Combination of plyometric and ladder drill: Its impact on improving speed, agility, and leg muscle power in badminton

Badminton is the fastest racquet sport in the world, so training methods are needed that can increase speed, agility, and leg muscle power. This research aims to determine the impact of a combination of plyometric and ladder drill training methods in increasing leg muscle speed, agility, and power. This research is a quantitative study with a quasi-experimental type and uses a nonequivalent control group design. Purposive sampling technique was used from 36 trained male students aged 12-16 years old from junior high school 1 to 36 years old badminton students. The research subjects were divided into three groups, namely TR (tuck jump-double leg run), SH (squat jump-double leg hop)


INTRODUCTION
Badminton is one of the sports achievements that is the pride of Indonesia because Indonesia's badminton achievements worldwide are Jurnal SPORTIF: Jurnal Penelitian Pembelajaran, 9 (2) 2023| 290-309 ISSN : 2477 (Online)  ISSN : 2548-7833 (Print) 291 quite encouraging (Maksum & Indahwati, 2023). It has become Indonesia's leading sport in obtaining championship titles in multi-event events such as the Olympics (Supriyanto et al., 2022). However, in the last decade, the inconsistency of Indonesian badminton players has become increasingly apparent, which has resulted in a decrease in the performance and achievement of athletes (Purwanti, 2023). We know that the highest sports achievements cannot be achieved instantly but require a long and complex process (Asri et al., 2021;Winarni et al., 2021). Many factors affect the achievement of sports achievements, including physical condition, mastery of techniques and tactics, mental factors, and strategies (Alim, 2018).
Physical conditions can be defined as components that become a unified whole, and each component cannot be separated, both in the context of maintaining and improving the components of the physical condition (Sidik et al., 2019). In addition, the physical condition has an essential role because it is the foundation for training activities (Piyana et al., 2020;Santika et al., 2020). However, to significantly improve physical condition, attention must be paid to the components of the dominant physical condition and the characteristics of the sport (Subarkah, 2020).
Badminton is one of the most popular sports in the world (Phomsoupha & Laffaye, 2015) and is the fastest racquet sport in the world (Stovba et al., 2020) because the speed of the shuttlecock can reach more than 250 km/hour in matches at the elite level (Malwanage et al., 2022).
Thus, badminton is a sport that requires speed in changing directions, explosive movements, lots of reflex movements, and good motor skills (Sholeh et al., 2020). Thus, speed, agility, and leg muscle power are essential and needed components in badminton. Experts note that speed and power are the determining factors for badminton athletes (Karatnyk et al., 2016). In addition, agility is also an essential component in badminton (Frederick et al., 2014). Knowing that speed, agility, and leg muscle power are essential in badminton show that training methods are needed to improve these three components. In badminton, explosive jumping movements and short-distance sprints are the most dominant elements (Liu & Wang, 2023). Agility in footwork is also vital for badminton athletes to win in competition (Jianping, 2021). Therefore, badminton has training methods that can be used to increase speed, agility, and leg muscle power, including plyometrics and ladder drills. Research has stated that plyometrics is a training method to increase leg muscle speed, agility, and power (Chandra et al., 2023), likewise with the ladder drill, which is more dominant in increasing the agility and speed components of badminton athletes (Anggraeni et al., 2019;Chandrakumar & Ramesh, 2015).
This type of plyometric training involves repeated rapid stretching and muscle contraction to increase power. It is also called an "explosivereactive" form of strength training (Hariyanto et al., 2022). Plyometric training can increase speed, agility, and vertical jump (leg muscle power) (Poomsalood & Pakulanon, 2015). In this study, the plyometric training models used were tuck jumps and squat jumps, which are popular variations of these exercises in increasing leg muscle strength and power (Hansen & Kennelly, 2017).
Various variations of ladder drill exercises are known to significantly increase the speed and agility components (Alviana et al., 2020;Anggraeni et al., 2019;Nawir & Jamaluddin, 2020). The ladder drill has many variations of the exercise, but this study uses variations of the double-leg run and double-leg hop. The double leg run has another name, namely fast feet or quick feet, which has the characteristic of the movement, namely that in one box, the ladder will be entered by both legs alternately between one leg and the other with fast movements (such as running movements) (Mbabho, 2021

293
The plyometric and ladder drill training methods have many positive impacts on athletes. However, when this research was made, researchers had yet to find a research topic that revealed the effect of a combination of plyometric and ladder drill exercises on speed, agility, and leg muscle power, especially in badminton athletes. Thus, this study aims to reveal the impact of a combination of plyometric and ladder drill exercises on badminton players' speed, agility, and leg muscle power so that this research will be able to contribute to developing the dimensions of sports coaching science that sports practitioners can implement in the training process. The subjects of this study were male badminton extracurricular students at SMP Negeri 1 Jogoroto, Jombang, who were trained and aged 12-16 years.

