Using plyometrics to develop speed and power
The following article was written by our Head Coach Luke Brown as part of his Masters Degree in Advanced Sports Coaching. The aim of the article is to provide a critique of the utilisation of plyometric training and their impact on levels of performance. The article delves into the strategic application of plyometric training in enhancing athletic performance within the current strategic Long Term Athlete Development plan of British Judo. Written in 2018, we have published it on our blog aiming to contribute valuable knowledge to our judo community.
Introduction
Typically involving jumping or bounding movements, plyometrics are considered a valuable training method in achieving conversion of maximal strength into power (Baechle and Earle 2000).
Researchers believe that this increase in power is a result of the stretch-shortening cycle (Cormie et al. 2011). This involves transition from a rapid eccentric muscle contraction to a rapid concentric muscle contraction (Markovic and Mikulic, 2010). Literature has indicated that stretching a muscle under load prior to an immediate concentric contraction may result in a more rapid and powerful concentric contraction (Malisoux et al. 2006). Two models have been proposed which provide a clear explanation for this; the mechanical model and the Neurophysical model.
The mechanical model detailed by Komi (2000) explains that muscle fibers are lengthened under load during the rapid eccentric phase of movement. Similar to a spring, elastic energy is stored within the musculotendinous components and is reused in the immediate concentric contraction thus resulting in an increase in force and speed of contraction (Gambetta, 2007). Unlike a spring however, research by Ettema (2006) proposes that potential elastic energy may be lost as heat if the eccentric phase is too long in duration. This may indicate that the rate of eccentric loading rather than the amount of load may be important in achieving a greater concentric contraction. This is in contrast to research which has identified low EMG-activity during the concentric phase of the stretch shorten cycle (Lambertz et al. 2003). These findings indicate that this model may not take into account possible neural structure involvement and therefore may lack validity.
The neurophysical model
Long Term Athlete Development Pathways (LTAD) are frequently used throughout sport in order to maximise athletic potential (Balyi and Hamilton, 2004). Although research has yet to validate the effectiveness of the use of conceptual frameworks, it is accepted that such pathways may provide an effective strategic planning tool to achieve optimal performance (Viru et al., 1999). LTAD’s outline possible key opportunities during childhood development, pre-pubescent and post-pubescent ‘windows of opportunity’ in which young athletes may be more physiologically responsive to correct training stimulus and thus potentially achieve significant improvements in performance (Balyi and Hamilton, 2004). Age related changes during the pre-pubescent window typically involve neuromuscular developments with increases in muscle mass occurring during the post-pubescent window (Viru et al., 1999).
Originally developed by Dr Istvan Balyi’s, the Long-term Athlete Development (LTAD) model proposed by the British Judo Association details a six-stage process categorised by chronological age for optimal development of judoka at every level (see appendix 1). As chronological age may not be an accurate indicator for athletic development, LTAD frameworks may lack reliability, as they may not take into account individual differences of physical, cognitive and emotional development rates of young athletes. Influenced by genetic and environmental factors, research has suggested that the use of Peak Height Velocity (PHV) may provide a more accurate indicator of athlete development stage (Iuliano-Burns et al., 2001). Based on biological age, use of this method may more accurately identify and increase the utilisation of the critical adaptation periods during development. However, similar to current LTAD, PHV measures may also not account for cognitive or emotional aspects of development.
Initially focused on basic movement literacy including agility, balance and coordination in addition to speed, strength through own body weight. Learning and development throughout the first FUNdamental’ stage (6-10 years old) is achieved through fun, activities and games with high training volume of low intensity. As the young athlete grows and develops, between the ages of 9-12 for boys and 8-11 girls, transition is made into the ‘Learning to Train’ stage with training primarily based on single periodisation of high volume with gradual increasing intensity. In addition to skills, physical development is increased throughout the ‘Train to Train’ stage (12 -16 boys and 11-15 girls) with volume of training reducing with increasing intensity in accordance to growth. Regional and National competition is also introduced during this stage. Frequency and duration of training is increased within the ‘Training to Compete’ stage of development (male 16-25 years, female 15 -23 years), which begins to introduce plyometric training of increasing intensity and high volume. Participation in National and International junior and senior competitions is also encouraged during this phase.
tRAINING TO WIN
As the athlete enters the performance stage referred to as ‘Training to Win’, individual and specific judo and conditioning training is performed. Training is high in volume and intensity comprising of 5-12 sessions of judo and 4-6 judo specific physical conditioning. Training is periodised in relation to major championships and key events during the calendar year. Lastly, the final stage of the LTAD refers to the retention of the judoka within the sport. Training frequency, intensity and volume is an individual choice with a mixture of judo and physical activity. Athletes may enter the LTAD at various stages during development however it is essential that each athlete demonstrates technical and physical competency prior to progressing to the next development stage.
