EFFECTS OF STABLE AND UNSTABLE LOAD ON STABLE AND UNSTABLE SURFACE ON EMG ACTIVITY DURING BACK SQUAT EXERCISE IN COLLEGE STUDENTS
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Abstract
Purpose : To study the effects of stable and unstable load on stable and unstable surface on EMG activity during the back squat exercise.
Methods : Twenty-four male sport science students, aged range between 18-25 years, were recruited for this study. Each subjects performed a parallel back squat at 75% 1RM under 4 different conditions; 1) a stable load on stable surface (SLSS), 2) a stable load on unstable surface (SLUS), 3) an unstable load on stable surface (ULSS) and 4) an unstable load on unstable surface (ULUS) in a counter-balance order. Surface electromyography (EMG) was used to detect muscle activities from 8 muscles (Biceps femoris, Rectus femoris, Vastus medialis, Vastus lateralis, Soleus, Rectus abdominis, External oblique and Erector spinae) and expressed as percentage of maximum voluntary isometric contraction (%MVIC). Data were analyzed using One-way Analysis of Variance with repeated measure, followed by the Bonferroni as post-hoc test. A level of 0.05 was considered statistical significance.
Results : The result showed that EMG activity of vastus lateralis was significant higher in SLSS than in ULUS (p<0.05), with no differences observed among other conditions. In addition, the EMG activity of soleus was significant higher in SLUS and ULUS than thos in SLSS and ULSS (p<0.05). However, no significant differences in EMG activities were observed in other muscles, regardless of conditions.
Conclusion : The findings suggest that a parallel back squat (75% 1RM) with stable load on stable surface increased activation of the vastus lateralis muscle in order to stabilize the knee joint. In addition, both squat exercise with stable load on unstable surface and unstable load on unstable surface resulted in increased activation of the soleus muscle for stabilizing the ankle joint.
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Adkin, A. L., Frank, J. S., Carpenter, M. G., and Peysar, G. W. (2002). Fear of falling modifies anticipatory postural control. Experimental Brain Research, 143(2), 160-170.
Anderson, K., and Behm, D. G. (2005). Trunk muscle activity increases with unstable squat movements. Canadian Journal of Applied Physiology, 30(1), 33-45.
Anderson, K. G., and Behm, D. G. (2004). Maintenance of EMG activity and loss of force output with instability. The Journal of Strength & Conditioning Research, 18(3), 637-640.
Behm, D. G., Anderson, K., and Curnew, R. S. (2002). Muscle force and activation under stable and unstable conditions. The Journal of Strength & Conditioning Research, 16(3), 416-422.
Behm, D. G., Muehlbauer, T., Kibele, A., and Granacher, U. (2015). Effects of strength training using unstable surfaces on strength, power and balance performance across the lifespan: a systematic review and meta-analysis. Sports Medicine, 45(12), 1645-1669.
Clarys, J. P., and Cabri, J. (1993). Electromyography and the study of sports movements: a review. Journal of Sports Sciences, 11(5), 379-448.
Day, S. (2002). Important factors in surface EMG measurement. Bortec Biomedical Ltd publishers, 1-17.
Dunnick, D. D., Brown, L. E., Coburn, J. W., Lynn, S. K., and Barillas, S. R. (2015). Bench press upper-body muscle activation between stable and unstable loads. The Journal of Strength & Conditioning Research, 29(12), 3279-3283.
Escamilla, R. F. (2001). Knee biomechanics of the dynamic squat exercise. Medicine & Science in Sports & Exercise, 33(1), 127-141.
Hirase, T., Inokuchi, S., Matsusaka, N., and Okita, M. (2015). Effects of a balance training program using a foam rubber pad in community-based older adults: a randomized controlled trial. Journal of Geriatric Physical Therapy, 38(2), 62-70.
Kenney, W. L., Wilmore, J. H., and Costill, D. L. (2015). Physiology of Sport and Exercise 6th Edition: Human kinetics.
Kohler, J. M., Flanagan, S. P., and Whiting, W. C. (2010). Muscle activation patterns while lifting stable and unstable loads on stable and unstable surfaces. The Journal of Strength & Conditioning Research, 24(2), 313-321.
Konrad, P. (2005). The ABC of EMG: A practical introduction to kinesiological electromyography. 1, 29-33.
Lawrence, M. A., and Carlson, L. A. (2015). Effects of an unstable load on force and muscle activation during a parallel back squat. The Journal of Strength & Conditioning Research, 29(10), 2949-2953.
Marshall, P. W., and Murphy, B. A. (2005). Core stability exercises on and off a Swiss ball. Archives of Physical Medicine and Rehabilitation, 86(2), 242-249.
Marshall, P. W., and Murphy, B. A. (2006). Increased deltoid and abdominal muscle activity during Swiss ball bench press. The Journal of Strength & Conditioning Research, 20(4), 745-750.
McBride, J. M., Cormie, P., and Deane, R. (2006). Isometric squat force output and muscle activity in stable and unstable conditions. Journal of Strength and Conditioning Research, 20(4), 915.
Ostrowski, S. J., Carlson, L. A., and Lawrence, M. A. (2017). Effect of an unstable load on primary and stabilizing muscles during the bench press. The Journal of Strength & Conditioning Research, 31(2), 430-434.
Padulo, J., Laffaye, G., Haddad, M., Chaouachi, A., Attene, G., Migliaccio, G. M., and Pizzolato, F. (2015). Repeated sprint ability in young basketball players: one vs. two changes of direction (Part 1). Journal of Sports Sciences, 33(14), 1480-1492.
Rab, G. T., Chao, E., and Stauffer, R. (1977). Muscle force analysis of the lumbar spine. The Orthopedic Clinics of North America, 8(1), 193-199.
Robertson, D., Wilson, J.-M. J., and Pierre, T. A. S. (2008). Lower extremity muscle functions during full squats. Journal of Applied Biomechanics, 24(4), 333-339.
Saeterbakken, A. H., Van den Tillaar, R., and Fimland, M. S. (2011). A comparison of muscle activity and 1-RM strength of three chest-press exercises with different stability requirements. Journal of Sports Sciences, 29(5), 533-538.
Schick, E. E., Coburn, J. W., Brown, L. E., Judelson, D. A., Khamoui, A. V., Tran, T. T., and Uribe, B. P. (2010). A comparison of muscle activation between a Smith machine and free weight bench press. The Journal of Strength & Conditioning Research, 24(3), 779-784.
Sharkey, B. J., and Gaskill, S. E. (2006). Sport physiology for coaches (Vol. 10): Human Kinetics.
Vera-Garcia, F. J., Grenier, S. G., and McGill, S. M. (2000). Abdominal muscle response during curl-ups on both stable and labile surfaces. Physical Therapy, 80(6), 564-569.
Zemková, E., Jelen, M., Kováciková, Z., Ollé, G., Vilman, T., and Hamar, D. (2012). Power outputs in the concentric phase of resistance exercises performed in the interval mode on stable and unstable surfaces. The Journal of Strength & Conditioning Research, 26(12), 3230-3236.