A Comprehensive Analysis of Strength and Power

Introduction

Soccer is a team sport characterized by prolonged high-intensity and intermittent exercise that is also interspersed with short bouts of recovery since players change movements task every moment during a soccer match (Banda et al., 2019). Soccer involves various activities such as changes of direction, sprint, dribbling, tackling, ball kicking as well as heading. All these activities are in inevitable need of force production by the muscles of the lower and upper limbs (Nunez et al, 2019). Soccer players thus have the necessity to have a well-developed physical conditioning considering strength, power and speed to perform highly during soccer matches (Garcia et al., 2018). Various strength and power training modalities have been adopted in the past in the efforts to achieve improvements in performance (Popowczak et al., 2019). Various studies have assessed the effects of training induced performance on players. Researchers have noted that soccer engages all the body muscles. This implies the significance of strength training for soccer players (Nunez et al., 2019). Soccer entails constant motion and alternation between steady state cardio to top speed. Strength training has been noted to be useful when they engage activities such as one-legged squats, leg presses as well as hamstring curls (Lockie et al., 2018). The upper body strength training similarly offers soccer players various benefits (Loturco et al., 2020). Researchers have worked to demonstrate a clear relationship between absolute and relative strength training in sprint jump performance in soccer players and its clear that absolute strength training enhances performance in soccer.

The significance of short sprint performance for soccer player is undoubted (Gonzaloz et al., 2019). Various studies have investigated the relationship between strength and sprint performances and have concluded that stronger athletes perform better perform better during sprints performances and soccer games (Hammami et al., 2019, Nunez et al., 2019, Beato et al 2016, Lotorco et al, 2020, Madruga-perera, 2020)). A detailed understanding of the strength training on linear speed and jump performance forms the basis of the formulation of the following literature review which assess the importance of Strength Training on Linear Speed and Jump Performance in Soccer Players.

Aim of this study

This literature review intends to assess the impacts of strength training on linear speed and jump performance in soccer players. In addition, this research will identify the most relevant, accurate and evidence-based conclusions on the effects of strength training on linear speed and jump performance in soccer players. This research will also analyze the specific categories of effects of the training which would either positively or negatively impact on the performance of soccer

players. Undoubtedly, various researchers have covered the topic on the effects of training on the overall performance of soccer players. However, this review aims to dig further into details of specific trainings for soccer players such as the strength training on linear speed and jump performance

Search strategy

For the following literature review, databases such as Google scholar, CINHAL and Cochrane databases were used (Ali & Usman, 2018). Keywords were used in searching the databases for relevant studies. These keywords used were inclusive of ‘strength training’- OR, ‘resistance training’-AND, ‘soccer’’-AND, ‘speed’-OR, ‘jump’-OR ‘sprint’. (Aveyard & Bradbury, 2021). The Boolean operators used the conjunctions to combine the keywords for the research. This led to a more focused and productive results for the literature review. Also, the Boolean operators helped save time while doing away with unsuitable and inappropriate studies. A total of 212 results were obtained from the Medline search while 253 results were for the sport search. Full-text and peer reviewed articles, journals or books were eligible for inclusion in the review. Only studies that were published in English were considered for the study. Exclusion criteria precluded magazines, reports as well as newspapers. Papers that were published in other languages apart from English were excluded from the study. The search had no geographical limitation thus study was conducted based on information across the globe that clearly highlights that Strength training can improve power ability in soccer players. Such power abilities include the 10, 30, and 0m sprints as well as long jump and triple hop tests (Banda et al., 2019). Madruga et al (2019) highlights the effects of training on children aged 8 and 9 years using jumps, squats and sprint exercise for a period of 26 weeks, his studies proved that there was improvement in hip flexibility hence performance quality in soccer players Critiquing tool Critical appraisal is described as a process by which research papers have been evaluated to asses for its reliability, validity and relevance. Critiquing tools have been identified in this research in order to appraise chosen literature (Larsen et al, 2019). A special tool known as Critical appraisal skill program (CASP) was used in critiquing this research. New research requires this tool in assessing the reliability and validity of data. To avoid irrelevancy in data used for research were evaluated using the same tool.

This tool has proven to be useful when evaluating research papers. However there is no standard tool that has been recommended for evaluating research. The choice of critique tools depends on the type of research design as well as the nature of data collected (Long et al, 2020). There have been similarities in the papers used for research which has proven the relevancy of this research. The appendix results show that this literature has been comprehensively structured hence accuracy and quality has been assured (Claydon et al, 2015). Different methodologies and data presentation techniques have explained the different results in these studies. However, there are various gaps that have been identified by this paper which were centered on publication dates, geographical location and language (Maurao et al, 2017). In United Kingdom there is limited research on the research topic as opposed to other states, hence only limited information was available. Only English articles were used and outdated information was not used which explains the gap in research as valuable information may have been missed out hence biasness.

