5 Principles for Electromyography use in Sport

Performance coaches and medical specialists are looking for the best approaches during screening to reduce injuries. With time being a precious and almost endangered resource, coaches and therapists are wanting to gain as much information and data as possible during testing and evaluations.  Professionals at all levels, be they in the clinic or in the field, are looking for the right data, not just more data. One of the best ways to improve outcomes in screening is to add surface electromyography (sEMG) to the common tests used for assessment to get deeper and more defined information that goes beyond simple video capture. While most movement screens are scored based on visible criteria, biomechanical compensation and neuromuscular recruitment patterns are difficult to discern solely through observation.

Integrating sEMG is easy, provided one knows what to look for. Noraxon’s wireless sEMG systems can capture the body’s muscles in action during a movement screen, sporting action, or an exercise in the weight room. sEMG helps practitioners evaluate what is going on at rapid speeds or can help validate interventions based on initial screenings. Currently there are five main principles clinics and organizations are finding to be the best practices in regards to complex injuries or effective screening programs. They are: 

Symmetry Threshold

An athlete’s body is not perfectly symmetrical and most sports are side-dominant, such as baseball and golf. While some asymmetry will exist between limbs from adaptation, the lower extremity especially is more predisposed to injury when dissimilarities become pronounced to the point of injury. No true percentage exists, but when the discrepancy becomes consistently greater than 10% risk will increase as the differentiation widens.

Coordination Scoring

EMG looks at how efficient an athlete’s muscle recruitment is based on quiet periods or times that muscles react and show little activation. The ability to efficiently move without various muscle groups being “on” is a cardinal sign of both coordinated movement and reduced risk of injury from proper timing. Coaches and medical professionals can create unique and individual scoring of efficient movement when surface EMG is used.

Optimized Sequence

Proper summation of forces will result in a more powerful movement, requiring a precise sequence of firing patterns through the kinetic chain. An error in timing, such as a muscle group in a joint action being too early or too late will increase the risk of injury through overload or reduce the performance of the action. EMG records the muscle firing pattern in milliseconds, meaning ballistic actions such as throwing, kicking, jumping, and sprinting can be analyzed at speeds the naked eye just can’t see.

Peak Activity

By using EMG to look at patterns of activation and amplitude changes, training programs can more effectively prepare the body and ensure it is properly rehabilitated with the appropriate work-rest dosages. Higher levels of activity can be signs of successful intervention or improved motor control. 

Evidence Based Norms

Ideal models tend to be averages of a larger population within research. Deviations from the norm contribute to increased risk of injury or a decrease in performance if not carefully managed. At times outliers will create a need for deeper analysis to properly assess individual differences, requiring medical and performance specialists to collaborate and support athletes with unique mechanics or styles.