Chapter 1c - Basic Principles of Biomechanics Flashcards
What is anatomical position. What are the three planes the body can then be divided into?
The position where a person is standing with arms at the side and the palms of the hands facing forward. Three planes are
- sagittal plane - body is divided from left to right. (elbow extension, hip flexion, knee flexion | shot put, punter, diving | Triceps push down, leg raises | leg curls)
- Frontal plane - Runs through center of the body from side to side, dividing the body into front and back halves.(body movement : shoulder adduction, ankle inversion, hip adduction| swimming, resisted inversion, and standing adduction machine | Wide grip lat pull down, soccer dribbling, soccer side step}
- Transverse plane - seperates body to upper and lower regions [ hip IR, lower back left rotation | Golf swing, batting, pivot in BB | Torso machine, med ball side toss, resisted IR \
Explain Joint angle and its relationship to torque.
Measured in degrees , between two body parts that are linked by a single joint. The force produced by a joint is expressed by torque.
Torque exerted varies by ROM, muscle length vs force, levarage , and speed of contraction around a joint.
Explain velocity and is it similar to speed?
Rate of change of distance over time. It’s not the same as speed. Speed is the rate at which an object covers a distance, and velocity is how fast and in what direction an object is moving.
Explain velocity and is it similar to speed?
Rate of change of distance over time. It’s not the same as speed. Speed is the rate at which an object covers a distance, and velocity is how fast and in what direction an object is moving.
What is force, what’s the equation of it, and what is it measured in.
Force is best visualized as a push or pull exerted on one object by a second object. Both objects have magnitude (Size) and direction. Force is measured in Newtons (N)
Formula - F = M (a + g). F = force , M = mass, A = instantaneous accel, g = acceleration resulting from gravity
Number of cross-bridges from actin , myosin filaments will help determine the amount of force produced at any moment in time.
What is the force-velocity curve. How does it relate to 1RM.
Represents the relationship between velocity (x-axis) and force (y axis) Inverse relationship between force and velocity, such as that force increases velocity decreases. For example - if an athlete is strong but not fast, more time should be spent training at a lower force.
Max strength - 90-100% 1RM
Strength -Speed - 80-90% 1RM
Peak Power - 30-80% 1RM
Speed Strength - 30-60% 1RM
Max Speed - < 30% 1RM
When curve shifts to the right, you’ve been training strength, shifting to the left means you’ve shifted to speed. The point of training often is to improve Rate of force development, resulting in a rightward shift of the curve.
What is the force - time curve. What is the rate of force development and why important.
Time - X-axis , Force - Y Axis
Rate of force development (RFF) - the RFD is the change in force divided by the change in time.Notable for sports where the time of movements or explosiveness is critical. The generation of maximal force with minimal time is an index of explosive strength
What is momentum? How is it calculated. Why relevant.
The amount of motion an object has. It’s calculated as the velocity multiplied by the objects mass, and like velocity it is a vector quantity with a direction. It’s relavent because it can be used for performace assessment.
Momentum is important in collision sports because athletes with a larger mass can hit or tackle with more momentum (football , rugby)
What is impulse?
Impulse is the product of time required to generate force. This quantity is represented as the area under the force-time curve. Impulse increases by improving RFD with the magnitude of change in the momentum of an object being contigent upon impulse
What’s work, what is it measured in, what’s the equation.
How is that different than power, what is power and its equation?
Work is measured in joules (J) and is calculated by force x displacement. It’s useful to help see how an athlete is handling a training program over days, weeks, and months.
Power is the rate that work is performed and it is P = Work / Time. Usually measured in W or Horse power Hp. Training should consider the power needed in the player’s sport. Power is the product of force and velocity, improving either will improve RFD and explosiveness.
What are the three main type of joints?
Fibrous joints - such as the skull allow almost no movement
Cartilaginous joints - such as IV joints, allow a limited amount of movement.
Synovial joints - such as the elbow, allow for the greatest amount of movement and ROM
Explain the 6 synovial joint types.
Ball and socket - Rotation and movement around all planes - Shoulder and hip
Condylar - No rotation; variety of movements in different planes - Joints between phalanges and metacarpals
Plane - Twisting or sliding - joints between various bones of the ankle and wrist
Hinge - Elbow - Flexion and extension
Pivot - Rotation - JOint between the prox ends of ulna and radius
Saddle - Joint between carpal and metacarpal of thumb - primarily two plane movement
Joints can also be classified based on the movement they allow, specifically number of directions that joint rotation can occur. Name them.
Uniaxial - elbow | Hinge and pivot joints
Biaxial - wrist and ankle | Condyloid and saddle joints
Multiaxial - shoulder and hip | Ball and socket joints
Explain a first class lever.
A Seesaw - Fm (muscle force) applioed at one end of the lever, the Fr (resistance force) is applied at the other end, with the fulcrum in the middle. The forearm can serve as a first class lever with tricep extensions. Fulcrum is elbow joint, Fm is from the triceps contraction and the Fr is the weight of the machine.
Explain a second class lever.
Fulcrum on one end, the Fm is on the other end, and the Fr is between the ends. A wheelbarrow is a second class lever. wheel is the fulcrum, Fr is the load in the wheelbarrow and the Fm is the handles. Standing on one’s toes.
