Biomechanics of Sprint Start - Literature review Example

Literature Review on Biomechanics of Sprint Start Introduction: An efficient start is very important part in winning sprint races. Hence the training of sprint races concentrate on exercising certain aspects of biomechanics that influence the start, including optimal block start angle, horizontal velocity take-off, center of gravity, stretch shortening cycle of the calf muscles, force production, optimal hip, knee and ankle joint angles etc., The present study observes the researches done in the above aspects to contribute a new knowledge in the area of exercise science on sprint start. The study intends to observe the similar and contrasting research on the biomechanical aspects during set, reaction time and force time activities. The study also observes the application of applied techniques in training the sprint start and their impact on the performance. The literature found could cover only few aspects of the scope showing a dearth and further need in other areas of biomechanics of sprint start. Sprint start enables the sprinter to start the race with his/her body sloping as required for acceleration  (McNeill Alexander, 1992). The sprint start has been the focus of much research over the past number of decades. The "set" position (Baumann, 1976; Mero, Luhtanen and Komi, 1983; Mero, 1988), reaction time (Baumann, 1976; Henry, 1952; Payne & Blader, 1970) and force-time characteristics (Baumann, 1976; Henry, 1952; Mero et al., 1983, Mero, 1988) have been the variables commonly investigated. The type of start does have great influence on further performance. (Henry, 1952). There are three main types of crouched positions: the bullet, the medium and the elongated positions (Hay, 1993).  A crouched start is more effective than a standing start as it places the sprinter in a position to move the centre of gravity rapidly well ahead of the feet and thus the runner must accelerate very quickly or else fall (Adrian & Cooper, 1995). According to Hay (1993) the main difference between these three starts lies in the longitudinal distance between the toes of the front foot and the toes of the rear foot when the athlete is in the "On your marks" position.  This distance can be referred to as the toe-to-toe distance or the inter-block spacing. McFarlane (1981:36) has noted that: "The medium start has been proven superior over both the bunch and elongated starting positions in providing the compromise needed to allow for a fast acceleration of the centre of gravity, good forward lean and the maximum impulse." But the study of Henry, F.M. Res. Quart. 23: 301-318, 1952., reveals that even though the bunch start gets the athlete out of the blocks earlier an elongated start gets the athlete out faster, however, over 5, 10, and 50 yd. the elongated start produced faster times. Movement from the set position in the sprint start must not only be fast and forceful but should permit the sprinter to rapidly take up a mechanically efficient running position (Barlow & Cooper, 1972). Hence the study observes the other factors influencing the sprint start: Drew Harrison & Tom Comyns refers the Sprint start as a Motor Skill. And according to Magill (1993:7) a motor skill is "an action or a task that has a goal and that requires voluntary body and/or limb movement to achieve the goal". Sprint start, involving the large muscular setting and positioning between different body parts to gain momentum against gravity has become a very crucial topic in exercise science to train up the students for efficient performance. “When untrained subjects in a study of Mero and Komi (1985) were towed to supramaximal running speed (above their normal maximal speed), they were unable to increase the stride rate, and instead, they responded to increased speed with inefficient increase of stride length. Well-trained athletes succeeded to increase both stride rate and stride length in the said study. This difference in running techniques between untrained and trained individuals indicates that with sprint exercise it is possible to adapt human neuromuscular performance to a higher level.” Surakka, J The block position also has great impact on the performance in sprinting and has a position in research for training and production of different block types. Many variables have been studied pertaining to the block sprint start. During Sprint start, the sprinter must be capable of developing a high force rate combined with a high maximum force, especially in the horizontal direction. This ability to create high force underlies other important indicators of starting performance such as minimum block clearance time, maximum block leaving velocity and maximum block leaving