The reasons for this are:- 1. The pace of the slide lends impetus to the trunk, and eases the labour of the forward swing; it transfers some of the exertion of recovering the trunk from the abdominal muscles, which are weak, to the flexors of legs and loins, which are much more powerful, and are better able to stand the strain.
"Boating"
W. B. Woodgate Commentator: Harvey Mason
There are flexors and extensors long before the anatomist discovers and names them, and we use our arms without inquiring by what wonderful mechanism they are made obedient to our will.
"The English Language"
Robert Gordon Latham
The most common cause for this unsoundness is inflammation of the muscles and tendons of the flexors of the digit.
"Common Diseases of Farm Animals"
R. A. Craig, D. V. M.