Introduction
Competitive team sports are highlighted by frequent intense accelerations and decelerations, with the highest standards of sport demonstrating a progression in the volume of high-intensity loading required (Bradley, P., Archer, D., Hogg, B., Schuth, G., Bush, M., Carling, C., Barnes, C.; 2016). Intense accelerations and decelerations make up a large part of this workload, yet have distinctive and separate loading demands on athletes (Vanrenterghem, J., Nedergaard, N., Robinson, M. and Drust, B.; 2017). Accelerations have been shown to have higher metabolic demands (Hader, K., Mendez-Villanueva, A., Palazzi, D., Ahmaidi, S. and Buchheit, M.; 2016), whereas decelerations create greater mechanical loads (Dalen, T., Ingebrigsten, J., Ettema, G., Hjelde, G. and Wisloff, U.; 2016). Due to these stressors, the frequency of high-intensity accelerations and decelerations have been shown to increase muscle damage and neuromusclular fatigue post-match (De Hoyo, M., Cohen, D., Sanudo, B., Carrasco, L., Alvarez-Mesa, A, Del Ojo, J., Dominguez-Cobo, S., Manas, V. and Otero-Esquina, C.; 2016).
Match play overview
Decelerations in team sports occur in reaction to other athletes’ movements with marking, evasion or collision avoidance, playing area boundaries or reacting to the movement of the ball (Hewit, J., Cronin, J., Button, C. and Hume, P.; 2011). A recent systematic review has shown that all team sports other than American Football have a greater frequency of decelerations compared to accelerations (Harper, D., Carling, C. and Kiely, J.; 2019), with evidence of soccer players performing up to 2.9 times more high-intensity decelerations compared to high-intensity accelerations (De Hoyo, M., Cohen, D., Sanudo, B., Carrasco, L., Alvarez-Mesa, A, Del Ojo, J., Dominguez-Cobo, S., Manas, V. and Otero-Esquina, C.; 2016). These demands can vary based on playing position and tactical approach (Tierney, P., Young, A., Clarke, N. and Duncan, M.; 2016), and are highly linked with spatial restraints which restrict the space afforded for high-speed running, resulting in more frequent short decelerations (Kempton, T., Sirotic, A., Rampinini, E. and Coutts, A.; 2015).
Deceleration definition
The aim of decelerating is to decrease the body’s momentum (mass x velocity) by applying as much force as possible over a very short timeframe, allowing for movement in a new direction or a complete stop (Hewit, J., Cronin, J., Button, C. and Hume, P.; 2011). The placement of the limbs in relation to the centre of mass determines the difference between acceleration and deceleration, with deceleration requiring greater braking forces and ground reaction times, with success dependent upon a greater impulse than the current momentum. This allows for large eccentric forces to be absorbed and dispersed throughout the body, with the primary muscles utilised being the quadriceps and gastrocnemius in an eccentric manner (Hewit, J., Cronin, J., Button, C. and Hume, P.; 2011).
Demands of DEC
High-intensity decelerations have been shown to be very short in duration (Bloomfield, J., Polman, R. and O’Donaghue, P.; 2007), and achieve the highest amount of mechanical load per metre with evidence showing 65% greater loads than any other match-play activity, and 37% greater than equally intense accelerations (Dalen, T., Ingebrigsten, J., Ettema, G., Hjelde, G. and Wisloff, U.; 2016).
Impact on performance
Research suggests that a large majority of sporting injuries are the result of inappropriate deceleration abilities in athletes, with a large emphasis having previously been on developing acceleration abilities instead (Proske, U., Morgan, D., Brockett, C. and Percival, P.; 2004). Repeated intense decelerations have been shown to result in increased muscle damage (Draganidis, D., Chatzinikolaou, A., Avloniti, A., Barbero-Alvarez, J., Mohr, M., Malliou, P. Gourgoulis, V., Deli, C., Douroudos, I., Margonis, K., Gioftsidou, A., Flouris, A., Jamurtas, A. and Fatouros, I.; 2015), reduced eccentric and concentric counter-movement jump performance (De Hoyo, M., Cohen, D., Sanudo, B., Carrasco, L., Alvarez-Mesa, A, Del Ojo, J., Dominguez-Cobo, S., Manas, V. and Otero-Esquina, C.; 2016).
Typical testing battery
Typical testing and development in team sports centres around positive movements of acceleration, maximal speed and speed endurance, power based jumps (broad jump, CMJ), agility/change of direction ability, aerobic capacity and reactive strength (Turner, A., Walker, S., Stembridge, M., Coneyworth, P., Reed, G., Birdsey, L., Barter, P. and Moody, J.; 2011). This may not reflect the highest-intensity demands of the sport where injury occurrence has been linked with accumulated high-frequency decelerations (Jaspers, A., Kuyvenhoven, J., Staes, F., Frencken, W., Helsen, W. and Brink, M.; 2018), as athletes able to reach greater velocities will also have greater braking demands (Nedergaard, N., Kersting, U. and Lake, M.; 2014). It has been shown that if increased velocity is not accompanied with greater eccentric strength, an athlete will have an increased risk of injury (Jones, P., Thomas, C., Dos’Santos, T., McMahon, J. and Graham-Smith, P.; 2017), and reduced change of direction ability (Jones, P., Herrington, L. and Graham-Smith, P.; 2015).
