It’s about performance

By May 26, 2017Technology

In pro & collegiate sport the Head Coach is god. Period.

Whether it’s the All Blacks, the Cleveland Cavaliers or Leicester City THE most important question a head coach asks of his or her high performance sports medicine, science and strength & conditioning staff is, ‘how hard can my athletes train / play today?

It’s a simple question with a complex answer and it’s a problem that we’re determined to solve here at IMeasureU (IMU). Good high performance staff capture a large number of data points to substantiate the answer… Great high performance staff synthesize that data and figure out the metrics that truly matter for their sport. Furthermore, they’ve built up enough trust with the head coach that their answer is implicitly trusted and acted on.

In a recent meeting with former All Blacks Rugby World Cup winning coach Sir Graham Henry I asked what was the most important question he asked of his high performance team. His answer, ‘who is available to train today and who are the players we need to modify this training session for?’.

No surprises there.

Sir Graham went on to emphasise the rise and rise, during his 30 odd years coaching Rugby at the highest level, of the high performance team when it comes to critical decision making around player availability and training intensity. Make no mistake the high performance team have a seat at the big table in 2016 and will only become more influential over time.

So how do IMeasureU (IMU) help pro teams answer the big question?

The short answer is:

1.      by accurately measuring ‘unmonitored’ load, over time

2.      precisely measuring readiness to train, right now

So what is ‘unmonitored’ load and why does it matter?

Think about basketball, soccer and tennis for example. Arguably the 3 biggest sports on the planet. The vast majority of training & playing workload that athletes endure in these sports are high intensity movements in a confined space and in the case of basketball and tennis, on a hard surface. A basketball court is 28 x 15 metres (91 x 49 feet). A half tennis court is 12 x 8 metres (39 x 26 feet). A soccer field is 100 x 64 metres which most would consider quite a large area but consider this, up to 80% of soccer workload is small sided games which FIFA recommends are played in areas as little as 12 x 20 metres (29 x 65 feet).

The preferred method of monitoring movement in these games, like most pro sports, is via GPS player trackers such as CatapultSports, StatSports and VXSport. The GPS sensor is placed in between the shoulders typically via a ‘sports bra’ and are designed to track WHERE the body moves, at what speed and at what heart rate.

More recently GPS trackers have included inertial measurement units to help teams better understand player load. CatapultSports, the global market leader in player monitoring, highlights the importance of inertial measurement on its website which states, ‘If your athletes move like robots from A to B, GPS is for you. If you’re serious about monitoring performance, Inertial Measurement Analysis is your next micro-measurement tool.’ 

Amen to that!

The challenge with GPS single unit sensors, with or without an inertial sensor in them, is they treat the body as a single unit of mass. And us humans are not single units of mass… we have limbs that rotate and bend relative to each other and our bodies.

This is where IMU comes in. We are able to put our miniaturised sensors on different body parts, sync them and then precisely measure, at up to 1000 times per second, HOW the limbs and body move.

Combine IMU data with GPS data and all of a sudden you have a much clearer measure of the true workload of an athlete. For example, we work with an NBA team where our sensors are placed above each ankle of players. We count and measure the impact of each left and right step. From this step data we can build a more accurate measure of the intensity and hence external load of a basketball training session, drill or game. It’s a similar story with small sided games in Soccer. And with Tennis we can place sensors on a player’s wrist as well as their shins to count & quantify the number of steps, forehands, backhands and serves.

In addition, via our proprietary cumulative bone load algorithm, pro teams also get an internal load metric thus enabling high performance practitioners to better manage high intensity, unmonitored external and internal player load.

Why measuring and managing load matters is a question answered by people much smarter than I am.

Professor Tim Gabbett is a leading applied sports scientist in the area of load measurement and management. He emphasises the importance of training harder & smarter. Many pro teams are successfully implementing Professor Gabbett’s research but to do that precisely they must be able to accurately measure load!

Tim’s paper outlines ways of monitoring training load (‘internal’ and ‘external’ loads) and suggests capturing both recent (‘acute’) training loads and more medium-term (‘chronic’) training loads to best capture a player’s training burden. In this paper Tim describes the critical variable—acute:chronic workload ratio—as a best practice predictor of training-related injuries. This provides the foundation for interventions to reduce players risk, and thus, time-loss injuries.