acceleration. (Harland MJ, Steele JR) The adoption of medium block spacing is preferred by Harland MJ, Steele JR with front and rear knee angles in the set position approximating 90 and 130 degrees, respectively, with the hips held moderately high. Once the sprinter has projected him/herself from the blocks at a low angle (40 to 45 degrees) relative to the ground, the following 2 post-block steps should occur with the total body centre of gravity ahead of the contacting foot at foot strike to minimize potential horizontal braking forces. (Harland MJ, Steele JR) The study conducted by Department of Biomechanics, University of Frankfurt, Germany on ‘Training of the sprint start technique with biomechanical feedback’ is aimed to improve the individual starting techniques. This study was carried with eight top junior sprinters using biomechanical feedback training. The technical parameters like blocks spacing to the start line, knee angle of the front leg and proportion of body mass falling on the hands were taken as variables. The horizontal velocity at take-off and the time to 10 m were the criteria used to evaluate the effect of the technical changes. All of the parameters were measured simultaneously and the athletes were provided with feedback immediately after each attempt. Seven of eight sprinters showed a statistically significant improvement in starting performance after modifying the position of their blocks. Though the study could not find correlation between improvement in 10-m time and horizontal velocity at take-off, there was a correlation with the power exerted during the starting action with the time to 10 m. The effective biomechanical feedback during the training of the sprint start should use power exerted as the principal criterion because horizontal velocity shows an intra-individual optimal trend in improvement.( Mendoza L, Schollhorn W.) The dynamics of muscle contraction and tendon function contribute to the performance of maximum effort activities such as jumping and sprinting.(Drew Harrison, Miriam Clegg). The passive muscle stretching can diminish the peak force output of subsequent maximal isometric, concentric and stretch-shortening contractions, (Journal of Sport Sciences). This is proved by the study conducted to know the ‘Acute effects of passive muscle stretching on sprint performance’ by Nelson, Arnold; Driscoll, Nicole; Landin, Dennis; Young, Michael; Schexnayder, Irving. The study shows that the pre-event stretching might negatively impact the performance of high-power short-term exercise. “The study tried to identify the matching between laboratory setting with the performance setting. Sixteen members with 11 males and 5 females of a Division I NCAA track athletics team performed electronically timed 20 m sprints with and without prior stretching of the legs. The four stretching protocols conducted on 4 days - were no-stretch of either leg (NS), both legs stretched (BS), forward leg in the starting position stretched (FS) and rear leg in the starting position stretched (RS). Three stretching exercises hamstring stretch, quadriceps stretch, calf stretch were used for the BS, FS and RS protocols. Each stretching exercise was performed four times, and each time the stretch was maintained for 30 minutes.”(Journal of Sport Sciences). Ageing and sedentary lifestyle leads to a decline in the function of the tendons and decreased strength of the joints (Kannus and Jozsa, 1991; Vailas and Vailas, 1994; Tuite et al., 1997), and consequently, flexibility exercises are important for reducing the stiffness of the muscles (Wilson et al., 1991). Thus the training aspect of sprinting does also need to consider the age and lifestyle factors on stiffness and functioning of the muscles. Department of Biology of Physical Activity, Neuromuscular Research Centre, University of Jyvaskyla, Jyvaskyla, Finland.observed the ‘Effects of muscle-tendon length on joint moment and power during sprint starts.’ The study suggests that the longer initial muscle-tendon lengths of the gastronomies and soleus in the block phase at the beginning of force production contribute to the greater peak ankle joint moment and power and consequently the greater block velocity during the sprint start. Cronin et al. (2000) stressed the importance of the adaptation of the neuromuscular system in concentric muscle actions that require higher rates of initial power production, such as in sprint races. Neuromuscular Research Center, Department of Biology of Physical Activity, University of Jyvaskyla, identified stiffness regulation aspects of ankle and knee joint on sprint running. The study observed constant ankle joint stiffness may depend on (constant) tendon stiffness because of its dominating role in