Ankle Dorsiflexion & Lifting Mechanics
How does ankle dorsiflexion range of motion affect lifting mechanics?
Accompanying Narrator's Script: During lifting, ankle dorsiflexion is important. You can see in this first slide how your lifting mechanics can change depending on your ankle dorsiflexion range of motion (ROM). If you have sufficient ankle dorsiflexion ROM (as seen in column 1) you can use more knee flexion and less hip range of motion to lift an object from the floor with a neutral spine. If you have limited ankle dorsiflexion ROM, it is more difficult to lift an object from the floor because by having less ankle dorsiflexion ROM, you have less knee flexion. One way to compensate for this is by flexing your spine (as seen in the 2nd column). This is not good because it adds excess strain to your lumbar spine. Another way to compensate for limited ankle dorsiflexion ROM is by lifting your heel. This may allow a person to maintain a neutral lumbar spine because the knees can be flexed; however, it also increases the external flexion moment about the knees.
Accompanying Narrator's Script: As said before, this is an example of proper lifting mechanics. When someone has sufficient ankle dorsiflexion ROM they have more knee flexion and less hip range of motion is needed to lift an object from the floor with a neutral lumbar spine. This way of lifting helps preserve intervertebral disk integrity and decreases the chances of injury.
Accompanying Narrator's Script: This is an example of improper lifting mechanics. As said before, people with limited ankle dorsiflexion ROM are unable to flex their knees as much. This prevents them from reaching the floor to lift an object. One way to compensate for this is to flex your lumbar spine. Lifting with a flexed spine loads passive tissues such as intervertebral discs, bones, and ligaments instead of muscles. This way of lifting increases the risk of lower back pain and injury such as a posterior disk bulge.
Accompanying Narrator's Script: In this slide, you can see a comparison between the knee moment arm of someone lifting with their heel firmly planted on the floor (with sufficient ankle dorsiflexion ROM) and someone lifting with their heel up (with limited ankle dorsiflexion ROM). Bending the knee with the heal firmly planted on the floor creates a shorter knee moment arm, reducing the load on the knees. As said before, to accommodate an ankle dorsiflexion restriction, lifters will be forced to increase the joint range of motion elsewhere. In contrast to lifting with a flexed lumbar spine, lifters may also raise their heels to pick up an object from the floor. Even though this may allow them to maintain a neutral lumbar spine because the knees can be flexed, it also increases the external flexion moment about the knees. In other words, it creates a longer knee moment arm. Lifting with a heel will increase the load on the knees, making them more prone to injury.
Initial research was conducted to understand how ankle immobilization alters the kinematics and kinetics of lifting.
Sketches were made iteratively with multiple feedback sessions with the client to ensure accurate and efficient storytelling.
The biggest challenge was communicating all the information onto one powerpoint slide. This turned out not to be the best design solution, as crucial information was left out. With the approval from the client, the issue was solved by increasing the number of powerpoint slides to four. In this manner, the storytelling could be completed properly by including an appropriate level of detail for each subject matter related to ankle dorsiflexion range-of-motion.