Educated Runner

Recovering from Increases in Running Mileage

educatedrunner — Tue, 06 Apr 2010 22:25:00 GMT

My first daughter, Cori, was born when I was still an undergraduate at the University of Rhode Island. She was a smiling beauty, so precious and dear to me. I loved her deeply from the first second I saw her (and still do).

When I arrived home from URI each day, I would help with her feeding and bathing, read to her, and make sure she was tucked in safely for the night - or at least for a few hours, in those frequent cases when hunger collaborated directly with the operation of her vocal cords.

After Cori’s birth, my schedule changed dramatically. I was loaded down with embryology, anatomy, genetics, ecology, and inorganic chemistry, and – prior to Cori’s arrival – would often study until midnight. With Cori making studying impossible during the early parts of evenings, I began staying up until 2 or 3 A. M. and yet could still be found at the corner of Elmwood and Sumter at 6:15 each morning, ready to take the bus to downtown Providence and then catch the 7:05 to South Kingstown. My work load increased, my sleep diminished, and my feelings of fatigue advanced steadily, but I assumed I would simply adjust and get through it all.

I didn’t. After four months of the new schedule, Cori and my course grades were fine, but I developed a serious inflammatory disorder, from which several weeks of recovery were required. I had forgotten that increases in work load, even when the work is wonderfully fulfilling and meaningful, require corresponding expansions of recovery. Recovery (which in my case was the recuperation produced by sleep) can not be ignored or discarded without a significant cost to health.

Many serious runners create an imbalance between training and recovery, and the result can be an unexpected fall-off in performance which is often called staleness. Increases in training volume (mileage or kilometrage) are a principal cause of staleness, because the new, higher amount of work being performed often exceeds the capacity of a runner’s body to recover from the augmented training stress and then adapt physiologically (just as the added challenges of fatherhood wiped me out physically). Each added mile places an additional stress on the body, and yet runners often blithely increase mileage without making corresponding and necessary changes in the ways they are preparing for and recovering from their workouts.

One key problem is that runners often advance volume without having the intrinsic running-specific strength to do so successfully (i. e., to do so without causing staleness and/or injury). Runners tend to believe that higher volume would be a good thing from the standpoint of aerobic-capacity expansion and thus pursue greater volume avidly, without taking into account the wear and tear on the muscular and connective-tissue systems which such running produces.

That destructive action, the lysis of myofibers and myofibrils in response to the thousands of additional running steps taken each week, has to be counteracted in some way, either by first expanding running-specific strength (prior to the mileage build-up) to protect the muscles or else by enhancing recovery processes in appropriate correspondence with the volume augmentation (actually both steps, upgraded strength and enhanced recovery, are recommended).

A firm bottom line is that a runner can’t simply proceed as usual when he/she ramps up mileage. The strength preparation must match the increase in work load, and the recovery processes must be enhanced in order to allow the body to adapt and re-build adequately despite the bruising blows of the longer-duration training.

Many different recovery modes can be effective. Certainly, if a runner’s weight has been at a desirable level, he/she can not increase mileage without also stepping up intakes of total calories and carbohydrate. Without adequate calories to fuel the additional miles, internal energy stores will run low. In the absence of copious carbohydrate intake, muscle-glycogen levels will drop, energy and endurance will dip, and overall performances will fall (yes, staleness can occur in this way). When volume expands, taking in more calories and carbs is a key part of recovery.

Sleep is an often-overlooked but amazingly effective recovery mode, as I learned after Cori’s birth. Many runners believe that they can advance from 30 to 45 miles per week without any change at all in sleep patterns, but such a strategy is extremely ill-advised. Sleep encompasses a variety of different recovery processes, not the least of which is a night-time surge in the pituitary production of human growth hormone, which in turn repairs bone and muscle tissues while enhancing the breakdown of fat. The relationship has not been carefully worked out in scientific settings, but it is clear that higher mileage creates a demand for more time in the sack, and – yes – even the occasional use of kindergarten-style afternoon naps, if possible – to restore the body and promote adaptation (I should have been napping on the South-Kingstown bus, instead of poring over chem. notes and talking with fellow riders).

Enhanced fluid intakes will also be optimal (because higher training volume means more sweat flowing out onto the skin), and it is impossible to over-estimate the value of “down time” – periods during the day when a runner relaxes totally and does something he/she truly enjoys. Such respites are absolutely without parallel for nervous-system recovery. For a runner who likes to read, a period of significant volume expansion represents the one time in his/her career when reading the collected stories of Isaac Babel will be the best thing for enhancing running economy – far better than kicking out extra reps on a steep hill.

