy for performing CPR. This is because when the heart is compressed between the sternum and the spinal column, it pumps as it is meant to do.

Blood is normally oxygenated by the lungs, but during normal function, the blood holds onto an excess of oxygen in case of an emergency. In the emergency of cardiac arrest, blood will effectively supply vital bodily tissues with its reserve of oxygen so long as the rescuer is providing breaths and manually pumping the victim’s heart. This is because oxygen delivery to the tissues relies on a concentration gradient – the more the tissue needs the oxygen, the more likely the blood is to unload oxygen at that specific tissue.

CPR is a skill that can save lives and it is highly recommended to take an instructional course to learn how to do it. Comment below if you have any questions about CPR or want to share your experience!

It’s strength Wednesday! Let’s talk about types of muscle contractions.

Muscle is a unique bodily tissue because it can “slide” over itself, shortening or lengthening in the process. When a joint achieves a smaller angle, we describe the muscle as shortening (called “concentric contraction”), and when a joint achieves a larger angle, we describe the muscle as lengthening (called “eccentric contraction”). Muscle can also contract by holding their position without changing a joint angle – this is called “isometric contraction.” Our bodies produce each of these three contractions in our daily activities.

Interestingly, nearly every joint in our body has a complementary muscle on the opposite side to produce contraction in that direction. For example, biceps (located on the front of the upper arm) act concentrically to decrease the angle of the elbow, while triceps (located on the back of the upper arm) act concentrically to increase the angle of the elbow. However, if you were lowering a cup from which you just drank, the biceps would actually be acting eccentrically to slow the straightening of the elbow against the force of gravity – so remember that every muscle can act in all three contraction types. The amazing part is that when you decide to move, your body instinctively selects which muscles should be working together and which contraction type is most appropriate! Below are a few common exercises and which type of contraction is involved:
- bicep curls (raising weight is concentric, lowering weight is eccentric, holding it midpoint is isometric)
- plank (holding it is isometric for abdominals, lowering body slowly is eccentric for abdominals)
- squats (lowering body is eccentric for front of thighs but the back of thighs are uninvolved due to gravity; raising body is concentric for front and back of thighs)

Next time you exercise, try to think of which muscles are working and in which mode of contraction. Stay tuned for more posts on muscle contractions and how they implicate post-workout soreness! Comment below if you have any questions about muscle contractions!

It’s mobility Tuesday! Let’s talk about the hamstrings and how to stretch them.

In case you didn’t know, the hamstrings are a group of muscles on the backside of your upper leg. Like all muscles, they act upon every joint they cross; since they cross two major joints, they produce movement at both. The hamstrings are primarily responsible for flexing (bending) your knees and extending (straightening) your hips. These joint actions play a critical role in athletics; acting together with the gluteal muscles of the buttocks, the hamstrings propel the body forward while running.

So, how do we stretch the hamstrings? A rule to remember is that to stretch a muscle, we must do the opposite movement to which it produces when contracting. Therefore, we must extend (straighten) the knees and flex (bend) the hips. The most common way to do this is to sit on the floor with your legs in front of you and gently reach towards your toes. Here are a few more tips:

1) If you are going to perform this stretch statically (holding it over a long period of time), do so only following your physical activity. Otherwise, you may suffer a reduction in your strength output.
2) Avoid leaning towards your toes and curling your back to do so. Instead, try to keep your spine relatively straight up as you instead use your hips to bend forward. The reason for this is it becomes more of a lower back stretch this way. If you avoid doing this, you can focus on isolating the hamstrings instead.

Comment below to ask questions or share your experiences with stretching!

It’s mobility Tuesday! Let’s talk about stretching the calf muscles.

You probably know that the “calf” is the back of the lower leg. What you might not know is that the calf is comprised of several individual muscles, the two largest being the gastrocnemius (gastroc, for short) and soleus. Gastroc is closer to your skin, while soleus is found a little deeper. So, what makes these two muscles distinct, given that they are found so close to one another? The answer is that gastroc originates from above the knee joint, and thus acts to move the knee joint as well as the ankle joint, while the soleus originates from below the knee joint, and thus acts to move only the ankle joint.

Why is this important when it comes to stretching the calves? The answer is that we must make a simple adjustment to our knee joint in order to change which muscles we want to stretch. The two stretches look similar, but there is one key change.

1) When stretching gastroc, the knee must be extended (straightened) first. Place your foot flat on the floor and lean forward so your ankle bends upwards towards your shin.

2) When stretching soleus, the knee must be flexed (bent) first or the gastroc will be stretched instead. Otherwise, follow the same procedure as the gastroc stretch.

Remember to stretch both of the primary calf muscles next time you stretch! This will help you on your journey to becoming a more flexible (and therefore happy) individual. Check the comments to see a video demonstration of how to stretch both of these muscles! Comment below to ask questions or share your experience with stretching the calves!