Over the last year, Dr. Anthony Romeo has been working in partnership with the Director of Sports Medicine Motion Analysis, Antonia Zaferiou, PhD, on a shoulder biomechanics research project focused on functional outcomes following surgical interventions and how overhead athletic maneuvers are performed. A major goal of their clinical shoulder biomechanics research is to understand the shoulder’s movement mechanics before and after surgery. In their athletic branch of biomechanics research, they are focusing on learning how female high school volleyball players execute a “spike”, “hit”, or “attack”; with the potential to link measured movement mechanics to performance outcomes and the potential to developing shoulder issues. This type of study entails measuring 3D motion of each body segment (for example, the forearm), estimated forces experienced by the body’s joints (for example, the shoulder), and muscle activation patterns. Using sensor systems provides a “behind the scenes” look at how the hitting motion is controlled at a whole-body and “sub-system”, or, joint-specific level.
Biomechanics research uses technology including wearable sensors and “optical motion capture” cameras to measure the motion of each part of the body. Below is an example of how these motion sensor systems are used to analyze the volleyball hit:
“In order to improve performance and reduce the risk of injury, we must be able to understand the details of the motion of interest,” Zaferiou states, and in the process of understanding how muscles, bones and soft tissues work while hitting the ball, we can see how the brain controls the body and what specific body part is being used at each stage of the movement. A volleyball spike can be broken into distinct phases, each of which has challenging mechanical objectives: the approach, pre-ball contact, and post-ball contact. The approach entails generating linear and angular momentum needed to jump into the air towards a moving target. Before ball contact, players accelerate their arms and shoulders using an overhead motion to hit the ball above the net as hard as possible. After ball contact, the players need to decelerate their arms and find a way to cushion their landing without touching the net that is right in front of them.
Volleyball players undergo repetitive loading during the hitting process, from jumping constantly and using the same motions over and over, which is thought to lead to chronic shoulder pathologies. Therefore, these efforts to understand muscle activation patterns and body movement used throughout the spike may be a way to reduce the risk of injury in the future.
Although this research takes time to acquire, process data, and to run this test multiple times for accuracy, one fascinating finding at this point in time has been the ability to see which specific muscles are being fired at each stage of the spike. This is interesting because we can see how the “core” or the abdominals are engaged, as well as how the trapezius, deltoids, and pectoralis muscles are used the moments leading up to the swing.
Be on the lookout for future posts about this research project! Follow both Dr. Anthony Romeo and Dr. Zaferiou on social media!
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