Adaptations to Training
When we “use” our bodies, our bodies adapt to the activity we are doing. The more we do, the more we are able to do. The less we do, the less we are able to do. This is essential in eliciting a training response.
When we train we want to cause stress to our body. (This may be our muscles, bones, cardiovascular system, etc.) We want to overload the system, which causes a degree of damage or micro-trauma. The body then responds by growing bigger / stronger / faster / fitter, so it can cope with that load in future. We cause stress to force adaptations.
Stress/load => damage => rest/recovery => adaptation/growth.
A lot of common gradual-onset injuries result from a failure to adapt to load.
There are a number of variables that can be multiplied to determine the total load:
The intensity of the activity is the most powerful multiplier in this list.
When we are considering total load, we also need to consider variables that make it harder for our bodies to adapt to load.
Variables that can be multiplied to determine how well we adapt to the load:
Recent research found that getting less than 8 hours sleep a day almost doubles the injury rate in athletes.
Often when I’m talking to my patient about their injury and why it has happened, they guiltily report that they don’t stretch enough.
We’ve all grown up being told how important is it to stretch:
Interestingly, health professionals have changed our tune about the importance of stretching. Research over the last 15 years has suggested static stretching is not as beneficial as was once thought. I’ve been having conversations about the reasons to stretch (or not) for at least the last 10 years, but the current science on stretching just isn’t catching on.
So, what do we know?…
DOES STRETCHING PREVENT INJURIES?
Therefore, in practical terms the average athlete would need to stretch for 23 years to prevent one injury. Definitely not worth it.
DOES STRETCHING HELP MUSCLE SORENESS?
DOES STRETCHING INCREASE RANGE OF MOVEMENT?
DOES STRETCHING HELP PERFORMANCE?
A substantial body of research has shown that sustained static stretching acutely decreases muscle strength and power (ref). Stretching before an endurance event lowers endurance performance and increases the energy cost of running (ref). Cycling efficiency and time to exhaustion are reduced after static stretching (ref).
Pretty much any measure of performance is made worse by stretching. Static stretching impairs:
- maximal voluntary contraction
- isometric force
- isokinetic torque
- one repetition maximum lifts
- vertical jump
- sprint times
- running economy
A comprehensive review (ref) from 2011 concludes:
WHAT ABOUT DYNAMIC STRETCHING?
SO WHY STRETCH?
SO SHOULD WE STOP STRETCHING?
Do you love a good stretch?
Or feel guilty you're not stretching enough?...
I’ve been frustrated this week by a couple of patients with Achilles problems that I thought should recover well. They’ve disappeared to go and have an injection, against my recommendation. It’s made me think about whether or not I should have made the referral myself? What are our options for injections, and do they work?
There are a range of commonly prescribed treatment options for tendinopathy, but very few are supported by quality, randomised, prospective, placebo-controlled trials.
SO WHAT DO I DO?
WHAT ABOUT INJECTIONS?
There are a range of drugs to inject into or around a tendon, depending on who you are referred to:
- Corticosteroid (A strong anti-inflammatory)
- Prolotherapy (An irritant to stimulate new tissue growth, e.g. hypertonic dextrose/glucose)
- Sclerotherapy (An irritant to decrease vascularisation, e.g. Polidocanol)
- Traumeel (A homeopathic preparation derived from arnica)
- Actovegin (derived from calf blood)
- Autologous blood (injecting your own blood into the tendon to promote healing)
- Platelet-rich plasma (blood is taken and PRP is extracted and injected to promote healing)
- High-volume injections (to damage the tissue and encourage new growth)
PROLOTHERAPY / SCLEROTHERAPY
AUTOLOGOUS BLOOD INJECTIONS
PLATELET RICH PLASMA (PRP)
WHY DO THE INJECTIONS WORK FOR SOME PEOPLE?
REGRESSION TO THE MEAN
Injections are a powerful way to administer a placebo effect. You need to see a specialist to receive it. You need to pay more money. There’s some high-tech equipment spinning the blood. Everything is set up for you to expect improvement and, in a decent percentage of cases, that’s all it takes to get better. If you believe the injection will help you then it is much more likely to work. However, the research tells us it doesn’t really matter what substance is injected, it is your belief in whether or not it will help that is the variable more likely to determine the outcome.
Have you had an injection for your tendon?
ACL Rehabilitation Guide (available here)
A criteria driven ACL rehabilitation protocol and guide for both clinicians and people who have undergone a surgical reconstruction of the Anterior Cruciate Ligament (ACL).
