|Year : 2017 | Volume
| Issue : 4 | Page : 855-860
|Effect of functional (aerobic) exercises on chest wall expansion and respiratory volumes in high school students
Mohammadmehdi Hassanzadeh-Taheri1, Hesam Moodi2, Toba Kazemi3, Mehran Hosseini4, Asghar Akbari5, Mohammadreza Doostabadi2, Saminesadat Fatemi6
1 Associate Professor, Department of Anatomy, Faculty of Medicine, Birjand University of Medical Sciences, Birjand, Iran
2 Cardiovascular Diseases Research Center, MSc, Student of Anatomical Sciences, Department of Anatomy, Birjand University of Medical Sciences, Birjand, Iran
3 Professor, Cardiovascular Diseases Research Center, Birjand University of Medical Sciences, Birjand, Iran
4 Cellular and Molecular Research Center, Birjand University of Medical Sciences, Birjand, Iran
5 Associate Professor, Department of Physiotherapy, Zahedan University of Medical Sciences, Zahedan, Iran
6 Department of Psychology, Islamic Azad University, Birjand, Iran
Click here for correspondence address and email
|Date of Web Publication||5-Oct-2017|
| Abstract|| |
Background and Objectives: Plyometric exercises are done by adults to improve muscle strength, neuromuscular coordination, and vertical jumping. Unfortunately, there is limited information about effects of this kind of exercises on respiratory system. This study evaluated the effects of plyometric and aerobic exercises on chest wall expansion and respiratory volumes in high school students. Methods: This randomized clinical trial was performed in Zahedan. Sixty girls and boys, ranging 14–18 years old, were recruited through simple nonprobability sampling. The students were randomly assigned to two groups: cycling (n = 30) and jump roping (n = 30). Each group performed the exercises 3 times a week for 12 sessions. Before and after exercises, we assessed chest wall expansion (at axillary and xiphoid levels), vital capacity (VC), expiratory reserved volume, forced VC, and forced expiratory volume in 1 s. Data were analyzed using independent and paired t-tests. Results: Chest wall expansion at axillary level increased from 76 ± 10 to 77.4 ± 10 in cycling group and from 77.7 ± 8.1 to 78.5 ± 8.7 in jump roping group (P = 0.0001) and at xyphoid level from 68.7 ± 8.9 to 70 ± 8 in cycling group and from 71.3 ± 6.4 to 72.3 ± 6.4 in jump roping group (P = 0.0001). In addition, the increase in respiratory volumes was statistically significant (P < 0.05). Conclusion: Findings showed that chest wall expansion and respiratory volume increased following plyometric exercises such as jump roping.
Keywords: Chest wall expansion, cycling, plyometric exercises, respiratory volumes
|How to cite this article:|
Hassanzadeh-Taheri M, Moodi H, Kazemi T, Hosseini M, Akbari A, Doostabadi M, Fatemi S. Effect of functional (aerobic) exercises on chest wall expansion and respiratory volumes in high school students. Ann Trop Med Public Health 2017;10:855-60
|How to cite this URL:|
Hassanzadeh-Taheri M, Moodi H, Kazemi T, Hosseini M, Akbari A, Doostabadi M, Fatemi S. Effect of functional (aerobic) exercises on chest wall expansion and respiratory volumes in high school students. Ann Trop Med Public Health [serial online] 2017 [cited 2020 Apr 3];10:855-60. Available from: http://www.atmph.org/text.asp?2017/10/4/855/215853
| Introduction|| |
Averagely, human breathes about 10–15 thousand liters of environmental air in 1 day. Coordinated function of cardiopulmonary pump, nervous system, respiratory muscle strength, appropriate lung dimension,,, and appropriate chest wall movements are necessary for an appropriate gas exchange between environment and the body.,,, It has been proved that physical activities are important in disease prevention and health promotion. Excess weight loss, cardiovascular and pulmonary compliance promotion, and increase in muscle strength are the beneficial impacts of sports on health promotion. Obviously, appropriate muscle performance has an important role in daily activities.,, Optimal muscle performance can lead to improved motor activities while reducing energy and time consumption., Increasing strength and endurance of the respiratory muscles is an effective technique to improve the lung function, the power to cough and sneeze, and the breathing. Moreover, muscle endurance in long-lasting sports results in increasing airway resistance and decreasing lung texture.,,, Benito et al. showed that aerobic incremental exercise, such as cycling, alters tidal volume and breathing rate as well as pattern. Marlin et al. showed that chest circumferential expansion increased after running. According to Tsumura et al., aerobic exercises such as cycling with 50% of workload could increase level of free fatty acids. Leech et al. in a research performed on lung function