I am a relatively late-comer to the world of Instagram (DC_Injury_Clinic, if you’re asking), and it has taken a bit of getting used to. There is some brilliant stuff put out on there, and some – well, bat sh*t crazy stuff. Something that caught my eye very early on, was the huge number of PT’s and gym-goers showing off their amazing ability to box-jump. They can jump, like, really high!
If we are being strict, plyometrics are “a form of exercise that involves rapid and repeated stretching and contracting of the muscles, designed to increase strength” – so exercises that require you to jump, land and then rebound into another jump straight away. So box jumps aren’t technically plyometrics but are a graded exposure to plyometrics – albeit top-end in my opinion. This form of training is governed by the stretch-shortening cycle (SSC) of the muscles utilised – where the muscle undergoes an eccentric contraction (lengthening), followed by a transitional period prior to the concentric contraction (shortening). SSC exists in all forms of human motion and so is important as a training tool for most of us. The benefits include (1);
- Improved storage and utilization of elastic strain energy
- Increased active muscle working range
- Enhanced involuntary nervous reflexes
- Enhanced length-tension characteristics
- Increased muscular pre-activity
- Enhanced motor coordination
Improving these qualities will – somewhat counterintuitively for the stretchers out there – lead to an increase in leg stiffness during contact with the ground, and so force production during the concentric (shortening) contraction. This increase in both leg stiffness and force production will likely lead to improvements in athletic performance.
They are also a key component of latter stage rehabilitation, as rehab is about exposing you to greater challenges in a graded and controlled manner. Plyometrics could be seen as the bridge between rehab and performance – research showing that injury reduction programmes that include plyometrics can reduce lower limb injury by 56%. In comparison, those that didn’t utilise plyometric movements reduced injury by only 26% (2)
So why did I start this blog with Box Jumps? It has always intrigued me how much time we spend learning to explosively jump (bizarrely often sold as ‘functional’), when many of us haven’t yet mastered the ability to land – the ultimate functional movement (think of walking down the stairs, stepping off a curb, coming down a ladder, running!). Approximately 70% of ACL injuries result from situations that do not involve direct contact (3), but are more likely a result of manoeuvres that involve some form of deceleration – for example, landing (4).
I absolutely recommend graded exposure to plyometrics, but they should not be seen as a given for every PT session. I often talk about “earning the right” to perform certain exercise, and plyometrics certainly fit that bill.
If you are not ‘strong’, yet, then we should not be training ‘power’, where;
Strength is the amount of force a muscle, or group of muscles, can exert .
Power is the ability to generate that force as fast as possible.
Focus on the basics first – the fun, Instagram friendly stuff will come.
- Rossler et al, 2014
- Boden et al. 2000; McNair, Marshall, and Matheson 1990
- Olsen et al. 2004; Cochrane et al. 2007
N.B. There are no ‘one size fits all’ style quick fixes in most injury scenarios, so these article shouldn’t be seen as such. They are merely guides to a better understanding of how our bodies work.