– Written by Dario Novak and Filip Sinkovic, Croatia

INTRODUCTION

Agility is considered one of the most significant abilities for success in many sports, including tennis. It is defined as the ability to quickly and efficiently change direction and/or movement¹. There are two relatively independent manifest forms of agility: non-reactive or pre-planned change of direction speed (CODS - Change of Direction Speed) and reactive or non-planned agility (RAG - Reactive Agility)¹. Agility training in tennis often focuses on developing both CODS and RAG abilities, as they are essential for quick and precise movement on the court. Effective agility drills and exercises help tennis players enhance their ability to react swiftly to unpredictable situations, such as opponent shots or changes in game dynamics, ultimately improving their overall performance on the court². Additionally, the development, construction, and modification of new and existing CODS and RAG tests are becoming increasingly popular topics in research circles. Therefore, the aim of this paper is to emphasize the practical application and difference in terminology between these two concepts and provide some of the tests used to measure them. These findings will provide valuable information for coaches to advance existing training procedures and design a variety of tennis-specific exercises aimed at improving performance, particularly in terms of players’ neuromuscular fitness.

CHANGE OF DIRECTION SPEED (CODS) PERFORMANCE IN SPORTS

Due to frequent changes in direction in many sports, including tennis, CODS and RAG are considered highly important motor abilities³. CODS involves a rapid change of direction that is pre-planned and known in advance, and players do not need to react to a specific stimulus³. In CODS tests, decision-making factors are not present, making participants less susceptible to errors during execution³. When evaluating the evidence relating to the importance of physical factors for CODS in different sports, a major difficulty is the huge variety of CODS tests. This is expected because different sports require different ranges of movement patterns. In other words, CODS is determined by technical factors and physical elements such as straight sprinting speed⁴. Additionally, an example of a CODS activity in sports is base-running in baseball or softball, where the batter runs a predetermined distance before changing direction at a different angle. Some sports involve lateral shuffling, such as basketball, while others, such as rugby, commonly require side-stepping movements. One element common to all of these tests is that the athlete is required to complete a preplanned task defined by obstacles, such as cones, in the shortest possible time, usually assessed with an electronic timing system⁴. CODS tests also vary greatly due to differences in the angle and the number of changes of direction, but there is no “gold-standard” generic CODS test that can be used for all sports.

REACTIVE AGILITY (RAG) PERFORMANCE IN SPORTS

Unlike CODS, RAG involves a cognitive component, including perception and decision-making factors⁵. Therefore, it can be concluded that RAG manifests in situations where an athlete needs to perform an agile movement but must react to a stimulus. In the context of sports, RAG typically involves a visual stimulus, as athletes base their agile movements on their visual perception of either the opponent’s movements or the trajectory of an incoming ball⁵. Due to the higher demand for reaction speed, tests of RAG are considered more complex and challenging to execute, resulting in slightly lower performance compared to the CODS⁶. Based on all the aforementioned, it is evident that RAG is influenced not only by motor abilities but also by various cognitive factors such as perception, anticipation, and decision-making speed in response to a stimulus⁵. In different sports, whether attacking or defending, agility skill requires the ability to perceive relevant information about opponents’ movements and react quickly and accurately⁶. Therefore, reactive agility performance is considered one of the most important motor abilities for achieving success in sports.

DEVELOPMENT OF NEW SPECIFIC CODS AND RAG TESTS IN TENNIS

According to the existing literature, a solid number of agility tests with various levels of specificity have been developed and used in tennis over the years, but the majority of the used tests were primarily change of direction (CODS) tests^7,8,9,10. Those tests did not really consider the cognitive aspect of agility, the “reaction to a stimulus,” which would be a much better representation of the kind of agility performance needed in a real tennis match rally situation. Despite the importance of reactive agility in tennis, there is a very limited number of scientific studies that have addressed this motor dimension, particularly under specific conditions. More specifically, a comprehensive systematic literature search yielded that there are only a few tennis-specific reactive agility tests, including a response to a stimulus, showing reliable and valid results^4,12,13.

EXAMPLES OF NEWLY CONSTRUCTED RAG TESTS IN TENNIS

One of the rare tennis-specific reactive agility tests (TAT) for monitoring tennis players has been designed in the research by Jansen et al¹¹. The TAT consists of four movements on stimulus at the back of the court around the baseline and one drop shot. According to established criteria, the TAT showed moderate relative reliability with an ICC of 0.74 (95% CI 0.34-0.92; p < 0.01). A significant positive moderate correlation of 0.70 (p < 0.01) was found between the TAT and the Spider Drill test. In conclusion, the test has shown solid test-retest reliability and concurrent validity in relation to a popular generic Spider Drill agility test. However, although the TAT test has been designed to be used in a practical setting by sports scientists and coaches, the test still requires some technical equipment and settings to be arranged (cones and light positions, etc.) for it to be successfully conducted. In addition to the mentioned research, Munivrana et al¹² designed a tennis-specific reactive agility test (TS-RAN) with a movement pattern that simulates the actual situation in the game, with participants not knowing the direction of movement in advance. They performed two strokes (forehand or backhand) on the baseline and two strokes (forehand or backhand) on the service line. The newly constructed tennis-specific reactive agility test (TS-RAN) showed to be on the margin between moderate and good reliability, with an ICC of 0.74 (95% CI 0.48–0.92; p < 0.01).
Another similar study was conducted by Sinkovic et al⁴, where they designed a new sport-specific TENRAG test (ICC = 0.72 – 0.74) in a way that participants imitated specific movements in tennis (Figure 1)⁴. In detail, participants start from a predetermined starting line, and the timing begins when the infrared signal (IR1) next to the starting line is interrupted by the “split step”. At this point, one of the two lights (L1 or L2) illuminates, and the participant must identify which light is lit, perform a run with overstepping and a lateral side-to-side technique to reach a stand with a ball (S1 or S2), and hit the ball with a forehand or backhand stroke in front of their body with sufficient force for the ball to hit the ground. After playing the shot, the player should quickly return to the device in front of the starting line, interrupting the infrared signal (IR2), which stops the measurement. In the TENCODS test, participants are aware in advance of which light will illuminate, allowing them to plan their running and shot execution. The test was performed nine times, with a 60-second break between measurement repetitions, and the mean value of the measurements was used for further analysis⁴.

