ﺗﺄﺛﯿﺮ ﭼﻬﺎر ﻫﻔﺘﻪ ﺗﻤﺮﯾﻦ ﭘﻼﯾﻮﻣﺘﺮﯾﮏ ﺑﺮ ﻣﯿﺰان ﻫﻢﻓﻌﺎﻟﯽ ﻋﻀﻼت ﻣﻮاﻓﻖ و ﻣﺨﺎﻟﻒ اﻧﺪام ﺗﺤﺘﺎﻧﯽ دﺧﺘﺮان ﻓﻌﺎل در ﻣﺮاﺣﻞ ﻣﺨﺘﻠﻒ ﭘﺮش ﻋﻤﻘﯽ

The Effect of 4 Weeks of Plyometric Training on Coactivation of Antagonist and Agonist Muscles in Lower Limb of Active Girls during Different Phases of dro‎p Jump

ﭼﮑﯿﺪه زﻧﺎن ورزﺷﮑﺎر ﺑﻪدﻟﯿﻞ ﻫﻢﻓﻌﺎﻟﯽ ﮐﻤﺘﺮ ﺑﯿﺸﺘﺮ از ﻣﺮدان دﭼﺎر آﺳﯿﺐدﯾﺪﮔﯽ ﻟﯿﮕﺎﻣﻨﺖﻫﺎي زاﻧﻮ ﻣﯽﺷﻮﻧﺪ. ﻫﺪف ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺗﻌﯿﯿﻦ اﺛﺮ 4 ﻫﻔﺘﻪ ﺗﻤﺮﯾﻦ ﭘﻼﯾﻮﻣﺘﺮﯾﮏ ﺑﺮ ﻣﯿﺰان ﻫﻢﻓﻌﺎﻟﯽ ﻋﻀﻼت اﻧﺪام ﺗﺤﺘﺎﻧﯽ دﺧﺘﺮان ﻓﻌﺎل در ﻣﺮاﺣﻞ ﻣﺨﺘﻠﻒ ﭘﺮش ﻋﻤﻘﯽ ﺑﻮد. ﺗﻌﺪاد 20 ﻧﻔﺮ از داﻧﺸﺠﻮﯾﺎن دﺧﺘﺮ ﺗﺮﺑﯿﺖ ﺑﺪﻧﯽ )ﻣﯿﺎﻧﮕﯿﻦ ﺳﻦ 21/8±0/63 ﺳﺎل، ﻗﺪ 1/64±0/05 ﻣﺘﺮ، وزن 9/26± 56/98 ﮐﯿﻠﻮﮔﺮم( ﺑﻪﺻﻮرت ﺗﺼﺎدﻓﯽ ﺑﻪ دو ﮔﺮوه ﺗﺠﺮﺑﯽ ﭘﻼﯾﻮﻣﺘﺮﯾﮏ )ده ﻧﻔﺮ( و ﮐﻨﺘﺮل )ده ﻧﻔﺮ( ﺗﻘﺴﯿﻢ ﺷﺪﻧﺪ. ﮔﺮوه ﺗﺠﺮﺑﯽ، ﺗﻤﺮﯾﻦ ﭘﻼﯾﻮﻣﺘﺮﯾﮏ را 4 ﻫﻔﺘﮥ ﻣﺘﻮاﻟﯽ ﻫﺮ ﻫﻔﺘﻪ دو ﺟﻠﺴﻪ اﻧﺠﺎم داد. در ﭘﯿﺶآزﻣﻮن و ﭘﺲآزﻣﻮن، اﻟﮑﺘﺮوﻣﯿﻮﮔﺮاﻓﯽ ﺳﻄﺤﯽ از ﻋﻀﻼت درﺷﺖﻧﯽ ﻗﺪاﻣﯽ، دوﻗﻠﻮي داﺧﻠﯽ، دوﺳﺮراﻧﯽ و راﺳﺖراﻧﯽ ﺑﻪﻋﻤﻞ آﻣﺪ. ﻣﯿﺰان ﻫﻢﻓﻌﺎﻟﯽ ﻋﻀﻼت ران و ﺳﺎق ﭘﺎي ﺑﺮﺗﺮ در ﺣﯿﻦ 3 ﻣﺮﺣﻠﻪ ﭘﺮش ﻋﻤﻘﯽ از ارﺗﻔﺎع 20 ﺳﺎﻧﺘﯽﻣﺘﺮ ﻣﺤﺎﺳﺒﻪ ﺷﺪ. از آﻧﺎﻟﯿﺰ ﮐﻮوارﯾﺎﻧﺲ ﺑﺮاي ﺑﺮرﺳﯽ اﺛﺮ ﺗﻤﺮﯾﻦ در ﺳﻄﺢ ﻣﻌﻨﺎداري 0/05≤p اﺳﺘﻔﺎده ﺷﺪ. ﻧﺘﺎﯾﺞ ﺗﺤﻠﯿﻞ ﮐﻮوارﯾﺎﻧﺲ ﺗﮏﻣﺘﻐﯿﺮه ﺑﺎ ﮐﻨﺘﺮل اﺛﺮ ﭘﯿﺶآزﻣﻮن ﻧﺸﺎن داد ﮐﻪ ﺑﯿﻦ ﮔﺮوه ﺗﺠﺮﺑﯽ و ﮐﻨﺘﺮل از ﻟﺤﺎظ ﭘﺲآزﻣﻮن ﻫﻢﻓﻌﺎﻟﯽ ﻋﻀﻼت ران و ﺳﺎق ﭘﺎ ﺑﻪﺗﺮﺗﯿﺐ در ﻣﺮﺣﻠﮥ 2 )ﭘﯿﺶ ﻓﻌﺎﻟﯿﺖ 14/ 0=P و 0/07= P(، ﻣﺮﺣﻠﮥ 3 ﺗﻤﺎس 0/41 = P و 0/11= P( و ﻣﺮﺣﻠﮥ 4 )ﭘﺮواز 0/65= P و 0/12= P( ﺗﻔﺎوت ﻣﻌﻨﺎداري دﯾﺪه ﻧﺸﺪ. در ﮔﺮوه ﭘﻼﯾﻮﻣﺘﺮﯾﮏ ﻣﯿﺰان ﻫﻢﻓﻌﺎﻟﯽ ﻋﻀﻼت ران، روﻧﺪ اﻓﺰاﯾﺸﯽ و ﻋﻀﻼت ﺳﺎق روﻧﺪ ﮐﺎﻫﺸﯽ را ﻧﺸﺎن داد. ﺣﺮﮐﺎت ﭘﻼﯾﻮﻣﺘﺮﯾﮏ رو ﺑﻪ ﻋﻘﺐ ﻓﻌﺎﻟﯿﺖ ﻋﻀﻼت ﺧﻠﻔﯽ ﭘﺎ را اﻓﺰاﯾﺶ دﻫﺪ و ﺑﻪ ﺛﺒﺎت ACL ﮐﻤﮏ ﮐﻨﺪ.

