Biomechanics of Running, Part 1

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Biomechanics of Running, Part 1

Submitted by Ian Golden

What will follow is a discussion of running form, or biomechanics. Historical and contemporary views on the topic as well as a synthesized vision of a recommended whole will be presented. Ultimately, it is possible that there is no more efficient form aside from the one your body is finding at this moment for quick, comfortable, injury-free running. That motion is the culmination of genetics paired with years of physiological development guided by your interests and societal demands. For most, some form of running comes naturally. For some, what comes naturally may not necessarily equate to the most economical method. What most individuals can thus benefit from is refocusing on certain aspects of running biomechanics that could be improved upon. It is the intent of this presentation to explore a few of these areas.

Elements and Foundations of Form

To achieve an introspection of ideal mechanics, walk for a period over a hard surface while barefoot. Relax your breathing, muscles and mind, and feel how your body moves without the aid of artificial cushioning or structure.

How must you land to best absorb the weight of your body? What must you do to move quicker? If you increase the length of your stride so that your knee is fully extended when you first contact the ground, where does your foot make contact and how does it feel? If you stand tall and lean back, where do you make first contact and does it feel more or less smooth. Conversely, what happens if you lean forward with your back still straight? Does it feel easier to swing your leg forward with a straight knee or to kick your heel up toward your buttocks? How does it feel to pump your arms faster than your legs are moving, and what changes must you make if you continue to walk with your arms completely fixed at your sides?

An ideal mechanical sequence will find you landing toward the outside of your foot between the ball of your foot and your heel with your knee slightly bent. The foot will accommodate the weight of your body through transferring force into the plantar fascia and smaller muscles of the foot, while creating a stable platform through your metatarsal heads (balls of your feet). The weight of impact is stored as energy in muscles and connective tissue to be further transferred into propulsion in toeing-off over the second toe. The ankles, knees, and hips are the hinges for the lower body, providing the attachments and fulcrums for the muscles of the lower body to promote flexion and extension while reducing side to side movement. The trunk and upper body are held erect with a degree of forward lean corresponding to speed or pace where an increased lean translates to an increased fall with gravity and need for stepping or turnover. The arms will swing at the shoulders to minimize rotation of the trunk, held by the side with slight variations in elbow flexion, and moving in sequence with the opposing foot. The wrists are straight and the fingers relaxed with a slight bend at each knuckle. Reflecting the symmetry of the body, the shoulders are level and head erect with eyes looking forward.

Running is merely an extension and magnification of walking. Strides increase from a range of 30 to 60 per minute to an ideal range of 180 to 190 in transitioning from walking to running. The float phase of a gait cycle increases substantially and the amount of weight placed on one leg increases from approximately 75% while walking, to 250% while running. With increased downward force comes the potential for increased plyometric loading of tendons with resulting increased recoil forces available. There is an increase in the forward lean of the trunk, and explosive forces generated as larger and more powerful muscle groups such as the gluteals and hip flexors become activated. The elbows drive further and more forcefully backward to generate the equal and opposite reaction of the hip driving the leg forward. Increased downward and forward forces are met with increased upward and forward reactive forces that permit greater explosion out of the calf musculature at toe off.

Each body part moves in sequence with another, achieving the goal of moving forward under the rule that every movement or force requires and elicits an equal and opposite force. Muscle groups must be balanced throughout the body for strong and effective postures and movement. What differentiates each runner is their specific anatomical structure and physiological development. An individual’s anatomical alignment, tendencies toward muscle and tissue development, oxygen carrying capacity, limits of lactic acid tolerance or utilization, as well as those demands which were present during an individual’s development and current lifestyle all play equal and critical roles in dictating running economy. It may be difficult to alter one’s skeletal alignment, propensity toward lesser or greater muscle mass, but oxygen carrying capacity, lactate threshold, and biomechanics all offer degrees of modification.

Historical Perspective

Part established by gene, part shaped by demands during development, and part shaped by training, each runner has a unique and identifiable form despite operating under the same physiological parameters of every other runner.