Research design
This research is quantitative research with a quasi-experimental research type. This type of research is known as the development of a true experiment, which has a control group. However, the control group cannot fully function to control various external variables that can affect experimental research (Sugiyono, 2017). Quasi-experimental research was applied because the researcher did not have full control over the research subjects on independent variables, such as rest time and daily food intake for each research subject. Meanwhile, the research design used was a nonequivalent control group design. This design provides treatment to the experimental group and provides a control group or other groups to serve Muhammad Labib Siena Ar Rasyid, Oce Wiriawan, Gigih Siantoro, Donny Ardy Kusuma, Afif Rusdiawan Combination of plyometric and ladder drill: Its impact on improving speed, agility, and leg muscle power in badminton 294 as a comparison (Sugiyono, 2022). The following is a picture of the research design shown below.

Research treatment
All 36 research subjects started the research phase with a pretest, and the pretest results were used as a reference for grouping with matched subject ordinal pairing (Gumanti et al., 2016). After grouping, the research subjects performed the treatment according to their respective groups.
Treatment is carried out with a training frequency of three days a week which is carried out for six weeks, with a total of 18 meetings (Guo et al., 2021). After the last meeting for treatment, the final stage of the research was carried out, namely the posttest. The training program compiled for the group that was given the combined treatment of plyometric and ladder drill exercises (TR and SH groups) can be seen in Table 1. was used as the control group in this study because they were not given plyometric treatment and ladder drills.

Data analysis
Data analysis techniques used were descriptive statistics, data requirements tests (normality and homogeneity tests), and inferential tests (paired sample t-test, Manova, and post hoc LSD). The data analysis process in this study used Microsoft Excel and SPSS applications.

RESULT
The research results obtained the characteristics of research subjects regarding age, height, and weight (N = 36). Thus, descriptive statistical analysis data are presented regarding the characteristics of research subjects using the mean and standard deviation (SD) values in Table 2 below.

297
The results of the Kolmogorov-Smirnov normality test presented in Table 3 show that all research variable data are normally distributed (p>0.05). The homogeneity test used next is Levene's Test homogeneity test which is presented in Table 4 below.    The results of the Manova test presented in Table 6 above show that the three groups have significant differences simultaneously in the variables of speed, agility, and leg muscle power (p<0.05).
After conducting the manova test, it showed that there were differences between the three groups in speed, agility, and leg muscle power. The results of the LSD post hoc test are presented in Table 7 below. The results showed that there was a significant difference between the group given the treatment (Group TR and SH) and the conventional training group (Group C) (P<0.05). However, there was no significant difference between the TR and SH groups in increasing speed, agility, and leg muscle power (P>0.05).

DISCUSSION
This study aims to determine the effect of a combination of plyometric and ladder drill exercises in increasing speed, agility, and leg muscle power.
The study results show that the combination of plyometric exercises and ladder drills (Group TR and SH) can increase speed, agility, and leg muscle power in badminton better than conventional exercises (Group C). The results of the paired sample t-test showed that the group that was given the  (Irawan, 2017). Adolescent badminton athletes also experience increased agility after being given plyometric training interventions (Ozmen & Aydoğmuş, 2017). Agility can occur due to explosive force (Kosni et al., 2022) and depends on muscle strength, speed, coordination, and dynamic balance (Heang et al., 2012). In addition, ladder drills can also be used to increase agility and speed (Dhanaraj, 2014). The ladder drill exercise uses a fitness tool in the form of a ladder that is placed on a floor/ground surface, where a person will run, jump, and jump by moving his feet quickly on the tool to develop the speed and agility of the person using it (Kusuma & Kardiawan, 2017). Another study revealed a significant increase in agility in badminton players after the intervention of ladder drill exercises (Chandrakumar & Ramesh, 2015).

