JKMU. Comparison of generalized and directed co-contraction of knee joint muscles during four different movements for strengthening the quadriceps

Transcription

1 JKMU Journal of Kerman University of Medical Sciences, 2017; 24(5): Comparison of generalized and directed co-contraction of knee joint muscles during four different movements for strengthening the quadriceps Amir Ali Jafarnezhadgero, Ph.D. 1, Mohammad Mahdi Bahramisharif, M.Sc. 2, Mahdi Majlesi, Ph.D Assistant Professor, Department of Physical Education and Sport Sciences, Faculty of Educational Science and Psychology, University of Mohaghegh Ardabili, Ardabil, Iran (Corresponding author; amiralijafarnezhad@gmail.com) 2- Master Student, Department of Sport Biomechanics, Faculty of Humanities, Islamic Azad University, Hamedan Branch, Hamedan, Iran 3. Assistant Professor, Department of Sport Biomechanics, Faculty of Humanities, Islamic Azad University, Hamedan Branch, Hamedan, Iran Received: 5 June, 2017 Accepted: 11 November, 2017 ARTICLE INFO Article type: Original article Electromyography Weight lifting Knee joint Different movements have a role in strengthening the quadriceps muscles based on knee joint co-contraction, hamstring to quadriceps and vastus medialis to vastus lateralis muscles activity ratios. This provides useful information about each movement s role in rehabilitating patients with anterior cruciate ligament injury, osteoarthritis and patellofemoral pain syndrome. This study compared the rate of generalized and directed co-contraction of knee joint muscles during free weight, Smith s one-legged and two-legged machine squats and deadlift movement. Fourteen healthy power lifters (mean age of 26 ± 7 years old) participated in this study. A portable electromyography system with six pairs of bipolar surface electrodes was used to record the activity of the gastrocnemious medialis, long head of biceps femoris, semitendinosus, vastus lateralis, rectus femoris, and vastus medialis muscles at a sampling frequency of 1200 Hz. The participants had enough experience to perform the four movements. The participants carried out each movement five times at intensity equal to 50% of one-repetition-maximum level. Repeatedmeasure analysis of variance was used for statistical analysis. Rate of medial co-contraction was higher in deadlift movement compared to Smith onelegged machine (P = 0.042) and free weight squats (P = 0.044), respectively. Ratio of hamstring to quadriceps muscles activity was higher during deadlift movement compared to free weight squat (P= 0.022). The generalized co-contraction value at the knee joint was the lowest in deadlift movement and highest in Smith one-legged machine squat. To strengthen quadriceps muscles in people suffering from anterior cruciate injury, deadlift movement is more effective than free weight squat. Smith one-legged machine squat is more effective than the other three movements for athletes who want to strengthen muscular groups. Introduction 368

2 Journal of Kerman University of Medical Sciences 2017, Vol. 24, Issue 5 Materials and Methods Participants 369

3 Comparing generalized and directed co-contraction to streng the quadriceps Jafarnezhadgero, et al Inclusion and exclusion criteria Kinematics record and muscles activity Procedure 370

4 Journal of Kerman University of Medical Sciences 2017, Vol. 24, Issue 5 Figure 1. Type of exercise (A: Smith one-legged machine squat, B: dead lift, C: Smith two-legged machine squat, D: Free weight squat. Data processing 371

5 VM / VL Comparing generalized and directed co-contraction to streng the quadriceps Jafarnezhadgero, et al Results Statistical analysis Fig 2. Ratio of activity in vastus medialis to vastus lateralis (VM / VL) during performing of four movements 372

6 Medial Medial - Lateral Journal of Kerman University of Medical Sciences 2017, Vol. 24, Issue Fig 3. The value of directed co-contraction between medio- lateral muscles of the knee joint muscles during performing of four movements Fig. 4.The value of directed co-contraction between medial knee joint muscles 373

7 % MVIC Hamstring / Quadriceps Comparing generalized and directed co-contraction to streng the quadriceps Jafarnezhadgero, et al * Fig. 5. The ratio of hamstring activity to quadriceps during performing of four movements *P< * * Fig. 6. Generalised co-contraction in knee joint muscles during performing of four movements *P<

8 Journal of Kerman University of Medical Sciences 2017, Vol. 24, Issue 5 Table 1. Amplitude (% MVIC) of electromyography activity (mean ± standard deviation) of selected lower limb muscles for all movements are presented Muscles Movements Vastus medialis 66.19±24.15 * 70.50±25.13 α $ ±38.87 * α η 43.09±23.79 $ η Rectus femoris 50.32± ±17.40 $ 59.27±24.43 η 30.42±16.69 $ η Vastus lateralis 60.26±31.85 * 57.62±34.62 α ±49.94 * α η 44.53±23.92 η Biceps femoris 9.88±7.66 * 8.91±6.55 α 21.30±14.97 * α η 10.65±7.95 η Semitendinosus 8.91± ± ± ±15.78 Medial gastrocnemius 9.99±6.39 * 8.64±7.44 α 21.47±12.35 * α η 11.15±6.91 η * Significant difference between FWS and SMSWOL Significant difference between FWS and DL ɑ Significant difference between SMS and SMSWOL $ Significant difference between SMS and DL η Significant difference between SMSWOL and DL Discussion 375

9 Comparing generalized and directed co-contraction to streng the quadriceps Jafarnezhadgero, et al Practical applications Acknowledgement We would like to thank all the participants for their participation. Also, we would like to thank Seyed Muhammed Hussein Mousavinasab for editing this text. References 376

10 Journal of Kerman University of Medical Sciences 2017, Vol. 24, Issue 5 377

11 Comparing generalized and directed co-contraction to streng the quadriceps Jafarnezhadgero, et al 378