Evidence indicates that age-appropriate plyometrics may be an effective method of training (Faigenbaum and Myer 2010). However, the use of plyometrics for children remains controversial due to concerns in relation to possible damage to immature epiphyseal growth plates (Faigenbaum et al., 2009). This concern is in contrast to research which has indicates that plyometric training may increase peak bone mass and reduced risk of growth plate fractures in prepubescent athletes (Witzke and Snow, 2000). Research has identified that children aged 7 -10 years old demonstrate neuromuscular inhibitory mechanisms including reduced stretch reflex response and increased antagonist muscle activation during landing in comparison to adults (Grosset et al., 2007). This indicates that plyometric training may not be beneficial for young athletes between the ages of seven to ten years old. The LTAD plan proposed by the BJA is in line with this research and includes no plyometric training during the first two development stages (ages 6 -12 boys and 6 -11 girls).
The Neurophysical model proposes the importance of the myotatic reflex of the nervous system commonly referred to as the ‘stretch reflex’. Research has identified increased alpha motor neuron activity as the muscle spindles rapidly increase in length due to the eccentric movement (Wilk et al., 1993). With increased motor neuron activity and force production in the agonist muscle, an enhanced concentric contraction is immediately produced. This is further supported by EMG-activity studies that have identified pronounced involvement of the stretch-reflex neural component during the stretch shorten cycle (Lambertz et al. 2003). This highlights crucial role of the myotatic reflex in the development of force and consequent power in plyometric training.
Plyometric training, timed right, becomes the dynamic force that propels athletic prowess. It's not just about the exercise; it's the strategic ignition that elevates performance to new heights.
LTAD AND Plyometric DEVELOPEMENT
Extensive research has highlighted the effectiveness of plyometrics when compared to other training methods (McLaughlin, 2001; Vossen et al., 2000). Studies have shown increased motor performance including speed and acceleration (Shalfawi et al., 2011), maximal and explosive strength (De Villarreal et al., 2010) and agility (Thomas et al., 2009) as a result of plyometric training. Other forms of training such as resistance training have also proved effective in increasing muscle strength and power (Fatouros et al., 2000). Evidence suggests that Olympic lifting may produce greater improvement in performance than power lifting or kettle bell training (Mangine et al.,2008). Although alternative methods may ultimately achieve similar results (Markovic et al. 2007), plyometric exercises may be considered technically simple in comparison and can be performed with or without external load. Therefore technique proficiency may be achieved more efficiently, reducing injury risk, without the need for expensive equipment (Arabatzi et al. 2010).
Neurophysical adaptations of plyometric training have also shown that increased performance levels may be achieved more rapidly with reduced volume of training in comparison to other training methods such as strength training (Matavulj et al., 2001). Research has also shown reduced muscle hypertrophy and increased muscular endurance of explosive movements (McLaughlin, 2001) as a consequence of utilising plyometric training in heavy strength training (Saunders et al. 2006). This may suggest that plyometrics may be more beneficial to dynamic, weight categorised sports such as judo in which explosive power and endurance is required without increase in body mass. As plyometric exercises can be modified to more sports specific movements and performed in an athlete’s sporting environment (Potteiger et al. 1999), plyometrics may be considered a more ecologically valid and versatile method of training to increase muscular power.
Despite research demonstrating the benefits of plyometric training, due to limited samples (athletes vs non-exerice, training experience, measures used and age/gender) and lack of control over external variables such as nutrition intake of participants (Diallo et al. 2001), research results may lack validity. As many studies have also used plyometrics in conjunction with other training methods, the effects of plyometrics alone may remain inconclusive. In 2008, Ronnestad et al. investigated the effects of plyometric training on the development on sprint speed in professional football. The results of the study found that using only strength training improved performance however plyometrics combined with strength training provided no statistically significant improvements. These findings may suggest that plyometrics may not provide superior advantages in performance in comparison to strength training. However, as the study did not include a plyometrics-only group and used limited performance measures, this research may lack validity and reliability regarding the effectiveness of plyometrics. Although the evidence is inconclusive regarding the positive effect of plyometrics alone, researchers have highlighted that greater results may be achieved when plyometrics are used in conjunction with other training methods including strength training than either methods when used alone (Fatouros et al., 2000).