triceps surae muscle-tendon unit. Thus, we conclude that in sprint running the spring-like behavior of the leg might be adjusted by changing the stiffness of the knee joint. However, in complicated motor task, such as sprint running, ankle and knee joint stiffness might be controlled by the individual mechanical and neural properties. Though the study of Mark D. Johnson, John G. Buckley observes the Muscle power patterns on sprinting, it was not on sprint start, but it was studied to observe them during the mid-acceleration phase. Conclusion: The literature review was done to understand impact of different start positions and phases of sprinting. And then due to the limited availability of literature on other phases of sprint start, the study could observe the literature on set position only. Then the study observed few researches conducted on the muscle strengthening, impact of training feed back on the performance, block position, center of gravity, knee and ankle fitness and angles. The study also observed experimenting on the stretching of muscles with different types of protocols, tendons and stiffness of muscles on the neuromuscular impact. And the study could not find much relevant information in the areas like muscle power patterns during sprint start, and the direct effect of horizontal velocity take-off, force production, optimal hip impact areas. Also the study found most of the studies conducted were on men subjects leaving a gender bias on the scope of the study. From this the study draws scope to identify the need of further research in the area of sprint start to increase the knowledge base for further training. References: Drew Harrison & Tom Comyns, Biomechanics of the sprint start. Retrieved October 05, 2006, from http://coachesinfo.com/article/219/ Biomechanics Research Unit, University of Limerick, May 2006, . Retrieved October 06, 2006, from ww.ul.ie/~pess/BRU/BRUReportMay2006.htm - 184k – Metter, E.J., Conwit, R., Tobin, J. and Fozard, J.L. (1997) Age-associated loss of power and strength in the upper extremities in women and men. The Journals of Gerontology (Series A, Biological sciences and medical sciences) 52, B267-276. Exploring Biomechanics: Animals in Motion, R. McNeill Alexander, Scientific American Library, W. H. Freeman and Company, New York (1992). Mero, A., Luhtanen, P., Viitasalo, J.P. and Komi, P.V. (1981) Relationships between the maximal running velocity, muscle fiber characteristics, force production and force relaxation of sprinters. Scandinavian Journal of Sports Sciences 3, 16-22. Mero, A. and Komi, P.V. (1985) Effects of supramaximal velocity on biomechanical variables in sprinting. International Journal of Sport Biomechanics 1, 240-252. Mero, A. and Komi, P.V. (1986) Force-, EMG-, and elasticity-velocity relationship at submaximal and supramaximal running speeds in sprinters. European Journal of Applied Physiology 55, 553-561. Komi, P.V., Karlsson, J., Tesch, P., Suominen, H. and Heikkinen, E. (1982) Effects of heavy resistance and explosive type strength training methods on mechanical, functional and metabolic aspects of performance. In: Exercise and Sport Biology. Ed: Komi, P.V. Champaign IL: Human Kinetics. 90. Komi, P.V. (1984) Physiological and biomechanical correlates of muscle function: effects of muscle structure and stretch-shortening cycle on force and speed. In: Exercise and Sports Sciences Reviews. Vol. 12. Ed: Terjung, R.L. Lexington, Mass.:The Collamore Press. 81-121. Jeff L. Hoskisson, Sprint Mechanics Revisited, Retrieved October 05, 2006, from http://www.elitetrack.com/articles/sprinthoskisson.pdf. JOHNSON Mark D., BUCKLEY John G., Muscle power patterns in the mid-acceleration phase of sprinting, Retrieved October 05, 2006, from http://cat.inist.fr/?aModele=afficheN&cpsidt=926446 Harland MJ, Steele JR., Biomechanics of the sprint start: Sports Med. 1997 Jan;23(1):11-20., Retrieved October 06, 2006, from http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=9017856&dopt=Abstract KUITUNEN Sami, KOMI Paavo V.,KYRÖLÄINEN Heikki, Knee and ankle joint stiffness in sprint running, Retrieved October 04, 2006, from http://cat.inist.fr/?aModele=afficheN&cpsidt=13433912 Mendoza L, Schollhorn W.,( J Sports Sci. 1993 Feb;11(1):25-9.) Training of the sprint start technique with biomechanical feedback., Retrieved October 05, 2006, from http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=8450581&dopt=Abstract Nelson, Arnold G.; Driscoll, Nicole M.; Landin, Dennis K.; Young, Michael A.; Schexnayder, Irving C., Acute effects of passive muscle stretching on sprint performance: Journal of Sports Sciences, May, 2005, Retrieved October 06, 2006, from http://www.findarticles.com/p/articles/mi_hb3063/is_200505/ai_n15045497 Read More