Author: Randall Cooper
I was thinking about what frustrates me about physiotherapy. What are the things that physios do that confuse me? If I was a patient, what would stop me coming back?
What I don't like is physios that make things super complicated. I'm not sure if that helps position them as an "expert", meaning you've got to pay them because you absolutely can't help yourself. Or it may be that they don't completely understand what they're talking about so can't explain it well. But I don't like smoke and mirrors. I think physio can be pretty simple.
This leads me to ask - if I boil it down, what are the most important things I do to help you recover from your injury?
I think it comes down to two key components:
- You need to understand what's wrong. I need to explain some complicated stuff to you in a way that my Nanna or my kids could understand. If you understand what's going on, you'll understand why it's important to do what I ask you to do to get yourself better.
- What are the one or two most important things you need to do? If it was just one thing, what would you do? Best bang for your buck?
Usually the most important thing comes down to you doing a stretch or strengthening exercise at home. More often than not it's you consistently making small gains with a home program that makes the biggest difference to your recovery. Not anything miraculous that I can do to you here.
If it's super important, why do some people do their home exercise and others don't? Life gets in the way. It's hard to remember. You've got better things to do.
So, I need to make it as easy as possible for you. That's my job. That's why I'm better than just googling it.
I understand that small stuff gets in the way. You remember to do the exercise when you're in the car and can't do it. Before you know it, you get to the end of the day and it's not been done. There's lots of little things that make a home exercise program hard to do "now" - meaning you leave it for "later". If you have to get on the floor you'll do it "later". If there's too many exercises to do, you'll do it "later". If you have to use equipment - it's not on hand. Any little barrier to getting it done means it doesn't get done. It needs to be easy.
So my practical solution for your recovery comes back to: WHAT WOULD I REALISTICALLY DO MYSELF?. It's lucky I've had a few injuries and have learnt what's realistic and what's not. If I had your injury, what is the one thing I would actually, realistically do myself?
I think that is a great question for all healthcare professionals. Because we know that around 40% of our health budget is wasted on unnecessary tests and treatments. Unnecessary healthcare expenses add up to $45 billion/year in Australia. It is amazing how many things healthcare practitioners recommend to patients that they wouldn't do themselves.
I think we could save a lot of time, effort, and money if all health practitioners had a tick box to sign-off on all investigations and treatments - Would they do it themselves?
So that's what I give you. Things that I would do. I understand what is practical and realistic.
Simple Explanations + Practical Solutions = Happy You!
Monitoring the athlete training response: subjective self-reported measures trump commonly used objective measures (Saw AE et al, 2015)
Monitoring athletes' response to training is crucial for improving performance and avoiding injury.
Elite level sport utilises an increasing number of ways to measure athlete well-being. Batteries of tests are packaged into commercial products attracting premium fees. This is justifiable if you are Sydney Swans or Liverpool FC, but where does that leave the rest of us? Are we missing out if we're not testing cortisol levels to know if we are over-training?
A recent paper carried out a systematic review where objective measure, such as:
- blood markers - hormonal / inflammatory / immune response
- heart rate
- oxygen consumption
- heart rate response
- perceived stress
The researchers concluded that the:
- Subjective measures responded well to training-induced changes in athlete well-being.
- Subjective well-being typically worsened with an acute increase in training load and with a chronic training load; and improved with an acute decrease in training load.
- Subjective measures for routine athlete monitoring are relatively cheap and simple to implement.
- Subjective measures are useful for athlete monitoring, and practitioners may employ them with confidence.
Knee and ankle injuries are common in netball, making up three quarters of all injuries. Devastating ACL injuries are unfortunately common, making up 25% of serious injuries.
The KNEE program offers a range of warm-up exercises that help prevent injury. There are a range of age and experience appropriate exercises for junior through to elite netballers. They are easily understood by players and coaches, with a number of options offering variability and progression.
It would be great to see this program widely adopted by Australia's largest participation sport for females.
Load Management For Injury Prevention
Managing training load is crucial in injury prevention and treatment. A graphic in Tom Goon’s recent blog visualises how training load outweighs all other factors.
Historically we have advised that training loads shouldn’t increase by more than 10% a week. I’m not sure where this figure comes from. I’ve got no problem with it, it seems reasonable, and I’ve quoted it hundreds of times.
There’s a recent BJSM podcast interview with Tim Gabbett on load management for injury prevention. Specifically Tim talks about this paper:
- Billy T Hulin, Tim J Gabbett, Peter Blanch, Paul Chapman, David Bailey, John W Orchard, 2013.
It is research into fast bowlers but I think the principles apply just as well to any athlete.