A key thing to remember is that neural recovery is highly individualized. For one runner, talking with a girl/boy friend might be the best recovery of all, while for another reading or getting a massage would be the right recovery ticket. Fortunately, each runner knows exactly what produces the maximal amount of mental relaxation and comfort (and thus unifies body and mind and increases the tolerance of hard work during subsequent training sessions).

It is only natural for an endurance runner to answer a period of staleness with an increase in total work. Most serious endurance runners believe that nothing in running can be attained without hard work, and the upswing in volume is viewed as a way to kick fitness back up again, as a way to reverse the downward fitness slide of staleness. The truth is that more hard work is exactly the wrong way to treat staleness; it may in fact push staleness “over the cliff” into the murky swamp we call the over-trained state.

While the human body is sometimes viewed as a kind of machine, the truth is that the body is dissimilar from a piece of machinery: For example, it can not be driven for increasingly long distances each day and yet be ready every morning for intense, hard work. The human body requires food and water, just as a machine needs fuel and oil. However, the body’s motor – the muscular system – is torn apart by extended training, while the engine of a machine remains intact for thousands of hours. The reality is that each longer-distance “drive” in your body needs to be accompanied by enhancements of your most-effective recovery strategies.

Top Three Reasons for Coming to One of Owen’s Running Camps

(1) Location, location, location: Owen has camps for you in some of the most beautiful and interesting places in the world, including the Snowy Mountains of Australia, Malibu Canyon in California, Track-Town USA (Eugene, Oregon), the Flatirons of Boulder, Colorado, Brigham Young University in Hawaii, the Green Mountains of Vermont, and yes – even little Oscoda County in northern Michigan. As a result, when you attend one of Owen’s camps you’ll get a transforming running week and a great vacation at the same time. Sign up for your week in running paradise right here.

(2) Running Form Improvement: Have you ever wondered whether tweaking your running form might decrease your risk of injury, enhance your economy, and/or upgrade your performances? Wonder no more! At camp, Owen will shoot video of you running at different speeds and sit down with you to analyze your form. He will then work with you individually to optimize the four key elements of great running form – cadence, mid-foot strike pattern, posture, and body angle. When you leave camp, you will be a transformed runner, with more-powerful strides, augmented economy, and greater fatigue-resistance. For your personal running-form makeover and the chance to dramatically increase your running speed, sign up here now.

(3) vVO₂max Training: When you come to camp, Owen will measure your vVO₂max and then show you exactly how to put together a training program which sends your vVO₂max through the roof. vVO₂max is a key predictor of running fitness and performance, so your vVO₂max advancement will help you carve significant chunks of time from your 5Ks, 10Ks, half-marathons, and marathons (and any other distances which you run). You will finally achieve those dream running goals which have been so elusive in the past. To push your vVO₂max and running capacity to the highest-possible levels, sign up right here.

Bear in mind that these three great features just touch the surface of what actually happens at Owen’s camps. For example, you will also learn an easy-to-carry-out, full progression of running-specific strength training which will shield you from the sharp arrows of staleness and overuse injury. You will make great new running friends and conduct workouts in unforgettable locations, for example Lake Jindabyne in Australia, Spencer’s Butte in Oregon, or the Appalachian Trail in Vermont. And you will enjoy getting to know Owen and appreciate his commitment to you and eagerness to help you, even after camp ends. To be part of an experience which changes your running life in so many positive ways, sign up right here.

Is The 10-Percent Rule Worth Even 10 Cents?

educatedrunner — Sun, 28 Sep 2008 13:59:00 GMT

About 65 percent of endurance runners get injured during an average training year, and research reveals that the injury rate may be even higher in individuals training for a marathon.

Some running advocates say that 65 percent may not be so bad, because the lower-limb damage rate for sedentary individuals is probably even higher (hypothetically due to a lack of coordination and muscular strength among sofa spuds). If 80 percent of couch potatoes are hurt during an average 12-month period, running might seem rather protective.

That debate has not yet been settled. I’m doing a survey of local running clubs and non-exercising residents from the community and will let you know soon about who has the worst knees, most-painful plantar fasciae, and greatest level of discomfort in their gluteus-maximum muscles. It’s not pitfall-free research, because one can always argue that runners are pre-selected: That is, individuals who are already less-prone to injury take up running and continue running because they know that their legs will be basically OK. Meanwhile, individuals who are more-prone to injury avoid running because they know it might flare up sensitive knees. In the end, the non-runners might have lower malady rates – but not because of the strengthening effect of running.

