Biomechanics Exam 3

What is qualitative biomechanical analysis?

Breaking a movement into basic elements and examining each element from a biomechanical perspective, usually through visual observation.

What is quantitative biomechanical analysis?

Measuring biomechanical elements of a skill numerically, such as timing, distance, force, or velocity.

Who most commonly uses qualitative biomechanical analysis?

Coaches and teachers.

What are examples of comparative descriptors in qualitative analysis?

Faster, slower, higher, lower, shorter, and longer.

What are the four steps of qualitative biomechanical analysis?

Description, observation, evaluation, and instruction.

What is the purpose of the description step?

To define ideal technique and distinguish what is important/unimportant, correct/incorrect, possible/impossible, effective/ineffective, and safe/unsafe.

What else is considered during the description step?

Rules, traditional techniques, equipment, desired outcome, performance measure, and success criteria.

What are the two ways to identify the most effective technique?

Study elite or traditional technique, or develop a deterministic cause-and-effect model based on biomechanical principles.

What should be decided during observation?

Who to observe, under what conditions, where to observe, and what to look for.

How do errors change as skill level increases?

Observable errors get smaller and trial-to-trial variability decreases.

Under what conditions should performance ideally be observed?

Under conditions similar to typical performance.

What is the purpose of initial trials in observation?

To get a general view of the performer's level and spot obvious technique violations.

What is the purpose of subsequent trials in observation?

To focus on characteristics of effective performance like orientation, ROM, velocity, and timing.

What can help improve observation besides sight?

Listening, self-evaluation by the performer, video recording, and an assistant.

What are the two steps in evaluation?

Identify errors/deficiencies and diagnose the magnitude of their effect on performance.

How are errors identified?

By comparing actual performance to the most effective technique and checking for differences in motion, position, or timing.

What must be distinguished from true technique errors?

Individual differences caused by morphological constraints such as anthropometry or strength.

Which errors should be corrected immediately?

Errors that increase injury risk.

For novice learners, what errors should be emphasized first?

Errors in the basic elements of the skill.

how do you rank technique priority

major to minor in terms of performance, earliest to latest in timing, and easiest to most difficult to correct

How can errors be prioritized?

By injury danger, effect on performance, timing from earliest to latest, and ease of correction.

what are some examples of good communication skills

descriptions/instructions kept simple, focused on the element to change, positive attitude, positive aspects of performance, keep in mind performance may initially decline stay patient

What are the three instruction steps after ranking errors?

Explain the error, explain ideal technique, and devise a plan to correct it.

What is a teaching progression?

break skill into discrete parts, devise drills to duplicate movements, use drills to develop correct technique for each part, extend drills to combine parts, and perform entire skills — the repeat the process

What is the principle of specificity in training?

Exercises and drills must be specific to the sport or activity.

What is technical training?

Practice time devoted to improving technique, either by performing the skill itself or drills that mimic parts of it.

What is physical training?

Practice aimed at improving physical capacities such as strength, power, endurance, flexibility, cardiovascular fitness, and body composition.

What is anatomical analysis used for?

To determine predominant muscle activity and periods of large stress during movement.

What are the five steps of qualitative anatomical analysis?

Divide into temporal phases, identify joint movements, determine muscle contraction type, identify rapid angular accelerations/impacts, and identify extreme ROM.

What are temporal phases?

Specific phases or motions that break down the performance.

What should be identified about joints during anatomical analysis?

Which joints and segments are involved and how they move during each phase.

What is the difference between joint motion and joint position?

Motion describes how the joint is moving; position describes where the joint is at a moment in time.

What is concentric contraction?

Muscle action that produces positive work and increases mechanical energy; the segment speeds up or rises.

What is eccentric contraction?

Muscle action that produces negative work and decreases mechanical energy; the segment slows down or is lowered.

What is isometric contraction?

Muscle action that produces force without movement and no change in mechanical energy.

Why are rapid joint angular accelerations and impacts important?

They show when active muscle groups must produce large forces and at what joint positions when the large forces must be produced.

Why are extreme joint ranges of motion important?

They identify times when muscles and soft tissues may be highly stretched and potentially injured.

What is mechanical stress?

The distribution of a force over the body it acts on.

What are the main types of mechanical stress?

Compressive, tensile, shear, and complex loading.

What is compressive stress?

Forces squeezing the body.

What is tensile stress?

