Originally posted on RunningPhysio
Funny what an injury does isn’t it? A few months ago I developed a hamstring tendinopathy and since then I’ve become a total tendon geek! The upside of all this is I have new knowledge that can help others manage troublesome tendons! Even injuries can lead to positive things if you can learn from them. This piece is part 1 of an overview of tendon rehab. It’s based on an excellent talk by Toby Smith from UK Athletics and a collection of recent research.
Runners reading this… please beware this is a complex condition and therefore a fairly technical piece. If you have a tendinopathy I highly recommend seeing a qualified Physio/ health professional for advice specific to your case. There is no recipe for tendon rehab! I have included ‘in a nutshell’ summaries at the end of each section and a ‘key point review’ at the end if you don’t want to read all the technical stuff!
Before tackling this piece on rehab I recommend you read our article on tendinopathy staging and compression as this is the foundation for much of the work here…
…done that? Good…then I’ll begin…
Despite recent advances in research tendinopathy rehab remains in its infancy. Our management of this condition is very different now than 10 years ago and 10 years from now will likely see different treatments again. There appears to be a bountiful supply of theoretical research but little in terms of high quality clinical trials. By this I mean that we have surprisingly few high quality studies proving clinically significant improvement from treatment.
Peter Malliaras et al. (2013) reviewed the literature recently on loading programmes for Achilles and patellar tendinopathy (2 of the most common) and found a number of methodological flaws. Just 2 studies were deemed ‘high quality’, only 2 described adequate blinding and the majority did not use a validated outcome measure. They also found that around 45% of patients didn’t improve significantly with exercise programmes. So, while we can make some recommendations, there is still some way to go before we have conclusive evidence on tendinopathy rehab.
As there are many treatment options for tendinopathy and many factors to consider, keep your main treatment goal in mind. A key goal in tendinopathy rehab is improving the capacity of the tendon and muscle to manage load. Tendon and muscle function together as a musculotendinous unit – we need to consider this in rehab, not just the tendon.
Scott et al. (2013) “Each component of the rehabilitation programme, in particular loading, must be manipulated in relation to the nature, speed and magnitude of the forces applied to the muscle/tendon/bone unit in order to achieve the goals of the particular management phase without causing an exacerbation of the pathological state or pain.”
So bearing this in mind then, how do we progress from pain to performance with tendinopathy? It helps to consider it in phases;
Phase 1 – reduce pain
Your first aim with managing tendinopathy is often to reduce pain. It is usually the most troubling complaint for a patient and pain in the tendon can lead to reduced activity in the muscle it’s attached to. Henriksen et al. (2011) tested the effect of experimentally induced Achilles tendon pain. They found that tendon pain causes “widespread and reduced motor responses with functional effects on the ground reaction force“.
Pain will often be more severe during a reactive tendinopathy. Typically the tendon swells in response to an increase in load. This has been described in more detail in our previous piece linked above. In short phase 1 is essentially about reducing pain in a reactive tendon (whether this is truly reactive or a reactive response on top of an underlying degenerate tendon).
Key to reducing pain is managing the load on the tendon. Try to avoid activities that place a compressive load on the tendon, usually this is any activity that would involve stretching the effected muscle or direct tendon compression (see table below).
Mechanism of tendon compression and potential solutions, adapted from Cook and Purdam (2012).
In addition cut out activities that involve the Stretch-Shortening-Cycle (SSC). The SSC occurs when the tendon has to behave a like a spring, stretching then shortening to store and then release energy. This usually occurs during high speed activities – namely running.
A painful reactive tendinopathy will often be aggravated by running; ideally running should be stopped or at least reduced to manageable levels during the reactive stage.
Few runners like to rest but it is often the best strategy in the early stages to help symptoms settle and ensure long term tendon health. It should be noted that avoiding any activity should only really be a short term strategy, in the longer term the aim is to gradually return to normal unrestricted movements.
Once load on the tendon has been reduced somewhat the reactive response will diminish. Anti-inflammatory medications, such as ibuprofen can be used to help this process by reducing tendon swelling (by regulating tenocyte activity). Always consult your GP or pharmacist before taking medication.
