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THE ACUTE EFFECT OF STRETCHING ON FORCE AND POWER
Authors: Nikolina Gerdijan, Dušan Perić and Elvir Kazazović
Number of views: 426
The sample of ten young healthy subjects, male, age 20, 21 (students of the Faculty of Sports,
University of Banja Luka, Bosnia and Herzegovina ), were examined for the effect of dynamic and
static stretching on exercise of force and power of quadriceps and ham- string muscle of the
dominant leg knee joint. Using the isokinetic dynamometer, both muscle groups were diagnosed with
variables: maximum torque (force), relative torque, explosive force and relative power.
Measurements were carried out under conditions of slow (60°/s) and fast speed (240°/s)
contractions. The same measurement protocols were implemented in three experimental situations:
without the initial stretching (WS), after the dynamic stretching (D) and after the static
stretching (S). Results of statistical analysis show that both types of expansion lead to an
increase of force and power of hamstring and quadriceps (quadriceps 60°/s: WS - 2,67 Nm/kg, D -
3,06 Nm/kg , S -3,05 Nm/kg; hamstring 60°/s: WS -2,25 Nm/kg , D -2,41 Nm/kg , S- 2,41 Nm/kg;
quadriceps 240°/s: WS- 1,42 Nm/kg , D- 1,70 Nm/kg , S- 1,64 Nm/kg; hamstring 240°/s: WS -1,51
Nm/kg , D- 1, 85 Nm/kg , S - 1, 71 Nm/kg). Looking at the results, both group of muscle
(quadriceps and hamstring) produced greater explosive force at a speed of 60°/s after the static
stretching. (Quadriceps: WS- 158,99 Nm, D- 188,13 Nm, S- 188,72 Nm; hamstring: WS- 149,53 Nm,
D-156,67 Nm, S-164,00 Nm). Both group of muscle produced greater explosive force at the speed of
240°/s after the dynamic stretching (quadriceps: WS-106,75 Nm ,D- 131, 50 Nm, S- 126,30 Nm;
hamstring : WS- 114,41 Nm, D-139,02 Nm, S-129,43 Nm). This indicates that static and dy- namic
stretching have positive acute effects when applied before the activities in which the rate of
contraction is small and external resistance is large, while only dynamic stretching has a positive
effect when it precedes the activities of higher muscle contraction speed. Regardless of the
elongation model applied, quadriceps is the dominant muscle group during the slow contractions
(60°/s),
while at high speeds, the role of hamstring significantly increases.