What is the difference between extrinsic biomechanics & intrinsic biomechanics?

Understanding the Difference Between Extrinsic and Intrinsic Biomechanics

Biomechanics, the science of movement, is a broad and intricate field. Today, we’ll explore two critical areas: extrinsic biomechanics and intrinsic biomechanics. We’ll clarify how they differ, how they influence each other, and why understanding both is essential.

 

What is extrinsic biomechanics?

 

Extrinsic biomechanics focuses on observable movements. It’s about what we see when someone performs an action, such as a client’s knee buckling inward (knee valgus) during a squat. Basic training might prompt us to correct this by telling the client to “push their knees out.” While this can sometimes work, persistent issues may require a deeper analysis through intrinsic biomechanics.

 

 

What is Intrinsic Biomechanics?

Intrinsic biomechanics delves into the anatomical substructures—myofascial, skeletal, and neural—behind movements. It seeks to understand why a movement occurs in a particular way. Using the knee valgus example, a practitioner trained in intrinsic biomechanics would evaluate the pelvis, spine, shoulders, knees, and feet. This comprehensive assessment helps identify the root causes of movement issues, which can involve multiple dysfunctions and compensations within the body’s kinetic chains.

Once the problematic body part and substructure are identified, the practitioner can prescribe targeted interventions. They can also re-test immediately after the intervention, providing objective evidence of the cause of the client’s movement limitations.

 

 

Similarities and Differences

Similarities:

• Both relate to movement and biomechanics.
• Both are observed from outside.
• Both are crucial for understanding movement.
• Both are key for practitioners involved in movement analysis.

Differences:

• Extrinsic Biomechanics: This is the more common approach, focusing on what we see during movements. It often involves equipment like gait analysis or motion monitoring tools. It answers the “what” of movement analysis.
• Intrinsic Biomechanics: This approach is newer and less commonly understood. It stems from over 20 years of research on 4,500 subjects. It requires specialized training and a deep understanding of anatomy. Practitioners assess various body types to create customized programs, answering the “why” behind movements.

 

Importance in understanding the difference – case study example

 

Consider a runner showing extrinsic over-pronation. Video gait analysis might suggest using orthotics or specific shoes to correct this. However, intrinsic biomechanics can reveal underlying causes such as:

• Functional leg length discrepancy
• Dysfunctional pelvis
• Tight lateral spine flexors
• Overactive shoulder protractors
• Ligament dominance
• Tight calves
• Tight sciatic nerve
• Loose subtalar or midtarsal joints
• Low arch height

Without assessing intrinsic biomechanics, these potential causes might be missed, leading to incomplete or ineffective interventions.

 

Conclusion

Extrinsic biomechanics can be misinterpreted without an understanding of intrinsic biomechanics. Biomechanics Coaches, specialising in intrinsic biomechanics, possess a deeper knowledge of the musculoskeletal system. They can assess clients more thoroughly and design tailored programmes to enhance movement efficiency.

Interested in a Career in Biomechanics?

If you’re passionate about biomechanics, consider becoming a Biomechanics Coach! Contact us at info@biomechanicseducation.com to discuss a career in intrinsic biomechanics and learn how you can make a difference in the science of movement.