Results

From the combined searches of all the databases, references lists and bibliographies, 465 studies were found. 300 were extracted due to duplication and165 studies were read. 145 more studies were removed since they did not pass the inclusion criteria. The full text articles thus retrieved were 20 in total where another 12 were removed as they did not completely meet the entire inclusion criteria. Eight studies were thus considered as had met the eligibility criteria as the main research studies and were considered as relevant to the topic of the study based on their abstracts, titles and their contexts.

Discussion

The main aim of this review is to determine the Effects of Strength Training on Linear Speed and Jump Performance in Soccer Players. This study has been synthesised data from different research and making comparisons and overall, it was determined that strength training increase the linear speed and improves jump performances in soccer players.

Jump performances

In a study conducted by Kotzamanidis and his associates in 2005 to investigate the effect of combined high intensity strength and speed training programs on the running and jumping ability of soccer players, a total of 35 individuals were divided into three groups for the training sessions (Kotzamanidis et al, 2005). The first group performed combined resistance and speed training the second group performed resistance training without speed training while the third group was used as a control group. Squat jump, drop jump and countermovement jumps were used as tests for evaluation. The two experimental groups showed significant improvements in the tests exercised on them hence combined resistance and running-speed program improves performance than conventional resistance training in soccer players.

Chelly and his colleagues investigated the effects of back squat training program on leg power and jump performances in junior soccer players. A total of 22 male soccer players participated in this study and were divided into 2 groups. Each group was composed of 11 players aged 17 year. The training sessions were twice a week for a period of 2 months countermovement jumps and squat jumps were performances were assessed (Chelly et al, 2009). Back half squats were used to determine the 1-repeatition maximum. The resistance training group showed improvements in jump performances after the strength training program. These dynamic constant external resistances exercise are recommended as training exercises for junior soccer players.

Hammami et al (2019), indicated that combining different modalities such as the vertical and horizontal jumps with other training programs is absolutely more beneficial than engaging only a single training modality on the soccer players in efforts to improve the s the jump performances of soccer players. A total of 30 players aged 15 were included in the study. Neural adaptations that are linked with strength training is associated with improvement in maximal voluntary contraction, intramuscular coordination, stretch flexibility as well as changes in the leg muscle activation that all contribute to an improvement to the jump as well as the speed performance of soccer players. Hammami et al notes that strength exercise can also cause acute responses (2019). Training should meet the biomechanical as well as the physiological demands of soccer playing. Appropriate strength training alongside multidirectional exercises provides benefits to power

Sprint performance

Jlid et al, research on effects of 10 months speed, strength and functionality on adolescent soccer players aimed to compare the impacts of plyometric and sprint in soccer performance. Longitudinal design was used in this study where 48 males were randomly recruited to undertake this training (Jlid et al, 2020). These athletes were divided into four groups and analysis of data was done using variance with repeated measurements. Hedges were used in calculating effect sizes in the control and experimental groups. After these 10 months of training, there was significant superior performances increase in these soccer players. Sprint training showed greater improvements in flexibility and hence traditional training is recommended to increases strength and speed in soccer In a similar study as Jlid’s, Christou and his colleagues investigated the effects of resistance training on physical capacities of male adolescent soccer players in 2006. A total of 18 soccer players were used in this resistance training program. 8 players who had a similar age were used as a control group (Christou et al, 2006). The other players followed a 5 times soccer training schedule a week. The program included 10 exercises with a repetition of 2-3 sets of 8-15with a load of 55-80% of 1 repetition maximum. After 16 weeks of training, the shuttle running speed and performance in soccer had improved as compared to the control group. Soccer training improves the normal growth and maximum strength in lower limbs, however additional resistance training improves more maximal strength in the upper and lower body. Hence overall development in the physical capacities of young soccer players depends on a combination of soccer and resistance training.

The study by González-Badillo et al (2015) aimed at analyzing the effects if velocity based resistance training on young soccer players of different age groups. 44 elite youth soccer players from 3 different teams were used in this study. Those who were aged 16 and bellow were 17 players, the under 18 team were 16 players while the under 21 composed 11 players who were used as control experiments for this study (González-Badillo et al, 2015). The first two groups performed maximum velocity RT programs for a period of 26 weeks while the last group did not perform resistance training but performed 20-m and countermovement jumps runs like the other two groups. At the end of the 26 weeks the under 16 and under 18 years showed significant improvement in performance and sprint speed. Hence velocity based resistance training with moderate loads per set improves physical performance in young soccer players. Parejo-Blanco et al (2016) compared the effects of two resistance training programs which differing velocity repetition loss on athletic performance. 22 young males were randomly selected and assigned 20 and 40% velocity loss with 12 and 10 participants respectively (Parejo-Blanco et al 2016). An 8-week velocity based program with squat exercised was administered to the two groups. The post and pre-training assessment included activities like vastus lateralis, magnetic resonance imaging and sprint running. Both groups showed an increase in mean fiber cross sectional area and the quadriceps muscle volume. In configuration of resistance exercise stimulus pronounced repetition velocity loss is an important factor as it influences functional and structural neuromuscular adaptations. In a different study, Rodríguez-Rosell et al (2016) examined the effects of high-speed strength training on physical performance of soccer players aged 18 and below. A total of 36 male players were used in the study. In the scope of their study, the researchers conducted strength training programs nonconsecutive days for a period of six weeks. The training program entailed strength training such as free-weight full squats alongside speed and changes of direction and each session of the training lasted for an approximately minima of thirty five minutes (Rosell et al., 2016). From the study, the results indicated significant and practically major improvements in strength and speed performance by the soccer players.