As plyometrics involve dynamic movement, high eccentric load and impact stress from landing (Humphries et al., 1995), research has identified an initial and delayed reduction of muscle function and reflex sensitivity (Avela et al., 1999). This may indicate an increased risk of primary and secondary injury as muscles become physiologically and neurally fatigued. Literature has highlighted the essential need for a dynamic warm up and longer rest periods to reduce injury risk and enable adequate recovery to maximise plyometric performance (Verkhoshansky, 2009). Furthermore, the monitoring and modification of plyometric volume, intensity and frequency may also reduce the risk of possible injury risk associated with overload and overtraining (Faigenbaum, 2008). Although injury risk is inherent utilising any training method, research has found that plyometric training combined with other neuromuscular training methods such as balance training may reduce biomechanical risk factors of injury including the significant reduction of ACL injury female athletes (Myer et al., 2006; Hewitt et al., 2006). These findings may suggest appropriately designed and progressive plyometric training may reduce biomechanical risk factors of injury when combined with other neuromuscular training methods.
British judo LTAD Framework
The current British Judo Association (BJA) framework proposes that plyometric training should be introduced during the post-pubescent ‘Training to Compete’ stage of development (male 16-25 and female 15- 23 years old). Recent research has identified potential periods of plyometric development between the ages of 10 -13 (Lloyd et al., 2011). In 2007, research conducted by Faigenbaum et al. investigated the effects of a six week plyometric training program combined with resistance training on pre-pubescent boys aged 12 -15. Training twice per week, the results of the study identified increased upper and lower limb performance measures (long jump, medicine ball toss, agility shuttle run time). These findings are further supported by research indicating that boys aged between 12 -18 and girls aged 14 -18 who perform plyometrics twice weekly, on nonconsecutive days, may result in increased upper and lower limb strength and power (Faigenbaum, 2001). This would suggest that the current LTAD framework may lack efficacy, as athletes may be susceptible to accelerated adaptations with exposure to the appropriate plyometric training stimulus during the ‘Train to Train’ stage of development.
Intensity of plyometric training is frequently determined by the amount of load placed on the musculotendinous components (Potach and Chu, 2008). As this may not measure the magnitude and velocity of the eccentric stretch, this method may not account for possible myotacic neural stress as a result of the stretch shorten cycle (SSC) (Cronin et al., 2002). Frequently used to measure optimal drop jump height (Flanagan and Comyns, 2008), research has indicated that the reactive strength index (RSI) may provide a more reliable method of measuring plyometric exercise intensity (McClymont, 2005). Calculated by dividing jump height (millimetres) by ground contact time (milliseconds), the index suggests slow SSC (high ground contact duration) exercises such as maximal vertical countermovement jumps could be considered high in intensity in comparison to fast SSC (low ground contact duration) exercises such as hopping which may be considered low in intensity. Possibly providing a more accurate measure of plyometric exercise intensity, this method may also provide a tool for exercise selection.
CURRENT FRAMEWORK
The current BJA LTAD model indicates high intensity of plyometric exercises should be introduced during the ‘Training to Compete’ stage of development (male 16-25 and female 15-23 years old). This would suggest that exercises of high magnitude and velocity such as maximal vertical countermovement jumps could be performed during this stage. This may take advantage of the post pubertal ‘window of opportunity’ and enable optimal adaptation of the athlete to increase strength and power during this stage. It is essential that developing athletes must begin with low intensity exercises that gradually increase in intensity (Faigenbaum, 2006). As low intensity plyometric exercises may be introduced during the ‘Train to Train’ stage of development, this addition may provide a natural progression of plyometric training and prove beneficial for the development of correct technique and experience prior to performing higher intensity plyometric exercises. As the LTAD proposes possible participation in regional and national competitions during the Train to Train phase, the introduction of plyometrics to develop explosive power during this stage my also positively impact competitive performance.
Plyometric training volume and frequency is frequently determined by the number of ground contacts during a session and the degree of muscle soreness respectively (Gambetta, 2007). However as young athletes may experience less muscle damage than adults (Marginson et al., 2005), this method of monitoring may be unreliable. Literature has highlighted that plyometric volume and frequency progression should be dependent on age, exercise intensity and level of experience (Faigenbaum and Chu, 2001). This suggests that young, inexperienced athletes should begin with low intensity plyometric training that increases in frequency of number of repetitions and sets with development. This is in line with the current BJA LTAD model that advises progressive increases in general training volume and frequency throughout LTAD.
Due to metabolic demands of plyometric training, research has identified increased ground reaction times due to metabolic fatigue or increases in intensity (Lloyd et al., 2011). As RSI measures may be utilised to establish plyometric intensity, such measures may provide a performance baseline index prior to plyometric training. If intensity levels are maintained, the resultant increase in ground reaction time may indicate possible fatigue. This would enhance the use of RSI as a reliable, athlete- centered tool to select appropriate plyometric exercise intensity, frequency and identify thresholds of performance. This may help to ensure optimal adaptations of plyometric and reduce the risk of possible injury.
