The age range (18–25 years) of the 50 soccer players who participated in the study was determined and included taking into account the possible changes in the effects of the physiological process. In the study, which investigated the acute effect of warming up with different stretching times on balance, male and female participants with an average age of about 25 years waited 26 minutes between tests of the exercises performed on the bicycle ergometer. A significant difference was found between balance scores when waiting 15 seconds between exercises instead of 45 seconds, and it was observed that waiting 45 seconds had no effect on balance( Costa et al., 2009). In our study, the waiting time after the warm-up exercises should not exceed 15 seconds. The waiting time and any changes that may occur are minimized and attention is drawn to the effects of the desired warm-up. Similar results were obtained as in the study. In a study investigating the acute effect of stretching exercises on balance and jumping, it was found that the balance performance of athletes was positively affected after 10 minutes of stretching exercises on the lower extremities(Handrakis et al., 2010). The reason for the better results with PNF-based warm-up is that the Golgi tendon organ and muscle spindle structures are affected and the reaction process to the difference, such as altered load transfer, increases, so we can see similar results with PNF-based warm-up and active warm-up applications. The reason for these similar results reduces the margin of error at the balance level (Jiang et al., 2023; Mesut Çelebi & Murat Zergeroğlu, 2017). The average margin of error of the dynamic balance data is taken into account for the balance parameters. These values play an important role in sporting activities (Castillo et al., 2022; Chen et al., 2022). Static and dynamic warm-up exercises on balance In studies investigating the effect of dynamic warm-up, the data obtained as a result of dynamic warm-up were statistically significant in the right-to-left and front-to-back deviation group compared to the static warm-up group Although there was no significance, the margin of error was found to be smaller. This situation shows that the balance is better. A similar situation can be observed with the values for active wam-up. The values of passive and general warm-up protocols were also observed in our study. It was found that the values for right and left deviation as well as anterior-posterior deviation were lower during active warm-up. This suggests that balance is better during active warm-up. In a study of 5-minute warm-up and static stretching exercises in university students, balance scores were found to be worse as a result of static stretching than in the control group. When only warm-up exercises were performed, positive differences were found in static balance scores. However, this positive difference was not significant(Behm et al., 2015). The lack of functional movement and the high total work effort measured after 5 minutes of jogging may suggest that a protocol with less than 15 minutes of warm-up time could have a greater immediate effect. However, as would be expected at other angular velocities, a longer warm-up is also shown to have a more effective acute effect. Studies have shown that dynamic stretching exercises have a positive effect on maximal strength performance (Fujisawa et al., 2014; Kafkas et al., 2018). It has been found that the warm-up protocol with neurophysiological effects such as PNF leads to higher force production.
Yamaguchi et al. investigated the effect of dynamic stretching exercises on the muscular performance of muscle movements under different weights against a concentric dynamic constant external resistance in 18 men without health problems. It was found that dynamic stretching exercises performed before the isokinetic strength test increased the gain (Yamaguchi & Ishii, 2005). In our study, dynamic warm-up was performed under active warm-up muscle movements including parameters. A similar result was obtained during active warm-up as in the study. It should be noted that the differences in our study are that there is a warm-up protocol beyond the 30-second stretches and only knee extension, i.e., quadriceps strength knee extension and flexion, hip and ankle flexion were included in the study (Fujisawa et al., 2014; Yamaguchi & Ishii, 2005). Kafkas et al. investigated the effect of different warm-up protocols on 1-max squat repetition performance in 9 male athletes who had been exercising regularly for at least 3 years. The warm-up protocols applied on different days were only 5 minutes of easy tempo running, static warm-up after 5 minutes of easy tempo running, dynamic warm-up after 5 minutes of easy tempo running, PNF warm-up after 5 minutes of easy tempo running. As a result, it was found that the dynamic warm-up led to higher results than the other warm-up protocols. When looking at the average values, it was found that the values achieved by the dynamic warm-up were the highest, followed by PNF and finally the static warm-up (Kafkas et al., 2018).
