Qualitative Biomechanical Analysis to Improve Technique

Objectives:

• Understand the difference between a qualitative and quantitative biomechanical analysis
• List the steps involved in a qualitative biomechanical analysis for technique improvement
• Understand the process of developing a theoretical mechanically based cause-and-effect model of a skill
• Describe the important guidelines for observing a performance
• Understand how to identify, evaluate, and prioritize errors in performance
• Understand how to give instruction to students or athletes that will help them correct errors in technique

Introductory Review...

Differences between a qualitative and quantitative biomechanical analysis...

Necessary tools for qualitative biomechanical analysis...

Advantages and disadvantages of both methods?

Four Parts of a Qualitative Biomechanical Analysis

1. Description
2. Observation
3. Evaluation
4. Instruction

• Gain a fundamental knowledge of the skill: participate in the skill, talk to coaches, or read books and journals.

  At the very least, know the rules. Why is this important?                                             

  1. hockey (www.nhl.com/hockeyu/rulebook/rule19.html),

  2. discus,

  3. pole vault, and

  4. baseball (http://mlb.mlb.com/mlb/official_info/official_rules/pitcher_8.jsp)

• Articulate the purpose or goal of the skill using mechanical terms; this is easy for some sports (e.g., track and field), yet more difficult for others (gymnastics or diving). The following terms are often helpful in completing this task: maximize, minimize, optimize, increase, and decrease.
• Tennis
• Football
• Ice Skating
• Choose a skill: Write the purpose in mechanical terms and the characteristics of most effective technique

• Identify the characteristics of the most effective technique (this requires biomechanical knowledge and common sense; it is also helpful to divide the skill temporally)
  • Assess traditional techniques: determine what matters and what doesn't. Do involved actions contribute mechanically to the objective, or are they detrimental?
  • Use a deterministic (cause and effect) approach

Consider the traditional and deterministic approaches in analyzing the high jump:

What is the purpose of the high jump?

Jump Height = COM Height₁ + D_Y

What affects the aforementioned variables?

2. Observe the Performance (video will usually improve your observations)

• Who will you observe? Beginners or experts; as skill level increases, gross error and performance variability decrease
• What will be the conditions? Competition or practice; try to replicate the competition environment, yet maintain the ideal observation vantage points
• Where will you observe from? Perpendicular or parallel to the plane of motion; close or far
• What will you look for? Body position, range of motion, duration, velocity and acceleration, and segmental timing; the mechanical variables you have previously identified in your deterministic approach will be most important to watch

3. Evaluate the Performer

• Identify errors
• Evaluate errors
• Does the error expose the performer to the danger of injury?
• Who are your clients?
• How easy is it to correct the error?
• Is the error a result of another error that occurred earlier in the performance?
• How great an effect does the error have on the performance?
• Is the error or deficiency due to poorly designed or inappropriate equipment?
• Is the error or deficiency due to inadequate strength?

4. Instruct the Performer

• Communicate with the performer--be positive, simple, and specific in verbal, demonstrative, and video feedback; focus on one error at a time; recognize that some decline in performance may occur throughout the correction process
• Correct the error
• Often, it is appropriate and beneficial to repeat the analysis numerous times