Future Developments

These studies have ranged from 2005 -2020 a period of 5 years to assess the effect of strength training programs on soccer performance of young players. Development in youth football is the fundamental objective any soccer governing body. Through strength training, these young boys and girls have been equipped with skills that enhance that performance in soccer players (Badillo et al, 2005). The game has changed over the years from how the trainings are done and how it is played. Since the studies began, rules have changed over time with introduction of new training techniques that have proven to be effective in enhancing performance. Gradually, since the implementation of strength straining since the studies began, there has been improvement in terms of speed and strength in this soccer players (Pulido et al 2020). The impact is more on junior players who are still undergoing growth developments as compared to adult players. In the past, coaches focused their coaching interventions such as weight training and plyometric training on technical and tactical aspects, however in the modern world work on multidisciplinary environment where players are supported, physically, technically, tactically and psychologically (Marques et al, 2006). High intensity strength training that involves traditional exercise aimed at enhancing resistance has been used as training intervention methods for modern strength training. The effect of training interventions on soccer athletes to improve their performance in future has been discussed by a study conducted by Pulido et al in 2020. The results showed that there have been significant changes in soccer due to the game strategy and training technique competencies from effective coaching intentions (Pulido et al 2020). There has been adoption of different training surfaces

to help achieve improvement in performance in tasks such as jumping and sprinting. Strength training in adolescent players has proven to an effective way of enhancing the jump height as well as the speed in soccer players (Bahtra et al, 2020). Soccer training at a young age is important as it enhances an individual’s skills as they grow older.

Practical application

This study is has reveled important facts that may be applied in future in an effort to improve soccer. The physiological requirements for soccer are very complex which is consequence of the nature of exercise patterns (Muracki et al, 2019). Aerobic and anaerobic energy systems have greatly been developed by intermitted exercises. The training programs for these players in future will need to include activities and exercises with specified prescriptions. Players will require strong and flexible muscles to improve soccer performance. Effective ways that that develop the strength and flexibility of the limbs needs to be systematically planned and performed during these training sessions. (Morin et al, 2017) The exercise needs to be muilti-dimentions as it would include different fitness components. Multiple types of physical training would need training plans. Frameworks that govern inclusion sessions have been more focused in physics. Acute and chronic physical training require detailed planning which will be efficient in delivery of training programs. This will help to improve performance in soccer. Published information soccer and training will characterize training load patterns in premier league soccer games.

There are three major fitness components that are required in soccer while training. These include endurance, agility and speed. The squats and plyometrics have been applied in soccer training to enhance speed in football (Pino-Ortega et al, 2021). One needs speed to be able to move quickly and powerfully which gives players a competitive advantage over others. Gaining possession of the ball and sprinting away requires speed which is a very important skill in football. Cone drills and power band drills have been used to enhance agility (Morin et al 2017). The use of these methods in training has enabled soccer players to move and change direction quickly while still in control of the ball. While there is need to focus on soccer skills by players and coaches, the importance of increasing physical capabilities should not be ignored.

Conclusion

Strength training is crucial to the improvement of the linear speed as well as the jump performance of soccer players. Soccer as an intermittent and very involving activity involves short sprints as well as frequent change of direction requires maximal strength. This paper has reviewed the effects that strength training thus has on the linear speed as well as the jump performances of soccer players. After identification of eight studies for review, the paper have been analyzed and detailed for various findings. The literature review has noted that strength training significantly improves the linear speed as well as the horizontal and vertical jump performances of soccer players. Performance in soccer relies upon a variety of skills and interaction for different players. Physical capabilities must be enhance in a person to enhance success. Since the past decade, the focus on soccer related activities has shifted from aerobic to anaerobic demands. Studies from the recent past suggest that Strength Training on Linear Speed and Jump increases performance in soccer. This review synthesizes the past research on the topic of discussion, identify the limitations in the methodology used and outline the practical application and specific training recommendations.

From the literature review, it has also been noted that the strength training improves the endurance and agility and endurance of soccer players besides improving muscle strength. Most of the studies have concluded that it is crucial to incorporate strength training in soccer training programs. This literature review is of utmost significance to understanding the effect that strength training has on the linear speed and the jump performance of soccer players. The ability to sprint in soccer is regulated by complex interactions between multiple factors. However, further research is still needed to better understand the effects. A lot of questions have remained regarding this topic of study and hence reason to believe that there exists gap between science and the best practices regarding strength and linear speed development. Conditioning programs should be focused on filling the gap between the positional demands of play and the actual individual capacity. Future studies should be more focused on progression models and conditioning programs from scientific strength and linear speed training literature.

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