In this study, the effects of functional resistance training organized at home with a small number of equipment and body weight, and preventive and corrective exercises on strength, muscular imbalance, lean body mass and fat percentage, and aerobic capacity, without field training during the pandemic period, were investigated.
There are periods when football players or football referees stay away from the field for various reasons such as injury, penalty, quality of the league, climate or pandemic. Such situations are important for athlete performance. Because the longer this period, the lower the performance due to detraining. Researchers have found that detraining improves muscle peak power generation, muscle size and muscle neural drive and aerobic capacity at maximal muscle strength was found to be associated with a decrease in physiological, muscle function, such as a decrease [34, 35, 36, 37, 38, 39]. In such a case, when the athlete returns to the field, his performance decreases and the risk of injury increases at the same time.
Similarly, Maciejczyk et al. found that high body mass, ie high body fat or high lean body mass, decreased MaxVO2 [40]. Dominski et al. reported that reaction times were positively correlated with body fat [41]. Similarly, Violanti et al. found a positive correlation between fat percentage and the time it took to run a 2.4 km run [42]. Especially considering the pandemic as a period when everyone in the society has to stay at home, S Bhutani et al. [43] found that weight gain and body mass index increased during the pandemic period. Researchers have shown that during the English Premier League, field judges covered a total distance of 11,770 ± 808 m in high speed running (> 19.8 km·h-1) and sprinted at a speed of over 25.2 [44]. In the two top Danish leagues, the field referees made 1269 activity changes per match [45] and in the first part of the Italian championship, the field referee was found to run back and sideways 13.2% of the match time [46]. Although assistant referees are characterized by short, intense forward and side runs interspersed with long, low activity periods [47], field officials spend more time walking, jogging and sprinting than assistant referees. In addition, it was observed that the referees working in the upper categories were more fit than the referees in the lower categories [47, 48]. In this study, we can say that thanks to this training program, the athletes managed to stay fit.
When the jumping performances of the participants were compared before and after the exercise, an improvement was found in all parameters. One-step jump, explosive strength and three-step forward jump can be defined as continuity in explosive strength. The fact that the participants pushed their body weights up repeatedly in “squat”, “jump squat”, “squat to jump squat”, “alternative lunge” exercises and the application of plyometric exercises repeated for weeks on the transverse plane such as “touch to ground” may have created this result. It can be thought that the minimization of the performance decline in "doggy doggy" running, which is highly related to the muscular strength and endurance skills of the participants, is due to the effects of the same exercises. Moreover, since the three-step cross-jump also includes a partial deflection, its relationship with diverting performance can be investigated by future researchers.
It can be thought that when working with functional resistance exercises only without field training for a long time and entering the maximal aerobic power test, higher strains will occur than in the field training period. Therefore, independent of the relative and absolute MaxVO2 values, it can be expected that the RPE values at the end of the test will be higher than the period before the field training was stopped. However, as seen in this study, RPE values remained stable or slightly decreased. This may be an effect of strength, continuity in strength, mobility and stability, which are thought to be increased due to functional strength exercises and injury preventative exercises. Beyond this stamina, it can also be partially defined as "stamina".
In the Yo-Yo R1 and R2 tests, there are 4 high-intensity 180-degree turns, 9 accelerations, and 4 deceleration, which is a violent turn, in a 180-meter section. In addition to these, there are 4 low-intensity decelerations with no return, which we can also define as “stopping”. The "doggy doggy" run with a "set" distance of 180 meters, which is used as a test in this study, includes 6 high-intensity accelerations, 5 high-intensity decelerations, and 5 high-intensity 180-degree turns. Compared to the Yo-Yo R1 and R2 tests, it contains much higher mechanical loads. For this reason, “doggy doggy” is an example of high-intensity, intermittent, shuttle run that requires very advanced muscular endurance. It is argued that even when the training volume is reduced by 60–90%, without allowing the formation of detraining conditions, the obtained adaptations can be maintained for a while [28, 29, 30, 31, 32, 33, 49, 50]. In fact, some studies show that there is no regression in football-specific skills even under 1 week of complete rest [51]. It is very difficult to develop and maintain high-intensity, intermittent, shuttle-running performance such as "doggy doggy", which requires advanced muscular endurance, without "self-specific exercise". Although universal studies do not report football-specific performance decline in short-term detraining conditions [51], it is difficult to speculate that the performance of "shuttle running"-like or related runs in many sports branches will not be affected if field training is not performed for a long period of time such as 2 months. However, this study showed that highly trained top-class referees maintained this performance significantly with "functional resistance exercises" they did only at home and "without field training for 2 months". The key point here is thought to be the movement choices, training design and developmental periodization applied in the study. Movements progressed from easy to hard, contraction cycle from concentric/eccentric balanced position to eccentric dominant position, training duration and weekly training frequency from low to high. The metabolic conditioning effect, which was not the main goal but was indirectly achieved, progressed from low to high. The lower body/upper body volumetric balance has reached a dominant position in the progressive phases. Although the lower extremity seems to be dominant in the last phases, the overall volume of the upper extremity continued to increase when all phases were taken into account. On the other hand, AMRAP is universally planned over 20 minutes with a combination of 3 different modes of exercise. However, since running mode cannot be used at home, a harmony was created with only resistance exercises and a 30-minute uninterrupted load level was reached with a systematically increasing design. Referees 4 moves in the first practice in the first phase of the cycle, without time pressure. They started with a total of 160 repetitions, which was standard for everyone, resting as they wished. At the end of the process, in the 40th training in the 9th phase, they reached the number of repetitions varying between 380 and 446 per person against time pressure with 7 movements with a very high difficulty level. Again, the average subjective strain values of the same referees in the 40th training are 7.2. From this point of view, it refers to the intensities of 9 METs and above. In the universally accepted way, exercises of 9 MET and above are expressed as sustainable for 10–30 minutes. In other words, the referees, especially in the last phases, loaded for 24–30 minutes, close to the limits they could withstand. Continuing a load of this intensity for 24–30 minutes may have created a stimulus supporting the anaerobic threshold development criteria for the cardiovascular system. The constantly fluctuating heart rate with 5–7 exercises and their transition to each other may have triggered the development of aerobic power in the HIIT nature. Accordingly, the decline in the aerobic power level was kept to a minimum and an improvement was achieved in the “doggy-doggy” run, which can be considered as a harmony of anaerobic power and capacity.
An increase in resting lactate concentrations was observed after the participants took a break from field training. It is not possible to talk about the accumulated fatigue of the participants because the program is clear and the same for everyone. The test and training setup was carried out at the same hours, in the same fields and in the same flow as in the previous period of field training. Theoretical training and perhaps exams that continue in the same period as the tests may have an effect on the organism, but it is impossible to prove this at the moment. On the other hand, it can be considered as an effect of the nutrition program they developed during the period when they were trained only through functional resistance exercises. In this period, they were included in the nutrition process that was free from simple carbohydrates, did not include processed foods, and mostly consisted of vegetables, some fruits, meat, fish, poultry meat, raw grain products, a small amount of dairy products, some seeds and kernels. Afterwards, it was observed that the participants consumed them in the open buffet system with pasta, desserts and acidic beverages. However, it is almost impossible to relate it as it is not recorded. On the other hand, the partial improvement observed in the lean body weight of the participants may have slightly increased the resting lactate concentration, but it is doubtful that it would have an effect at this level.