sprint performance study proposal
Introduction
In sports, one athletic quality that is very important for many athletes is sprint running. Sprinting can be divided into two segments accelerating sprint running and constant speed running. In the sport of track and field most of the training focuses in improving sprint running as it is a major key quality, but many other popular team sports, such as football, rugby and American football, sprint running is also very important for success. Depending what sport acceleration is deferent, for example track athletes seem to accelerate for longer distances between 50-60 metres than team sports 20-30 meters but they may not necessarily accelerate to the fullest. Although sprinting is important it is still unclear the best way to maximize the performance for team and track athletes. Conventional training methods can increase the speed in sprinting, like sprint running training, resisted sprinting, resistance training, ballistic training, plyometrics (Taylor, 2010) Sport scientists have not yet compered which training method is best and also the training status can affect the selection of the better methods. Genetics are identified to be an necessary component (Alonso et al. 2016), and gains as a result of any kind of training are generally small even over very long periods of time (Tønnessen et al. 2015). This has made some critics quite doubtful about the “trainability” of sprinting. Various research showed that resistance training can be very effective to increase sprinting speed in athletes and many coaches use squats because is the most frequently explored resistance training exercise. Not a lot of research has been done in one factor that is very important in sprint running, that is the force vector theory and how it transfers the abilities of the athletes. The force vector is the direction in which force is applied with respect to the body. Typically, these are referred to as “vertical” and “horizontal” although strictly the correct terms are axial (for vertical) and anteroposterior (for horizontal), as these refer to force directed from the feet towards the head, and force directed from the back of the body to the front of the body, respectively.
Literature review
Previous studies have focused in squat strength, and showed that are strongly linked with improvement in speed. However studies showed that using light weight and faster bar speed throughout resistance training does not seem to produce better results compared to heavy loads and slow bar speeds (Bishop, 2015). A study stated that resisted training is very affective in improving an athlete’s speed and the most common resisted sprinting method used is sled towing. It also suggested that the load on the sled seems to have slight effect on results of both light and heavy sled weights can prove to be very successful. Research showed that plyometric are very effective and is the most used by coaches to improve sprinting speed in athletes, also studies suggested no specific plyometric training exercise prove to be more effective than any other however using a variety of different plyometric showed to be better than one exercise alone. (Randell et al. 2010) has suggested that training methods that demonstrate biomechanical similarity to sprint running can be very beneficial, for example exercises such as unilateral exercises, exercises for the hamstrings and gluteus Maximus, exercises involving horizontally-directed forces and training methods involving high-velocity force production.
Not a lot of research has been done to help identify what training method is better to achieve peak performance. Restricted biomechanics research proposes that exercises intended to improve horizontal force in athletes can be more current than those projected to improve vertical force production.
Studies had to consider that there are different sorts in sprint running that are different amongst track athletes and team sports such as the type of running surface also what is the sprint direction of the athlete (linear or change of direction). Most research commonly focuses on what sprinting phase is performed (accelerating vs. constant speed) and the different starting positions in a variety of sports. Although many reviewers have detected that between track athletes and team sports athletes there are a biomechanics dissimilarities.
(Novacheck, 1998) has detected in his study that when track athletes are in stance phase may show less change in knee flexion. Indicting that shock absorption is actually delivered by other ways than leg extension. Furthermore explained the cause is leading athletes to take longer stride length may be that track and field sprinters have a tendency during the swing phase to produce large hip flexion while performing the movement. This study has also proposed that sprinters have a much greater peak knee flexion during the swing phase than sprint running in team sports although until a direct assessment of team sport athletes and athletics sprinters is made the biomechanics precise differences of the two groups will continue to be inaccurate. Another study (Young, 2006) looked on the gait cycle during a sprint running, this can be separated in to two sections; stance stage (when the athlete has one foot on the ground) and flight stage (when neither food is on the ground). In the flight stage the athlete applies no force, in the stance stage in order for the sprinter to continue moving a force need to be applied into the ground. The term for this type of forces is ground reacting forces (GRF). The common way in biomechanics to analyse complete force into two angle components which are horizontal and vertical. During the flight stage the athlete’s centre of mas falls accelerating back towards the ground due to gravity forces acting upon all athletes. In order for the athlete to raise back upwards the centre of mass a considerable vertical forces are then necessary during following stance stage. Lastly at the start of every stance stage there are horizontal breaking forces which are the reason of the slowdown, this is because when the athlete foot touches the ground is not frictionless. For the athlete to continue moving at the same speed or faster requires horizontal propulsive forces that cause the stance phase to be reversed toward the middle and end.