of seventy osteoporotic females in 1990 stated that all of them were afflicted by hypokyphosis. In the study, patients underwent respiratory tests so they concluded that fractures affect forced vital capacity (FVC) in cases with a history of a compressive fracture of spinal column compared with healthy cases. A study showed that physical activity is important in disease prevention and health promotion. A newly raised exercise which according to some scholars can cause rapid and better strengthened muscles in the shortest time, and association with increased agility, improved endurance and promptitude, and harmony is plyometric exercise. In these exercises, the muscle is rapidly pulled and subsequent to the stretch, constrict contraction is immediately done. These exercises have beneficial effects even on healthy people with relative muscle power., Study on twenty healthy male athletes in Lismore sports medicine center reported that exercises with weights increased muscle strength and plyometric exercises increased power, promptitude, and agility. Performing plyometric exercises and dynamic stabilization and balance training is recommended to prevent injuries. Running forward or backward is an example of plyometric movement. Clarkson et al. stated that these exercises affected oxygen uptake and heart rate., In a research on female athletes by Lephart et al., it was shown that performing basic resistant programs for 8 weeks resulted in biomechanical and neuromuscular changes while the plyometric activities had a greater role in improving the pattern of muscle activities. Maffiuletti et al. reported that combined electrostimulation and plyometric training for 4 weeks improved vertical jump height and strengthened the knee extensor muscles and plantar flexors. Also, Pezzullo et al. showed that functional plyometric exercises strengthened shoulder muscles in throwing athletes. In the conducted studies on the effect of proper plyometric exercises on increasing and improving breathing and lung volumes, we did not find coherent studies on the effects of these exercises. Plyometric exercises are known to involve more jumping and mobility in comparison with aerobic ones and recommended for increasing dexterity and agility during everyday activities and sports. To be agile in activities, one requires to have an appropriate respiratory system and increased cardiopulmonary function., This theory is discussed: can plyometric exercises have a direct effect on the respiratory system or not? Therefore, with the assumption that jump roping as a plyometric exercise can increase lung volumes and ability to stretch the chest, we decided to compare the effect of plyometric exercise (a specific and proposed exercise) and aerobic exercises (a general and routine exercise) on lung function and chest wall expansion.
| Methods|| |
This clinical trial was conducted in Razmjoo Moghaddam Physiotherapy Center in 2014 based on the estimation in an experimental study on ten individuals. Samples required for the main study was estimated as 15 individuals each group with confidence interval of 95% and the power of the test of 90%. Sixty samples ranging 14–18 years old participated into aerobic exercise group (15 girls, 15 boys) and plyometric exercise group (15 girls, 15 boys). Individuals were randomly selected from the high schools of Zahedan city by cluster sampling. The students who participated in the study had no history of any kind of cardiovascular, respiratory, or muscular disease, surgery, skeletal malformation, neuromuscular disease, or a regular history of sports, were not affected by any respiratory disorder such as common cold or sore throat, and could bike and jump rope for 20 min. Individuals having any history of expressed disease, not finished the sport course, or lacking the qualification for participating in the study were omitted. In addition, students were evaluated by a cardiologist before the study, all stages of the research were described and all participated with full consent and voluntarily. Finally, the students were allocated using random numbers table into one of the aerobic and plyometric exercise groups.
Aerobic exercise group
The students sat on an exercise bike equipped with a digital speedometer (model: Sport Arts 5100R, Taiwan) in a position that the angle of backrest of the bike was between 90° and 100°. By adjusting the saddle of the bike, lower limb was situated in a suitable angle so that the participant could pedal easily and feet did not get apart from the pedal. Finally, the resistance of the bike was adjusted to the least and nearly zero, the participant pedaled slowly for 10 min and then in mean rate of 30 km/h for 20 min, and at the end of the steps, continued slowly for 5 min.
