Biomechanic Basics for Sport and Exercise
Improving Sport and Exercise Performance Requires an Understanding of Biomechanics.
Biomechanics is the study of forces and their effects on living systems.
Sport and exercise biomechanics are the study of forces and their effects on humans in exercise and sport.
The ultimate goal of sport and exercise biomechanics is performance improvements in exercise or sport.
A secondary goal is injury prevention.
Obviously, someone who is uninjured will perform better so both goals are closely related.
If you have attended any of my lectures, you have heard me repeatedly say:
“Rule #1 for all IFPA Certified Personal Trainers is: DO NO HARM!”
Your understanding of sport and exercise biomechanics will go a long way to preventing your personal training clients from being harmed.
If you do advance your career into sports conditioning and deal with highly competitive amateur and professional athletes, safety may become a secondary consideration to the only thing that truly matters to champion athletes… WINNING!
In these situations, athletes are willing to risk their safety in order to bring home the prize. Even in these circumstances, your knowledge of biomechanics becomes paramount to increase performance while reducing the risk of injury.
Your analysis through Phase One: Client Consult and Phase Two: Fitness Testing, can help you identify specific weaknesses in your clients’ strength, speed, power, muscular endurance or flexibility, your client will need to improve their technique and performance.
For Example: Your client, a tennis player, has overly tight hip flexors. You observe that your tennis player has a limited range of motion in rotating her torso in preparation for a hard, backhand shot.
Your exercise prescription would be to do PNF stretches once/day and have her do two static stretches each day on her own. This exercise prescription can dramatically improve not only how hard she can hit the ball, but improve her accuracy as well.
For many of us, myself included, injury prevention and rehabilitation should be the primary goal of sport and exercise biomechanics, but keep in mind, most of the biomechanics research is focused on the primary goal of improved performance.
One example of injury prevention in tennis concerned EPICONDYLITIS, tennis elbow (which also occurs in other sports).
One cause of epicondylitis was the overexertion of the extensor carpi radialis brevis muscle, that was corrected by biomechanics research, showing tennis players who keep their wrist neutral on their backhand stroke, greatly reduced injuries compared to those who used the flexed wrist technique.
Likewise, the Key Teaching Points (KTPs) you learned in your IFPA Personal Trainer certification course are all based on industry standard and safe training techniques.
To understand the foundation of the IFPA KTPs, let us go back to the definition of Biomechanics: the study of forces and their effects of living systems.
Forces are simply defined as a push or a pull.
Forces are exerted by objects on other objects.
The muscles in your body can only contract. That means muscles simply PULL!
Because of an intricate system of levers in your Musculo-Skeletal System, (the bones your muscles are connected to) your body can generate both PUSH and PULL Forces.
Your goal as a Personal Trainer is to improve performance and manage safety by teaching your personal training client the safest and most effect techniques to manage those improvements.
Biomechanics will also help you decide on which MODE of training will be most effective at meeting your client’s performance goals, i.e.: weightlifting, Olympic lifting, strength training on machines, calisthenics and gymnastics, can all improve strength.
The difference on the Forces inside and outside the body from something like weightlifting, where the equipment, moves around your body and gymnastics, where your body moves around the equipment is HUGE!
Classic Bodybuilding places huge stress on about 35-40 major muscles in your body, gymnastics places stress on nearly all 606 muscles in your body.
In terms of injury prevention, controlling stress is critical.
While a certain degree of muscular stress is essential for the body to adapt to make bigger, stronger and more powerful muscles, bones, tendons, ligaments and other body tissues, understanding internal and external stresses and the variations of stress: Mechanical Stress, strain, tension, compression, shear, torsion loads, stiffness, ductile, brittle, pliant, toughness and other biomechanical concepts will make you a master of your craft.
While it is impossible to provide you an in-depth and comprehensive discussion of each of these stressors, the following definitions are provided to you to increase your awareness of the potential areas of injury prevention, rehabilitation and caution.
Stress, in terms of external forces, (which are forces outside the body) that act on the body to impose loads that affect the internal structures of the body, i.e.: bones, cartilage, fascia, ligaments, muscles and tendons.
Mechanical Stress is the internal force divided by the cross-sectional area of the surface on which the internal force acts.
Tension is one of the two axial stresses or longitudinal stress and one of the three principal stresses.
Tension is a state of an object resulting from the forces pulling on it. This tension produces tensile stress.
Imagine you hanging from a Pull-Up bar and executing a Set of Pull-ups. The precise amount of Tension can be calculated at each point of your repetitions, which will change in relationship to your joint’s degrees of flexion/extension.
Tensile Stress is the axial stress or normal stress that occurs at the analysis plane, as a result of a force or load that tends to pull apart the molecules bonding the structure together at that plane.
In your body, very large tensile loads may rupture or sprain ligaments and tendons, tear muscles and cartilage and fracture bones.
Compression or Compressive Stress is the axial stress that results when a load tends to push or squash the molecules of a structure more tightly together at the analysis plane.
Imagine you have a heavy barbell on your shoulders, as you prepare to squat, nearly every structure from your shoulder, through your spinal column, pelvis, femur, tibia, ankle and foot are under Compressive Stress. Following all your IFPA KTPs controls the Compressive Stress.
Violating the IFPA KTPs can result in serious injury to your personal training client.
Another example is “Lifting your hips off the Bech while Bench Pressing. The Compressive Stress on the Lumbar Vertebrae can result in a herniated or rupture disc.
Shear Stress is a transverse stress that acts parallel to the analysis plane as a result of forces acting parallel to this plane.
Shear stress is equal to the forces at the analysis plane divided by the cross-sectional area of the object at the analysis plane.
Imagine a client doing a Squat incorrectly and exceeding ‘Knee-Toe-Line’ while “Twisting the Femur in Relation to the Tibia”: two violations of IFPA KTP’s. This Shear Stress can be sufficient to severely damage the structure of the knee capsule.
These are just a few examples of how understanding Biomechanics can elevate your knowledge and professionalism far beyond that of a typical, personal trainer and demonstrate how you can meet your clients’ needs faster and safer than other trainers.