Biomechanics and Medicine in Swimming XI

Figure 1. General biomechanical parameters (v, SL
front crawl effort.
2.3
Figure 1. General biomechanical parameters (v, SL and SR) values during the 200m
v
1.6
0.9
front crawl effort.
SR
43
BiomechanicsandmedicineinswimmingXi
ously on 0.9the
video and EMG recordings. The EMG data analysis was
1.5
performed using the MATLAB 2008a software environment (Math-
41
Works Inc., 0.8 Natick, Massachusetts, USA). A new highly sensitive spectral
index (FInsmk), proposed by Dimitrov et al. (2006), was calculated
1.4
for one 0.7 stroke cycle for 40 each 25m. The FInsmk has been proposed to
overcome the relatively low sensitivity of the median frequency and the
IVVx
mean frequency. 0.6 The FInsmk indices were calculated as the ratio between
the 0.3 1.3 39
IVVy
spectral moments of order (-1) and order, k:
results
0.2
In Figure 1 it is possible to observe the decay of v, SL and SR through
the 200 m front crawl with a slightly increasing of the SR in the last
0.1
length.
Values for IVV (x, y and z) and coordinative organisation param-
0.0
eters (IdC and stroke phases) 1st are 50mpresented 2nd 50m in fig. 3rd 2 (left 50mpanel 4th and 50mright
panel, respectively) 43 for the four laps of the 200m Lapsfront
crawl test. 2.3
Velocity (m.s -1 )
(1)
where k was 5, PS(f ) was the spectral power for the currency frequency f
and f1 = 8 Hz and f2 = 500 Hz were the high and low-pass frequencies
of the amplifier filter. The relative changes in values of the spectral index,
Figure for different 2. repetitions Values were calculated for intracyclic against the first velocity repetition of the variation (IVV) in x, y and z axes (left panel)
corresponding set: for instance, FInnsmk/FI1nsmk x 100, % (n = 1, 2,
and values of velocity (v), stroke rate (SR), stroke length (SL), index of coordination
..., 8 lap number).
(IdC), Linear regression entry/catch, analysis method pull, was push, performed recovery, on muscle EMG propulsive phase and non-propulsive phase in
parameters (laps 1–8). The regression line gradients were analysed to
the four laps of the 200m front crawl.
compare rate of change and, hence, rate of fatigue development. The
97
level of significance for all statistical tests was set at p < 0.05.
Biomechanics and Medicine XI Chapter 2 Biomechanics
The kinetics of bioenergetical parameters (Ė, VO2 and [La - 0.0
-20
1st 50m 2nd 50m 3rd 50m 4th 50m
1st 50m 2nd 50m 3rd 50m 4th 50m
Laps
Laps
Figure 2. Values for intracyclic velocity variation (IVV) in x, y and z
axes (left panel) and values of velocity (v), stroke rate (SR), stroke length
(SL), index of coordination (IdC), entry/catch, pull, push, recovery, propulsive
phase and non-propulsive phase in the four laps of the 200m
front crawl.
The kinetics of bioenergetical parameters (Ė, VO2 and [La
]) and the spectral
indices, revealing the muscular function during the 200m front crawl are shown in fig. 3
(left and right panel, respectively). For the spectral indices high relationships were
observed (r>0.74, p0.74, p0.74, anterior (r=-0.18, p0.74, p