Plyometric exercise group
In this exercise, the participant stood on a jump rope holding two ends in hands and elbow joints in 90° flexion, thus the length of jump rope for each participant was determined individually and the participant used his or her specific jump rope until the end of the test. After choosing the appropriate length, to warm up, they performed simple exercises (Sweden sport) including short-height and up-down jumping, then jump roped for 10 min and ultimately to cool down, and then performed short-height jumping again for 5 min. All groups performed the mentioned exercises for 3 days/week for 4 weeks (12 sessions). Before and after 12 intervention sessions, the following indicators were measured and results were recorded: the intensity of exercises in the first 2 weeks was set low (60%–65% of maximal heart rate) and for the next 2 weeks progressively high (70%–75%). To control the intensity of exercises, the formula 220−age was used and the participant's heart rate was measured at every session (at the beginning, in the course of, and at the end of the exercise).,
Chest wall expansion assay
To measure the chest wall expansion, the subject laid in supine position on a tape on the examination bed and the investigator put the tape at axillary level first. The subject was asked to breathe deeply and hold, then the investigator brought the two ends of the tape together once at sternum level and the other time at xiphoid level. The resultant value was recorded. This procedure was repeated three times and then the mean of three values was considered as the determinant of chest wall expansion. The procedure was also repeated at rest (expiration). Afterward, the investigator put the tape at xiphoid level and measured chest wall expansion in deep inspiration and expiration the same way.,, It should be mentioned that the investigator who performed the measurement had no information about the individual's exercise group.
Lung volume evaluation
To measure lung volume, a spirometer (model: Medics Cyber, Cybermedics Inc, Louisville, Colorado, USA) was used. The subject sat on a chair, a clip fastened on his or her nose; after the respiration stabilized (i.e., seeing at least three normal breaths), the subject was asked to gently have a deep inspiration and then perform a forced deep expiration. The values of vital capacity (VC), reserved expiratory volume (REV), FVC, and forced expiratory volume in 1 s (FEV1) which, respectively, stand for VC, REV, FVC, and FEV1 were recorded. The data were analyzed using SPSS software version 12, SPSS, Inc., Chicago, IL, USA. The normalization of the distribution was examined by Kolmogorov–Smirnov test. Paired and independent t-tests were used to compare the findings of pre- and post-exercise and the findings of two groups, respectively. P < 0.05 indicated a statistically significant difference.
| Results|| |
In total, 30 boys, mean age of 18 ± 2.1 and mean body mass index (BMI) of 24 ± 3.1, and 30 girls, mean age of 18 ± 1.4 and mean BMI of 23 ± 2.0, participated in the study. Comparison of variables before exercise was not significant in either group which indicates the appropriate sample unification before exercise.
The results of paired t-test, comparison of pre- and post-exercise results, and the P value of paired t-test are shown in [Table 1]. The results emphasize that both exercises can improve lung volume and chest wall expansion. The mean chest wall expansion during inspiration and expiration at axillary level increased from 5.5 ± 1.5 to 6.7 ± 1.3 in cycling group (P = 0.0001) and from 6.5 ± 2.2 to 7 ± 2.2 in jump roping group (P = 0.0001). The mean chest wall expansion during inspiration and expiration at xiphoid level increased from 4.2 ± 1.4 to 5.5 ± 1.4 in cycling group (P = 0.0001) and from 5 ± 1.6 to 5.9 ± 1.7 in jump roping group (P = 0.0001). Postexercise increase in chest wall expansion at xiphoid level and mean lung volumes were also seen in both cycling and jump roping groups (P < 0.05), while FVC and VC were significant just in jump roping group (P < 0.05).
|Table 1: Effects of functional exercises on the chest wall expansion and respiratory volumes in both experimental groups|
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Results of independent t-test showed that there was no significant difference in mean chest wall expansion and lung volumes between jump roping and cycling groups (P > 0.05) [Table 1].
