Isometrics in tendinopathy – a wonder weapon to decrease pain?

Isometrics in tendinopathy – a wonder weapon to decrease pain?

Are isometrics the wonder weapon to decrease pain in tendinopathy? In this blog we will discuss where the isometrics “trend” came from and what the evidence says about it!

In 2015 Dr. Ebonie Rio and colleagues started a bit of trend when they conducted a cross-over trial in 6 volleyball players with patellar tendinopathy. Their results were astonishing with all players experiencing an immediate decrease in pain from an average of 7/10 on the NRS to 0 with only one of the 6 reporting a remaining pain of 1– for at least 45 minutes after the isometric contractions.The protocol they used were 5 sets with 45 seconds contraction in a leg extension machine and an effort of 70% of the maximal voluntary effort. They also found that isometrcis were able to decrease cortical inhibition and an increase in strength of 19%.They compared the isometric intervention with an isotonic intervention and the effects seen in the isometric group could not be achieved in the isotonic group:

Figure from Rio et al. (2015)

The same authors did a follow up in-season study with jumping athlets two years later in which they compared an isometric programme and an isotonic programme to each other. In this study the results were a bit more heterogenous with both groups with a greater immediate pain decrease in the isometric group:

Figure from Rio et al. (2017)

A recent study by Holden et al. (2019) looked at the effect of isometrics in patellar tendinopathy as well and did not find any analgesic effect:

Holden et al. (2019)

However, a high percentage of women and a relative high average age is untypical for patellar tendinopathy, which is usually a disease of young jumping men. So it could be that the diagnosis of patellar tendinopathy was no correct in some cases.
Now while those two studies were conducted for patellar tendinopathy, let’s look if we can transfer these results to other tendons.
Looking at the Achilles tendon, Seth O’Neill and colleagues did a study in 2018 in which they had a group of patients with Achilles tendinopathy performing isometric contractions of the plantar flexors. They found no immediate pain relief nor improved motor output in patients with Achilles tendinopathy:

Figure from O'Neill et al. (2018)

A study of Riel et al. In the year 2018 examined the effects of isometrics, isotonics and walking on pain for plantar fasciitis. They found that there was no change in pain for any of the groups before to after the exercises:

Riel et al. (2019)

At last, Coombes et al. In the year 2016 looked at isometrics on lateral epicondylalgia. In their study, isometric contractions above the patients’ pain threshold actually increased their pain levels after the exercise, while isometric contractions below the patients’ pain threshold had no effect compared to a control group:

Figure from Coombes et al. (2016)

Another study from Stasinopoulos et al. In the year 2017 compared three exercise groups in the treatment of lateral epicondylalgia: One group performed eccentric training, another eccentric-concentric training and the third group combined eccentric-concentric training with isometrics. The authors argued that most grip activities require isometric contraction of the wrist flexors and extensors, so adding isometric exercises for LE makes absolute sense. They found that adding concentric led to superior results at pain, function and grip strength at 4 and 8 weeks:

Table from Stasinopoulos et al. (2017)

However, the follow up time of the study was rather short and should at least have been 12 weeks. On top of that the combined isometrics group performed a higher exercise volume with more time under tension which could explain the superior results.

So while isometrics are certainly no magic bullet, what role do they play in tendinopathy rehab? First of all,  isometrics are a great option to start exercising if everything else is too painful – and this is not only limited to tendinopathy but other conditions as well. Be aware that they must progress to isotonic exercises, because you want to recover muscle function over the full range of motion instead of just 1 angle. So move on as soon as a patient is able to tolerate isotonic loads.
What can be derived from all of those studies is that isometrics do seem to work really well in some subjects and can actually make things worse in other subjects. To keep it simple, give them a try with the patient in front of you and if they respond favourably, keep doing them, if they don’t move on.
While 45 minutes of pain relief might not be a goal that is important in the average patient, this might be useful for athletes as a warm-up to decrease pain during the ensuing exercise session or competition. Isometrics are also less tiring for athletes in-season as they are less tiring than isotonic exercises. One can surely argue if it is desirable to achieve short-term pain reduction in order to load a painful tendon during sporting activities and if this might actually lead to detrimental effects.