The Horizontal and vertical forces due to comparative importance has been a topic of a lot of debate between strength and containing coaches, sprint coaches and researches. Some believe that in order to improve sprint performance increasing horizontal forces are of most importance to be more effective, while others have confidence that improving vertical forces would increase sprinting performance.
(Mann, 2011) stated in his research that horizontal and vertical forces have two different stages, in one stage the net horizontal forces are by requirement bigger than zero when the athlete is accelerating in a sprint performance. At this acceleration stage researches agree that horizontal forces to some degree are of significant importance but in this matter there is still disagreements whether horizontal is of equal importance as vertical forces. On the other stage when an athlete is at constant speed or maximal sprint speed, the net horizontal forces are by requirement zero. This does not mean the athlete is not creating and executing anymore horizontal force, it means zero is the sum of forces that they are working against together which are the athlete propulsive horizontal force created and the net braking horizontal force. The studies that support vertical forces being more required for an athlete to achieve faster speeds in sprinting than horizontal force, have suggested three key hypotheses on why it is more important. One hypotheses is in the accelerating phase the net horizontal force decrease to zero while the athlete increases the running speed, also the vertical force increases (Mann, 2011). In track sprinting the most important phase happens in the starting blocks because much of the acceleration takes place, then the athlete is able to maintain the speed generated by the force originated on the starting blocks (; Clark & Weyand, 2015). Most significantly some studies have displayed that slow sprinters don’t produce as much vertical force than faster sprinters.
A study, examined the performance of short maximal sprints over 10 metres which was performed 10 Finnish sprint athletes. The study found there was a significant moderate correlation (r = 0.56) in the first step and 10m sprinting speed amongst mean and peak horizontal force, on the other hand they also found no correlation amongst mean or peak vertical forces in the first step and 10m sprinting speed. However on this study it was only measured forces during the first step, this made the research limited. Kawamori et al. (2012) studied the short maximal sprints performance over 10m over a force platform, using 30 semi-pro athletes of team sports background. This study concluded Sprint running time was significantly and moderately correlated with the relative net horizontal impulse and the relative propulsive horizontal impulse at 8 meters but not with the relative vertical impulse
An interventional study carried out by Kobal (2015) analysed the training method on sprint performance and jumping in a football team and how adding horizontal/vertical plyometrics has an effect on the athletes. This study was divided in two groups, one group performed horizontal jumps, while the other group only executed vertical jumping (countermoment jumping). In each training session the volume had to be changed between 32 and 60 jumps per training, this was done in interventions of 11 sessions. The analyses of this study revealed the vertical group improved countermoment jumps height and peak performance, the horizontal jump peak performance and distance improved in both groups. Also found that velocity in the 20 metres did not improve in both groups, but in the horizontal group displayed a moderate positive effect in the 10 metres sprint, while the vertical group showed large improvement in the 10-20 metres acceleration and it was largely negative in the horizontal group. The results presented herein indicate that the plyometric training-axis is significant in defining neuromechanical training responses in high-level football players.