| Discussion|| |
The results showed that either aerobic or plyometric exercises increase chest wall expansion and respiratory volumes and there was no difference between two groups. The important finding of the study is that plyometric exercise, like aerobic exercises affect the respiratory system. Kisner reported that performing aerobic exercises induces some changes in muscular, cardiovascular, and pulmonary systems which increase the capacity of individual tolerance. These changes included increase in blood circulation, heart rate, arterial blood pressure, oxygen demand, and rate and depth of breath which is caused by accessory respiratory muscles getting in action. In the first second of the exercise, respiratory system have been motivated by body temperature Enhancment and muscle and joint stimulation; as a result minute ventilation, breath frequency and all the respiratory volumes increased. Benito et al. reported that cycling changed vital volume of breath pattern. Increased breath rate improved minute ventilation. Increased ventilation during exercise is due to increased lung volume receiver data and other receptors that are breath control center of vagous nerve, thus an increases occurs in tidal volume first and then after in breathing rate. Results of the current research emphasize that an increase in the respiratory volume and the chest wall expansion occurred by performing aerobic exercises which indicates better oxygenation and distribution of oxygen into different organs; in general, pulmonary function after aerobic exercise increases. Fisher et al. and Gromby and Soderholm reported that VC, that is, the maximum air expiated by a deep inspiration followed by a fully deep expiration is measured as an indicator of lung function in clinic and gives beneficial information about the strength of respiratory muscles and lung function. The air expiated in the first second of a deep expiration also provides invaluable information about airway resistance., Hauge showed that an increase in these values indicates improved strength of muscles and lung function. Increased FEV1 indicates decreased airway resistance after doing aerobic exercises; this is also demonstrated in the present research that FEV1 increased following aerobic and plyometric exercises. All mentioned studies reported that, by doing aerobic exercises, the respiratory muscles' endurance increases which can improve chest wall expansion and respiratory volume. Increased cardiovascular fitness is due to exercises such as walking and cycling to improve compliance ,,, which is also reported by this research.
Plyometric exercises are a kind of exercise that induces the contraction cycle of muscle fibers to become short and long, respectively, to improve coordination, strength, and power of all muscles of the body including cardiovascular system which in turn influences the pulmonary function and volumes.,, Toumi et al. studied the effect of plyometric exercises using slow and rapid stretching contraction, on the jumping ability and muscular feature in males aged 19–22 years old concluding that, by doing rapid plyometric exercises, the height of vertical jump for hitting increased and the time of transition stage decreased. A study about the effect of plyometric exercises on the mechanical properties of ankle joint reported that the stiffness and viscosity decreased as a result of exercises. In a research on female volleyball players by evaluating the effect of plyometric jumping exercises on muscle strength and mechanics of landing, Hewett et al. found that these exercises increased the mean height jumping and stability of knee joint and decreased the risk of injury. Arazi et al. studied the effect of exercises with weights and plyometric ones on the running speed and explosive power of athletes. Some researchers believe that the plyometric exercises should be a part of female athlete training regimen to improve the functional stability of the joints of lower limbs and as a result decreased risk of injury. As shown in some studies, most of the researchers have evaluated plyometric exercises in young athlete cases that might be caused by the nature of plyometric exercises which are a kind of heavy and explosive activity, need a lot of primary energy, and impose a heavy pressure on cardiovascular and musculoskeletal systems. Up to now, there are not enough findings to clarify the exact effect of plyometric exercises and the imposed pressure on different structures and systems of the body. Besides, as the role of resistant training on improving the power is identified, it is recommended to do these exercises to prevent injuries and probable risks in patients who suffer from decreased muscle strength, but plyometric exercises can be used among young and healthy people. While there are different studies about the effects of plyometric exercises on the muscle strength,, the running speed, and the coordination of neuromuscular system, we daily encounter patients who are referred to health centers due to respiratory diseases. We can therefore easily improve their lung function and respiratory condition by performing a simple aerobic or plyometric exercise. Finally, we can conclude that there is no difference between aerobic and plyometric exercises in increasing respiratory volume.
| Conclusion|| |
According to the results of this study, plyometric exercises can also have positive effects on respiratory system; as a result, they also increase chest wall expansion and respiratory volume. Based on that, the cardiovascular pulmonary condition of students can be improved and respiratory diseases can be prevented by accurate planning in different educational levels and using plyometric exercises in students' sports time.
Our sincere thanks to the authorities and the studious personnel of Razmjoo Moghaddam Physiotherapy Center, Mr. Ramezan Nazok, Mrs. Rahem, and education organization who helped us in performing this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Celli BR, MacNee W; ATS/ERS Task Force. Standards for the diagnosis and treatment of patients with COPD: A summary of the ATS/ERS position paper. Eur Respir J 2004;23:932-46.
Chanavirut R, Khaidjapho K, Jaree P, Pongnaratorn P. Yoga exercise increases chest wall expansion and lung volumes in young healthy Thais. Thai J Physiol Sci 2006;19:1-7.