Alright, this was our blog on isometrics for tendinopathy. If you were surprised by the results, you will love our blog on 7 facts about tendinopathy you didn’t know! Thanks so much for reading. 

 

References:

Coombes BK, Wiebusch M, Heales L, Stephenson A, Vicenzino B. Isometric exercise above but not below an individual’s pain threshold influences pain perception in people with lateral Epicondylalgia. The Clinical journal of pain. 2016 Dec 1;32(12):1069-75.

Holden S, Lyng K, Graven-Nielsen T, Riel H, Olesen JL, Larsen LH, Rathleff MS. Isometric exercise and pain in patellar tendinopathy: A randomized crossover trial. Journal of Science and Medicine in Sport. 2020 Mar 1;23(3):208-14.

O’Neill S, Radia J, Bird K, Rathleff MS, Bandholm T, Jorgensen M, Thorborg K. Acute sensory and motor response to 45-S heavy isometric holds for the plantar flexors in patients with Achilles tendinopathy. Knee Surgery, Sports Traumatology, Arthroscopy. 2019 Sep 1;27(9):2765-73.

Rio E, Kidgell D, Purdam C, Gaida J, Moseley GL, Pearce AJ, Cook J. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British journal of sports medicine. 2015 Oct 1;49(19):1277-83.

Rio E, Van Ark M, Docking S, Moseley GL, Kidgell D, Gaida JE, Van Den Akker-Scheek I, Zwerver J, Cook J. Isometric contractions are more analgesic than isotonic contractions for patellar tendon pain: an in-season randomized clinical trial. Clinical Journal of Sport Medicine. 2017 May 1;27(3):253-9.

Silbernagel KG, Vicenzino BT, Rathleff MS, Thorborg K. Isometric exercise for acute pain relief: is it relevant in tendinopathy management?.

Riel H, Vicenzino B, Jensen MB, Olesen JL, Holden S, Rathleff MS. The effect of isometric exercise on pain in individuals with plantar fasciopathy: a randomized crossover trial. Scandinavian journal of medicine & science in sports. 2018 Dec;28(12):2643-50.

Stasinopoulos D, Stasinopoulos I. Comparison of effects of eccentric training, eccentric-concentric training, and eccentric-concentric training combined with isometric contraction in the treatment of lateral elbow tendinopathy. Journal of Hand Therapy. 2017 Jan 1;30(1):13-9.

ATTENTION THERAPISTS WHO WANT TO PREVENT MUSCLE AND TENDON INJURIES IN THEIR ATHLETES

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Pathomechanics of lower limb muscle and tendon injuries
7 crucial facts about lower limb tendons

7 CRUCIAL FACTS ABOUT LOWER LIMB TENDONS YOU DIDN’T KNOW

7 crucial facts you didn’t know about tendons

7 crucial facts about lower limb tendons

In this blog post we are going to discuss 7 absolutely crucial facts about tendons that you probably didn’t know, but that are very important to improve your tendinopathy rehab.

Let’s jump right into it:

1. The nociceptive driver of pain in tendons is unknown. Pathology seen on imaging is not the driver of pain. Vascularity is not the source of pain, merely a marker of tendon degeneration. On top of that, there are no sensory nerves deep in the tendon, but in the periphery around the tendon. Nerves that grow into a pathological tendon, are sympathetic nerves, not sensory. At last, central sensitization is probably less a problem in lower limb pathology compared to upper limb pathology (Plinsinga et al. 2015, Plinsinga et al. 2018).

 

2. We are not able to repair/heal degenerative tendon pathology. In other words, no surgery, no shockwave therapy, no injections whatsoever and not even exercise is able to repair or heal a degenerated tendon. Docking et al.(2019) reason that with little ability to sense tensile load, the cells in the degenerative part of the tendon may be under-stimulated and not receive the necessary mechanical stimuli to remodel, explaining the limited capacity of the pathological tendon to remodel and normalize. While you think that this might be bad news, the good news is: it’s also not necessary. A study by Tsehaie et al.(2017) showed that 24 weeks of eccentric exercises for the Achilles tendon did not produce changes outside the limits of detectable change in the tendon, but yet patients improved. They also found that o MRI parameter at baseline predicted the change in symptoms, so even if your MRI looks terrible, it doesn’t matter.

