Summary:
The study’s purpose was to investigate the possible effect of a dynamic
stabilization program on balance and jumping ability of young basketball
players. Nine preadolescent basketball players (age 12.1±0.7 years, mass
52.4±17.9 kg, height 158.1±10.1 cm) with 3.3±1.4 years of training
experience, followed an 8-week dynamic stabilization balance intervention
program, with a frequency of twice/week and a duration of 20 min/session.
The intervention was carried out before the main part of the typical basketball
training and after a standardized warm-up, whereas there was a 48-hour break
between intervention sessions to ensure full recovery of the participants. The
intervention program consisted of static and dynamic balance exercises with
and without limitation of vision, as well as jumping exercises. It was based
on a progressive increase in difficulty between the first 4 and the later 4 weeks
of the intervention program with relation to the requirements for postural
control, the direction of displacement and the execution’s speed of the
exercises. Before (PRE) and after (POST) the 8-week intervention,
measurements were carried out in randomized order to evaluate the: a) static
balance ability with bipedal and unipedal quiet stance tests for both lower
limbs with 2 trials per stance condition and with eyes open (EO) and eyes
closed (EC) for a trial duration of 20 and 15 seconds respectively, b) dynamic
balance ability using the anterior Limits of Stability test, and c) vertical
jumping ability using the CMJ and SJ tests. A custom-made uniaxial balance
platform (Wii Biovision, Fs=1000 HZ) was used for all tests to record the
Center of Pressure (CoP) and vertical force data. Performance in static
balance was determined by the parameters of a) path length of CoP (cm), b)
sway area of CoP (cm2
) and, c-d) range of CoP sway in the anterior-posterior
and medial-lateral direction (cm), while performance in dynamic balance was
determined by the difference between the anterior limit of the balance
platform and the subject's maximal anterior CoP displacement (cm). Vertical
jump performance was determined by selected temporal, dynamic and
derivative parameters of the impulse phase. The statistical analysis was based
on t-test for dependent samples to check for possible differences due to
intervention (Pre vs Post measurements), visual condition (OE vs CE) and
support limb (Left vs Right) on the dependent parameters (a = 0.05). Post
iv
intervention, the results showed that there was a significant (p<0.001)
increase in body height of the young athletes by 0.8%. Static bipedal as well
as unipedal balance performance for the left and right lower limb showed a
non-statistically significant (p>0.05) deterioration in all the examined CoP
parameters, with the exception of the non-statistically significant (p>0.05)
improvement in the area and range of anteroposterior and mediolateral CoP
sway, only for the right lower limb with eyes closed. In addition, it was found
that restriction of vision had a negative effect regardless of the intervention,
except for a significant (p<0.05) reduction of this negative effect on the sway
area and range of anteroposterior and mediolateral CoP displacement in the
bipedal stance. Dynamic balance performance was similar between pre- and
post-intervention (p>0.05), while vertical jumping ability performance
showed a significant (p<0.05) increase in the maximal impulse force in the
CMJ, as well as in the maximal relative vertical force and maximal relative
power in the SJ. It can be concluded that the static and dynamic balance ability
of young preadolescent basketball players was not improved after an 8-week
dynamic stabilization balance intervention program, however the observed
increased CoP parameter values may indicate a relatively better postural
control and balance performance of the athletes. The few significant
improvements in vertical jumping ability of the athletes after the end of the
intervention period provide possible evidence for a transfer of the positive
effect of intervention on the athletes' lower limb muscle strength and power.
Keywords:
static balance, dynamic balance, unipedal stance, bipedal stance, jumping ability, vertical jump, CMJ, SJ