Furthermore research confirm the ability of plyometric to transfer neuromuscular improvements in acceleration and speed skills of football players. To achieve his improvements is possible without a preparatory strength foundation phase, vertical and horizontal exercises could be applied in the beginning of the preseason. Some studies demonstrated the effectiveness of both methods on increasing sprinting speed, but it seems horizontal jumps are more effective for improving acceleration over short distances up to 10 metres whereas for longer sprinting distances from 10 to 30 metres, vertical oriented plyometrics would be more focused in developing top speed. This findings provide strength and condition coaches with a base of which is the best training routine to choose for each different athlete. However more studies are necessary to analyse longer phases of plymotrics training are able to increase and maintain sprinting speed ability in elite trained athletes. Also in order to investigate the potential effects on the neuromechaincal capacities of football players, mixed neuromuscular training approaches such as performing vertical and horizontal plyometrics simultaneously, contrast/complex methods need to be applied during preseason.

References

Abe, T., Kumagai, K., & Brechue, W. F. (2000). Fascicle length of leg muscles is greater in sprinters than distance runners. Medicine and Science in Sports and Exercise, 32(6), 1125
Bartolini, J. A., Brown, L. E., Coburn, J. W., Judelson, D. A., Spiering, B. A., Aguirre, N. W., & Harris, K. B. (2011). Optimal elastic cord assistance for sprinting in collegiate women soccer players. The Journal of Strength & Conditioning Research, 25(5), 1263-1270
Beneke, R., & Taylor, M. J. (2010). What gives Bolt the edge—AV Hill knew it already!. Journal of biomechanics, 43(11), 2241-2243
Bentley, I., Atkins, S., Edmundson, C., Metcalfe, J., & Sinclair, J. (2015). Impact of harness attachment point on kinetics and kinematics during sled towing. Journal of strength and conditioning research.[Citation]
Bex, T., Iannaccone, F., Stautemas, J., Baguet, A., De Beule, M., Verhegghe, B., & Derave, W. (2016). Discriminant musculo‐skeletal leg characteristics between sprint and endurance elite Caucasian runners. Scandinavian Journal of Medicine & Science in Sports.[]
Bezodis, I. N., Kerwin, D. G., & Salo, A. I. (2008). Lower-limb mechanics during the support phase of maximum-velocity sprint running. Medicine and science in sports and exercise, 40(4), 707.[PubMed]
Bezodis, I. N., Salo, A. I., & Kerwin, D. G. (2009). Athlete-specific analyses of leg joint kinetics during maximum velocity sprint running. Proceedings of the XXVII International Conference on Biomechanics in Sports.International Society of Biomechanics in Sports, pp. 378-381.[Citation]
Bissas, A. I., & Havenetidis, K. (2008). The use of various strength-power tests as predictors of sprint running performance. Journal of sports medicine and physical fitness, 48(1), 49-54.
de Villarreal, E.S., Requena, B. and Cronin, J.B., 2012. The effects of plyometric training on sprint performance: a meta-analysis. The Journal of Strength & Conditioning Research, 26(2), pp.575-584.
Edouard, P., Arnal, P., Gimenez, P., Samozino, P., Jimenez-Reyes, P., Brughelli, M., Mendiguchia, J. & Morin, J. 2016, “Athletic injury prevention: Determinants of sprint performance”, Annals of Physical and Rehabilitation Medicine, vol. 59, pp. e22-e23
Girard, O., Brocherie, F. & Bishop, D.J. 2015, “Sprint performance under heat stress: A review”, Scandinavian Journal of Medicine & Science in Sports, vol. 25, no. S1, pp. 79-89.
Loturco, I., Pereira, L.A., Kobal, R., Zanetti, V., Kitamura, K., Abad, C.C.C. and Nakamura, F.Y., 2015. Transference effect of vertical and horizontal plyometrics on sprint performance of high-level U-20 soccer players. Journal of sports sciences, 33(20), pp.2182-2191.
Rumpf, M. C., Lockie, R. G., Cronin, J. B., & Jalilvand, F. (2015). The effect of different sprint training methods on sprint performance over various distances: a brief review. The Journal of Strength & Conditioning Research.
Rumpf, M.C., Lockie, R.G., Cronin, J.B. & Jalilvand, F. 2016;2015;, “Effect of Different Sprint Training Methods on Sprint Performance Over Various Distances: A Brief Review”, Journal of Strength and Conditioning Research, vol. 30, no. 6, pp. 1767-1785.