Romagnoli I, Gigliotti F, Galarducci A, Lanini B, Bianchi R, Cammelli D, et al.
Chest wall kinematics and respiratory muscle action in ankylosing spondylitis patients. Eur Respir J 2004;24:453-60.
Sanna A, Bertoli F, Misuri G, Gigliotti F, Iandelli I, Mancini M, et al.
Chest wall kinematics and respiratory muscle action in walking healthy humans. J Appl Physiol 1999;87:938-46.
McMinn RM. Last's Anatomy Regional and Applied. 8th
ed. New York: Churchill Livingston; 1990. p. 241-57.
Kaneko H, Horie J. Breathing movements of the chest and abdominal wall in healthy subjects. Respir Care 2012;57:1442-51.
Hertling D, Kessler RM. Management of common musculoskeletal disorders. Physical Therapy Principle. 3th
ed. Philadelphia: Lippincott; 1996. p. 570-606.
Pelkonen M, Notkola IL, Lakka T, Tukiainen HO, Kivinen P, Nissinen A. Delaying decline in pulmonary function with physical activity: A 25-year follow-up. Am J Respir Crit Care Med 2003;168:494-9.
Prentic WE. Rehabilitation Techniques for Sports Medicine and Athletic Training. 4th
ed. Boston: WCB/McGraw-Hill; 2003. p. 305-45.
Magee DJ, Quillen WS, Zachazewski JE. Athletic Injuries and Rehabilitation. 1st
ed. Philadelphia: Saunders WB Company; 1996. p. 784-841.
Hewett TE, Stroupe AL, Nance TA, Noyes FR. Plyometric training in female athletes. Decreased impact forces and increased hamstring torques. Am J Sports Med 1996;24:765-73.
Hazel M. Musculoskeletal Assessment. Philadelphia; Lippincott Williams and Wilkins; 2000. p. 76.
Norkin C. Joint Structure and Function. Philadelphia: F. A. Davis Company; 2001. p. 170-183.
Irwin S, Tecklin JS. Cardiopulmonary Physical Therapy. California: C. V. Mosby Company; 1990. p. 285.
Hawes MC, Brooks WJ. Improved chest expansion in idiopathic scoliosis after intensive, multiple-modality, nonsurgical treatment in an adult. Chest 2001;120:672-4.
Benito PJ, Calderón FJ, García-Zapico A, Legido JC, Caballero JA. Response of tidal volume to inspiratory time ratio during incremental exercise. Arch Bronconeumol 2006;42:62-7.
Marlin DJ, Schrotert RC, Cashman PM, Deaton CM, Poole DC, Kindig CA, et al.
Movements of thoracic and abdominal compartments during ventilation at rest and during exercise. Equine Vet J Suppl 2002;35:384-90.
Tsumura H, Kataoka M, Uchida K, Torisu T. Influence of aerobic exercise with an intermission, using a bicycle ergometer, on fat metabolism in obese patients with gonarthrosis. J Orthop Sci 2002;7:38-42.
Leech JA, Dulberg C, Kellie S, Pattee L, Gay J. Relationship of lung function to severity of osteoporosis in women. Am Rev Respir Dis 1990;141:68-71.
Kisner C, Colby LA. Therapeutic Exercise: Foundations and Techniques. 4th
ed. Philadelphia: F. A. Davis Company; 2002. p. 143-67.
Wilson GJ, Murphy AJ. Strength diagnosis: The use of test data to determine specific strength training. J Sports Sci 1996;14:167-73.
Cossor JM, Blanksby BA, Elliott BC. The influence of plyometric training on the freestyle tumble turn. J Sci Med Sport 1999;2:106-16.
Myer GD, Ford KR, Brent JL, Hewett TE. The effects of plyometric vs. dynamic stabilization and balance training on power, balance, and landing force in female athletes. J Strength Cond Res 2006;20:345-53.
Clarkson E, Cameron S, Osmon P, McGraw C, Smutok M, Stetts D, et al.
Oxygen consumption, heart rate, and rating of perceived exertion in young adult women during backward walking at different speeds. J Orthop Sports Phys Ther 1997;25:113-8.
Myatt G, Baxter R, Dougherty R, Williams G, Halle J, Stetts D, et al.
The cardiopulmonary cost of backward walking at selected speeds. J Orthop Sports Phys Ther 1995;21:132-8.
