The Effect of Pedaling and Fatigue on Changes of Knee Muscles Co-contraction During Running in Triathletes

• Main Authors: Mehrdad Anbarian, Mostafa Sepehrian, Farzad Nazem, Behrooz Hajiloo
• Format: Article
• Language: fas
• Published: Islamic Azad University, Hamedan Branch 2015-09-01
• Series: Biyumikānīk-i varzishī
• Subjects: Fatigue; Cycling; Running; Triathlon
• Online Access: http://biomechanics.iauh.ac.ir/browse.php?a_code=A-10-39-1&slc_lang=en&sid=1&sw=Fatigue
• ISSN: 2476-4906; 2476-5937

Objective: The purpose of this study was to determine the effect of cycling fatigue on co-activation of knee muscles during running in novice triathletes. Methods: Twelve novice male triathletes aged 23.7±2.1 years participated in this quasi experimental study. Surface electromyographic activity from gastrocnemius, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus were recorded during support and non-support phases of running before and after cycling fatigue protocol. General and directed co-activation of the knee muscles were calculated. Paired t-test was used to analyze the data(p<0.05). Results: General co-activation was significantly reduced in propulsion sub-phase, total support and non-support phases after fatigue (p=0.001), but there were not any differences in heel contact and midstance sub-phases. Fatigue only altered directed co-activation of medial and lateral knee muscles during heel contact sub-phase (p=0.034). Extensor and flexor directed co-activation during non-support phase of running significantly decreased after fatigue (p=0.011). Conclusion: Changes in the co-activation during running after cycling fatigue can alter running pattern and reduce the knee function consequently, causing injuries to the lower limbs in novice triathletes.