Conclusion
Research has indicated that plyometric training may play a crucial role in the development of speed and power. Although shown to increase performance outcome measures, research has highlighted that plyometric training is more effective when combined with training modalities such as strength training. Literature has highlighted that the introduction of plyometric training to the ‘Training to Train’ stage may be increase power and strength. Based empirical evidence, a modified LTAD for judo has been proposed (see appendix 2). The modified model proposes the earlier introduction of low intensity plyometric training may provide a more comprehensive and progressive LTAD model. These suggestions are also supported by Lloyd et al., (2011) as a more comprehensive youth based plyometric exercise model. Furthermore, the use of RSI, may provide a more reliable tool to measure the intensity and frequency of plyometric training. This may increase the effectiveness plyometric training in the development of speed and power.
References
ANDERSON, Lorin., KRATHWOHL, David., AIRASIAN, Peter., Cruikshank, Kirk., MAYER, Richard., PINTRICH, Paul., RATHS, James. and WITTROCK, Merlin. (2001). A Taxonomy for Learning, Teaching, and Assessing: A revision of Bloom’s Taxonomy of Educational Objectives. New York, Longmann.
BIGGS, John. (1995). Assessing for learning: Some dimensions underlying new approaches to educational assessment. The alberta journal of educational research, 41 (1), 1-17.
BLOOM, Benjamin. (1956). Taxonomy of educational objectives: The classification of educational goals, by a committee of college and university examiners. Cognitive Domain. New York, McKay.
BULL, Stephen., ALBINSON, John. and SHAMBROOK, Christopher. (1996). The mental game plan: Getting psyched for sport. Sport Dynamics. Eastbourne, UK.
CUSHION, Christopher. (2006) Mentoring: harnessing the power of experience, in: R. Jones, The sports coach as educator: reconceptualising sports coaching. International journal of sports science and coaching, 1 (4), 405-412.
CUSHION, Christopher., ARMOUR, Kathryn. and JONES, Robert. (2003). Coach education and continuing professional development: Experience and learning to coach. Quest, 55 (3), 215-230.
DRUST, Barry (2010). Performance analysis research: Meeting the challenge. Journal of DUDA, Joan. (1989). Relationship between task and ego orientation and the perceived purpose of sport among high school athletes. Journal of sport and exercise psychology, 11 (3), 318-335.
ERICKSON, Kirk., BRUNER, Mark., MACDONALD, David. and COTE, Jean. (2008). Gaining insight into actual and preferred sources of coaching knowledge. International journal of sports science and coaching, 3, 527-538.
FLETCHER, David. and SCOTT, Michael. (2010). Psychological stress in sports coaches: A review of concepts, research, and practice. Journal of sports sciences, 28, 127-137.
FORD, Paul., DE STE CROIX, Mark, LLOYD, Rhodri., MEYERS, Robert., MOOSAVI, Marjan., OLIVER, Jon., TILL, Kevin., and WILLIAMS, Criag. (2011). The long-term athlete development model: Physiological evidence and application. Journal of sports sciences, 29 (4), 389-402.
GILBERT, Wade. (2009). Formal vs. informal coach education: A commentary. International journal of sports science and coaching, 4, 335-337.
GILBERT, Wade., COTE, Jean., and MALLETT, Clifford. (2006). The talented coach: Developmental paths and activities of successful sport coaches. International journal of sport sciences and coaching, 1, 69-76.
GILBERT, Wade. and TRUDEL, Pierre. (2001). Learning to coach through experience: Reflection in model youth sport coaches. Journal of teaching in physical education, 21, 16-34.
GUCCIARDI, Daniel. and GORDON, Sandy. (2009). Revisiting the performance profile technique: Theoretical underpinnings and application. The sport psychologist, 23, 93- 117.
GLAZER, Douglas. (2005). Development and preliminary validation of the injury- psychological readiness to return to sport (I-PRRS) scale. Journal of athletic training, 44 (2), 185-189.
HAMILTON, Ryan., SCOTT, David. and MACDOUGALL, Michael. (2007) Assessing the effectiveness of self-talk interventions on endurance performance. Journal of applied sport psychology, 19 (2), 226-239.
HAYS, Kate., THOMAS, Owen., MAYNARD, Ian. and BAWDEN, Mark. (2009). The role of confidence in world-class sport performance. Journal of sport sciences, 27, 1185– 1199.
