REACTIVE AGILITY: PERCEPTION, DECISION AND ACTION

 

Erika Zemková1,2

1Department of Biological and Medical Sciences, Faculty of Physical Education and Sport, Comenius University in Bratislava, Slovakia

2Sports Technology Institute, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology in Bratislava, Slovakia

 

Abstract

Reactive agility consists of stimulus perception, decision-making and movement execution. This study deals with i) within and between-group differences in sensory and motor components of agility performance, and ii) an acute response to sport-specific exercise and adaptive changes in agility components following the athletic training. Providing information on each components of reactive agility is useful for revealing weaknesses in performance when designing exercise programs.

 

Introduction

Traditional view on agility was based on pre-planned movements with no perceptual component in a form of reaction to a given stimulus. Reactive agility addresses both the physical component, such as change of direction speed, and the cognitive component, such as anticipation and pattern recognition. From a practical point of view, information regarding these components of agility performance is of great interest. The sensory component include simple reaction time, i.e. the interval between the appearance of the stimulus and the beginning of response, and multi-choice reaction time, i.e. the stimulus identification and response selection, and the motor component is a movement time. Thus, agility time is an indicator of the speed of movement in response to visual stimuli.

To measure agility time, subjects are instructed to use either the left or right lower limb to make contact with one of the four mats located in four corners outside of a pre-defined square (Figure 1). They are encouraged to execute leg movements as quickly as possible and to touch the mats in accordance with the location of the stimulus in one of the corners of the screen. The results is total agility time and agility time in each movement direction.

 

Individual differences in sensory and motor components of agility performance

We compared simple reaction time, multi-choice reaction time, and agility time (reaction time plus movement time) in two athletes with varied demands on their agility skills. Simple and multi-choice reaction times were longer in the subject A than B. However, agility time was better in the subject A than B. This indicates that movement time was shorter in the subject A than B. This may be ascribed to the fact that the subject A was an elite karate-kata competitor who does not need to respond any stimuli but must be able to move a short distance very quickly. On the other hand, the subject B was not able to transfer his/her ability to react quicker to visual stimuli than subject A into better agility performance. While multi-choice reaction time represented 64% of the agility time in the subject A, in the subject B it was only 43%. In addition, individual differences in agility time were greater (about 26%) than in simple and multi-choice reaction times (18% and 9% respectively). These individual differences in sensory and motor components of agility reflect sport-specific adaptation.

 

Between-group differences in sensory and motor components of agility performance

The contribution of sensory and motor component on agility performance was also tested in groups of athletes with different demands on decision-making and movement velocity (Zemková, 2016). Groups of karate-kata competitors, karate-kumite competitors, hockeyball goalies, hockeyball players, soccer goalies, and soccer players underwent measurements of simple reaction time, two-choice reaction time, step initiation velocity and reactive agility time while moving different distances (i.e. the distance of 0.8 m and responses to 40 stimuli for karate-kata and -kumite competitors, 1.6 m and 20 stimuli for hockeyball players and goalies, and 3.2 m and 10 stimuli for soccer players and goalies). The Agility Index that quantifies the relative contribution of movement time to the agility performance was calculated (Zemková, 2017). The remaining part is attributed to the change of direction, running speed and anaerobic/aerobic capacity when moving longer distances.

Both simple and two-choice reaction times were significantly shorter in karate-kumite competitors than in karate-kata competitors (19.6% and 23.0% respectively). The agility time with movement distance of 0.8 m between the subject and the mats was also significantly shorter in karate-kumite competitors than in karate-kata competitors (8.2%). However, maximal step velocity did not differ significantly between these groups (3.3%).

Hockeyball goalies achieved significantly better values than players in both the simple (7.9%) and two-choice reaction time (10.3%). However, agility time with movement distance of 1.6 m between the subject and the mats was significantly shorter in players than in goalies (10.9%). Also, maximal step velocity was significantly higher in players than in goalies (13.8%).

Soccer goalies surpassed players in both the simple (10.3%) and two-choice reaction time (12.0%). However, agility time with movement distance of 3.2 m between the subject and the mats was significantly shorter in players than in goalies (14.2%). The maximal step velocity was also significantly higher in players than in goalies (16.8%).

Further analysis revealed (Zemková, Hamar, 2017) that simple reaction time, two-choice reaction time, and maximal step velocity were highly related to agility time in the test with a shorter traveling distance of 0.8 m. While simple and two-choice reaction times also strongly correlated with agility time in the test with longer traveling distances of 1.6 m, there still remains considerable variation in the factors that contribute to performance over each traveling distance. There were no significant relations of maximal step velocity to agility time in the tests with traveling distances of 1.6 m and 3.2 m. Therefore, other factors most likely contributed to agility performance, namely change-of-direction running velocity and anaerobic/aerobic capacity when responding 20 stimuli on a distance of 1.6 m and 10 stimuli on a distance of 3.2 m.

These findings were corroborated by a higher Agility Index found in karate-kumite than karate-kata competitors. Similarly, a higher Agility Index was identified in hockeyball and soccer goalies than in hockeyball and soccer players. While higher Agility Indexes indicate the use of both sensory and motor components in their performance, their lower values signify the predominant contribution of speed abilities to agility performance. It menas that players may require varied agility skill training utilising motor rather than sensory functions, as the longer distances appear more reliant on change-of-direction running velocity and anaerobic/aerobic capabilities.