But let’s move on and think about what can be done to lower that distressing 65 number. As we ponder this, a key thing to remember is that training is the key cause of injury in runners. Yes, it’s not shoes, a lack of flexibility, poor warm-up practices, or a too-low frequency of massage therapy. Training is the culprit.

For each runner on this planet of ours, there is a level of training beyond which injury will occur and below which workouts will proceed trouble-free. This “injury threshold” varies dramatically between runners. An elite Kenyan runner might surpass his/her staying-healthy limit with a weekly load of 25 quality miles and 100 total miles, while a novice American runner could cross over the injury threshold with just 10 total miles and one quality mile per week (a “quality mile” is one which is completed at 10-K pace or faster; for a marathon trainer a mile which is conducted at goal marathon pace can also be considered to be “quality”).

Traditionally, we have thought about the injury threshold in terms of training volume (number of miles run per week), but intensity is the often-forgotten wild card. An endurance runner who can log 40 miles per week at a moderate pace without trouble might find herself injured within a few weeks if she adjusts her training so that six to eight of those miles are quality in nature. Both intensity and volume of training have an effect on the likelihood of injury.

The good news is that the injury threshold tends to rise for each runner as strength and fitness improve. Runners should look for ways to lift the limit as high as possible, and of course they should attempt to avoid crossing over the threshold. In general, the educated runner works to keep training stresses from out-pacing adaptive processes in muscles, tendons, ligaments, cartilage, and bones.

One of the most-popular strategies for preventing injury is the use of the “10-percent rule,” which states that running volume should not increase by more than 10 percent from one week to the next. The 10-percenter has always seemed pretty reasonable to runners, since it recognizes that an injury threshold exists and that runners should be careful about moving beyond this important borderline, which has successful adaptation on the near side and injury on the far side. 10 percent would appear to be a prudent “governor” of the rate at which training volume is expanded.

But no scientific research has ever documented the benefits of the 10-percent dictum. The 10-percent rule also has a few injuries of its own. First, it focuses only on mileage, without taking training intensity (average running speed or percent VO₂max or the number of quality miles) into account. Advancing volume by 10 percent from one week to the next while reducing intensity or holding it constant should place a quite-different total stress on the leg muscles and connective tissues, compared with augmenting volume by 10 percent and boosting intensity by 7 percent, for example. From an injury prevention standpoint, it is possible that intensity should be temporarily decreased whenever volume increases, although there has been little research in this area.

A second problem is that the 10-percent rule can be too conservative in many cases. For example, an athlete who runs six miles per workout, three times a week, without a hint of injury, could probably boost volume by 20 percent (from 18 to 21.6 mpw) without significantly expanding injury risk by adding in a fourth workout of 3.6 miles on another day of the week.

A third failing is that the 10-percent scheme ignores workout duration. Let’s take our athlete from the preceding paragraph. If he/she boosts volume by 10 percent, moving from 18 to 19.8 miles, he/she could run into trouble if the schedule changes to two workouts per week of 9.9 miles instead of 3 X 6.6. The nine-mile runs should have a more-damaging effect on the legs (because of the number of miles run in a state of significant fatigue), compared with the combination of 6.6-mile sessions.

Another factor that should be considered is that expanding from 20 to 22 miles per week probably is much easier to do without raising injury risk, compared with augmenting training from 70 to 77 miles per week, even though both moves involve a 10-percent change. The latter transformation would add seven miles per week – and thus more than 7000 additional impacts with the ground per week - to legs already fairly heavily stressed by training (although it could also be argued that the 70-mile per week legs would be stronger and would thus be more prepared for the advancement, compared with lower limbs which can handle “only” 20 weekly miles).

Experience suggests that a too-rapid advance in training can increase the risk of injury dramatically. However, the strategy designed to prevent overly quick advancements - the 10-percent rule - appears to be too general and unscientific to be used dependably. The rate at which a runner can increase his/her level of training is highly individualized, and it is up to each runner to recognize his/her limits. “Listening to one’s body” and reducing volume and/or intensity at the first sign of lower-limb discomfort (often with a complete rest day) is an un-scientific yet sound principle to follow. When a runner carries out a workout on sore, stressed-out legs, he/she becomes a risk-taker, not an educated trainer.

