23 3.6 Applications to Human Movement Analysis
Measuring kinematic variables in one-dimension can be useful for both athletic assessment of performance and rehabilitation. Let’s consider two examples:
- Sydney is a College sprinter with her eye on a National title. She can maintain a top velocity of 10.89 m/s for most of the 100m sprint. This is comparable, in fact better, to the current National champion at 10.85 m/s. Can you help Sydney beat her opponent and become champion?
As a biomechanist, you may be ask to analyze Sydney’s performance and offer advice for improvements. You watch her run 5 race-efforts and notice a trend. Sydney reaches her top speed of 10.89 m/s at the 30-m mark. She manages to maintain that top speed until the end of the 100-m. Her opponent can only reach 10.85 m/s but she reaches her top speed at the 18-m mark. What advice do you have for Sydney and her strength and conditioning coach?
2. Alfred is recovering from a stroke. A stroke is a blockage of blood to parts of the brain, causing the brain tissues to be affected from the lack of oxygen. The right -half of Alfred’s body was affected, causing weakness to his right leg. This greatly affected his walking pattern (also called gait pattern). He has recovered enough function for activities of daily living which is encouraging to regain independence. The only obstacle standing in the way between himself and the grocery store is the ability to cross the street quickly enough to make the green light. How can you help Alfred increase his walking speed?
As a biomechanist, your first job is to assess Alfred’s walking speed. You set up a straight 10-m walkway and time how long it takes him to complete the course. Using your knowledge of kinematics, you divide the displacement (10-m) by the time he took (12.3 seconds). You can then compare this value (0.81 m/s) to the required velocity to safely crossed the street (1 m/s).
You have a few options to increase walking velocity. The variables that determine walking velocity include step length and step frequency. Which do you recommend Alfred work on? What strategies would you recommend?