Isometric exercises can help to reduce pain in reactive tendinopathy. There is little research that I’m aware of on this that is specific to tendinopathy. However Naugle et al. (2012) reviewed the evidence on the role of exercise in reducing pain and found that, “isometric exercise appears to exert a generalized pain inhibitory response”. They found that long duration, low to moderate intensity contractions (25-50% Maximal Voluntary Contraction) had optimal analgesic effect. Obviously there are limitations of utilising these suggestions on tendinopathy. Cook and Purdam (2013) discuss isometric exercises in their recent paper;
“…these loads can be repeated several times a day, utilising 40-60 s holds, 4-5 times, to reduce pain and maintain some muscle capacity and tendon load. In highly irritable tendons, a bilateral exercise, shorter holding time and fewer repetitions per day may be indicated.”
This contraction should be done in a position where there is no tendon compression, usually in the mid-range of the muscle.
Phase 1 – in a nutshell – reduce excessive load and aggravating movements, consider taking ibuprofen, use isometrics to help reduce pain and maintain strength.
Phase 2 – improve strength
Once pain has settled you can progress to phase 2 and work on strength. Progression to this phase should be guided by your Physio/ health professional.
Strength is the ability to produce force. When we think of strengthening in this context we are aiming to improve the muscle and tendon’s ability to produce force and manage load. Muscle and tendon respond to load but it is thought that repetitive loading, such as walking or running, is unlikely to stimulate significant adaptive changes. Instead heavy load is needed to promote changes in muscle and tendon that improve their load capacity. Strength is an essential building block for muscle function, without adequate strength muscle will have poor power and endurance. Improving strength through resistance training has been shown to improve running economy (how efficient you are as a runner) and management of ground reaction force (the impact associated with running).
There are a number of options available to us in terms of exercise prescription, there is no recipe for this. It will depend on your pain and areas of weakness, your goals and the requirement of your sport. The question of how much strength is needed? is a complex one. In general we aim to achieve equal strength left and right and this can be measured using 10 rep max (10RM – maximum weight you can lift 10 times). There are some suggestions in terms of how strong we should aim to be as runners but little solid evidence to base this on. For example for quads strength, measured on leg press, many recommend your 10RM should equal around 1.5 times your body weight.
Research has focused on tendinopathy loading programmes that generally fit within 3 categories eccentric, combined or heavy slow resistance training;
For this phase of rehab you are aiming to achieve strength changes by exercising with sufficient load in a a muscle’s mid-range position. Avoid exercising with heavy loads in positions where there is likely to be tendon compression.
In the late 1990s eccentric exercises (such as ‘heel drops’) were considered the gold standard following research by Alfredson et al. (1998). They remain an option but more recently we have realised that the concentric part of the exercise needn’t be left out.
Heavy Slow Resistance training (HSR) has emerged more recently as another exercise option. Gaida and Cook discuss HSR and eccentric exercise briefly in their 2011 paper on patellar tendinopathy. They note there are pros and cons of each approach; eccentric work is often prescribed as a high frequency exercise – with Alfredson’s work recommending 3 x 15 reps of 2 exercises done twice per day. That’s 180 reps per day altogether! HSR by contrast is usually done 2-3 times per week but in many cases will require access to gym equipment. I often choose HSR as it can fit well into an athletes usual strength and conditioning programme at the gym and you have more control over load.
HSR involves using high loads – approx. 70-85% of 1RM (1RM – 1 repetition maximum – refers to the maximal weight you can lift once with good technique). Determining 1RM is difficult, especially in patients with pain so it can be approximated (see below). 80% of 1RM is roughly equal to 8RM i.e. the maximal weight you can lift 8 times with good technique.
To date there are only 2 studies that I’m aware of on HSR both on patellar tendinopathy; Kongsgaard et al. (2009) and (2010) used a graduated approach starting with lower loads at 15RM and building up to 6RM over 9-12 weeks providing there was no significant increase in pain. They used the squat, leg press and ‘hack squat’ and recommended 4 sets of each exercise with a 2-3 minute rest between sets, repeating 3 times per week.