PRACTICAL APPLICATION OF CODS AND RAG IN TENNIS

Athletes and their coaches are always seeking new ways to improve their motor abilities in order to achieve better results in their sports. Sport-specific tests provide more detailed information about the actual state of the attributes and abilities that ultimately ensure a player’s success at an elite competitive level. These tests better describe a player’s motor abilities associated with technical performance compared to general tests. Moreover, these tests enable coaches and sports scientists to track athletes’ progress over time, providing valuable insights into how their motor abilities develop with training and experience. In summary, in order to understand and enhance CODS and RAG in tennis, it is necessary to develop and validate specific tests that provide relevant information about these motor abilities. This would enable a better understanding and improvement of players’ performance. To conclude, the application and development of specific CODS and RAG tests can contribute to:

1. Diagnostic tools: They allow coaches to analyze athletes’ sports performance in detail, providing deeper insights into their abilities for changing direction and rapid acceleration and deceleration.
2. Injury prevention: By identifying weaknesses in CODS and RAG, coaches can shape workouts that strengthen the muscles needed to stabilize during rapid changes in direction, reducing the risk of injuries such as knee or ankle injuries.
3. Rehabilitation programs: Using specific tests during rehabilitation enables monitoring of patients’ progress in returning to full functionality after injuries, such as knee or ankle injuries.
4. Personalized training regimens: They allow coaches to tailor workouts to the individual needs of each player, focusing on improving specific aspects of speed and agility.
5. Enhanced tactical planning: Coaches can use information obtained from tests to better understand the strengths and weaknesses of each player and develop a tactical plan that maximizes their performance on the court.
6. Mental preparation: Increasing players’ self-confidence through improving speed and agility can positively impact their mental preparation for matches, increasing their ability to adapt to dynamic situations on the court.

Dario Novak, Ph. D.

Faculty of Kinesiology, University of Zagreb

Zagreb, Croatia

Filip Sinkovic, Ph. D.

Faculty of Kinesiology, University of Zagreb

Zagreb, Croatia

Contact: dario.novak@kif.unizg.hr

References

1. Paul DJ, Gabbett TJ, Nassis GP. Agility in team sports: Testing, training, and factors affecting performance. Sports Med. 2016;46(3):421-442.
2. Smith J, Johnson A, Davis R. The Effects of Agility Training on Tennis Performance. J Sports Sci. 2022;10(2):123-135.
3. Sekulic D, Pehar M, Krolo A, Spasic M, Uljevic O, Calleja-González J, Sattler T. Evaluation of Basketball-Specific Agility: Applicability of Preplanned and Nonplanned Agility Performances for Differentiating Playing Positions and Playing Levels. J Strength Cond Res. 2017;31(8):2278-2288.
4. Sinkovic F, Foretic N, Novak D. Reliability, validity and sensitivity of newly developed tennis-specific reactive agility tests. Sustainability. 2022;14(20):13321.
5. Henry GJ, Dawson B, Lay BS, Young WB. Decision-making accuracy in reactive agility: quantifying the cost of poor decisions. J Strength Cond Res. 2013;27:3190-3196.
6. Sekulic D, Krolo A, Spasic M, Uljevic O, Peric M. The development of a new stop'n'go reactive-agility test. J Strength Cond Res. 2014;28(11):3306-3312.
7. Sekulic D, Uljevic O, Peric M, Spasic M, Kondric M. Reliability and Factorial Validity of Non-Specific and Tennis-Specific Pre-Planned Agility Tests; Preliminary Analysis. J Hum Kinet. 2017;55:107-116.
8. Eriksson A, Johansson FR, Bäck M. Reliability and criterion-related validity of the 20-yard shuttle test in competitive junior tennis players. Open Access J Sports Med. 2015;6:269-276.
9. Huggins J, Jarvis P, Brazier J, Kyriacou Y, Bishop C. Within - and between - Session Reliability of the Spider Drill Test to Assess Change of Direction Speed in Youth Tennis Athletes. Int J Sports Exerc Med. 2017;3:74.
10. Barber-Westin SD, Hermet A, Noyes FR. A six-week neuromuscular training program for competitive junior tennis players. J Strength Cond Res. 2010;24(9):2372-2382.
11. Jansen MGT, Elferink-Gemser MT, Hoekstra AE, Faber IR, Huijgen BCH. Design of a Tennis-Specific Agility Test (TAT) for Monitoring Tennis Players. J Hum Kinet. 2021;80:239-250.
12. Munivrana G, Jelaska I, Tomljanovic M. Design and Validation of a New Tennis-Specific Reactive Agility Test-A Pilot Study. Int J Environ Res Public Health. 2022;19(16):10039.

Header image by Rob Keating (Cropped)