Taken together, better simple and two-choice reaction times in karate-kumite than karate-kata competitors most likely contributed to enhanced agility performance, as there were no significant differences in movement velocity between these groups. The contribution of movement time to the agility time was 33.5% in karate-kata competitors and 44.2% in karate-kumite competitors. Simple and two-choice reactions were also shorter in hockeyball goalies than players when traveling distance of 1.6 m, as well as in soccer goalies than players when traveling longer distance of 3.2 m. In contrast, higher maximal step velocity was recorded in both hockeyball and soccer players than goalies. Higher movement time most likely contributed to better agility time in both hockeyball and soccer players than goalies. The contribution of movement time to the agility time was lower in players of hockeyball (28.3%) and soccer (19.9%) than goalies of hockeyball (42.7%) and soccer (39.4%).

These findings highlighted differential contributions of reaction time and step velocity to the agility time, depending upon traveling distances. It appears that cognitive and motor skills are better in karate-kumite than karate-kata competitors, when only stepping reactions are required. When moving longer distances, better agility time is in soccer and hockeyball players than goalies. While the motor component of agility performance seems to be predominant in players in terms of faster movement execution, in goalies it is the sensory component allowing faster decision making.

 

Effect of exercise on sensory and motor components of agility performance

Our next study investigated the effect of soccer match induced fatigue on agility, explosive power of lower limbs, static and dynamic balance, speed of step initiation and the soccer kick (Zemková, Hamar, 2009). After the first half of a match, only dynamic balance with eyes closed was impaired, and ground contact time significantly increased. A further increase was observed after the second half of a match. Along with dynamic balance with eyes open, agility performance in the test with shorter (0.8 m) distance between mats was also affected. However, there were no significant changes in static balance with eyes open and eyes closed, agility performance in the test with longer (1.5 m) distance between mats, speed of step initiation and the soccer kick, squat and countermovement jump height after the match.

Taking into account no significant changes in speed of step initiation, it is most likely that impairment of sensory rather than motor component contributed to an increased agility time when moving a shorter distance after the soccer match.

 

Pre-post training changes in sensory and motor components of agility performance

Finally, the effect of 6 weeks of combined agility-balance training (4–5 sessions a week in duration of 30 minutes) on simple and two-choice reaction times, simple and two-choice agility times, static and dynamic balance, speed of step initiation, strength differentiation accuracy, and explosive power of lower limbs (10-second maximal jumps, countermovement jump, squat jump, drop jump from a 45 cm box) in basketball players was evaluated (Zemková, Hamar, 2010). They performed reaction tasks similar to game-like situations on either wobble boards (experimental group 1) or a stable surface (experimental group 2).

Combined agility-balance training in experimental group 1 improved dynamic balance not only under visual control but also when the eyes were closed. Training also increased run out speed that most likely contributed to enhanced agility performance, reduced ground contact time during drop jump, and improved the ability to differentiate the intensity of muscle contraction during repeated jumps. However, such training has proven to be insufficient to improve static balance, simple and two-choice reaction times, and jumping performance. On the other hand, the experimental group 2 failed to show any significant improvement in these abilities except for the enhancement of jump performance.

Thus, there were no significant changes in simple and two-choice reaction times after the training. However, a significantly shorter simple and two-choice agility times were found. Maximal velocity of step initiation also significantly increased. This faster movement execution very probably contributed to the enhancement of agility performance. This assumption was corroborated by a significant correlation between the reduction in agility time and an increase in maximal velocity of step initiation after the training.

Also of interest, was the additional finding that the improvement in agility performance in older players (on average 21 years) was greater than in their younger, less experienced counterparts (on average 15 years). This may be attributed to faster feedback control of movement execution, i.e. as experience level increased with practice, the movement time decreased.

 

Conclusion

Within and between-group differences exist in sensory and motor components of agility performance, particularly among athletes of combat and team sports. It seems that fatigue induced by a sport-specific exercises induces impairment of the sensory rather than the motor component of agility performance. On the other hand, improvement in the motor component contribute to an improvement in agility time after the athletic training. These findings have to be taken into account when exercise programs in athletes with different demands on agility skills are designed. More information can be found in a book entitled ”Toward an understanding of agility performance” (Zemková, Hamar, 2015).

 

Acknowledgments

This work was supported by the Scientific Grant Agency of the Ministry of Education, Science, Research and Sport of the Slovak Republic and the Slovak Academy of Sciences (No. 1/0089/20).

 

References

Zemková E, Hamar D (2009). The effect of soccer match induced fatigue on neuromuscular performance. Kinesiology, 41(2): 195?202.

Zemková E, Hamar D (2010). The effect of 6-week of combined agility-balance training on neuromuscular performance in basketball players. Journal of Sports Medicine and Physical Fitness, 50(3): 262?267.

Zemková E, Hamar D (2015). Toward an understanding of agility performance. 2nd edition. Boskovice: František Šalé – Albert.

Zemková E (2016). Differential contribution of reaction time and movement velocity to the agility performance reflects sport-specific demands. Human Movement, 17(2): 94?101.

Zemková E (2017). Agility index as a measurement tool based on stimuli number and traveling distances. Journal of Strength and Conditioning Research, 31(8): 2141?2146.

Zemková E, Hamar D (2017). Association of speed of decision making and change of direction. Functional Neurology, Rehabilitation, and Ergonomics, 7(4): 10?15.