full text - Akademia Wychowania Fizycznego w Krakowie

The influence of plyometrics training on the maximal power of the lower limbs in basketball players aged 16–18
Table 6. Descriptive statistics and significance level of the differences for the left lower extremity extensor muscles [Nm]
Test
Angular
velocity
N x ± S min – max Sk Ku T p
I
II
60 deg/s
60 deg/s
18
259,56 ± 62,41
267,06 ± 60,41
162,0 – 416,0
178,0 – 411,0
1,001
0,948
1,650
1,034
–1,205 0,246
I
II
120 deg/s
120 deg/s
18
211,25 ± 39,50
223,44 ± 43,87
160,0 – 317,0
172,0 – 319,0
1,499
0,937
2,526
0,341
–2,674 0,017
I
II
240 deg/s
240 deg/s
18
150,56 ± 26,45
164,94 ± 23,54
105,0 – 187,0
126,0 – 218,0
–0,080
0,518
–1,140
0,495
–3,560 0,002
this ratio was incorrect and at 240º/s angular velocity it
exceeded normative data (0.98) (Table 8).
Out of 40 parameters describing speed and speed
endurance, its derivative, statistically signifi cant changes
were observed in the values before and after the experiment
in 19 cases in the experiment group; no such changes
were recorded in the control group (Table 9–12, Figure
1 and 2). It should also be noted that what improved was
endurance abilities, not speed abilities, as could be suggested
by the type of the training experiment. All signifi -
cant differences in the running test were only noticed in
the 6th or 7th repetition (when the subjects had already
run 5 × 30m). The differences were not recorded in any
of the fi rst runs at 5 m, 10 m, 20 m or 30 m distance,
which confi rms the above mentioned observation on the
endurance type of changes in motor abilities of basketball
players. According to Wachowski et al. [13] there was
no correlation between the running speed and the power
and strength tests. The obtained results show that there is
a small relation (too many components) between running
speed and strength and power. Therefore, it should not
be assumed that a plyometric training focused on power
development will result in better results in running tests.
– 39 –
Moreover, the authors claim that in optimal conditions for
strength and power development, running speed level depends
on the running technique (the length and frequency
of step).
Changes in motor abilities in the experiment group
resulted from the plyometric training structure, as well
as from the subjects susceptibility to training impulses
(sensitive periods). Thus the research question should be
considered from two perspectives; that is, from the educational
and ontogenetic perspective.
Literature analysis [5, 13, 14, 17, 32–36] allows for
a conclusion that the slowest is the annual speed increase
(5%) which grows best up to age 16. Faster development
can be observed in the case of jumping abilities
(7%) and power (6%), and the sensitive period for these
abilities occurs at age 13–15.
The development of jumping abilities is mainly related
to the training of the capability of fast and economic
use of muscle strength (neuromuscular coordination)
of lower extremities. It depends, among others, on the
elastic elements acting within the ankle joint. It can thus
be said that the experiment was too short to cause any
signifi cant changes in the level of relative strength,
Table 7. Descriptive statistics and significance level of the differences for the right lower extremity extensor muscles [Nm]
Test
Angular
velocity
N x ± S min – max S k K u T p
I 60 deg/s
261,56 ± 54,69 187,0 – 400,0 1,105 1,483
18
II 60 deg/s 268,81 ± 64,72 181,0 – 412,0 0,948 0,224
I 120 deg/s
209,81 ± 49,46 145,0 – 333,0 1,324 1,312
18
II 120 deg/s 218,37 ± 47,48 154,0 – 327,0 0,971 0,589
I 240 deg/s
141,81 ± 26,28 101,0 – 202,0 0,705 0,363
18
II 240 deg/s 152,69 ± 23,64 116,0 – 194,0 0,434 –0,700
–0,978 0,343
–1,593 0,131
–2,193 0,044