Changing throwing pattern: instruction and control parameter.

Area of Science:

• Biomechanics
• Motor Learning

Background:

• Throwing involves complex coordination of body segments.
• Understanding how instruction and velocity manipulation affect motor patterns is crucial for skill acquisition.

Purpose of the Study:

• To investigate the impact of velocity scaling and instructional feedback on throwing pattern development.
• To determine the influence of these factors on the use of the order parameter and distal lag in the kinetic chain.

Main Methods:

• Sixty adult females practiced throwing with their non-dominant arm over 5 weeks.
• Four groups were assigned: velocity scaling with/without instruction, and constant velocity with/without instruction.
• Trunk rotation was encouraged for groups receiving instruction.

Main Results:

• All groups showed improvement in using the open kinetic chain.
• Increased velocity led to faster attainment of the order parameter, particularly without instruction.
• Velocity increase without instruction resulted in earlier optimal distal lag compared to velocity increase with instruction.
• In non-instructional groups, hand-to-forearm lag preceded humeral lag.

Conclusions:

• Emphasizing trunk rotation without velocity increase does not optimize hand-to-forearm lag.
• Scaling throwing velocity is a more effective strategy for rapidly developing optimal throwing mechanics, especially when instruction is absent.