We have previously discussed the application of plyometric training to boxing and have outlined the speed and power benefits that can be derived from this training method. (Read more here: https://boxingscience.co.uk/power-for-boxing-power-circuits-plyometrics/)
This article will go into more detail about plyometric training, in particular the safe and effective use of single-leg plyometrics for boxers.
The main points that will be discussed include:
The science behind plyometrics and the underpinning mechanisms that facilitate strength and power adaptations.
How plyometric training can improve boxing performance.
Practical guidelines on how to incorporate single leg plyometric training into a boxer’s program.
SCIENCE BEHIND PLYOMETRIC TRAINING
Plyometric training is considered a classification of strength training that elicits adaptations in impulsive muscular qualities such as speed-strength and reactive strength.
This type of training usually entails jumping variations that exploit the stretch shortening cycle.
Common exercises that are associated with plyometrics include: Countermovement jumps, drop jumps and various bounding activities.
There has been extensive research conducted on plyometrics and this training method has consistently proven to be effective at developing jumping, sprinting and change of direction ability and therefore is often implemented in sports such as soccer, rugby and basketball.
THE STRETCH-SHORTENING CYCLE
The stretch-shortening cycle (SSC) is synonymous with plyometric training and is considered a natural neuromuscular function utilised in many sporting activities, most notably sprinting, changing direction or cutting and jumping.
This mechanism ultimately involves the coupling of eccentric and concentric muscle actions, without which, we would display gross inefficiencies during explosive actions such as sprinting, jumping and even punching.
SSC activities are comprised of three phases: eccentric (active lengthening or stretch of the musculotendinous unit or MTU), amortization phase (brief time interval between eccentric and concentric muscle actions), and the concentric phase (shortening of the muscle fiber).
The stretch provided in the eccentric phase enhances subsequent concentric muscle action and is commonly referred to as SSC potentiation.
A classic example of the SSC at play is the countermovement jump and squat jump.
In the countermovement jump (CMJ) the athlete is instructed to lower down and explode up in one motion whereas the squat jump (SJ) involves a three second pause in a self selected squat position before jumping.
Availing of the stretch shortening cycle in the CMJ, we frequently observe greater heights jumped in comparison to the squat jump.
The prolonged amortization phase in the squat jump tends to dissipate stored energy from the eccentric phase and thus reduces any SSC potentiation effect.
In terms of the force-velocity continuum, SSC activities are firmly situated on the high velocity side of the spectrum and therefore tend to take priority in speed-strength and speed phases, however can also be performed in lower volumes throughout training camp to maintain impulsive qualities.
MECHANISMS OF SSC POTENTIATION
The main mechanisms proposed to explain the potentiation effect derived from the coupling of eccentric and concentric muscle actions can be categorised as neurophysiological and mechanical.
Neurophysiologically, it is thought that an involuntary stretch reflex plays a substantial role in the enhancement of concentric muscle actions following active lengthening.
This reflex action is modulated by muscle spindles which are sensitive to changes in muscle length and essentially act as a built-in defensive mechanism that detects potentially harmful degrees of stretch and forces the muscle fiber to recoil explosively, preventing damage to the MTU.
Mechanical mechanisms of SSC potentiation relate to the storage and utilisation of elastic energy.
Essentially, during the eccentric or lengthening phase of a stretch shortening cycle activity, elastic energy is stored in the MTU.
So long as the amortization phase is brief, this elastic energy can accumulate sufficiently and be used to enhance force and power during the concentric muscle action.
However, if the amortization is too long which may occur if the athlete is exposed to too great of an eccentric demand (e.g landing from an excessive height), this elastic energy is dissipated and given off as heat.
From a biomechanical perspective we can also highlight the importance of the SSC in increasing the activate state of the muscle which shortens the tie required to produce high amounts of force, allowing for greater generation of impulse throughout the concentric phase of the SSC.
It has also been suggested that the SSC places the muscle fiber at a more optimal length to produce force which facilitates improved fore production upon initiation of the concentric muscle action.
ASSESSING STRETCH-SHORTENING CYCLE UTILISATION
Identification of an athletes weaknesses when it comes to the SSC is important to guide the direction of subsequent programming.
The most common way to determine an athlete’s SSC capabilities is through the Reactive Strength Index (RSI).
There are many ways to assess an athlete’s RSI, however, we prefer the 10/5 test as it is less technically demanding and is easily performed.
This testing procedure can be administered via the commercially available MyJump application and involves instructing the athlete to perform 10 consecutive pogo jumps. Using the cue ‘Jump as high as possible whilst spending as little time on the ground as possible’ tends to allow the athlete to understand what is expected.
With this assessment we are essentially testing the athlete’s ability to load and explode through the lower body, particularly the tendons around the knee and the ankle.
ADAPTATIONS TO PLYOMETRIC TRAINING
Plyometric training has been shown to induce an array of neuromuscular adaptations.
Morphological changes to muscle including muscle fiber hypertrophy of type I, type IIa and type IIx fibres have been observed in relatively untrained athletes.
Positive changes to muscle fiber function have also been noted such as increased peak contraction velocity and peak fiber force.
Predominately, plyometric training is associated with neural mechanisms that enhance force production such as increased motor unit recruitment, increased rate of motor unit stimulation, increased reflex excitability and reduced activity of mechanisms that inhibit reflex action.
These adaptations all contribute to maximising an athlete’s ability to produce large amounts of force in a short period of time which is imperative for many aspects of sporting performance.