Schache, A. G., Blanch, P. D., Dorn, T. W., Brown, N. A., Rosemond, D., & Pandy, M. G. (2011). Effect of running speed on lower limb joint kinetics. Medicine & Science in Sports & Exercise, 43(7), 1260.
Schache, A. G., Brown, N. A., & Pandy, M. G. (2015). Modulation of work and power by the human lower-limb joints with increasing steady-state locomotion speed. Journal of Experimental Biology, 218(15), 2472-2481.
Schache, A. G., Dorn, T. W., Williams, G. P., Brown, N. A., & Pandy, M. G. (2014). Lower-limb muscular strategies for increasing running speed. Journal of Orthopaedic & Sports Physical Therapy, 44(10), 813-824.
Schuster, D., & Jones, P. A. (2016). Relationships between unilateral horizontal and vertical drop jumps and 20 metre sprint performance. Physical Therapy in Sport.
Scott, S.L. and Docherty, D., 2004. Acute effects of heavy preloading on vertical and horizontal jump performance. The Journal of Strength & Conditioning Research, 18(2), pp.201-205.
Seitz, L. B., Reyes, A., Tran, T. T., de Villarreal, E. S., & Haff, G. G. (2014). Increases in lower-body strength transfer positively to sprint performance: a systematic review with meta-analysis. Sports Medicine, 44(12), 1693-1702.
Sekiguchi, H., Nakazawa, K., & Hortobágyi, T. (2013). Neural control of muscle lengthening: Task-and muscle-specificity. The Journal of Physical Fitness and Sports Medicine, 2(2), 191-201.
Siff, M. C. (2003). Supertraining. Supertraining Institute.
Simpson, K. J., & Bates, B. T. (1990). The effects of running speed on lower extremity joint moments generated during the support phase. International Journal of Sport Biomechanics, 6, 309-324.
Speirs, D. E., Bennett, M. A., Finn, C. V., & Turner, A. P. (2016). Unilateral vs. Bilateral Squat Training for Strength, Sprints, and Agility in Academy Rugby Players. The Journal of Strength & Conditioning Research, 30(2), 386-392.
Swinton, P. A., Lloyd, R., Keogh, J. W., Agouris, I., & Stewart, A. D. (2014). Regression models of sprint, vertical jump, and change of direction performance. The Journal of Strength & Conditioning Research, 28(7), 1839-1848.
Thomas, C., Comfort, P., Chiang, C. Y., & A. Jones, P. (2015). Relationship between isometric mid-thigh pull variables and sprint and change of direction performance in collegiate athletes. Journal of Trainology, 4(1), 6-10.
Thomas, C., Dos’ Santos, T., Comfort, P., & A. Jones, P. (2016). Relationship between Isometric Strength, Sprint, and Change of Direction Speed in Male Academy Cricketers. Journal of Trainology, 5(2), 18-23.
Thomas, C., Mather, D., & Comfort, P. (2014). Changes in sprint, change of direction and jump performance during a competitive season in male lacrosse players. Journal of Athletic Enhancement, 3(5), 1-8.
Tillin, N. A., Pain, M. T., & Folland, J. P. (2011). Short‐term unilateral resistance training affects the agonist–antagonist but not the force–agonist activation relationship. Muscle & Nerve, 43(3), 375-384.
Tillin, N. A., Pain, M. T., & Folland, J. P. (2012a). Contraction type influences the human ability to use the available torque capacity of skeletal muscle during explosive efforts. Proceedings of the Royal Society B: Biological Sciences, 279(1736), 2106.
Tillin, N. A., Pain, M. T., & Folland, J. P. (2012b). Short‐term training for explosive strength causes neural and mechanical adaptations. Experimental Physiology, 97(5), 630-641.
Young, W.B., 2006. Transfer of strength and power training to sports performance. International journal of sports physiology and performance, 1(2), pp.74-83.