Title: Biomechanics is a branch of science which employs mechanical and engineering principles to study bio
1What is Biomechanics
- Biomechanics is a branch of science which employs
mechanical and engineering principles to study
biological systems - The objectives of Biomechanics are
- To understand human physical performance how do
we perform movement and apply forces? how is
human motion controlled and how can it be
refined - To understand how the biological tissues
(materials) such as muscles, bones, cartilage,
tendons and other soft tissues participate in
such performance
2Objectives of Biomechanics Cont.
- To determine what kind of forces are acting on
musculoskeletal tissue elements during physical
activity - To find out what are the mechanical properties of
the relevant biological tissues how do they
deform and endure the application of forces and
how do they remodel - To understand the mechanisms of injury what kind
of loads cause tissues to fail (lose their
structural integrity)
3Examples of Questions that Biomechanics can Answer
- Truck drivers are known to develop chronic lower
back pain. Is there a critical vibration spectrum
which will cause injury? - Running can produce injuries to the joints of the
lower limbs. Can athletic shoes help prevent
injury by improving dynamic foot-ground
interaction? - Leg amputation and a continuous use of prosthesis
is likely to produce lower back pain in later
life. Can such arthritic development be prevented
via control of the limb structural parameters?
4Examples of Biomechanical Applications
- Plastic surgeon needs to perform skin graft to
cover an affected area of burned skin. What is
the best way to prepare skin for grafting? - Plastic surgeon needs to perform reconstructive
surgery by transplanting cartilage from the
sternum to the nose. How can he prevent stress
related deformity - How does one control an overuse syndrome in
articular cartilage such as in osteoarthritis of
the knee or hip
5Examples Cont.
- An orthopedic surgeon is presented with a case of
a child where the hip joint is abnormally
overloaded such that it causes degeneration of
the joint cartilage. What kind of solution can be
applied and what are the consequences - Degenerative changes in a joint (Ankle, knee,
hip, spine) may cause unbearable pain. The
surgeon may consider fusion of the bony elements
of the joint. What are the benefits and the
shortcomings of the procedure.
6Examples Cont.
- An alternative solution to the same problem could
be to resurface the joint with prosthetic
components, what kind of loads need to be
considered? how should the prosthetic component
be interfaced to the bony tissue? what kind of
geometry need to be reproduced? - Runners often suffer joint injuries as a result
of the frequent and extensive loading. Are shoes
contributory to the alleviation of such stresses?
Which shoe characteristics need to be considered?
- A child broke his tibia. Is plaster casting a
good solution?
7Examples Cont.
- In the design of high acceleration equipment,
such as airplanes, space rockets, roller
coasters and road vehicles, how does one decide
what kind of accelerations can the body sustain
without being injured? - In the design of off road equipment and vehicles,
exposure to vibrations considers frequencies
amplitudes duty cycle exposure time, etc.? - In the design of seat belts for automotive
application, what would be an optimal
configuration to prevent rib fractures?
8Human Performance Biomech.
- Biomechanics in Rehabilitation
- Biomechanics in Sport
- Occupational Biomechanics
9Performance of Movement
- 1. How do we perform movement and/or apply
forces
10The Musculoskeletal System
Anatomy Physiology
11Musculoskeletal Biomechanics
- Modeling of the MSK system with the objective of
identifying forces exerted/acting on the Bones,
Joints, Muscles and other soft tissues - Application to Trauma, Prosthetics and Orthopedic
Implant Design.
12Tissue Biomechanics
- The study of the mechanical behavior of
biological tissues - Force
- Deformation
- Growth and Remodeling
- Failure
13Bone Mechanics Remodeling
14Knowledge Required to deal with Biomechanical
Problems
- Anatomy understanding body structural
composition - Physiology understanding the body operational
principles - Applied Engineering-Mechanics The modeling tools
15The Principles of Biomechanical Analysis
- We approach the biomechanical analysis similarly
to the mechanical analysis - Determine the external forces either by static
modeling or by dynamic modeling - Determine the internal forces via fragmentation
and free body diagrams - Attribute the internal forces and moments to the
corresponding tissues - Perform Tissue Mechanics analysis
16Performance Analysis is the way to Determine the
External Loading
- Document the motion (kinematics)
- Measure the applied forces
- Assess muscular activity (EMG)
- Analyze trajectories of motion
- Develop a dynamic model to determine the forces
- Suggest ways to ptimize the performance
- Alternatively, analyze the motions of an elite
athlete and adopt his/her criteria
17A Typical Protocol For Tissue Mechanics Study
- Determine the performance characteristics
- Motion, External Forces (measurable)
- Focus on a particular body part/tissue of
interest and determine the forces acting on it - Typically a model is required
- Subject the specific part/tissue to the applied
forces and obtain its mechanical behavior
comparing loads and deformations - Compare the forces to the tissue endurance values
181. Document the motion (kinematics)
Data Presentation
192. Measure the applied forces
Ground Forces acting during locomotion
20Analyze Trajectories of Motion
Determine velocities and accelerations