Forces pulling the body.

What is shear stress?

Forces that tend to slide two parts of a body across each other.

How does tissue respond to higher stress?

Through hypertrophy, increasing size and strength.

How does tissue respond to lower stress?

Through atrophy, decreasing size and losing strength.

What is the physiologic loading zone?

The level of stress to which tissue is currently adapted.

What is the physiologic training zone?

A stress level above current adaptation that causes microdamage and beneficial remodeling.

What is the overload principle?

Systematically loading tissue above its current threshold while allowing adequate rest for remodeling.

What is the pathologic underload zone?

Prolonged low stress leading to detraining and weakened tissue.

What is the pathologic overload zone?

High stress causing substantial tissue damage and injury.

What is a traumatic injury?

An injury caused by a single application of high stress.

What is an overuse injury?

Injury from repeated applications of lower stress over time.

What determines overuse injury risk?

Stress magnitude, number of repetitions, and whether adequate rest occurs for remodeling.

Why is adequate rest important in preventing overuse injury?

Without rest, stress is reapplied to still-damaged tissue before remodeling is complete.

Why is injury prevention complicated?

Because tissues differ in thresholds, stress directions tolerated, individual factors, and remodeling times.

What are intrinsic factors in injury development?

Factors related to the individual that determine ability to withstand loading.

What are extrinsic factors in injury development?

Factors related to the task and environment that determine the imposed loading.

What is cross-training?

Rotating among different activities so tissues experience different loading patterns and have time to remodel.

Name ways to reduce injury risk.

Match skills to anthropometrics, improve posture, select proper equipment and locations, use cross-training, and progress frequency/intensity/duration gradually.

What biomechanical variables are quantified?

Temporal, kinematic, and kinetic variables.

What are temporal variables?

Timing variables.

What are kinematic variables?

Position, displacement, velocity, and acceleration.

What are kinetic variables?

Force, energy, work, and power.

What are benefits of laboratory data collection?

It allows strong environmental control and helps minimize measurement error.

Conditions similar for each repeat of skill performance and much of the intrumentation is permanently set-up

What is one limitation of laboratory data collection?

The environment may feel unnatural and affect performance.

What is one benefit of in-the-field data collection?

It captures performance in the athlete's actual or more natural setting. Actual competition may be the best environment for athlete

What are limitations of in-the-field data collection?

technology not easily portable, instrumentation not easily mounted in competitive setting, limited control of the environment

What is an analog signal?

A continuously varying signal, often measured as electronic voltage.

What is sampling rate?

The frequency at which an analog signal is measured and converted to digital form.

In video analysis, what does sampling rate mean?

Frames per second (fps).

What is the typical fps for consumer video cameras?

About 30 to 60 fps.

What is the typical fps for smartphones and digital cameras?

About 120 to 240 fps.

What is the typical fps for high-speed video cameras?

About 1,000 fps, usually with lower resolution.

For most analyses, what frame rate is adequate?

Less than 100 fps.

When are higher frame rates needed?

For faster actions and impacts.

What are examples of kinematic measurement tools?

Stopwatches, pressure-sensitive mats, photogates, radar guns, LIDAR, and video systems.

What is EMG used for in biomechanics?

To monitor muscle electrical activity.

What is the stress continuum from low to high for the zones

pathologic underload zone, physiologic loading zone, physiologic training zone, and pathologic overload zone

What is the stress continuum from low to high for stress

distress and increased injury risk, eustress, and distress (injury)

analog signals and sampling rate

most biomechanical parameters vary with time, and many instruments record the variable in analog form like electronic voltage

what do intrinsic factors set?

the threshold value for the level of stress that may cause injury

what do extrinsic factors reflect

the potential for a given performance to impose a stress exceeding threshold value

How does stress thresholds differ among tissues

bone > tendon > ligament > catilage

How does tissue thresholds vary according to stress direction in bones

compression > tension > shear

How does tissue thresholds vary according to stress direction in ligaments and tendon

tension > shear

how does thresholds differ among people

reflects genetics, training, nutrition, previous tissue adaptations

time to remodel differs among tissues and individuals

what are two types of the pathologic overload zone

traumatic and overuse injury

what are examples of traumatic injury

ligament tear, bone fracture, muscle avulsion

what zones are in the eustress stress continuum

physiologic loading and training zone

what zones are in the distress stress continuum

pathologic underload and overload zone