Reaction time

The reaction time is the time required for a person to respond to a given stimulus. This time has been widely studied, both in sports and in everyday life as its practical implications are the basis of many daily and motor activities. In football, for example, a shorter reaction time allows the goalkeeper to respond faster to a penalty kick. In the driver a good reaction time can allow him to brake promptly if a traffic light suddenly turns red. Many factors affect reaction times: age, gender, fitness, fatigue, distraction, alcohol, personality type, and type of stimulus.

In the study of this topic it is important to recognize the difference between reaction and reflex. Reflexes are in fact involuntary, used to protect the body and are faster than reactions. They act to help restore the body to its normal functional stability. A reaction is the result of a complex brain action that by processing more information controls multiple muscles simultaneously to achieve the goal. The information flow model in vertebrates can be represented as in Figure 1

Figure 1 The image shows the different flow of information in the case of reflex and reaction. In reflexes the brain is not involved.

Sensory neurones convert a stimulus into an electrochemical signal, which travels through one or more neurones of the central nervous system, and hence motor neurones. Generally, motor neurones cause contraction of a muscle or gland to secrete a substance. Reactions involving only the receptor, spinal cord, and effector are faster than those involving processing in the brain and represent reflexes such as withdrawing a hand from a hot stove. In the case of a reaction, there is always information processing by the brain.

The reaction time can be improved and in many sports part of the training is now dedicated to this important aspect. In athletics, the ability to respond to the auditory stimulus of the gunshot can mean valuable milliseconds in a 60 or 100 metre race. In boxing a shorter reaction time can avoid a punch and in tennis it can determine the ability to return a serve.

There are several training methods that can be used to improve one’s reaction ability. For running, for example, it is advisable to prefer uneven surfaces to a treadmill to get the body used to responding quickly to different surfaces.

OptoJump enables performing plyometric tests such as the drop Jump: in this case it is possible to evaluate the ability of the body to react to a physical stimulus represented by dropping from a variable height.

Witty SEM on the other hand enables performing many exercises that help improve reaction times such as changes in direction following a stimulus. The system's modularity allows defining specific tests according to the motor activity to be improved. For example, the subject may be required to follow a specific symbol (such as the green number 1) from among several symbols for a duration of 20 tests. The system will simultaneously display a different symbol on each semaphore; only by standing in front of the semaphore with the green number 1 will the system record the pulse and display the performance time on the timer (or Witty TAB). After 20 tests, the exercise is finished and the total and partial time are displayed on the timer, which are extremely useful for evaluating the athlete's performance.