Rehabbing teenagers can be awkward! – sensorimotor function during adolescence

There is a bit of a buzz phrase in rehab about “individualising programs” and while it is something we wholeheartedly agree with, it is a phrase that is very easy to say and yet very difficult to implement. Especially when you work with a population where said individual changes rapidly through time, like a teenager! It is a common sight on a training pitch to see a star player in their age group suddenly tripping over cones or developing a heavy touch where there was previously effortless control. Side effects of the adolescent growth spurt, where the brain is now controlling a much longer lever. It’s like giving a champion gardener a new set of garden sheers when for the past year they have used little hand-held scissors and asking to them maintain their award-winning standards. (My garden embarrassingly needs some attention and it’s affecting my analogies).

The control and precision between these two instruments is influenced by the lever length of the handles…

…Similar to a rapidly growing femur and tibia which is still being operated by muscles that have length and strength suitable for shorter levers.

 

 

 

 

 

 

 

 

Alongside the performance related issues, there is suggestion that this period of growth may coincide with increased risk of injury (Caine et al 2008). We believe that bone grows quicker than soft tissue, so we are asking a neuromuscular system to control a new, longer lever using prior proprioceptive wiring. Imagine our gardener again, for a long time he has been able to keep his pair of scissors close and controlled, now with his extra long shears the load is further away from his body, his back and shoulders are starting to ache. Not sure what I mean? With one hand hold a pencil to the tip of your nose. Now, with one hand hold a broom handle to your nose. The longer lever is harder to control. **I promise it gets a bit more sciencey than gardening and broom handles. **

Managing these growth spurts is something we have talked about before and recently contributed to a BJSM podcast on the topic (Part 1 & Part 2) and a complimentary BJSM blog about “biobanding” during periods of growth and development (here). This particular blog was inspired by a recent (2015) systematic review looking into exactly which sensorimotor mechanisms are mature or immature at the time of adolescence by Catherine Quatman-Yates and colleagues over in Cincinnati (here). The following is a combination of their summary and our examples of how these findings can influence our rehab programs.

Tailoring the program:

We have so many options for exercise programs, that’s what makes the task of designing them so fun. It challenges our creativity. When working with a teenager with sensorimotor function deficits, let’s call them “Motor Morons” for short, we don’t have to totally re-think our exercise list, just perhaps the way we deliver them. We previously spoke about motor control and motor learning (here) and how our instructions can progress just as our exercises do, but the following relates to children and adolescents in particular.

Consider the stimuli.

Children aged between 14-16 have well-developed visual perception of static objects however their perception of moving objects and visual cues for postural control continue to mature through adolescence. When very young children learn new skills such as standing and walking, they become heavily reliant on visual cues. Quatman-Yates et al suggest that puberty and growth spurts (think gardener with new shears) brings new postural challenges that causes adolescents to regress proprioceptive feedback and increase reliance on visual cues again. From a rehab perspective, we need to consider this as part of our balance and proprioception program. How many of us default to a single leg stand and throwing a tennis ball back & forth from therapist to athlete? For our Motor Moron, this may not be an optimal form of treatment in early stages, where it is commonly used, however it may incredibly beneficial to that athlete in the later stages or as part of ongoing rehab as we try to develop that dynamic perception.

Consider the amount of stimuli involved in an exercise versus what your goal of that exercise is

We should also consider the amount of stimuli we add to an exercise. Postural stability in children is believed to be affected by multiple sensory cues. If we consider that children are more dependent on visual cues than adults are, perhaps our delivery of external stimuli should be tailored also. With a multi directional running drill for example, there is sometimes an element where the athlete is given a decision making task (a red cone in one direction and a yellow cone in another) and they have to react quickly to instructions from the therapist or coach. Rather than shouting instructions like “red cone”, “yellow cone” etc, hold up the coloured cone for the corresponding drill. This way we are utilising this developed visual perception, minimising the number of stimuli and also encouraging the athlete to get their head up and look around rather than looking at their feet.

