Lower Body Plyometrics 101 – by Adam Bishop CSCS

A huge number of sports and activities require leg and hip strength for athletes to be successful. Collision sports such as rugby and American football involve explosive extension of the hip for running, jumping and changes of direction while static sports such as weightlifting and powerlifting are heavily dependant on leg and hip strength. Indeed any sport that involves running of any kind, especially sprinting and sports that involve rapid changes of direction, such as racket sports, rely on similar lower body strength.

Plyometrics training has been used to successfully increase athletes vertical jump heights, a test that requires a lot of leg and hip power production. As I’ve stated in previous articles, it is impossible to jump “non-explosively”. When performing plyometrics, an athlete uses gravity to store energy with the muscle structure of the body, which is then immediately followed by an equal and opposite reaction, using the elastic properties of the muscles to produce a kinetic energy system (1). Plyometric drills develop explosiveness, the ability to use strength as quickly and as forcefully as possible (2).

Ok that’s great but how do we apply it to sporting situations? Well firstly let’s take a look at a rugby union player preparing to perform a front on tackle on an attacker. Hip and knee flexion occurs as they sink into a low body position followed by rapid hip and knee extension as they drive up and into the midsection of the opposing player. The more force the tackler is able the produce, the greater the chance of them “winning the collision” and driving the opposing player backwards. The rate of force development (RFD) of the movement can be improved with similar the jumping movements of a plyometric program.

Next let’s take a look at a sprinter, or indeed any athlete where their sport requires them to run at maximum velocity. In order to run as fast as possible the sprinter needs to reduce ground contact time while also applying a large amount of force through the ankle joint in order to best provide forward propulsion. This is the basis that plyometric training techniques are based on; applying the greatest amount of force in the shortest period of time.

PLYOMETRIC EXERCISES

 Lower body plyometric exercises are based around jumping, hopping or skipping movements where an eccentric muscle action is rapidly followed by a concentric one. Different exercises have differing levels of intensity and therefore much thought must be taken when deciding which exercises to include in an athlete’s training program as well as the frequency and rest periods of the sessions.

To give a little bit of guidance for selecting the correct plyometric exercises for your training I have split a small number of techniques into low, medium and high intensity. All the exercises below are to be performed in series (each rep performed straight after each other no rest).

Low Intensity

  • 2 footed ankle hop
  • Squat jump
  • Double leg vertical jump

Medium Intensity

  • Box Jumps
  • Split squat jump
  • Barrier hops

High Intensity

  • Depth Jump
  • Single leg vertical jump
  • Pike Jump

All of the exercises above are aiming to utilise the stretch shortening cycle which combines mechanical and neurophyiological mechanisms to increase the amount of forced produced.

Jumping exercises involve a rapid eccentric muscle action which stimulates a stretch reflex and results in the storage of elastic energy within the series elastic component. This is followed by a rapid concentric muscle action which utilises this stored energy allowing for a greater force to be produced.

IMPLEMENTING PLYOMETRICS INTO A TRAINING PROGRAM

 Plyometrics should not be thought of as just warm up exercises, they are a session in their own right and the intensity dictates the frequency. The higher the intensity is, the lower the frequency should be to allow for optimum recovery.

As a general rule, sessions should be separated by 42-72 hours, this means athletes can perform between 2-4 sessions a week depending on training age and experience. In regards to rest periods between sets, a work to rest ratio of 1:5 – 1:10 should be used to optimise performance. Another consideration that should be taken when implementing a plyometric program is that of the athlete themselves. A heavier athlete should avoid single leg and high intensity exercises to begin with to avoid excessive stress being placed on the joints.

Studies have shown that combining a simple 2 day a week plyometric program with a 2 day a week squat program produces the greatest gains in hip and leg strength in regards to jumping ability(3). Adams et al found that vertical jump scores increased 3 times greater in athletes who partook in a 6 week squat and plyometric regime over those who performed a squat or plyometric only regime of similar volume.

FINAL THOUGHTS

 Ok so I know many of you will be thinking “well that’s great but I am a static athlete who doesn’t need to jump”. Think again.

Jumping movements produces the holy grail of strength training, triple extension of the hip, knee and ankle which is used in a huge number of sports.