Lephart SM, Abt JP, Ferris CM, Sell TC, Nagai T, Myers JB, et al.
Neuromuscular and biomechanical characteristic changes in high school athletes: A plyometric versus basic resistance program. Br J Sports Med 2005;39:932-8.
Maffiuletti NA, Dugnani S, Folz M, Di Pierno E, Mauro F. Effect of combined electrostimulation and plyometric training on vertical jump height. Med Sci Sports Exerc 2002;34:1638-44.
Pezzullo DJ, Karas S, Irrgang JJ. Functional plyometric exercises for the throwing athlete. J Athl Train 1995;30:22-6.
Barnnon FJ, Foley MW, Starr JA, Saul LM. Additional components of pulmonary rehabilitation. In: Brannon FJ, Foley MW, Starr JA, Saul LM, editors. Cardiopulmonary Rehabilitation: Basic Theory and Application. Philadelphia: F. A. Davis; 1993. p. 430-2.
Chaitow L, Bradley D. The structure and function of breathing. In: Chaitow L, Bradley D, Gilbert C, editors. Multidisciplinary Approaches to Breathing Pattern Disorder. Edinburgh: Churchill Livingstone; 2002. p. 1-41.
Northridge DB, Grant S, Ford I, Christie J, McLenachan J, Connelly D, et al.
Novel exercise protocol suitable for use on a treadmill or a bicycle ergometer. Br Heart J 1990;64:313-6.
Yekkeh Fallah L. The effect of physical exercise on the pulmonary function and quality of life in asthmatic patients. J Sabzevar Sch Med Sci 2006;4:4-19.
Porranjbar M, Mahani KN. The effects of aerobic and anaerobic exercises on the anxiety. J Kerman Univ Med Sci 2006;1:51-6.
Kisner C, Colby LA. Theraputc Exercise, Function and Techniques. 3th
ed. India: Jaypee Brother's Medical Publishers; 1996. p. 111-41.
LaPier TK. Chest wall expansion values in supine and standing across the adult lifespan. Occup Ther Geriatr 2002;21:65-81.
Bockenhauer SE, Chen H, Julliard KN, Weedon J. Measuring thoracic excursion: Reliability of the cloth tape measure technique. J Am Osteopath Assoc 2007;107:191-6.
Moll JM, Wright V. An objective clinical study of chest expansion. Ann Rheum Dis 1972;31:1-8.
Fisher LR, Cawley MI, Holgate ST. Relation between chest expansion, pulmonary function, and exercise tolerance in patients with ankylosing spondylitis. Ann Rheum Dis 1990;49:921-5.
Gromby G, Soderholm B. Spirometric studies in normal subject. Static lung volumes and maximum voluntary ventilation in adults with a note on physical fitness. Acta Med Scand 1963;173:199-206.
Hauge BN. Diaphragmatic movement and spirometric volume in patients with ankylosing spondylitis. Scand J Respir Dis 1973;54:38-44.
McArdle WD, Katch FI, Katch VL, editors. Body composition assessment and sport-specific observations. In: Sports and Exercise Nutrition. Baltimore: Lippincott Williams and Wilkins; 1999. p. 372-425.
Diallo O, Dore E, Duche P, Van Praagh E. Effects of plyometric training followed by a reduced training programme on physical performance in prepubescent soccer players. J Sports Med Phys Fitness 2001;41:342-8.
Toumi H, Best TM, Martin A, F'Guyer S, Poumarat G. Effects of eccentric phase velocity of plyometric training on the vertical jump. Int J Sports Med 2004;25:391-8.
Cornu C, Almeida Silveira MI, Goubel F. Influence of plyometric training on the mechanical impedance of the human ankle joint. Eur J Appl Physiol Occup Physiol 1997;76:282-8.
Arazi H, Damirchi A, Gandomi RT. Investigation and comparison of strengthening exercise with plyometric on the running speed and explosive power of athletes. Harakat J 2006;8:5-17.
Chimera NJ, Swanik KA, Swanik CB, Straub SJ. Effects of plyometric training on muscle-activation strategies and performance in female athletes. J Athl Train 2004;39:24-31.
Cardiovascular Diseases Research Center, MSc, Student of Anatomical Sciences, Department of Anatomy, Birjand University of Medical Sciences, Birjand, Iran
Source of Support: None, Conflict of Interest: None
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