Biomechanics and Medicine in Swimming XI

BiomechanicsandmedicineinswimmingXi
rivative of the instantaneous mean frequency (MNF) was noted for the
M. antagonist Flexor and Extensor carpi (Caty et al, 2007) (Figure 3)
Figure 3: Mean (SD) of the percentage of decrease (PD%) of the Instantaneous
Mean Frequency (MNF) between the 1 st 25m and the last
25m of the maximal 4*50m test (adapted from Caty et al, 2007).
These changes were associated with a decrease in force production either
for the maximal dry land strength or for maximal tethered force or for
maximal power (Rouard et al, 2006) (Figure 4).
Figure 4: Means (SD) of Isometric (Fiso), full tethered (Fpmax), ½
tethered (Fp) forces and power (P) before and after a maximal 4*50m
test (Rouard et al, 2006).
Concerning the hand forces, both the Resultant and Efficient components
decreased during the insweep phase and increased during the outsweep
in a state of fatigue indicating a shift of the force production from
the in-sweep to the out-sweep at the end of the maximal 400m front
crawl test, swum in a flume (Monteil et al, 1996) (figure 5).
Figure 5: Resultant and Efficient component forces at the beginning
and at the end of a 400m test swam in a flume (N=9) (adapted from
Monteil, 1996).
Kinematic data corroborated the EMG and kinetics results. In a fatigue
state, the spatial hand path remained unchanged with a greater duration
of the catch, insweep and outsweep phases (Aujouannet et al, 2006)
(figure 6).
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Figure 6: Spatial (A) and temporal (B) values of the hand path for the
1 st 50 (white bar) and the 4 th 50 m (grey bar) of the maximal 4*50m test:
F (maximal forward coordinate), B (maximal backward), Ex (exit from
the water), D (maximal depth), O (maximal outward) and I (maximal
inward) * significant difference between the 1 st and 4 th 50 m at p