The influence of muscle soreness on the speed of performing a motor reaction speed task in football goalkeepers during a training camp

Aim: To investigate the influence of muscle soreness on the speed of performing a motor reaction speed task in football goalkeepers. Methods: Twenty-four young healthy football goalkeepers, aged 1618 years old (average 16.7 ±0.67 year), with an average body height of 175.6 ±5.4 cm and body weight of 65 ±5 kg, participated in a study conducted during a 6-day training camp. The first day, referred to as day 0, was intended for initial tests and the following 5 days, referred to as days 15, consisted of training. On day 0, before the training period, anthropometric parameters such as weight and height were measured, subjects were questioned to determine the rate of perceived exertion (RPE) and perceived psychophysical readiness (PPR), a speed test with motor reaction choice (ST) was performed using a Smart Speed System and areas with muscle soreness (MS) were recorded by means of a computer tablet with the Navigate Pain application. The goalkeepers participated in two training sessions on each of the following 5 days. Before each training session, the same speed test was performed. Lap times for 5 m and 15 m were recorded. After the second training session each day, the participants drew digital pain maps using a computer tablet, marking separate areas of the body where they felt muscle soreness. These data were consolidated and the total area was analyzed to investigate if, throughout the training, there were any changes to the size of the area that was indicated as having MS. A categorization of body areas was also made to determine areas where muscle soreness was most frequently indicated. Each training session was monitored with heart rate (HR) registration and each goalkeeper determined his fatigue (RPE) and readiness to exercise (PPR) on a 110-point scale. Results: Twenty-three out of twenty-four (98.5%) goalkeepers indicated that they had MS during the study. Day 2 showed the highest incidence rate with 21 participants indicating that they felt MS. The biggest area of MS was also indicated on day 2, yet statistical analysis did not show significant differences in the area of MS between the training days. MS was most often indicated in the upper leg, i.e. the thighs. The average time of the first 5 m was 1.3 [s] (SD = 0.09), ranging from 1.28 [s] to 1.33 [s], while the average time of the following 10 m was 2.07 [s] (SD = 0.18), ranging from 2.04 to 2.1 [s]. The average total speed test time equaled 3.37 [s] (SD = 0.21), ranging from 3.33 to 3.38. Statistical analysis did not show significant differences in any of the results between the training days. Conclusions: Most of the goalkeepers felt muscle soreness as an effect of specific goalkeeper training, measured by indicating painful zones on digital pain drawings. In this study, where muscle soreness was induced by technical-tactical specific goalkeeper training, no significant changes were noticed in the speed of performing a motor speed test with reaction choice or on the area of muscle soreness indicated on digital pain drawings, although almost every goalkeeper had a large area of muscle soreness. Discussion: Many studies show that delayed onset muscle soreness (DOMS) causes a decrease in strength, power, range of motion and speed. However, in many cases, these studies are designed to induce high intensity DOMS and then conduct isolated motor skill tests. In this study the objective was not to induce high intensity DOMS but to investigate the effect of muscle pain, which is present naturally during training processes, and then assess its effect on a speed test which reflects real game situations – with a component of reaction choice and change of movement and direction. Approaching the subject from a different viewpoint allows us to see that the reliable assessment of the psychophysical state of players, made by observing their actions on the pitch or even using photocells to measure motion speed, is difficult without an insight into the parameters of soreness that players experience. These can be monitored, for example, through digital pain mapping software.