Choosing load depends on the stage and severity of your condition and how confident you are with resistance training. Those with less pain that respond well to heavy loads may start closer 8RM. Others may need to build up more gradually. Ultimately though the goal is to reach these higher loads to create optimal tendon adaptation and muscle strength changes. The ACSM guidelines (2009) recommend working at between 8 and 12RM when starting strength work, although there is some debate on exact parameters and this is based on research on a health population not those with tendinopathy. They suggest 3 sets of 8-12 reps separated by 2-3 minute rest periods, repeated 2-3 times per week.
A third option with strength work is the combined approach of Karen Silbernagel et al. (2007). They used rehab phases and progressed patients depending on their symptoms. They also encouraged a monitored return to sport. Silbernagel et al. did not describe a specific amount of load in terms of % of 1RM, instead they start with the resistance of body weight (for calf raises) and progress in a similar manner to Alfredson – using a back pack or weights machine to increase load. There are however several key differences. Silbernagel et al. include both the concentric and eccentric component of the exercise and progress to include power and plyometric exercises. As such the findings from Silbernagel apply across most of the phases discussed in this article, not just strength.
As discussed above there is a paucity of quality research comparing tendon loading programmes and there appear to be very few outside of achilles and patellar tendinopathy. I’m not aware of any RCTs on proximal hamstring or gluteal tendinopathy (although I’m happy to be proved wrong here!). I recommend caution in extrapolating the results from achilles and patellar tendon studies to other tendons.
In Malliaras et al. (2013) previously mentioned review of Achilles and patellar tendinopathy, they reported that HSR training was more likely to lead to tendon adaptation but required further research. They didn’t find evidence to support isolating the eccentric component (as in Alfredson) although they did acknowledge that several potential mechanisms, such as neural adaptations, had not been investigated.
Overall Malliaras et al. (2013) found Silbernagel – combined and eccentric (for achilles tendon) as well as HSR loading (for patellar tendon) had the highest level of evidence for improving neuromuscular function.
There are a host of variables that can be modified to tailor strength work to an individuals needs and to have specific effects on the musculotendinous unit. These include time under tension, speed of contraction, position of limbs during exercise, range of movement covered, rest between sets and scheduling of exercise sessions. For example increasing time under tension during heavy slow loading may increase strain on the tendon and result in greater adaptation, however increasing speed will be more likely to improve power and prepare for activities involving the Stretch Shortening Cycle. Changing limb position during exercise (e.g. Foot position with squat) will vary the direction of the load and is useful to consider as people move in multiple directions so will encounter varying loads.
On a practical note it is worth remembering that tendon response to load takes time, consider both short term and long term reaction to load. In the short term there will be a net loss of collagen production for around 24-36 hours post exercise – so allow adequate rest days between strength sessions.
Reproduced from Magnusson et al. (2010) freely available online here.
In the longer term consider that significant changes in muscle strength take 6-8 weeks and tendons change slowly so may take 3-4 months to respond to a loading programme. All the studies mentioned above included at least 12 weeks of rehab – there’s no quick fix!
Phase 2 – in a nutshell – tendinopathy is likely to result in reduced muscle strength and function. Restoring this is essential for the long term health of the tendon. Several strengthening options exist but all share a common goal – gradually increase the load on the muscle and tendon while carefully monitoring pain. Strength work should be done in mid-range positions to avoid tendon compression. Ideally for optimum strength changes the load should be sufficient that you can only manage around 8-12 reps (i.e. 8-12RM) you may need to build up for this as pain allows.
Closing thoughts: tendinopathy is a complex condition and one that requires management based not on a standardised set of exercises but instead on each individual case. For some, reducing pain and building strength will be adequate to allow a graded return to running, in which case progression into the more advanced stages of rehab may not be necessary. In other cases, especially those hoping to return to running high mileage or intensity, progression through the phases to include rehab of movement dysfunction, power, and plyometrics may be needed. As with all advice on RunningPhysio this is not meant to replace assessment and treatment from a trained health professional. It’s is especially true when exercising with heavy weights or in pain. Getting a professional opinion can prevent a tendinopathy becoming a persistent problem that impedes your running so as ever if in doubt get checked out!
Coming in Part 2 – progression to phase 3 – functional strength and treating movement dysfunction and planning your return to running….