Carrying out running-specific strength training (rsst) is the most-fundamental way to lift the injury threshold. We’ll cover rsst in detail in the coming months. Educated Runner offers seminars on running-specific strength training. To sign up for one, please click on the Seminars flag at the top of this page or go to http://www.educatedrunner.com/Seminars.aspx

Why Hip Kidnaps Can't Stop ITBS

educatedrunner — Tue, 12 Aug 2008 18:13:00 GMT

Iliotibial band syndrome is the most-common cause of lateral knee pain in endurance runners, and the troublesome condition can account for up to 12 percent of all running injuries.

The iliotibial band, a slab of muscle and connective tissue which runs down the outside of the leg from the hip to just below the knee, tends to impinge on a lateral projection of the femur at the knee just after foot strike occurs. Repetitive rubbing of the iliotibial band on the femoral projection can produce a painful, chronic inflammation which we call iliotibial-band syndrome (ITBS). An old-fashioned case of ITBS can set your training back for six weeks or more, putting the damper on your hopes for a PR in a 5K or success in an upcoming marathon.

So what steps should you take if you already have ITBS, and how can you prevent ITBS from occurring in the future?

When an injury like ITBS occurs, taking anti-inflammatory medications and cutting back on training can ease the pain, but they are not the solution to the problem. A runner who ingests anti-inflammatories, runs fewer miles than usual, and enjoys a relief from ITBS symptoms after a few weeks has not solved his/her difficulties. He/she will be at increased risk of more ITBS trouble in the future.

That’s because the appearance of ITBS was not a random event, a lightning bolt out of the blue which struck for no apparent reason. The development of ITB means that the ITB has been too weak to stand up to the training which has been conducted. The real solution, then, is to reduce training on a permanent basis, usually not a very desirable strategy, or to strengthen the ITB. But how in the world can you strengthen the ITB so as to block future injury to the tissue?

Human-anatomy texts tell us that the function of the ITB is to abduct the leg at the hip, i. e., to move the leg laterally, away from the midline of the body. This definition strikes many runners as odd, since they can’t recall any workout or race in which they were running by moving their legs to the sides instead of straight forward. If the function of the ITB is to abduct the leg, how does it get hurt during endurance running, an activity which appears to call for no abduction?

The answer is that the writers of human-anatomy books are generally not overly concerned about the functions of muscles during running. If they were, they would write that the role of the ITB is to control adduction of the hip during ambling. The ITB works eccentrically to prevent the thigh from moving inward when the foot is on the ground during the stance phase of gait. When it does so, the ITB is stretched out, because some adduction must inevitably occur. The ITB is also active, because it must try to limit adduction. And so the action is eccentric – the poor ITB is trying to contract but is stretched out nonetheless.

What about the connection between that rubbing action of the ITB on the femoral projection and this eccentric activity? If the ITB is weak, it permits greater adduction (inward movement of the thigh) during stance. That stretches the ITB, puts it under greater tension, and presses it down on the femoral projection. Weakness of the ITB is thus the key risk factor for ITBS.

To reverse this weakness, you can head to the gym and carry out hip-abduction exercises until you are blue in the face, but these hip kidnappings will not strengthen your ITB for running, because concentric hip abductions are not specific to the eccentric, control-of-adduction function of the ITB during running. What we have learned from a couple of decades of scientific research is that strengthening exercises must be specific to a particular movement, in terms of muscle-activation pattern, neural control, joint range of motion, and velocity, in order for that movement to be actually fortified. As many experts have pointed out, the desired goal is to strengthen movements, not individual muscles.

Karen Ward comes to our rescue here. The brilliant, creative, Atlanta personal trainer (see her web site at http://www.dynamicfitnessconcepts.com) has developed an excellent exercise for advancing ITB function and strength during running, an exertion which will keep ITBS at bay. Her routine is called Frankenstein Marching with a Band (Karen has a sense of humor, too).

The drill is straightforward to carry out. To perform Frankenstein Marching, stand on a stretch band, with the handles of the band in your hands and the middle portion of the band directly under the arches of your feet. Cross the band handles in front of you, so that your left hand is now holding the handle which was in your right hand and your right hand is holding the left’s. This will make an X in front of your legs with the band. Then rotate each arm out to the side, so that your thumbs are pointing laterally. Retract your shoulders, and keep your feet parallel, shoulder-width apart, pointing straight forward. Walk forward briskly with relatively straight legs while maintaining a standing-tall alignment. Keep your head up and pointed straight forward (don’t look at your feet). Avoid the common mistakes associated with Frankenstein Marching - feet turning out as you move forward, distance between feet too small, head directed downward, and shoulders falling forward.

