Mid-season core tune-up, part 2: The extensor chain

Last month we mentioned our second installment of foundational core exercises would address the "extensor chain." The extensor chain is a term used to denote the activation of the glutes, hamstrings and erector spinae.

During extension, the glute is the primary muscle responsible for movement, while the hamstring and erectors act together for stabilization. Muscle functioning of the chain can include dynamic movement, postural stability or a combination of the two.

A common dynamic (moving) example would be the motion of picking something up from the ground (returning from a flexed position). A postural example would be holding yourself upright or standing, as gravity works to pull you over. A combination of the two is exemplified during walking or running since the glutes, hamstrings, and erectors perform movement and stabilization at the same time.

Faulty link in the chain

Here are potential causes of muscle dysfunction or faulty activation in the chain:

  • weakness or inhibition of the glutes
  • being de-conditioned due to inactivity or injury
  • overuse due to excessive repetitive motion
  • over-activity of an opposing muscle group
  • For endurance athletes, it's particularly important to recognize a dysfunction to ensure muscle imbalances don't occur. The psosas muscle (primary hip flexor) and the rectus femoris (synergistic hip flexor) are heavily involved, overworked and overused.

    When you're cycling and running, you're predominately using the flexors -- the extensors are used, but on a limited basis. The extensors are activated when you're out of the saddle climbing or sprinting on the bike, or when you sprint for the finish on your run (as in beating the challenger who snuck up on you prior to the finish line).

    Here's another example: Let's say you visit to the local track for an interval workout (which you haven't done for a few months, years) and you run a few 100-meter repeats or 400- and 800-meter accelerations.

    The next day, or even that night, you may feel the sting of inactivity in the "chain." The glutes, hamstrings, and low back will probably be crying out in pain. Anytime an imbalance occurs and continues for an extended period of time, your chance of injury dramatically increases. Left unchecked, these imbalances will eventually alter skeletal position. Imbalances can be further aggravated by sitting (flexion at the hip) at a desk all day.

    Figure 1

    Exercises to keep the chain in line

    Let's look at some exercises that will keep the flexors in check. Make sure you stretch to ensure that you receive maximum benefits from the exercises.

    Horse Stance. Assume a kneeling position with the knees directly under the hips and the hands placed directly under the shoulders (Figure 1).

    Keep the spine in a neutral position. To activate the transverse abdominis muscle (TVA), pull your belly button in and then extend the opposite arm and leg (Figure 2).

    Figure 2

    Once the leg is extended, focus on contracting the glutes for increased stability. Your arm should be slightly out to the side or at a 15 degree angle away from your head, with your leg held straight back. Make sure your hips stay square to the floor when you lift your leg. Hold this position for seven to 10 seconds and switch to the other side, alternating for two to three minutes.

    Once you're able to perform the exercise easily, perform the exercise with weights by using a dumbbell in your hand and an ankle weight for the leg. Try to use the same weights here.

    Figure 3

    For the most challenging version, perform the exercise from a push-up position. Don't sacrifice form for weight.

    Reverse Hyper-Extension. This exercise will further recruit the core musculature.

    Position the ball so that the hips are fully supported and the upper body is partly supported (Figure 3). Your hands should be on the floor in front of you. Activate the TVA by pulling your belly button in, while simultaneously lifting the legs toward the ceiling (Figure 4).

    Use your hands to counter balance your legs like a semi-handstand, only raising the legs to a position that allows you to maintain a neutral spine (It's not necessary to go beyond that).

    Figure 4

    Once the legs are up, contract (squeeze) the glutes strongly, then lower and repeat for 10-15 reps for at least three sets. Variations of this exercise can include raising one leg at a time, or ankle weights to increase difficulty. Again, form is paramount.

    These exercises are designed to keep you performance efficient, injury free, and balanced. To learn more about the complete program design and exercise selection that coincides with the specific phases of your racing calendar, visit www.endurofit.com.

    Next month we'll focus on the upper body and address exercises for the rotator cuff and correction of "upper cross syndrome". Until then, train smart and stay safe and go for it!

  • Click here for Mid-season core tune-up, part 1.

  • All exercises shown in this article can be found in the DVD: The Next Level, Strength Training for Endurance Athletes. For more information, visit www.endurofit.com.


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