The notion of muscles working eccentrically can be tricky to grasp even for seasoned athletes, as it includes two seemingly opposing actions: a muscle lengthening and contracting at the same time. Eccentric contractions, though, are occurring constantly during even the simplest actions, helping to make our movements smooth and controlled. Training muscles to function well in eccentric scenarios is a very effective way to build both strength and functional mobility, making eccentric exercises of particular relevance to athletes looking to enhance performance and increase functional, sport-specific flexibility.
In order to better understand how eccentric contractions work, let’s focus on one set of muscles: the hamstrings. As both extensors of the hip and flexors of the knee, the hamstrings generate power crucial to athletic performance, and are also a frequent site of chronic tension and injury. Hip extension and knee flexion are both achieved by the hamstrings contracting concentrically, meaning that the muscles shorten to create the joint action. Conversely, when the hip flexes and/or the knee extends, the hamstrings don’t simply go loose and floppy to allow these movements to happen; instead, the hamstrings continue to engage at the same time as they lengthen. This is eccentric contraction. In the context of hip flexion, the hamstrings’ eccentric contraction provides a sort of light, steady braking action that counters the concentric effort of the hip flexors in the heel strike phase of the gait cycle. Another way to think about it: the eccentric action of the hamstrings in hip flexion is what makes the difference between your leg lifting smoothly and steadily, rather than just being flung out in front of you.
With this in mind, it hopefully become easier to understand why the hamstrings and their tendons are vulnerable to injury, especially in high-level sports that require the hamstrings to function eccentrically at a much higher level of intensity than most of us encounter in normal life. Some examples of this include situations that demand hip extension under extreme load (an Olympic weightlifter pressing up from a weighted squat), or a combination of hip flexion and knee extension (a sprinter, or any runner overstriding). In other words, the hamstrings become vulnerable when tasked with generating power in a lengthened position. Injuries happen when the muscles are eccentrically overloaded, in which case a tear in either the muscle or the tendon can occur. It’s also worth noting that most athletes are incredibly tight to begin with, which can add to the risk of acute injury. While athletes need high levels of muscular tension for good performance, in their hamstrings and elsewhere, it’s easy to see how too much tension can make them prone to injury, too.
So, how do we minimize the risk of injury? As we’ve discovered, stretching the hamstrings for the sake of flexibility alone isn’t that useful, since what we really need is for them to lengthen and still have the ability to contract and generate power. This is exactly what eccentric hamstring exercises are for! The more familiar the contracting-while-lengthening scenario becomes, neurologically speaking, the more the athlete will reduce the risk of a hamstring blowout during the most demanding parts of their workout.
Below is an effective way to start building eccentric hamstring strength. It should be noted that the intensity in sensation is in direct proportion to the effectiveness of this exercise (as in, most people agree that it feels, shall we say, “challenging”). I would not recommend this for beginner-level athletes or yogis.
- Start in a low lunge, and scoot your hips back as you straighten your front leg to come to Ardha Hanumanasana. The hip of your front leg is now flexed, and the hamstrings are in a lengthened position- you should be feeling a stretch in the back of the thigh. You can place blocks under your hands if it prevents you from hunching forward- this will ensure that the stretch is isolated to the hamstrings, rather than letting it go into the low back. If the hamstrings are very tight, keep a little bend in the knee.
- Flex your front foot, and firmly press the heel down into the ground.
- Without actually moving the foot, attempt to drag the heel towards the back knee. In addition to the hamstring stretch, you should now also feel the muscle contracting.
- This is usually a great time to remind your student(s) to breathe, and maybe ease up a little if the stretch is very intense. Many athletes/ sensation junkies will work way too hard here; remind them that it’s best to stay at roughly 80% of what their maximum effort would feel like.
- While you’re here, explore sensations around the hamstrings. Maintain all the above engagements in your front leg, and carefully roll onto the outer heel so that the toes turn slightly outwards; you’ll feel the stretch move into the inner hamstrings. Roll onto the inner heel to bring the stretch into the outer hamstrings.
- When you’re done, slowly come forward into a lunge, and step into Uttanasana. Take your time here, paying attention to differences between the right and left sides. The hamstrings you worked on probably feel noticeably more open and loose (teacher tip: most athletes absolutely love it when they can feel immediate results from a stretch or exercise- play it up). It’s also useful to notice the breadth of the sensation: the entire back of the stretched thigh should feel pretty warm, which is a cool way to visualize the physical placement and width of the hamstring muscles.
- Repeat on the other side!
Jenni Tarma is a Los Angeles-based yoga teacher, writer, runner and CrossFitter. She specializes in making the yoga practice accessible and beneficial to athletes. She loves learning about anatomy and is currently studying for her 500hr certification with Yoga Medicine. You can find her on Facebook, or follow her on Instagram @jennitarma.