More and more runners love to wear rashguard and compression pants these days. If you are not one of them, read this article.
Wearing rashguard and compression pants is believed to have many benefits when we do our endurance training. Research and tests show that rashguards can approximate the positive effect of aquatic therapy in our muscles.
At first, it was hard for me to believe that aquatic therapy and wearing rashguard or compression short have something in common. Because of my training as an engineer, I don't want to believe such claims unless I can find a written scientific calculation or unless I can prove it myself.
Since I can not find any written scientific calculation, I had to do one. Applying my basic knowledge in engineering mechanics, I did a tensile test to determine the compression pressure that a fabric exerts on the skin. I use the Elastic Energy theory that explains how elastic energy is created when an object like spandex fabric is stretched. The energy created is potential as it will be converted into another form of energy, such as kinetic energy.
In the case of the 300 GSM spandex fabric, which is the most commonly used compression fabric, the kinetic energy transferred to the skin shows interesting results. A series of testing and calculations resulted to a derived value from 0.40 psi to 0.75, for different compression ratio factor (CRF) starting from 12% to 20%.
Interestingly, the derived compression pressure of 300GSM spandex approximates that of water. I f you look at your physics book, the water pressure per 1-foot of depth is 0.43 psi (for fresh water) and 0.44 psi (for sea water), which is within the derived values of 0.40 psi to 0.75 psi. This means that wearing compression apparel in certain parts of the body from the calf to upper torso will also approximate the different pressure levels exerted by water.
Hence, our calculations show that wearing compression apparel may be as effective as the well-known Aquatic therapy.
No, we understand why some physical therapists recommend wearing compression apparel with 0.45 psi at the chest, 0.50 psi at the thigh, 0.41 psi at the upper calf, and 0.70 psi at the lower calf. These pressure levels contribute to reduced delayed onset muscle soreness (DOMS), less fatigue, improved performance, improved venous return, less edema post-competition and faster recovery.
Other physical therapists also recommend Aquatic Physical therapy as an evidence-based intervention to support restoration of function for many areas of orthopedics, including sports medicine, work conditioning, joint arthroplasty, and back rehabilitation programs.
Compression and aquatic therapy may seem entirely different from each other in approach. But a closer look and calculations show that they both actually work on the same pressure levels.
Based on theoretical calculations, there are similarities between compression apparel and aquatic therapy in terms of pressure applications.
You can do this experiment to have a first hand experience. Please refer to the diagram below.
1) Wear a tight-fitting rashguard and feel the pressure of the fabric on your chest area. Try to store that feeling in your memory. Then, remove your rashguard. Dive into the swimming pool and find a place in the pool where the water level reaches your chin. Stand in that spot and feel the water pressure on your chest area. Now, go back to your memory a while ago about the pressure you felt on your chest while wearing your rashguard. How do you compare the feeling?
2) Do the same test with a compression short. Wear one and store in your memory the pressure you feel on your thighs. Then, remove your compression shorts. Wear another loose fitting short (as this experiment don't give you the privilege to walk around naked). Find a place in the pool where the water level reaches your belly. Stay there standing for a while and feel the water pressure on your thighs. Then, recall your memory a while ago about the pressure you felt on your thighs while wearing a compression short. How do you compare the feeling?