Female athletes are more likely to have knee ligament injuries than men due to less coactivation. The aim of this study was to determine the effect of 4 weeks of plyometric training on the coactivation level of the lower limb muscles of active girls in different phases of drop jump. 20 female physical education students (mean age: 21.8±0.63 years, height: 1.64± 0.05 m, weight: 56.98± 9.26 kg) were randomly divided into two groups: experimental plyometrics (n=10) and control (n=10). The experimental group performed plyometric training twice a week for four consecutive weeks. In pretest and posttest, surface electromyography was performed on tibialis anterior, medial gastrocnemius, biceps femoris and rectus femoris. The coactivation level of dominant thigh and shin muscles was calculated during 3 phases of drop jump from 20 cm height. Analysis of covariance was used to investigate the effect of training at the significance level of P≤0.05. The results of univariate analysis of covariance with controlling the pretest effect showed no significant differences between experimental and control groups in posttest coactivation of thigh and shin muscles in phase 2 (pre-activity, P=0.14 and P=0.07), phase 3 (contact, P=0.41 and P=0.11) and phase 4 (fly, P=0.65 and P=0.12). In the plyometric group, the coactivation level of thigh and shin muscles showed increasing and decreasing trends respectively. Backward plyometric movements increase the activity level of leg dorsal muscles and help the ACL stability.