After a few steps, you’ll begin to feel your ITBs zinging eccentrically, but that zinginess and resulting ITB fatigue will be far better for you than the six-week bout of ITBS which Frankenstein Marching can help prevent. Start with 2 X 15 meters of Frankenstein Marching as part of your warm-up or regular strengthening routine, carry it out a couple of times a week, and progress to 3 X 20 meters with a much-more-resistant stretch band. When you do, you’ll be keeping yourself out of future ITB peril. And while no scientific research has been conducted in this area, the increased control of adduction you’ll gain by strengthening your iliotibial bands should enhance your running economy, an important predictor of running fitness and performance.

Frankenstein Marching is one of the activities which will strengthen the iliotibial bands and prevent ITBS. Many other ITB-strengtheners will be presented at our Strength Training for Runners & Triathletes Conference in Atlanta on October 24-25, 2008.

Reference

“Iliotibial Band Syndrome in Runners: Innovations in Treatment,” Sports Medicine, Vol. 35 (5), pp. 451-459, 2005

Biomechanics and Injury

Wed, 23 Jul 2008 15:17:00 GMT

If you are like many runners, you have probably wondered whether you could improve your biomechanics – and whether that improvement might upgrade your performances and decrease your risk of injury.

Before I address whether that is possible, let’s take note of the fact that biomechanics is the study of the forces which act on the body during running, especially with regards to the muscles and skeletal system. Kinetics is a branch of biomechanics which studies the forces and motions which are characteristic of the running gait. Kinematics focuses only on the motions of the body during running without worrying about the forces, including the positioning of the joints and the movements of the legs, arms, trunk, and head.

In theory, there is an optimal way to move while running, a best-possible way to position the joints and create propulsive forces as you scamper along. This could be viewed from a performance-improvement or injury prevention standpoint. In the former situation, this would mean positioning the joints and creating forces in ways which maximize speed. In the latter case, the idea would be that there is a specific way of running which minimizes stresses placed on the bones, connective tissues, and muscles of your legs and thus keeps running injuries at bay.

Exercise scientists have searched for such optima among elite runners, thinking that the very best runners would have naturally developed biomechanical patterns which promote the highest-possible running velocities and simultaneously block injuries. Instead of finding predictable kinetics among the elites, however, the scientists have discovered wide variation in biomechanical variables.

Take maximum knee flexion during the swing phase of the gait cycle, for example. Some elites flex their knees a lot during swing, reaching angles as great at 140 degrees, but others only flex to 109 degrees (the angle of the knee during running is defined as the angle between the actual position of the shin and an imaginary line drawn to indicate the position that the shin would occupy if the leg were perfectly straight; knee angle is zero when the leg is perfectly straight). This kind of variation is found when almost all other biomechanical variables are studied.

In other words, scientific research suggests that running biomechanics are highly personal and probably depend on such individual characteristics as skeletal structure, flexibility, joint stiffness, muscle length, overall muscular strength, and neural coordination of gait. There is not an optimal biomechanical pattern which can be applied to you – which can be used to change your individual biomechanics and thus alter your performances and risk of injury in a predictable way.

As a result, no coach or exercise scientist can make specific biomechanical recommendations to an individual runner with the assurance that the advised changes will work. There is no optimal thigh angle for the various stages of stance or swing, for example, which has been identified as being better for performance or injury prevention. There is no optimal degree of ankle dorsi-flexion during stance. There is no optimal duration of the stance phase. And so on.

What makes more sense is that increased activity and force production by the muscles of running, if they are produced at the correct times during the gait cycle, should improve running performances and might also provide a protective effect and lower the risk of injury. This is probably why strength training for running has been linked with improved performances and a reduced rate of injury. Thus, a sensible approach for runners to follow would be to strengthen the various movements involved in gait in a running-specific way, instead of artificially tinkering with movement patterns.

The perils of making recommendations about biomechanics are illustrated by a recent study from Belgium in which 84 individuals were monitored for knee (patello-femoral) pain during a six-week training period. Subjects who were most likely to develop knee discomfort tended to land more toward the outsides of their heels during gait, compared with injury free individuals – and to roll toward the outsides of their feet during stance.

Now, we could tell these people to change their biomechanics in hopes of eliminating the knee injuries. We could instruct them to land more toward the centers of their heels and to focus on not letting their feet roll toward the outside during stance. We could get them to run more like the pain-free runners.