When to include unilateral exercises:

Within adult populations, it is often considered gold standard to make exercises unilateral as soon as tolerable. If they can deep squat pain free and fully weight bear through the affected side, progress them to pistol squats ASAP, or single leg knee drives. However, young children (pre-pubescent) may struggle with this for a couple of reasons.

Difficult enough even for an adult to perform, but uncoupling the actions of the each leg & fine muscle movements to maintain balance are extra challenging for children

Firstly, we need to consider postural adjustments. Where as adults and young adults can adjust their balance with smooth control and multiple, small oscillations, children rely on larger ballistic adjustments. There is also reduced anterior-posterior control in younger athletes which suggests reduced intrinsic ankle control. Put this alongside immature structures and (if working a physio, most probably) an injury then single leg exercise become a progression that may be further down the line than an adult counterpart with the same injury. Instead, consider semi-stable exercises. Support the contralateral leg with a football or a bosu ball – something that is difficult to fixate through but provides enough stability to support the standing leg.

Secondly, we understand that coupled movements are mastered earlier in adolescence, around 12-15 years old but uncoupled movement patterns take longer to develop, 15-18 years old (Largo et al). A good example is watching a young child reach for a full cup of water at the dinner table. It is much easier and more natural for them to reach with both hands than it is with one, as coupled movements are unintended. Rarely do you see a child taking a drink with one hand filling their fork with the other – yet this is something commonly seen with adults as they are able to uncouple and segmentalise. Another example is watching a child dynamically turn, watch how the head, trunk and limbs all turn as a “block”, it is not until further down the line where dynamic movements become more fluid. The argument here is that surely running is an uncoupled movement? Or kicking a football, swinging a tennis racket, pirouetting in ballet – they are all uncoupled, segmental movement patterns that we expect kids to do, and in all they cope with. Correct, but it is usually in rehab programs for kids that we begin to introduce unfamiliar tasks and exercises that they may not have encountered before. Also, we should respect the impact of the injury on proprioception and control. So these are all considerations for starting points in exercise & if a regression is ever required.

For this reason, it is important that exercises are monitored and reviewed regularly. There is no need to hold an athlete back because of their age and making assumptions on motor function because of their age. If they can cope, then progress them. But be mindful of “over-control” where speed and variability of movement are sacrificed in place of accuracy and control (Quatman-Yates et al 2015).

Become a Motor Moron hunter

It is worth spending some time watching training, watching warm ups, watching gym sessions and talking with coaches and S&C’s trying to identify a Motor Moron as soon as possible. It’s important to minimise the chances of an immature sensorimotor mechanism ever meeting a growth spurt. It is when these two things combine that we see kids doing immaculate Mr Bean impressions and therefore increase their risk of injury.

Regularly re-assess your exercise programs. If things arent quite progressing as quickly as they should, it may not be failed healing of an injury, but it may be that we are providing the sensorimotor mechanism with too much information!

 

Yours in sport,

Sam

 

“The Young Athlete” conference 9-10th Oct, Brighton. Here

The Osgood, the bad and the ugly

One of my best sources for recent literature is via a good friend of mine, Mr Jonny King (@Jonny_King_PT). Before he shot off to Doha to have his moment in the sun, he left a multitude of articles on my desk for me to read, one of which was a study looking at that persistent pest in my clinic, Osgoods Schlatters Disease (OSD).

OSD falls under the apophysitis or enthesopathy umbrella along with severs disease and Sinding Larsen Johansen disease amongst others. In our injury audit for the last season, these injuries alone accounted for 20% of our total injuries (u9-18s).

However, with a little bit of education to players, parents and coaches we feel confident that we can manage these numbers even better.

We are very lucky to be part of an in depth, ongoing study with the brilliant and very knowledgable Jenny Strickland at the University of Greenwich. With her guidance and protocol, we are bringing the days spent on the treatment table down considerably, but ideally we want to learn about these conditions to help prevent them in the first place.

What do we think we know?

OSD is a growth related condition, we think it can be attributed to high levels of activity during periods of growth. Unlike an adult presentation of a tendinosis, the condition affects the soft cartilaginous junction between the patella tendon and the immature anterior tibial tuberosity (ATT). (See my previous blog for the BJSM about differences between adult and Paeds injury management here).