The measurements obtained are similar to those in our study as they cover the structures of the lower extremities. Since the angular velocities of the hip, knee and ankle structures in the lower extremities were measured with isokinetic forces of 60o/sec, 180o/sec and 240o/sec, it is assumed that the peak torque values produced with maximal effort are related to the maximal repetition performed. However, in our study, PNF-based warm-up was found to have more positive effects than other warm-up protocols. Another difference chosen for PNF is that the patterns were selected according to the closed kinetic chain principle. It is assumed that these patterns cover complicated behaviors such as running, stopping, kicking or ball holding in sports, which is a different result than in this study. In addition, isometric contraction is less prevalent in the warm-up parameters selected for PNF. This contributes to balance, but its main contribution is to maintain muscle contraction and make the performance of muscle contraction with neuromuscular facilitation effective (Denerel et al., 2019; Kafkas et al., 2018). There are also studies showing that static and dynamic activities have no effect on the strength performance of individuals (Papadopoulos et al., 2006; Torres-Banduc et al., 2021).
Dynamic stretching exercises have been used in studies of skills requiring strength. When we examined the research, we found that the results obtained in this work supported the data. When examining the data, it was found that the parameters of maximal strength were negatively affected by PNF and static stretching exercises, while this effect was more positive with dynamic stretching. The reason for this is that an elastic force is required for maximal strength performance. It is the rapid application of a high level of force in which the muscle or muscle group performs a concentric contraction immediately after the eccentric contraction. However, PNF and static stretching exercises reduce long-term myotatic reflex sensitivity, which has a negative effect on strength (El-Ashker et al., 2022). There are several studies that conclude that static exercise has no specific effect on an individual's balance performance (Bugnet, 2011; Chatzopoulos et al., 2015; P. B. Costa et al., 2009). There are studies that show that PNF-inclusive activities have a positive effect on an individual's balance performance (Arcanjo et al., 2022; J. Kim et al., n.d.; Leblebici et al., 2017; Pereira et al., 2012; K. C. Seo et al., 2015).
Pereira et al. had 14 people over the age of 60 perform PNF exercises three days a week for 10 weeks and found a statistically significant improvement in balance test scores (Pereira et al., 2012). Kim et al. reported that continuous PNF exercises positively improved balance ability (K. Kim et al., 2015). Seo et al. found that the type of chronic PNF exercises had a positive effect on balance performance (K. Seo et al., 2015). Jeon found in his study that PNF exercise types improve people's balance (Jeon, 2013). Madak investigated the effect of 8 weeks of PNF exercises on the performance of the Star Balance Test in elite taekwondo athletes in the form of a pre-test and a post-test and found that the athletes' balance performance improved significantly (Madak, 2020). Techniques covering muscle-specific movements were used. Hamstring, medial hip adductors, quadriceps muscles and targeted isometric contraction. the application of force and resistance applied in the opposite direction resulted in a situation where there was no movement and contraction. One of the main differences in our study is that no PNF protocol was performed on any muscle. According to the isokinetic endurance values in Table 5, the warm-up values for the hip 240O/sec (ext) were found as follows: PNF-based warm-up (89.91 ± 2.641), active warm-up (86.55 ± 3.418), passive warm-up (72.18 ± 5.292) and general warm-up (74.49 ± 6.454). When the values were analyzed, the isokinetic endurance values were higher for the PNF-based warm-up. In the study, participants were trained for 8 weeks and their isokinetic endurance was assessed before and after training. Participants who performed only isokinetic strength training showed an increase in fatigue indices (Lazarou et al., 2018). The results of this study are consistent with the findings from our study. In the other study, an increase in strength was found in modern dancers before and after the dance season. The fatigue index also increased (Martyn-Stevens et al., 2012). In soccer players, the effect of a short-term training interruption on fatigue was found to be a 5% reduction (Joo, 2016).