Proposals
Research has shown that stronger athletes can produce greater braking forces than weaker ones (Spiteri, T., Cochrane, J., Hart, N., Haff, G. and Nimphius, S.; 2013), and deceleration is considered a biomotor skill that is highly utilised in agility and multidirectional movement training (Kovacs, M., Roetert, P. and Ellenbecker, T.; 2008). Harper and Kiely (2018) suggested prioritising an increase in the load-bearing ability of the lower limbs, alongside improving the coordinative aspects of the deceleration skills. A focus on eccentric strength development has been shown to enhance deceleration ability (de Hoyo, M., Sanudo, B., Carrasco, L., Mateo-Cortes, J., Dominguez-Cobo, S., Fernandes, O., Del Ojo, J. and Gonzalo-Skok, O.; 2016), specifically focussing on an eccentric overload. This, along with isometric exercise, has also been shown to increase resistance to muscle damage (Hyldahl, R., Chen, T. and Nosaka, K.; 2017). By reducing the amount of damage accumulated with each deceleration action results in less mechanical fatigue, which has been referred to as deceleration efficiency (Edwards, W.; 2018).
Plyometric training (PT) has been shown to increase power outputs and the rate at which force is developed (Miller, M., Herniman, T., Ricard, M., Cheatham, C. and Michael, T.; 2006), along with reactive strength through its use of the stretch-shortening cycle (Vaczi, M., Racz, L., Hortobagyi, T. and Tihanyi, J.; 2013) and dynamic stability as measured by functional reaching (Lockie, R., Schultz, A., Callaghan, S. and Jeffriess, M.; 2014), which has been proposed to be a key element in deceleration (Kovacs, M., Roetert, P. and Ellenbecker, T.; 2008). However, a variety of PT exercises must be used. A recent meta-analysis (Asadi, A., Arazi, H., Young, W. and de Villarreal, E.; 2016) looking at the relationship between PT and change of direction ability (COD), found that vertical and horizontal PT was more beneficial than a single direction alone, and it must be considered that team-sports athletes will be decelerating in multiple directions.
Increasing the time over which braking forces are applied upon landing is essential, which can be achieved with the use of technical cues. Encouraging ground contact with the order of heel, midfoot, and foot will enhance linear deceleration, along with planting the lead leg ahead of the body. This can be achieved by using deceleration drills, encompassing maximal/high velocity running with an enforced stopping distance. Coaches must take into consideration the stopping distances afforded however, as Lakomy and Haydon (2004) found athletes given less than 6m to decelerate refrained from sprinting maximally. In their study, subjects would begin decelerating early, potentially hampering speed development over 10-20m distances. A solution to this would be to use drills beginning with larger deceleration zones and progressively reducing in size over time, therefore placing greater emphasis on the braking forces required. It was also noted that athletes may favour one leg when stopping, which could lead to the development of knee flexor asymmetry in the legs, and contribute to an increased risk of injury (Knapik, J., Bauman, C., Jones, B., Harris, J. and Vaughn, L.; 1991).
Summary
Athlete development in general focuses primarily on enhancing acceleration and high-velocity running capacity, which whilst important may not meet the highest demands of the sport which is high-intensity deceleration. Developing greater braking force capacity through eccentric strength training and multi-directional plyometrics is key, along with cueing the correct loading patterns which will develop the key skills, using progressively smaller stopping zones in drills. Finally, careful attention to develop the athlete unilaterally and progressively should minimise injury risks.
References:
Asadi, A., Arazi, H., Young, W. and de Villarreal, E.; (2016). The effects of plyometric training on change-of-direction ability: a meta-analysis. International journal of sports physiology and performance. 11, 563-573.
Bloomfield, J., Polman, R. and O’Donaghue, P.; (2007). Deceleration movements performed during FA premier league soccer matches. Journal of sport science and medicine. 6, 6-11.
Bradley, P., Archer, D., Hogg, B., Schuth, G., Bush, M., Carling, C., Barnes, C.; (2016). Tier-specific evolution of match performance characteristics in the English Premier League: it’s getting tougher at the top. Journal of sports science. 34, 980-987.
Dalen, T., Ingebrigsten, J., Ettema, G., Hjelde, G. and Wisloff, U.; (2016). Player load, acceleration, and deceleration in forty-five competitive matches of elite soccer. Journal of strength and conditioning research. 30, 351-359.
Draganidis, D., Chatzinikolaou, A., Avloniti, A., Barbero-Alvarez, J., Mohr, M., Malliou, P. Gourgoulis, V., Deli, C., Douroudos, I., Margonis, K., Gioftsidou, A., Flouris, A., Jamurtas, A. and Fatouros, I.; (2015). Recovery kinetics of knee flexor and extensor strength after a football match. Plos one. 10(6), 1-22.
