An Isometric exercise or isometrics are a type of strength training in which the joint angle and muscle length do not change during contraction (compared to concentric or eccentriccontractions, called dynamic/isotonic movements). Isometrics are done in static positions, rather than being dynamic through a range of motion.We learn these basic concepts during our college days.
Eccentrics versus Isometrics :
According to cook et all, even as eccentric exercising is the mainstay of maximum rehabilitation programs for tendinopathies, a few patient experienced them very painful to complete and hard to carry out full program.there is no effect of eccentric training in patella tendinopathy patient.
Conversely,model et all demonstrate study on pressure pain threshold.they said that the effect of isometric contraction on pressure pain thresholds (PPTs) yields promising effects. when asymptomatic volunteers held a quadriceps isometric contraction at 21% MVIC till exhaustion (maximum of five-minute length), patient demonstrated a extensive increase in PPT at the begin of contraction. PPT persisted to growth until the middle of the contraction period and stayed accelerated for as much as five mins post-intervention.
Reduced Perceived Pain:
In a similar study, PPTs have been determined after 14 healthful women finished 2 sets of submaximal (40-50% MVIC) isometric exercise consisting of compacting a dynamometer for 2 minutes with their dominant hand.This trial established a nice contralateral and ipsilateral hypoalgesic effect with expanded PPTs and a discount in self-perceived ache score for both arms following isometric exercising. while this affords an excellent basis of guide, it does now not provide information concerning isometric workout’s impact on people with a painful circumstance.
What the research said…,,,
a randomized cross-over study performed to investigate the hypoalgesic impact of a single bout of isometric contractions on individuals with patellar tendinopathy. Those in the intervention group performed 5 sets of 45 second isometric quadriceps contractions (70% MVIC) with a 2 minute rest break between each set. Those in the control group performed 4 sets of 8 repetitions (100% 8-repition maximum) of an isotonic leg extension exercise with a 4 second eccentric phase and 3 second concentric phase.
the conclusion of the study, isometric contractions reduced pain during single-leg decline squat.Also, cortical inhibition increased from 27.5% to 54.9%, which may factor into the underlying mechanism of this hypoalgesia.The reduction in pain was paralleled by a reduction in cortical inhibition, providing insight into potential mechanisms. Isometric contractions can be completed without pain for people with PT.
Further supporting the previous article , Rio and colleagues done another clinical study in depth of this area. They used a within-session randomized controlled trial to compare isometric leg extension at 60 degrees of knee flexion to isotonic leg extension in volleyball or basketball players with patellar tendinopathy. At the conclusion of the study, those randomized to the isometric knee extension group demonstrated significantly greater immediate analgesia throughout the 4 weeks trial.
Now let’s back to the basic :
When hypoalgesic effects are far more impactful then most of us recognize. However, we are not sure why isometrics are efficacious in these tendinopathies but they give us an intervention that is successful.
when it comes to clinical practice we have to do is go back to the basics!
Evidence based Exercises:
From the research we recommends the following isometric exercises for Patellar Tendinopathy:
- Supine Quad Set on Towel Roll,
- Seated Quad Set
- Prone Terminal Knee Extension.
Take home message:
Perhaps the most widely considered mechanism is that the activation of the endogenous opioid system during exercise reduces pain perception following exercise.
Exercise of sufficient intensity and duration results in the release of peripheral and central beta-endorphins which have been associated with changes in pain sensitivity
Rio E, Kidgell D, Purdam C, et al. Isometric exercise induces analgesia and reduces inhibition in patellar tendinopathy. British Journal of Sports Medicine. 2015;49(19):1277-1283. doi:10.1136/bjsports-2014-094386.
- Rio E, Kidgell D, Moseley GL, et al. Tendon neuroplastic training: changing the way we think about tendon rehabilitation: a narrative review. British Journal of Sports Medicine. September 2015:bjsports–2015–095215–9. doi:10.1136/bjsports-2015-095215.
- Rio E, van Ark M, Docking S, Moseley GL, Dawson K, Gaida J, 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. 2016.
- Contralateral attenuation of pain after short-duration submaximal isometric exercise. J Pain 2007;8:887–92.
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- Kisner, Carolyn, and Lynn Allen. Colby. Therapeutic Exercise: Foundations and Techniques. 5th ed. Philadelphia: F.A. Davis, 2007. Print.
- Alfredson H, Pietila T, Jonsson P, et al. Heavy-load eccentric calf muscle training for the treatment of chronic Achilles tendinosis. Am J Sports Med 1998;26:360–6. — Highlighted Jul 31, 2016
- Visnes H, Hoksrud A, Cook J, et al. No effect of eccentric training on jumper’s knee in volleyball players during the competitive season: a randomized clinical trial. Clin J Sport Med 2005;15:227–34.
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