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Running Research News And Events
December 10, 2007
HAMS GIVE OUT BEFORE QUADS IN MARATHON
In a marathon or prolonged run, especially one involving a fair amount of downhill running, one would expect the quads to take quite a pounding. However, new research indicates that the hamstrings are the muscles which are most fatigued by very long bouts of running— and thus may be the muscles which are mostlimiting during extended efforts. Exercises for bolstering the eccentric strength of your hamstrings,including leg swings and pistol squats, are prescribed.
The Tirol Speed Marathon itself is a very interesting race (http://www.tirol-speed-marathon.com/home.1.0.html?&L=2). It begins in the world famous Brenner Pass in the Austrian Alps and ends in the historic Innsbruck, Austria and is called a “Speed Marathon” for good reason: The Brenner Pass is at about 1400 meters of altitude, but the finish in Innsbruck is elevated by only ~ 585 meters. Thus, the average downhill inclination is approximately 2 percent, which is conducive to running a very fast marathon time. In addition to promoting speed, this is the kind of course which should really beat up the quads. The quadriceps muscles, after all, are responsible for controlling knee flexion each time a foot hits the ground during running. They are the “insurance” which in effect keeps a leg from collapsing at the knee every time a force of three to four times body weight travels up the lower limb after foot contact. On a downhill course, the foot falls farther prior to each impact, and thus the downward acceleration is greater, producing increased stress on the quads as they attempt to keep the knee joint (and whole leg) under control during the first milliseconds of stance. In short, the quads could possibly take a heck of a beating on a downhill marathon course like Tirol. Their efforts to maintain leg stability during steady, downhill running over the marathon distance could produce incredible fatigue. It is not much of a stretch to say that the quads might “give out first” during the marathon, or at least might be the muscle group which is the initial one to lose a significant fraction of its normal functional capacity, especially on a course involving lots of downhill running.
In other words, it was the hamstrings which were blown away by the marathon effort, not the quads. And – the poor hammies were hurting not during routine, concentric activity (during which the fellahs exert force and shorten) but were wiped out for eccentric actions (during which they attempt to shorten but end up being stretched out). What was going on? Why were the hams hurt more by the marathon than the quads? And – why did the hams fall down during eccentric – but not concentric – testing?
Well, many studies have shown that endurance-runners’ quads tend to be stronger than their hamstrings. There are various reasons for this, but one key factor is that many endurance runners have not yet developed an understanding of the strengthening techniques which are important for bolstering hamstring strength. In addition, many endurance runners tend to have very tight hamstrings, and there is some evidence that inflexible hams are more likely to be injured, compared with supple ‘strings (2). Thus, it is not overly surprising that the hams took a tougher Tirol beating, compared with their confederates in the front part of the thigh.
Additionally, the hamstrings do bear a unique burden during endurance running. Yes, the quads are stuck with the job of preventing leg collapse during stance, but the hamstrings are responsible for controlling forward swing each time a leg accelerates ahead during gait, so that the front-moving action is not carried out with an excessive range of motion or in an uncontrolled way. The hamstrings work, attempting to shorten, as forward swing occurs, but the leg accelerates ahead anyway, and thus the hamstrings undergo eccentric strain (they are attempting to contract but are elongated nonetheless). Studies have shown that eccentric actions are particularly damaging to muscles, compared with concentric activities (which involve attempts to contract – and then nice, rewarding contractions). Studies have also shown that injuries to the hamstrings in particular tend to occur in the eccentric phase of their activity, rather than the concentric phase (3-6). In a marathon the hamstrings of each leg have to control forward swing, on average, an incredible 18,500 times!! In other words, the hamstrings are at great risk during the marathon – for excessive fatigue, cramping, and injury.
The question we have to ask, then, is whether you have been preparing your hamstrings for this kind of stress during your marathon and other types of training. Of course, even if you don’t run marathons it is good to prepare your hamstrings for duress. If you run 5Ks, for example, the number of stresses on the hamstrings per race is lower, of course, but the magnitude of each stress is greater, since you run at a faster pace in the 5K, compared with the marathon.