Edwards, W.; (2018). Modelling overuse injuries in sport as a mechanical fatigue phenomenon. Exercise and sports sciences reviews. 46, 224-231.
Hader, K., Mendez-Villanueva, A., Palazzi, D., Ahmaidi, S. and Buchheit, M.; (2016). Metabolic power requirement of change of direction speed in young soccer players: not all what it seems. Plos one. 11, 1-21.
Harper, D., Carling, C. and Kiely, J.; (2019). High-intensity acceleration and deceleration demands in elite team sports competitive match play: a systematic review and meta-analysis of observational studies. Sports medicine. 49, 1923-1947.
Harper, D. and Kiely, J.; (2018). Damaging nature of decelerations: do we adequately prepare players? BMJ open sport and exercise medicine. 4, 1-3.
Hewit, J., Cronin, J., Button, C. and Hume, P.; (2011). Understanding deceleration in sport. Journal of strength and conditioning research. 33(1), 47-52.
de Hoyo, M., Cohen, D., Sanudo, B., Carrasco, L., Alvarez-Mesa, A, Del Ojo, J., Dominguez-Cobo, S., Manas, V. and Otero-Esquina, C.; (2016). Influence of football match time-motion parameters on recovery time course of muscle damage and jump ability. Journal of sport science. 34, 1-8.
de Hoyo, M., Sanudo, B., Carrasco, L., Mateo-Cortes, J., Dominguez-Cobo, S., Fernandes, O., Del Ojo, J. and Gonzalo-Skok, O.; (2016). Effects of 10-week eccentric overload training on kinetic parameters during change of direction in football players. Journal of sports sciences. 34(14), 1380-1387.
Hyldahl, R., Chen, T. and Nosaka, K.; (2017). Mechanisms and mediators of the skeletal muscle repeated bout effect. Exercise and sports sciences reviews. 45, 24-33.
Jaspers, A., Kuyvenhoven, J., Staes, F., Frencken, W., Helsen, W. and Brink, M.; (2018). Examination of the external and internal load indicators’ association with overuse injuries in professional soccer players. Journal of science and medicine in sport. 21, 579-585.
Jones, P., Thomas, C., Dos’Santos, T., McMahon, J. and Graham-Smith, P.; (2017). The role of eccentric strength in 180o turns in female soccer players. Sports (Basel). 5(2), 42.
Jones, P., Herrington, L. and Graham-Smith, P.; (2015). Technique determinants of knee joint loads during cutting in female soccer players. Human movement science. 42, 203-211.
Kempton, T., Sirotic, A., Rampinini, E. and Coutts, A.; (2015). Metabolic power demands of rugby league match play. International journal of sports physiology. 10, 23-28.
Knapik, J., Bauman, C., Jones, B., Harris, J. and Vaughn, L.; (1991). Preseason strength and flexibility imbalances associated with athletic injuries in female collegiate athletes. American journal of sports medicine. 19, 76-81.
Kovacs, M., Roetert, P. and Ellenbecker, T.; (2008). Efficient deceleration: the forgotten factor in tennis-specific training. Journal of strength and conditioning research. 30(6), 58-69.
Lakomy, J. and Haydon, D.; (2004). The effects of enforced, rapid deceleration on performance in a multiple sprint test. Journal of strength and conditioning research. 18, 579-583.
Lockie, R., Schultz, A., Callaghan, S. and Jeffriess, M.; (2014). The effects of traditional and enforced stopping speed and agility training on multidirectional speed and athletic function. Journal of strength and conditioning research. 28(6), 1538-1551.
Miller, M., Herniman, T., Ricard, M., Cheatham, C. and Michael, T.; (2006). The effects of a 6-week plyometric training program on agility. Journal of sports science and medicine. 5, 459-465.
Nedergaard, N., Kersting, U. and Lake, M.; (2014). Using accelerometry to quantify deceleration during a high-intensity soccer turning manoeuvre. Journal of sports sciences. 32, 1897-1905.
Spiteri, T., Cochrane, J., Hart, N., Haff, G. and Nimphius, S.; (2013). Effect of strength on plant foot kinematics during a change of direction task. European journal of sport science. 13(6), 646-652.
Tierney, P., Young, A., Clarke, N. and Duncan, M.; (2016). Match play demands of 11 versus 11 professional football using global positioning system tracking: variations across common playing formations. Human movement science. 49, 1-8.
Turner, A., Walker, S., Stembridge, M., Coneyworth, P., Reed, G., Birdsey, L., Barter, P. and Moody, J.; (2011). A testing battery for the assessment of fitness in soccer players. Journal of strength and conditioning research. 33(5), 29-39.
Vaczi, M., Racz, L., Hortobagyi, T. and Tihanyi, J.; (2013). Dynamic contractility
Vanrenterghem, J., Nedergaard, N., Robinson, M. and Drust, B.; (2017). Training load monitoring in team sports: a novel framework separating physiological and biomechanical load-adaptation pathways. Sports med. 47, 2135-2142.
Carbon Training. 