KIN 825 Sp 2003 Week 10 Preventing and treating injuries Reading assignments –Adrian, Chapter 14 –Nigg Article in J Biomech –Sitler Article in Am J Sp Med –Junge Article in Am J Sport Med –Eils article in Clinical Biomechanics –Stacoff article in MSSE

Collisions and Impacts (Adrian, Ch 14) Understanding and measuring the forces of a collision Mechanics of stopping moving objects Protective equipment for catching –Foot protection –Baseball and softball –Biomechanics of head injuries and protection Falling and landing Sport surfaces

GRF’s and Tibial Accelerations

Measurement of Head Impact Tolerance

Mechanics of a collision To decrease impact forces –Increase surface contact area –Increase distance and time of impact –Increase mass involved in catching to reduce accelerations –Use materials other than the human body

Evaluation of Playing Surfaces Correlation of material and subject test results is very low!

Evaluation of playing surfaces For area-elastic floors –Cannot use force platform –Impact accelerations and/or deformation during controlled –Performance-related (maximum) jumping and bouncing –Friction For point-elastic floors –Can use force platform –Impact force-time characteristics during controlled jumps –Performance-related (maximum) jumping and bouncing –Friction

Nigg, M. (1990) On the potential of various approaches in load analysis to reduce the frequency of sports injuries. Journal of Biomechanics, 23 (Suppl. 1):3-12, 1990 PURPOSE: to discuss two approaches used in load analysis regarding: –(1) Is there evidence that these approaches have actually contributed to a reduction of injuries? –(2) Is there potential for these approaches to reduce the frequency of injuries?

Nigg cont’d GENERAL PATTERN OF INJURY PREVENTION RESEARCH: (1) Study factors influencing particular injury of interest (Epidemiological studies) (2) Understand the connection between these factors and the injuries (Cause-effect or empirical?) (3) Influence the relevant factors to reduce the frequency of injuries (Cause-effect or empirical?) (4) Find evidence to verify that strategies have reduced the frequency of injuries (Epidemiological studies)

Nigg (cont’d) CAUSE-EFFECT APPROACH (1) Identify endangered or injured structure (e.g., shin splints) (2) Determine individual critical limits of endangered structure (e.g., tibia) (3) Determine stress actually imposed on endangered structure (4) Identify factors influencing stress (use comparison technique) Conclusion: Attempts to do steps 1, 2, 3 have been unsuccessful; therefore, this method has limited potential

Nigg cont’d EMPIRICAL APPROACH: (1) Identify factors influencing injury (e.g., type of shoe) (2) Identify kinetics/kinematics related to injury (e.g., foot pronation, peak vert force) (3) Design equipment, conditioning, training programs to cause changes in kinetics/kinematics (4) Verify effects of equipment, etc., on kinetics/kinematics Conclusion: This method has been successfully used in the design of running shoes and seems to have more potential