Figure from https://www.ultrasoundcases.info/partial-ruptures-7335/#gallery-2

 

3. The tendon loading rate probably explains why tendinopathy is associated with repetitive stretch-shorten cycle (SSC) rather than heavy loads. The SSC occurs during any activity that requires the tendon to store and release energy like a spring. Everything else is easy for a tendon e.g. eccentric movements, high weight. The loading rate is calculated in BW/sec. Here are two examples for the patellar and the Achilles tendon in different activities. So the highest loading rate for the patellar tendon is to land in a stop jump sequence, like in a basketball or volleyball, while leg pressing 3x bodyweight has a very low loading rate. This is the same for the Achilles tendon where calf raises have a very low loading rate for the tendon while running and hopping have a very high strain rate. Interestingly, the very best athletes who can run fast or jump high are the ones who are also at risk to develop tendon pathology the most, probably because they can load their tendons faster than anyone else. This phenomenon is also called the “Jumper’s knee paradox”, described in an article by Visnes et al. (2013)

Patellar tendon tensile load and loading rate in typical activities:

Figure from a presentation of Jill Cook

Achilles tendon tensile load and loading rate in typical activities:

Figure from a presentation of Jill Cook

4. The Combination of compressive loads and tensile loads are more damaging to any of the two alone. A study by Soslowsky et al. (2002) compared 3 groups of mice to each other: In 1 group they manipulated the acromial arch to simulate external compression, one group had higher tensile loads as they had to run on a treadmill more than other groups and a combined group. They found that extrinsic compression did not cause injury until overuse activity was introduced. While compressive properties may be important, tensile properties are more relevant properties in a tissue such as a tendon. The results show that the combination of external compression plus tensile loads led to the greatest injury.

Figure from Soslowksy et al. (2002): Injury created by overuse plus extrinsic compression is greater than the injuries created by overuse or extrinsic compression alone. Significant differences relative to control are indicated by a ‘‘*’’ inside each bar (average +- standard deviation). Significant differences between single factors (E=Extrinsic, OV=Overload and multiple factors (OV/E) are indicated by a ‘‘*’’ above each pair of bars.

5. Intense loading of tendons results in net collagen degradation for up to 36h. A study by Magnussen et al.(2010) showed this effect in three groups of very intense exercise, which were 36km of running, 1 hour of repetitive kicking and 10 sets of 10 repetitions of knee extension at 70% maximal voluntary contraction. This means that we need sufficient recovery time to prevent tendinopathy and it’s advisable to space out training sessions for the tendon to every other day or less.

Figure from Magnussen et al. (2010)

6. A pathological tendon has more good structure than a normal tendon (Docking et al. 2015). This means we can load these tendons because we have loads of good tissue. Any therapies for tendon pathology are not necessary, because we cannot change the structure of the pathological part anyways. For this reason, Docking and colleagues came up with the quote “Treat the donut, not the hole” – in other words, focus on the healthy structure and not the pathological part.

Figure from Docking & Cook et al. (2015)

 

7. 66% of Achilles tendon ruptures are asymptomatic ruptures (Kannus et al. 1991). This means these people never had Achilles tenderness, stiffness, pain or dysfunction. However, there had to be some kind of pathology present in the tendon as the authors showed that 98% of ruptured tendons had degenerative pathology, while 2% had other pathology. Jill Cook explained this in a Twitter post stating that it’s impossible to rupture a normal tendon in vivo without pathology.

Interestingly, a study by Yasui et al. (2017) showed that only 4% with Achilles tendinopathy go on to rupture the tendon. So pain in tendinopathy might actually be protective of a rupture and this is a very good and re-assuring message for patients who are in tendon pain and afraid to rupture their tendons.

Alright, how many of those 7 were completely new to you?
As always, thanks a lot for reading!

ATTENTION THERAPISTS WHO WANT TO PREVENT MUSCLE AND TENDON INJURIES IN THEIR ATHLETES

100% FREE Webinar: What to Look for in Athletes to Prevent Hamstring, Calf and Quadricpes Injuries

Whether you're working with high-level or amateur athletes you don't want to miss these risk factors which could expose them to higher risk of injury. This webinar will enable you to spot those risk factors to work on them during rehab!

Pathomechanics of lower limb muscle and tendon injuries