Figure 1
Demonstrating the close relationship between the enthesis, the patella tendon, the infra patella fat pad and the physis of the tibia.

Historically OSD has been labelled as “growing pains” (a genuine medical entity, but no clinical similarities to OSD) and sufferers of the condition may well have been told to “just get on with it” or that “you’ll grow out of it”. Unfortunately this attitude still exists amongst some parents and, regrettably, GP’s – we see first hand evidence of this in our academy. When I first started in my role, I was guilty of just sitting a lad on the plinth with some ice, telling him to rest for a few weeks and we’ll see how we go.

OSD can almost certainly be attributed to growth spurts, where high levels of cellular activity in the growth zones of bone can’t be matched by the attaching muscles, resulting in traction on the inherently weak enthesis. Usual subjective presentation is that of an ache during, or more prominently, after activity. Gradually pain has been worsening over a period of days or weeks. Eases with rest. However, occasionally we see examples of players that have been kicked or landed on their knees in acute incidents but will display all the characteristics of OSD. But this doesn’t fit with our understanding of growth and traction…

Sailly et al (2013) looked at symptomatic adolescent male athletes competing in elite sport and using Doppler ultrasound they compared the ATT complex to gauge different stages of maturation. Within these stages of maturation, they could attribute pain scores from symptomatic athletes to determine the more vulnerable stages of growth (figure 2 below). The best descriptions for these stages that I have heard are from Sid Ahamed on his Adolescent Injuries course. He describes the enthesis as a continuum that develops with maturation from a stable state to an increasingly unstable state as the cartilage calcified with age.

Figure 2
Classification system of the maturation status of the ATT from stages 1 to 4. ATT, anterior tibial tuberosity; B, bursa; FP, fat pad; HC, hyaline cartilage; M, metaphysic; O, ossicle; P, physis; PT, patellar.

In Sailly’s study they found that no players reported pain during the “stable” first phase but increasing scores of VAS in stage 2. As the enthesis calcified and unites in stage 3 and 4, the numbers decrease again.
So what is happening in this 2nd stage of maturation? The use of Doppler ultrasound opens some new theories. In these symptomatic stage 2 patients, there was Doppler activity within the pre-patella and deep infra patella bursa, indicating the presence of neo-vessels within these structures. Recently, Seth O’Neil (physio matters podcast) explained that most of these pain inducing neovascular structures are actually present in peritendon & surrounding tissues like the bursa, fat pads and fascia. Maybe the same is true with the adolescent population.
The synovium that surrounds the enthesis is highly prone to compressive forces and as such, prone to inflammation. In the developing ATT, the patellar ligament attaches to the tibial tubercle but also to the physis of the tibial growth plate and to the periosteum of the metaphysis of the tibia (see figure 1 at top) . Sailley et al propose that this anatomical area is not only prone to traction that we normally associate with OSD, but also compression. Perhaps this explains the sudden onset OSD in the clinic alongside those rumbling insidious case loads.

Management:

As I mentioned, we now follow the Strickland protocol at our club in terms of treatment, but I still believe the key is in prevention rather cure. We regularly discuss loading with our coaches at every age group. If you consider that most of our players at school boy level will also play and train for their school, probably be selected for other sports such as cricket and rugby and will generally tear around everywhere at 100mph. Basically their day consists of sprinting, jumping, bounding and kicking. Consider the load on those immature structures (both compressive and tensile). As part of a warm up, does that player then need to do a series of hurdle drills or jumps? Could they not spend their conditioning sessions doing low impact movement patterns, balance & proprioception, or co-ordination drills for their newly elongated and uncontrollable limbs? Perhaps every now and then having a training session where the lads don’t have to strike a ball? Like basketball maybe, where you teach spacial awareness and evading the opponent? Or placing a technical bias on the session and reducing the pace?
If we can help coaches, players and parents understand that modifying activities and occasionally, resting, is the best thing in the long run for all parties, I think we will continue to see a drop in training / matches missed due to OSD.

Yours in sport
Sam