So, what kinds of things are good for strengthening your hamstrings in a manner that matters for running? Bear in mind that the best hamstring activities won’t just dampen fatigue: they will also boost performance, because they will keep the hamstrings firing functionally and optimally all the way through your competitions, including your marathons, and thus will economize gait.
It is important that the hamstring exercises you choose emphasize the eccentric component of hamstring activity. As mentioned, this is the element of hamstring activity which is most likely to fatigue and injure the hams. In addition, many investigations have shown that eccentric muscle training is more efficient than traditional, concentric training. That is, eccentric muscle actions can produce higher forces with about 20-percent less oxygen consumption and energy expenditure, compared with similar concentric work (7-9). Some research has also suggested that eccentric training can produce greater total gains in overall strength, compared with concentric effort (10). In addition, careful inquiries have shown that eccentric training can create greater gains in concentric strength, compared with concentric training itself (11).
And so, here are two, great, running-specific,hamstring-strengthening exercises for you which emphasize the eccentric component of hamstring action:
When you feel comfortable carrying out the basic routine, purchase an intermediate-strength “stretch cord” from a reliable supplier such as the M-F AthleticCompany http://www.performbetter.com), preferably one with Velcro ™ straps at each end, and complete the exercise while utilizing the stretch cord, which should be attached to your “swing” (non-support) ankle at one end and a firm post, table leg, fence, railing, or other structure (at roughly knee height) at the other end. Stand facing the post, table leg, fence, or railing, with enough distance between you and the structure so that the stretch cord significantly accelerates your leg forward during the forward-swing phase of the exercise. This enhanced forward acceleration will put your hamstrings under additional stress – and will ultimately be very strengthening for your hams.
Don’t forget that hamstring tightness may increase the risk of fatigue and injury, so be sure to use the following routine after all workouts:
Musa’s Rotational Hamstring Stretches. To carry these out, please stand with your weight on your left foot, and place your right heel on a table or bench at or near waist height. Face straight forward with your upper body, and keep both legs nearly straight. As you stand with your right heel on the table and your left foot on the ground, rotate your left foot outward (to the left) approximately 45 degrees, keeping your body weight on the full surface of your left foot (both heel and toes are in contact with the ground). You are now ready to begin the stretch.
Lean forward with your navel and shoulders until you feel a steady tension in the hamstrings of your right leg. Don’t increase the stretch to the point of pain or severe discomfort, but do maintain an extensive stretch in your right hamstrings while simultaneously rotating your right knee in a clockwise - and then counter-clockwise – direction for 20 repetitions. As you move the right leg in the clockwise and counter-clockwise directions, stays relaxed, and keep your movements slow and under control.
After these 20 reps, please remove your right leg from the table and rest for a moment.
Then, lift your right leg up onto the table again, and repeat this clockwise and counterclockwise stretch of the right hamstrings, but this time keep the left (support) foot rotated inward (to the right) approximately 10 degrees as you carry out the appropriate movements. Perform 20 reps (clockwise and counter-clockwise) before resting.
Finally, repeat this entire sequence of stretches, but this time have the right foot in support and the left foot on the table for the repetitions. Perform 20 clockwise and counter-clockwise reps with the left foot on the table and the right (support) foot turned out 45 degrees, and 20 more reps with the right foot turned in.
If you perform the Bicycle Leg Swings and Pistol Squats a couple of times each week during your training (and you progress with the resistance and number of reps), and if you complete Musa’s Rotational Hamstring Stretches after nearly all workouts, you’ll end up with hamstrings which are significantly stronger – eccentrically and concentrically. As a result, your hams will be less likely to fatigue during your races, including any marathons that you decide to run, and their risk of injury will also be lower, increasing the likelihood that you can carry out your planned training without disruption. The best news is that you will be a better runner: You will have a feeling of greater control, energy, and strength as you run, and you will be very happy with the readings on the race clocks at your finishing lines. ©