I. Introduction - Concentric Exercise Device

This day in age, having a healthy exercise regime is becoming an important part of people's lives. However, becoming sore refrains you from using your muscles to their full potential when you want to workout again the next day. This soreness comes from eccentric exercises which are exercises that work with the force of gravity such as lowering your arms from a bicep curl. These are called “negative movements.” On the other hand, there are concentric exercises that are “positive movements” that work against gravity and do not result in delayed onset muscle soreness (DOMS). Figure 1 displays an example of isometric, concentric, and eccentric movements when performing a bicep curl.

Figure 1: Isometric, Concentric, and Eccentric Movements (Cannon, 2020)

Some advantages and disadvantages for concentric movements and eccentric movements are displayed on the right:

Concentric:

Quicker recovery time
Muscles can be trained more often
Helps prevent fatigue
Helps rehabilitation of injuries

Eccentric:

Cause muscle damage
Can’t work muscles to full potential due to muscle weakness

With this, the primary function of the mechanism we designed is to avoid the negative effects from eccentric exercises, we will be creating a concentric exercise device that works against gravity throughout the entire movement. This mechanism will allow for various concentric-only exercises and will be mostly gravity-independent. To gauge how successful the end product is, we have created a list of success criteria below:

Complete an estimated cost of production for the MED-2 vs our final product.
Create an air resistance network which allows for smaller components with a relatively large resistance capability.
Conduct a series of usability tests (such as a “non-dominant hand oil” test).
Compile a list of concentric-only exercises it can be used for (this may involve the use of attachments for the device).
Measure the accuracy of the device’s set resistance compared to the actual resistance.

Figure 2: Muscle Pain (Victor, 2019)