They measured the acute workload of the last 7 days (and call it “fatigue”) and compare that to the chronic workload of the previous 4 weeks (which they call “fitness”).
Measuring Training Load
Or we could be more accurate and account for a mixed training program that may include a variety of hills / sprints / cross training etc, by giving each session a rate of perceived exertion (RPE) out of 10, and multiply that score by the number of training minutes:
The research subtracted the current 1-week average from the previous 4-week average and called this number the “training-stress balance”.
A negative training-stress balance increases the risk of injury 4 times.
Negative balance = 4 times risk of injury
For people that may be more vulnerable to injury I would change the 4-week average to a 6-week average, therefore, bringing the increase in load each week down from 25% to 16%.
This more cautious group could include:
- Pre-season training
- Kids going through growth spurts
- Athletes returning from injury
- Known history of over training injuries
- People without any training history
- Novel exercise modality
- The rate of hamstring injuries is as bad as it’s always been, and the recurrence rate remains high.
- Central tendon injuries and over-stretch style injuries (proximal semaimembranosous tendon) take longer to return to play than the more common sprinting style injury (long head of biceps femoris).
- Strengthening based rehab should be performed in a lengthened position.
- No evidence to support PRP injections for hamstring injury.
- Nordic curls are effective at preventing hamstring injury.
- The volume of muscle injured, as measured on MRI, does not predict the prognosis for the time taken to return to play (RTP).
- Self-predicted time to RTP is reasonably accurate.
- Biceps femoris injuries have a high recurrence rate.
- Eccentric hamstring strength is reduced even after RTP.
- Early reduction of pain (to decrease muscle inhibition).
- Early muscle activation.
- Eccentric exercise at longer muscle lengths.
- Early return to running.
- Rapid progression to high-speed running.
After an initial ankle sprain, athletes are prone to re-injury of the same ankle. The risk of suffering an ankle sprain is doubled in the year following initial injury.
Common interventions aimed at preventing ankle sprains include taping, bracing, muscle strengthening, and balance training.
Taping and bracing have shown to be effective prevention for ankle sprains, however disadvantages include hindering performance, loosening with activity, and skin irritation.
A 2015 systematic review and meta-analysis from La Trobe University has concluded that balance training programmes are effective at reducing the rate of ankle sprains in sporting participants, particularly those with a history of ankle sprains.
Approximately 17 sporting participants, or 13 participants with a history of ankle sprain need to undergo balance training in order to prevent one future ankle sprain.
It’s theoretically possible to return to play as soon as you’re able to stand up again, but obviously there’s a high chance of injury aggravation &/or recurrence. So, successful return to play isn’t just getting back on the field, but also doing our best to make sure:
- your performance is up to standard
- and the injury doesn’t happen again.
For a lot of injuries we can agree on a rough timeframe of recovery based on our previous experience with similar injuries, and a known pattern of tissue healing. However, time alone is only a small component in determining successful return to play.
This article (Creighton, 2010) outlines the extensive range of other considerations for negotiating a successful return to play:
After assessing an injury I like to outline the milestones that are necessary to achieve a successful return to play.
Physical factors may include:
- Pain is tolerable
- Swelling / effusion has gone down
- Strength is similar to the other side
- Range of movement is similar to the other side
This guides our treatment & gives us goals to work on with rehab, which may include:
- Tissue healing
- Pain modulation
Functional milestones need to be achieved sequentially. You need to pass one level to get to the next.
Roughly, this might look like:
- Walk without limping &/or pain
- Non-contact training
- Train with contact
Progression through each of these functional stages may include:
- Increasing volume
- Increasing intensity
- Introducing hills
- Second daily running
- Two days on, one day off
- Daily running
By the time we return to the playing field we have confidence in the injury because we’ve done the work. Doing the rehab in a graded, progressive manner serves two purposes:
1). The exercise is conditioning, or “mechanotherapy”, to aid recovery.
2). It serves as a screening program, answering the question “am I OK to return to play?”.
Doing the rehab gives us confidence that you’re OK to do “Z” because you’ve successfully completed “W”, “X”, & “Y”.
Here is a graded, progressive running program I like you to progress through before returning to training.
Here is a graded, progressive rehab programs for throwing & a similar rehab program for kicking.
We know the biggest risk factor for any injury is a previous history of the same injury. That means once you’ve had an injury, you’re at risk of re-injury.
So successful return to play must include rehab aimed at preventing the same thing happening again. This might include specific stretching, strengthening, taping, bracing, proprioception, or skills. The job is only half done if you’re still at risk.