Downhill Running as an Eccentric Exercise and its effect of Muscle Strength and Damage

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  • 1. Sports CoachingPedagogyDownhill Running as an EccentricExercise and its effect on Muscle Strength and DamageBy Jaclyn Sweeny

2. Overview of Presentation Definitions of Key Terms Background on Downhill Running and Importanceof Study Review of Literature Practical Applications Further Research Conclusion and Summation 3. Definitions Downhill running is an activity whereby muscles strongly contracteccentrically. Eccentric Muscle Contractions Occur when activated muscles are forcibly lengthened (ENOKA, R. 1996). Take place as a braking force working in opposition to a concentric contraction. Muscle Strength Encompasses physiological strength, neurological strength and mechanical strength of the muscle. Muscle Hypertrophy Increase in the cross-sectional size of a muscle due to muscle cell growth. Exercise Induced Muscle Damage (EIMD) Involves partaking in heavy and lengthy exercise in which the muscles are not adapted to, particularly eccentric muscle contractions. Delayed Onset Muscle Soreness (DOMS) Occurs after unaccustomed eccentric muscle action of sufficient intensity and/or duration causes disruption of connective and/or contractile tissue (BYRNES , CLARKSON, WHITE et al. 2008). 4. Downhill Running Significantly easier for metabolic andcardiovascular systems. Muscles of the hip, legs and ankles, particularlyknee and hip extensors, must work hard indownhill running. Studies involving downhill running and musclestrength or damage are very important inassessing and implemented eccentric musclecontracting exercises into an athletes trainingregime. You Tube Video http://www.youtube.com/watch?v=mFxs7ESuxWc 5. Literature Review 1- Changes in Power Assessed bythe Windgate Anaerobic Test Following DownhillRunning. Purpose The effect of eccentric induced muscle damage on power is a key performance variable in a variety of sporting contexts. Aim Examine changes in anaerobic power (through a 30 second Windgate test), isometric strength of knee extensors and flexors, muscle soreness and plasma Creatine Kinase (CK) activity following downhill running (NOTTLE , NASAKA. 2007). Method 8 men ran a downhill running protocol of a -7% gradient for 40 minutes before testing parameters 6. Results 7. Literature Review 2 Leukocytes, Cytokines, Growth Factorsand Hormones in Human Skeletal Muscle and Blood AfterUphill or Downhill Running Purpose investigate inflammatory processes in humanskeletal muscle and epimysium after acute physicalexercise with large eccentric contractions (MALM,SJODIN, SJOBERG et al. 2004.). Method 25 male and 3 female subjects were randomlyassigned downhill running protocols of -4 degree or-8 degree gradient, an uphill running protocol of 4degree gradient or control group. The subjects performed the run for 45mins. Muscle biopsy, knee extensor muscles, musclesoreness , immunohistochemistry, image analysis,blood samples, flow cytometry and serumhormones and proteins. 8. Results Indicated only the subjects who undertook the downhill running protocol experienced DOMS as well as a decrease in muscle function and an increase in creatine Kinase activity. 9. Literature Review 3- Changes in Running EconomyFollowing Downhill Running. Purpose to establish any changes in running economy after a 30minute downhill run Method 10 male soccer players. 30minute downhill run and subsequent level runs. Parameters included oxygen consumption, respiratory exchanged ratio, heat rate, ratings of perceived exhaustion, blood lactate, stride length, stride frequency and range of motion of ankle, knee and hip. 10. Results 11. Practical Applications Utilisation in training programs. Understanding adaptive mechanisms of muscles. Eccentric Exercises and the advantages fortraining. EIMD and DOMS - how detrimentally effect themuscles and for what period of time (alter trainingand recovery around these findings). Benefits of exercise and physical activity onsufferers of inflammatory muscle diseases. 12. Further Research Specific Downhill running protocols and trainingsessions to optimise muscle power and strengthgains. Research into the benefits and detriments ofdownhill running on various sports to ensure thatthe utilisation of eccentric training is enhancingperformance sports specifically. 13. Conclusion and Summation Downhill running is a very prominent eccentricexercise used by many coaches and athletes asa part of their training regime. Through the literature evaluated it can beconcluded that eccentric exercise such asdownhill running decreases peak and averagepower, strength, increases creatine Kinaseactivity and is associated with EIMD and DOMS. 14. Reference ListJournal ArticlesNOTTLE , NASAKA. 2007. Changes in Power Assessed by the Windgate Anaerobic Test Following Downhill Running. Journal of Strength and Conditioning Research, 21, 145-150.MALM, SJODIN, SJOBERG et al. 2004. Leukocytes, Cytokines, Growth Factors and Hormones in Human Skeletal Muscle and Blood after Uphill or Downhill Running. Journal of Physiology, 3, 983-1000.CHEN, NOSAKA, TU. 2007. Changes in Running Economy Following Downhill Running. Journal of Sports Sciences, 25, 55-63.ENOKA, R. 1996. Eccentric Contractions Require Unique Activation Strategies by the Nervous System. Journal of Applied Physiology, 81, 2339-2346.BYRNES , CLARKSON, WHITE et al. 2008. Delayed onset muscle soreness following repeated bouts of downhill running. Journal of Applied Physiology, 1.UNIVERSITY, E. C. 1991. Acute inflammation: the underlying mechanism in delayed onset muscle soreness? . Medicine and Science in Sport and Exercise, 23.CLARKSON, HUBEL. 2002. Exercise Induced Muscle Damage in Humans. Journal of Physiology Medical Rehabilitation, 81, 52-69.You tubeYOU TUBE,. 2011. Downhill Trail Running. In: ENDUROEXPLORER (ed.). Date Viewed 03/04/2012http://www.youtube.com/watch?v=mFxs7ESuxWcImagesImage 1 http://www.usatriathlon.org/about-multisport/multisport-zone/multisport- lab/articles/~/media/7daee9855b174a9ba6dfcff15492c9d5.ashxImage 2 http://static.flickr.com/53/131607152_3a01c5276f_m.jpg