IMPLICATIONS FOR BOXING
How do plyometrics improve boxing performance?
We know that a successful punching action is dependent on producing large amounts of force in a short space of time, often less than 0.2 seconds.
Substantial amounts of this force is generated from the lower body, which is then transmitted through the core and on to the upper extremities.
Improving the athlete’s ability to load and explode through the musculotendinous units of the lower body can therefore have a profound impact on impulse and thus punch impact.
If we also consider the in-house research we have conducted that has established the correlation between jump height and punch power (80% correlation), we can use plyometrics to enhance the stretch-shortening cycle function of the lower body which will contribute to greater jump heights and thus punch power outputs.
It can be also be speculated that athletes with greater RSI scores move more efficiently and thus waste less energy when performing sub maximal intensity activities during competition.
Examples in boxing include cutting off the ring, moving in and out of the pocket and various defensive manoeuvres.
Perhaps a more obvious application of improved SSC function in the ring is the counter punch, where there is an evident lengthening/loading phase prior to a vicious shortening or exploding phase.
SINGLE-LEG PLYOMETRICS FOR BOXING
We have previously discussed the basics of plyometric programming for boxing, particularly the use of bi-lateral or double leg plyometrics in a recent article: https://boxingscience.co.uk/power-for-boxing-power-circuits-plyometrics/
We consistently avail of bi-lateral plyometric activities such as drop jumps, countermovement jumps, altitude landings and repeated vertical jumps to maximise the adaptations in force production and impulse that were aiming to achieve.
In the past, we may have been wary about the use of single-leg plyometrics due to the greater stability demands associated with these exercises which can compromise the amount of force that can be produced and the rate at which this force is produced.
Additionally, if we consider the low strength training history and thus poor eccentric utilisation capabilities associated with boxers, we can understand how single-leg plyometric activities may increase the likelihood of injury.
However, most athletic movements require actions on single leg (sprinting, change of direction). Single leg plyos are often used to improve Sprint speed, agility and acceleration
In boxing we’re constantly bouncing, moving in and out of range by transferring weight from front to rear leg to evade shots and set up attacks.
We’ve highlighted many times that there are muscular imbalances between the legs, and this can effect the reactivity and strength around the ankle joint.
This means that Single leg plyometrics are important for speed, co-ordination and reactivity to help boost explosive performance and reduce the likelihood of injury.
SAFE AND EFFECTIVE SINGLE-LEG PLYOMETRICS
To address the aforementioned concerns related to implementing single-leg plyometrics with boxers we can approach this in a few different ways.
FOOT CONTACT TIME
First of all we can go assisted … whether that’s with a bench, a band or going into a split stance. Single leg plyos doesn’t mean you need to balance on one leg, just the majority of your mass is going through one side.
If you go on one leg, make the exercise as simple as possible to encourage short ground contact times – we like the single leg pogos you target reactive strength of the calf complex.
Running mechanics are an under appreciated tool for single leg plyometrics, as they encourage fast contact times and explosive performance. Running mechanics are also relatively low impact and will help with a boxer’s running technique during conditioning, allowing them to be more efficient and less likely to sustain an injury during HIIT sessions.
Making the exercise more complex with fast pogos (alternate) and slaloms can add a co-ordination challenge, which will increase muscle activity whilst keeping the contact times short.
These are also great exercises to develop ankle stability and calf conditioning as they provide a more chaotic component which replicates the multi-planar nature of boxing.
Along with benefiting performance these low-impact, short ground contract exercises will also minimise the chances of achilles irritation which can significantly impair movement in the ring.
We don’t just want to target the calf complex with single leg plyometrics, We also want to challenge the long strength-shortening cycle to develop explosive strength.
We often go for Ice Skaters For this as this can transfer to improvements in lateral movement. This is a more hip dominant exercise utilising the Glute muscles, whilst discouraging the single leg exercise to become more anterior dominant.
We’ve also thrown in a solid vertical single leg jump using a bench, introduced to us by two time olympian and former GB Bobsleigh member, Ben Simons.
Check out some of the other plyometric exercise that Ben introduced to us and that we now regularly implement with our athletes at Boxing Science allowing them to jump higher and therefore punch harder, BELOW.
We use the short ground contact exercises as part of our warm-ups for conditioning sessions – as this prepares the ankle joint and Achilles for high forces during high speed running.
This may include pogos, slaloms, various footwork drills through ladders or even basic running mechanics.
With these short ground contact exercises we tend to performing 2-3 exercises for 8-10 reps x 3 sets.
We use 1 long SSC exercise for strength – this is part of an extended warm-up. 5-8 reps each side x 3 sets.
Examples include countermovement jumps, ice skaters, assisted vertical jumps and lateral shuffles.
Try implementing some of these exercises at the start of your strength or conditioning sessions to comprehensively develop reactive strength that will improve impulsiveness and thus punch power.
Plyometric training is a strength training philosophy that improves impulsive qualities such as speed strength and reactive strength.
Reactive strength is relevant to boxing performance as it is an accurate indicator of an athlete’s stretch-shortening cycle utilisation which is a key component of generating large amounts of force from the lower body that is then transferred to the fist during a punching action.
Single-leg plyometrics can be adapted to ensure they are safe and effective for boxers. The main ways to optimise safety and effectiveness with single leg plyos for boxers include assisted jumps and short ground contact movements such as single-leg pogos and slaloms.
These exercises generally feature in warm ups prior to strength or conditioning sessions to gain strength speed and explosiveness along with adequately preparing the achilles complex for dynamic movement.