An example of this is shown in the following video of a hero of mine Werner Gunthor the shot putt legend with a PB of 22.75m. Take a look at what this 2m tall (6ft 6) 130kg man could do when it came to jumping:

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Now tell me that plyometrics don’t make you powerful…

References

(1)     Verhoshansky, Y. 1968. Are depth jumps useful? Sov. Sports Rev. 3:75-76

(2)     Yessis, M and Hatfield, F. 1986. Plyometric training, achieving explosive power in sports. Canoga Park, CA: Fitness Systems.

(3)     Adams, K. O’shea, J.P. O’Shea, K.L. and Climstein, M. 1992. The effects of 6 weeks of squat, plyometric and squat-plyometric training on power production. Applied sports science research. 6:1 pp 36-41.

Pull Heavy to Move Fast – by Ben Coker

There is a common misconception that lifting heavy weights will make you slow among sprint coaches. Many will stick to body weight and plyometric workouts, using only weights that are sub maximal and moving them fast if any weights are used at all. Lifting around 50-60%1RM and doing speed work isn’t wrong but it’s only one possible way to address the issue. 

When lifting heavy weights the nervous system is forced to recruit as many motor units as possible to move the weight. In sprinting, surely you want to have all of your fibres at maximum efficiency, ready to all contract at the same time for maximum force output. Now yes you can partially get this from trying to move a weight fast or indeed sprinting itself but there’s more. If you try to move an even heavier weight fast then your body is forced to recruit even more fibres. What I’m getting at here is the concept of motor unit potential. Have you ever noticed that when you’ve lifted a heavy weight when you release it and perform the same anatomical movement without the weight it feels extremely light? Your brain still thinks it needs all the fibres it had just recruited to do the movement. Simply put for a short period after lifting a weight all those fibres that were activated are on standby in case you have to perform the movement again.

This phenomenon only last a short time (seconds) so we must be quick. I’m aware that many track/gym facilities are substandard but if you have access to a sled or a lifting platform that is near a track then you’re sorted.

Approach one: Potentiate then perform – aka contrast sprints

Choose an exercise that requires hip extension and knee extension (the drive of sprinting) that allows for large weights to be lifted. I prefer squats, deadlift or sled pulls. Next set out a sprint distance you want to train over. Perform 2 repetition of the exercise at about 80-90% 1RM then get to the start line promptly and then sprint the distance. Why 2 reps? Well it takes about this time for your brain to fully recognise the force needed to move the weight. In a sense the first rep is ‘sluggish’ as the body wakes up and its the 2nd and even 3rd rep (if the weight isn’t too heavy), that the body produces most power as the relevant motor units are now all awake and firing together. If your pulling the sled/prowler simply choose a weight at about 80-90% 1RM then pull/push the sled/prowler for between 5-10m. It is important not to overdue it as the effect is lessened if fatigued! Remember we are activating not fatiguing ourselves here.

Plyometrics are used to accomplish similar results but they recruit fibres by quick lifting whereas lifting heavy recruits fibres by creating the need for many fibres to lift the weight. One must also remember that if one attempts a 1RM then by definition they are moving the weight as fast as they can, no matter how slow, it is at maximum speed! 

Approach two: Pure heavy pulling sessions mimicking sprinting

Here I am speaking specifically about the use of sleds and prowlers. Continued use of pulling heavy in a way that mimics sprinting means the body will eventually adopt and be able to pull a given weight faster over time. Now you’ll have to be mad to try and disprove that this won’t carry over into being able to propel your body weight faster if you’ve become accustomed to pulling a damn heavy sled at a worthy pace! It is worth noting that to pull a substantially heavy sled or prowler involves the person naturally getting into the correct or optimum position for the drive phase in sprinting! If you don’t quite simply the thing won’t move! So in using sleds and prowlers you are also grooving correct body angles and positions for sprinting as an added side benefit!

Wrap up
Not only do these exercises carry over into an immediate sprint, allowing one to groove quickness of limb movement but I speak from experience in saying that this approach also makes you faster in the long run. But if that isn’t enough then have a browse through the training methodologies & youtube pages of trainers like Joe Defranco, who are hugely successful in producing elite athletes year in year out and frequently use both techniques in their programmes. I’ll leave it at that.
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