"In humans, ST fibers aren't always the first recruited, orderly recruitment goes from smallest to largest motor unit (which means how many fibers are in each unit. small MU would have less fibers, large MU more fibers) some small motor units contain FT fibers and some large contain ST fibers. [Neuromechanics de Enoka]
Donc on dirait que le principe de la taille vise plutot la TAILLE DES UNITES MOTRICES plutot que celles des fibres, ce qui est logique du moment qu'il est admi que des petites UM pourraient contenir des FF et inversément.
"In humans, FT and ST fatigue the same and have the same strength per size". [Neuromechanics de Enoka]
La meme force par rapport à leur taille ok, mais qu'ils fatiguent de la meme facon, meme vitesse !? Y une étude ci-dessous qui tend à montrer cela, mais je comprends pas trop comment ils en viennent à leur conclusion ???!
Andrew J. Fuglevand, Vaughan G. Macefield, and Brenda Bigland-Ritchie
John B. Pierce Laboratory, New Haven, Connecticut 06519
Twitch contraction times were significantly different between these two groups (groups of fibers some st some ft) (group 1 = 66. 5 ms; group 2 = 45.9 ms). Overall 18% of the units were fatigue resistant [fatigue index (FI) > 0.75], 64% had intermediate fatigue sensitivity (0.25 FI 0.75), and 18% were fatigable (FI < 0.25). However, fatigability and tetanic force were not significantly different among groups. Therefore unlike findings in some other mammals, fast-contracting motor units were neither stronger nor more susceptible to fatigue than slowly contracting units. Fatigue, however, was found to be greatest in those units that initially exerted the largest forces
La fin je comprends pas ils semblent se contredire.......