So we know we can use GPS, IMU and RPE (rate of perceived exertion multiplied by length of training session or game) to build an accurate picture of athlete workload over time. That’s well and good but what if you have a squad of 10 pro basketballers or 22 pro soccer players who present to training and a few of them have mentioned in their daily wellness survey that they are a bit sore or didn’t sleep well or feel unwell. How can we objectively test readiness to train / play right now?

Again, people way smarter than myself have and continue to debate the best & most practical way to objectively measure readiness to train.

One of the most commonly accepted ways of quantifying readiness quickly and accurately is via the (vertical) Counter Movement Jump or CMJ for short.

Per ScienceForSport, ‘the CMJ is a simple, practical, valid, and very reliable measure of lower-body power. As a consequence, it is no surprise that this has become a cornerstone test for many strength and conditioning coaches and sports scientists. The CMJ has been shown to be the most reliable measure of lower-body power compared to other jump tests. Furthermore, the CMJ has been shown to have relationships with sprint performances, 1RM maximal strength, and explosive-strength tests. This suggests that performances in the CMJ are linked with maximal speed, maximal strength, and explosive-strength. Contact mats, force platforms, accelerometers, high-speed cameras, and infrared platforms have all been shown to provide a valid and reliable measure of CMJ performance’.

In simple terms athletes stand on the spot with their hand on their hips and jump as high as they can by bending down, at the knees, and jumping up as high as they can. Typically, this is done 3 times with a few seconds break in between. Protocols vary but generally speaking if an athlete is more than 1.2 standard deviations down on their average jump height, take off velocity or there are significant changes (10%+) in the time taken to load (concentric) and de-load (eccentric) their jumps then an intervention is made by the sports medicine, sports science and or strength and conditioning practitioner. That could be a conversation to further qualify the athlete’s physical and mental state or a reduction / increase in training volume and intensity. The key with the CMJ protocol for testing readiness to train / play is the difference between an athlete’s metrics today and their long term average. By definition then, whatever the tool used to measure CMJs must be extremely accurate because if there are large variances from jump to jump then how on earth can a practitioner determine if variation is due athlete readiness or the tool itself!?

Other key considerations are mobility & throughput. The best readiness testing tools have to be precise but what’s the point if the tool can’t be used daily when the athletes are playing away from home or are out on the court or field? And if it takes 5 minutes to test 1 athlete and 22 turn up to training at 9am for a 9:30 start how the heck is the high performance coach going to be able to answer the head coach when he or she says, ‘who is available for training today and how hard can I push them?

IMU are solving this problem with an app we call IMU Ready. By attaching one of our sensors to an athlete’s centre of mass, we are able to quickly & precisely quantify CMJ metrics in real time so high performance teams can make fast and informed calls on player readiness. Believe me when I say building this app did not come easy. It’s taken us many many moons of hard core algorithm testing against Vicon high speed video to deliver the metrics below:

  • Mean absolute % error height = 2.7% in currnet state
  • Mean absolute % error peak velocity = 2.3% in current state
  • Mean absolute % eccentric time = 3.8% in current state
  • Mean absolute % concentric time = 1.6% in current state

It goes without saying our team will relentlessly seek to improve on these metrics and the sensor and software end user experience. A special and massive thanks to all of our awesome early adopter customers who have helped us design and deliver a user experience that fits seamlessly into their existing athlete readiness workflow.

Clearly I’m biased but in IMU Step and IMU Ready I genuinely believe we’re building a world class, precise, mobile athlete readiness & workload management solution. I think Professor Tim Cable, director of sports performance at Aspetar, sums it up perfectly in this interview (16 minutes in) when he says, and I paraphrase, sports scientists and analysts can deal with all the data but when it boils down to it, they must answer one question, can this player train today at this intensity?’  

If you’re a pro or collegiate Basketball, Soccer, Tennis coach and interested to find out more about how IMU Step & Ready can help you more precisely manage training load, performance & injury prevention, feel free to contact me via directly at or via our contact page.

Leave a Reply