Muhammad Labib Siena Ar Rasyid, Oce Wiriawan, Gigih Siantoro, Donny Ardy Kusuma, Afif Rusdiawan
Combination of plyometric and ladder drill: Its impact on improving speed, agility, and leg muscle power in badminton 300 In general, plyometric exercises have been implemented in all sports to help increase muscle strength and power, where plyometric exercises consist of eccentric movements followed by concentric contractions of the same muscle group (Irawan, 2017). Plyometrics are designed to improve jumping performance abilities which are used to increase power output and explosiveness by training the muscles to work more in a short time (Bhosale et al., 2020). This plyometric training method increases strength, acceleration, and power (Váczi et al., 2011). According to research on 90 badminton athletes, there is an increase in the achievement of faster sprint times and better jumping abilities (Panda et al., 2022). The ability to jump in badminton is closely related to leg muscle power (Wea & Samri, 2022).
Plyometrics also significantly improves jumping smash skills in badminton games (Wea & Samri, 2022). Even plyometric training is a training method that can improve forehand smashes in badminton (Sholeh et al., 2020). Not only plyometric exercises, ladder drill exercises also can significantly increase the leg muscle power component (Kusuma & Kardiawan, 2017). In addition, ladder drill exercises are effective and significant in developing speed, agility, and power (Sethu, 2014).
The group that did conventional exercises or the group that was not given treatment (group C) could increase speed, agility, and leg muscle power in badminton players because badminton is a sport that has benefits in increasing physical fitness in adolescents, including: increasing muscle endurance, strength, power, flexibility, and cardiorespiratory fitness The Manova test results showed significant differences between the three groups' increasing speed, agility, and leg muscle power in badminton players (p<0.05). However, the results of the post hoc test showed that there was a significant difference between the group given the combination treatment of plyometric and ladder drill exercises (Group TR and SH) and Jurnal SPORTIF: Jurnal Penelitian Pembelajaran,9 (2)  301 the conventional training group (Group C) (p<0.05). If the two groups that were given treatment were compared to each other, namely between the TR and SH groups, they showed no significant difference in increasing speed, agility, and leg muscle power in badminton players. According to previous research, the most effective plyometric training program can be carried out routinely, lasting 6 to 8 weeks (Fernandez-Fernandez et al., 2016;Filipas et al., 2023;Guo et al., 2021;Lu et al., 2022;Ozbar et al., 2014), as well as the ladder drill training program. This research provides results and novelty in the form of a positive impact from a combination of plyometric and ladder drill exercises on badminton players in increasing speed, agility, and leg muscle power. As we know that badminton is one of the most popular sports in the world (Phomsoupha & Laffaye, 2015) and is the fastest racquet sport in the world (Stovba et al., 2020) because the speed of the shuttlecock can reach more than 250 km/hour in matches at the elite level (Malwanage et al., 2022).
This is due to the demands of modern sports, which require athletes to be faster and stronger (Polglaze & Hoppe, 2019), including in badminton.

Muhammad Labib Siena Ar Rasyid, Oce Wiriawan, Gigih Siantoro, Donny Ardy Kusuma, Afif Rusdiawan
Combination of plyometric and ladder drill: Its impact on improving speed, agility, and leg muscle power in badminton 302 Badminton needs speed and leg muscle power, especially when attacking (Liu & Wang, 2023). In addition, the ability of fast and accurate footwork techniques on the athlete's field must have good lower leg strength and agility (Jianping, 2021). This study's results will positively contribute to badminton sports coaching if coaches or practitioners implement them on their athletes in the training process. The limitations of this study are that the research subjects used are still not at the sub-elite or elite level, and the gender or sex of the research subjects is only male. Therefore, the recommendation for further research is to use sub-elite or elite athletes and women as research subjects. Thus, the combined plyometric and ladder training results from elite, sub-elite, amateur, and novice athletes can be compared. In addition, there will be comparisons between male and female badminton athletes. In addition, the weakness of this study is that the research subjects used were in their teens, and the number was small.
Thus, gaps for future research could use research subjects in adulthood or the golden age who are at the peak performance stage and a larger number of research subjects.

CONCLUSION
From the results of the research and discussion above, the conclusions of this study are: (1) the combination of plyometric and ladder drill exercises can increase the speed, agility, and leg muscle power, and (2) there is no significant difference between the two groups given the treatment, namely TR (tuck jump-double leg run) and SH (squat jumpdouble leg hop) in increasing speed, agility, and leg muscle power. This research implies that the combination of plyometric and ladder drill training methods can be implemented and used in the training process in badminton. So that it can increase speed, agility, and leg muscle power, which can help improve the performance of badminton athletes.