Hello BIOMECH-Lers,

I have been looking for information on the training adaptions to
plyometrics. The literature is fairly ambiguous and is a lot of 'coach
speak' which confuses the picture. I have considered adaptions in the
following areas: adaptions at the level of the cross bridges which
enable athletes to utilise the stretch-shortening cycle more
effectively, adaptions to the tendon, effects of over-load in the
eccentric phase, adaptions to motor control patterns (e.g. increased
activation, adaptions which allow athletes to use the
countermovement more effectively) and the effect of the stretch reflex
to (1) activate more fibres in the eccentric phase for simple strength
training effects, (2) be trained to improve the activation of muscles
when it is elicited.
I would be grateful for help/ references in the following areas:
1) what would be the effect on performance of complex movements of
these adaptions?
2) I can only find papers where lengthening velocities of 85mm/sec
have to be used to elicit the stretch reflex. Is there any evidence that
the stretch reflex is used at velocities comparable to those found in
plyometric type exercises (and what lengthening velocities are found
in plyometric exercises)?
3) Are there any published (or unpublished) kinetic analyses of
plyometric exercises showing the forces generated in the eccentric
phase compared to those generated during normal concentric training
(for the strength training effects), or analyses of different movements
looking at variations in the charecteristics that may lead to different
adaptions between different types of exercises?

Can anyone help?

Thank you.

Sam Winter
School of Sport and Exercise Sciences, University of Birmingham,