اثرات ماساژ پيش از فعاليت و گرم كردن بر خستگي عصبي - عضلاني عضله گاستروكنميوس در طول انقباض وامانده‌ساز

The Effects of Pre-exercise Massage and Warm-up on Neuromuscular Fatigue of Gastrocnemius Muscle during Exhausting Isometric Contraction

هدف از اين تحقيق مقايسه اثر ماساژ و گرم كردن پيش از فعاليت بر خستگي عصبي- عضلاني عضله گاستروكنميوس در طول انقباض ايزومتريك زيربيشينه بود. طرح تحقيق از نوع اندازه گيري مجدد بود. 15 مرد سالم بدون سابقه آسيب‌ديدگي اندام تحتاني و تمرين منظم براي اين تحقيق داوطلب شدند. آزمودني‌ها به طور تصادفي براي اجراي يك پروتكل گرم كردن يا ماساژ تخصيص يافتند. اين فرآيند چند روز بعد تحت شرايط ديگر تكرار شد. انقباض وامانده ساز شامل50 تكرار ايستادن روي پنجه پا و بلافاصله 60 ثانيه انقباض ايزومتريك پلانتار فلكشن مچ پا بود. فركانس ميانه(MF)، فركانس توان ميانگين(MPF)، نرخ تقاطع صفر (ZCR) و ميانگين الكتروميوگرافي (AEMG)، از سيگنال‌هاي الكتروميوگرافي ثبت شده از عضلات گاستروكنميوس داخلي و خارجي پاي غيربرتر، در طول انقباض ايزومتريك پلانتار فلكشن مچ پا مورد محاسبه قرار گرفت. جهت تجزيه و تحليل داده‌ها از آزمون تحليل واريانس دوطرفه (2×12، شرايط×زمان) و آزمون t وابسته در سطح معني داري P?0.05 استفاده شد. در بخش خارجي عضله گاستروكنميوس، تحت شرايط ماساژ، تمام شاخص‌هاي خستگي كاهش را نشان داد، اما پس از گرم كردنMF، MPF و ZCR افزايش يافت. در بخش داخلي عضله، در هر دو شرايط، تغيير قابل ملاحظه اي رخ نداد. به‌طور كلي تفاوت معني داري در MF وMPF بين گرم كردن با ماساژ وجود داشت. يافته هاي اين تحقيق از ماساژ پيش از فعاليت به واسطه بالا بردن مقادير پايه MF و MPF حمايت مي‌كند. همچنين ورزشكاران را جهت به تاخير انداختن خستگي عصبي- عضلاني تشويق به گرم كردن فعال مي‌كند.

Massage and warm-up are widely believed to have a beneficial effect on preventing and treating muscle fatigue and has been used in clinical and sports settings for that purpose. However, the benefit of these pre-exercise interventions before an exhausting exercise has recently been questioned. The aim of this study was to compare the effects of pre-exercise massage and warm-up on the neuromuscular fatigue in the gastrocnemius muscle during submaximal isometric contraction. This study was a within-subject repeated measure design. Fifteen healthy male subjects with no history of lower limb injury and no experience in regular exercise volunteered for this study. Subjects were randomly allocated to a warm-up or massage protocol. The process was repeated a few days later with the alternative condition. The exhausting contraction involved 50 repetitions of calf raise and 1 min isometric plantar flexion immediately. The median frequency (MF), mean power frequency (MPF), Zero Crossing Rate (ZCR) and Average rectified electromyography (AEMG) of electromyographic signal, that was recorded from undominant lateral and medial gastrocnemius, during sustained isometric plantar flexion (per five second) were calculated. Two way ANOVA (2 × 12, condition × time) and paired- sample t test were used for data analysis at the significant level of 0.05. In lateral part of Gastrocnemius, all of fatigue index significantly declined with time under massage. But, after warm-up, MF, MPF and ZCR were increased. After two interventions, in medial part, no significant change was occurred. Also the basic values of MF and MPF after massage were greater than warm-up. On the whole EMG signal, there were significant differences in MF and MPF between warm-up and massage. More statistical analyses indicated that there was significant difference in MF and MPF between two interventions at first 30s of EMG signal. No significant differences were found between two interventions at subsequent 30s. The findings of this study support pre-exercise massage due to enhance the basic MF and MPF values and encourage athletes to perform warm-up due to retard neuromuscular fatigue. Further research is needed about fatigue and performance-based effects of massage and warm-up with respect to the different protocols and synthetic approaches.