IRWIN, Gareth., HANTON, Sheldon. and KERWIN, David. (2004). Reflective practice and the origins of elite coaching knowledge. Reflective Practice: International and Multidisciplinary Perspectives, 5, 425-442.
IULIANO-BURNS, Sandra., MIRWALD, Robert., and BAILEY, Donald. (2001). Timing and magnitude of peak height velocity and peak tissue velocities for early, average, and late maturing boys and girls. American Journal of Human Biology, 13 (1), 1-8.
JOWETT, Sophia. and COCKERILL, Ian. (2002). Incompatibility in the coach–athlete relationship. Solutions in sport psychology, 16-31.
JOWETT, Sophia and NTOUMANIS, Nikos. (2004). The Coach–Athlete Relationship Questionnaire (CART-Q): Development and Initial Validation. Scandinavian journal of medicine and science in sports, 14 (4), 245-257.
KELLY, George. (1991). The psychology of personal constructs: A theory of personality. Clinical Diagnosis and Psychotherapy. London, Routledge.
KNOWLES, Zoe., GILBOURNE, David., BORRIE, Andrew., and NEVILLE, Alan. (2001). Developing the reflective sports coach: A study exploring the processes of reflection within a higher education coaching programme. Reflective Practice, 2, 185-207.
LAIRD, Peter. and WATERS, Laura. (2008). Eyewitness recollection of sport coaches International journal of performance analysis in sport, 8 (9), 76-84.
LYLE, John. (2002). Sports coaching concepts: A framework for coaches’ behaviour. Psychology Press. 237-237.
MARTENS, Ranier., BURTON, Damon., VEALEY, Robin., BUMP, Linda. and SMITH, Daniel. (1990). Development and validation of the competitive state anxiety inventory-2. Competitive anxiety in sport, 117-190.
MILLER, Patricia. and KERR, Gretchen. (2002). Conceptualising excellence: Past, present, and future. Journal of applied sport psychology, 14, 140–153.
NELSON, Lee. and CUSHION, Christopher. (2006). Reflection in coach education: The case of the National Governing Body coaching certificate. The sport psychologist, 20, 174-183.
NEVILL, Alan., ATKINSON, Greg. and HUGHES, Mike (2008). Twenty-five years of sport performance research. Journal of sports science, 26, (4), 413-426.
PODLOG, Leslie. and DIONIGI, Rylee. (2010). Coach strategies for addressing psychosocial challenges during the return to sport from injury. Journal of sports sciences, 28 (11), 197-1208.
SCHON, Donald. (1983). The reflective practitioner. How professionals think in action. The journal of continuing higher education, 34 (3), 29-30.
SMITH, Ronald., SMOLL, Frank., and HUNT, Earl. (2013). A System for the Behavioural Assessment of Athletic Coaches. Research Quarterly. American Alliance for Health, Physical Education and Recreation, 48 (2), 401-407.
THOMAS, Patrick., MURPHY, Shane., and HARDY, Lew. (1999). Test of performance strategies: Development and preliminary validation of a comprehensive measure of athletes’ psychological skills. Journal of sports sciences, 17 (9), 697-711.
VEALEY, Robin. (1986). Conceptualisation of sport confidence and competitive orientation: preliminary investigation and instrument development. Journal of sport exercise psychology, 8 (3), 221–246.
VERGEER, Ineke. (2006). Exploring the mental representation of athletic injury: a longitudinal case study. Psychology of sport and exercise, 7, 99-114.
The power of goal setting
In the realm of goal setting, each stride is purposeful, each achievement a testament to dedication. As you embark on your goal-setting journey, let purpose guide your steps, clarity shape your vision, and discipline fuel your perseverance. Goals are not mere destinations; they are the milestones that mark a life sculpted by intent and achievement. Embrace the power of goal setting, and unlock the doors to a future where success is not just a possibility but a certainty.
A New Chapter
From the days of a run-down gym in Leigh to embracing an old, dormant community building as our home, and now basking in the glory of a state-of-the-art, purpose-built dojo nestled in the heart of our warm and welcoming community facility. The evolution of Leigh Judo Club has been nothing short of extraordinary. A journey that unfolded faster and more profoundly than anyone could have imagined. And as we stand here today, we can’t help but feel excited about the bright future that awaits our club.
The power of intrinsic motivation
The power of intrinsic motivation is an exploration to unraveling the innate drive that propels individuals towards enduring achievement. Dive into the core of intrinsic motivation, where passion meets purpose, and discover the wellspring that fuels self-determination. Join us on a journey where goals cease to be tasks and become expressions of personal fulfilment. It is an invitation to harness the internal flame that not only sparks change but lights the path to sustained and meaningful success.
follow