But it probably wouldn’t work. The fundamental problem with these subjects was most likely a lack of running-specific strength, not the pronation per se. The strength inadequacy let the ankles pronate to a greater extent, and this pronation might have put extra stress “up the chain” in the knees. If we got these runners to land squarely on the middles of their heels and to focus on avoiding pronation, the lack of strength associated with their new biomechanical patterns might simply produce a new kind of injury.

But if you’re going to strengthen yourself, how should you do it? The key is to make sure your strengthening movement mimics some part of the gait cycle of running. Otherwise, the gains in strength will not transfer well to running, and you’ll end up stronger in the gym but not out on the roads.

Take hamstring strengthening, for example (a good thing to take, since hamstring injuries are so common among runners). Many runners think that the key function of the hamstrings during running is to contract and extend the hip while the foot is on the ground, thus providing forward propulsive force.

In reality, the hamstrings are most-active during the swing phase of gait, when the foot is off the ground and the leg is swinging forward, getting ready for the next contact with the ground.

This is an eccentric action of the hams, one in which these key muscles are being stretched out while they produce force to control the forward swing of the leg, preventing this forward swing from getting out of control.

So here’s the picture: The hams are most active during running when the foot is off the ground and the leg is swinging forward. Does this fact make it sound like hamstring curls, a very popular gym exercise, would be the best hamstring-strengthening drill? To perform hamstring curls, a runner usually lies prone on a bench and uses the hamstrings to contract concentrically and flex the knee, with resistance provided by a bar positioned against the ankle. Well, at least the foot is off the ground!

Even the classic exercise for the hamstrings – lunges - is not optimal, since it is performed in a way which puts most stress on the hams while the foot is in stance, not swing.

A much better hamstring-strengthening exercise for runners, one which includes hamstring activation towards the end of swing, would be bicycle leg swings. To carry these out properly, you stand with your usual running-tall alignment, with weight fully supported on your left leg (initially, the right hand may be placed on a wall or other support structure to maintain balance). You begin by flexing your right hip and raising the right knee up to waist height (the right thigh should be parallel with the ground); as this is done, the right knee should be flexed to 90 degrees or more. Once the thigh is parallel to the ground, you begin to extend the right knee (by swinging the lower part of the right leg forward, unflexing the knee) until the knee is nearly fully extended (the leg is nearly straight), with the right thigh still parallel to the ground.

As your right knee nears full extension, your right thigh drops downwards and backwards (scraping the right foot on the floor/ground as the leg moves back, something like rubbing mud off the bottom of the shoe) until the entire thigh and leg are extended behind the body (as if you were following through on a running stride). Your right knee should be near full extension (the leg should be basically straight) until it reaches the peak of the backswing. As your right hip nears full extension (as you approach the end of the backswing), you raise the right heel by bending your right knee; the heel should move closely towards the buttocks as this is done. As this happens, your right knee is moved forward until it returns to the appropriate position in front of the body, with the right thigh parallel to the ground again. This entire sequence of actions is repeated in a smooth manner so that the hip and leg move through a continuous arc without stopping or pausing.

Once you are able to coordinate the movement, the swings should be performed at a cadence of about 12 swings every 10 seconds or so (slightly faster than one swing per second). To enhance the effectiveness of the exercise, a stretch cord should be attached to the “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. You stand facing the post, table leg, fence, or railing, with enough distance between yourself and the structure so that the stretch cord significantly accelerates your leg forward during the forward-swing phase of the exercise (this forces the hamstrings to create a braking force during swing, exactly as they do during actual running). This enhanced forward acceleration created by the stretch cord puts the hamstrings under considerable stress (as they try to brake the frontward movement of the leg) and is ultimately be very strengthening for the hamstrings in a running-specific way.

The hips should be kept fairly level as the exercise is performed. Naturally, once you complete the required number of reps with the left leg as the support leg, you should change over to standing on the right foot while the left leg performs the swings. Important things to avoid include too little tension on the stretch band (creating a situation in which the band won’t accelerate the leg forward properly), not getting good hip extension on “back swing,” a lack of explosive forward thigh movement, and a wobbling of the body as the swings are performed. Begin with about 20 bicycle swings per leg, work up to three sets of 60, and gradually increase the resistance (and thus snap-back power) of the stretch cord.

It’s very likely that this exercise will help you avoid hamstring injuries far more than any biomechanical adjustments which could be suggested for you.