RESUMO
Varieties of exercise therapy methods are used in rehabilitation in order to improve muscle function. Optimal function of muscles results in improvement of functional activities; as a result, these activities would be achieved in a shorter time with the reduction of energy wasting. The purpose of this study was to evaluate the effects of plyometric and strengthening exercises on the quadriceps muscle strength in girl students of Zahedan University of Medical Sciences. This experimental study was performed in Zahedan in 2005. Thirty six girl students aging 20 +/- 1.2 years among residents of Mojtameh dormitory of Zahedan University of Medical Sciences were studied through simple non-probability sampling. Subjects were randomly assigned to either a plyometric exercises group or a strengthening exercises group. The quadriceps muscle strength [kg] was measured using hand-held dynamometer before and after 10 sessions of intervention. The first group received plyometric exercises. Strengthening exercises were given to the second group. Independent and paired t-tests were used for comparison between the pre-treatment and post treatment results between groups and within groups, respectively. The strength of quadriceps muscle was increased from 12.1 +/- 3 to 14.7 +/- 3.8 [kg] in the plyometric exercises group and from 12.4 +/- 3.7 to 14.9 +/- 3.9 [kg] in the strengthening exercises group [P<0.0001]. No significant difference was seen between two groups after and before intervention. Independent-samples t-test identified that there was no significant difference between two groups with respect to mean difference of the quadriceps strength. The results, in spite of conventional opinions, showed that there was no difference between plyometric and strengthening exercises regarding quadriceps muscle strengthening. Both types of exercises increased the quadriceps muscle strength. Therefore, according to patient conditions, either type of these exercises can be used for exercise therapy in knee pathologies and the quadriceps muscle strength deficit