Quoting an earlier work titled “Track and Field Omnibook” by Ken Doherty, the Complete Runner indicates, “a sound rule of thumb when it comes to running technique is to leave it alone”. They further indicate that it wasn’t that small form inefficiencies couldn’t be addressed, but that gross and often aesthetically weighted aspects may be more trouble than they were worth to correct when considering some the flawed forms of some of the finest runner’s in the world. Dougherty continued, “Do what comes naturally, as long as ‘naturally’ is mechanically sound. If it isn’t, do what is mechanically sound until it comes naturally.” Citing the coach of former Olympic miler Herb Elliot, Percy Cerutty, others at the time believed that runners had lost their semblance to animals with regard to running through evolution and development, and that the focus should be on breaking back down motor elements and starting anew with biomechanics.

Several elite coaches of the time fell in between the opinions of Doherty and Cerutty, that biomechanics weren’t necessarily the ultimate goal but that they could be improved upon to enhance a runner’s capacity. Core parameters of running mechanics included an adjustment of foot-fall and stride length according to desired speed, maintaining an erect body to maximize power and efficiency, and using the arms as critical elements of balance and drive.

The complete runner uses the work of Toni Nett, a photographer of elite runners who published Track Technique in 1964 to address foot-fall and stride length, who referenced foot-planting patterns as the only universally applicable techniques found. His conclusion was that runners at all distances land first on the outside edge of the foot and then roll inward as shock is absorbed. The point at which the foot made contact was dependent upon pace, with sprinters landing toward the toes, mid-distance runners at the meta-tarsal arch area, and at heel for longer distances. Dependent also on pace was the element of stride length.

Citing Bill Bowerman, legendary University of Oregon coach, two fundamental rules for controlling stride-length: the foot should strike after it has reached the farthest point of advance and has actually started to swing back, and that the point of contact should be directly under the knee and not in front of it, and as nearly as possible squarely beneath the center of gravity. According to Bowerman, both could be achieved by keeping the knees slightly bent at all times. Further, by not over-striding, braking forces attributed to landing on an outstretched would be minimized.

Regarding the body positions of distance runners and sprinters alike, Bowerman and others including Cerutty felt that the body should be positioned erect so as to center one’s weight over the hips in order maximize the potential of the legs. They further believed that the arms, when rhythmically used, would be the driving force and engine for the legs to follow. Shoulders were to be held straight, arms bent but not locked by the side, arm swing linear with minimal chest crossing, wrists neutral with fingers cupped but relaxed.

p. 230 – 241, The Complete Runner 1st edition, 1974, Runner’s World

“The only sensible way to run is your own, no matter how much it deviates from textbook style. Above all, don’t try to land on the balls of your feet like a sprinter. If you do, you’ll almost certainly hurt your Achilles tendons. Instead, land on your heels and roll forward, pushing off with your toes.”

p. 177, The Complete Book of Running 1st edition, Jim Fixx, 1977

“For most runners, a shoe should be higher at the heel than at the ball of the foot, so that the rear of the shoe lands first and absorbs most of the body’s weight. A fairly thick heel also minimizes stretching of the Achilles tendon, an important consideration if you’re a woman and wear high heels much of the time.”

p. 121, Jim Fixx’s Second Book of Running, 1980.

Contemporary Theories

The Pose Method (Dr. Nicholas Romanov, 1997)

The Pose Method focuses on achieving an S-curved posture aligning the shoulders hips and ankles over the base of support in the ball of the foot. With and from this pose, energy is transferred quickly and rhythmically from one foot strike to the next along a horizontal line using gravity for propulsion with minimal active muscle recruitment.

Centering the body over its base of support, runners are encouraged to assume a slight forward lean stemming from the ankles. Allowing the body to fall forward, the supportive foot is pulled from beneath and replaced by the opposing foot. Utilizing gravity and pulling rather than pushing limits vertical displacement and insures that propulsion remains horizontal. The impact force that occurs in each foot is harnessed as plyometric or elastic energy and used in propelling the body forward. Ground contact time should be minimized, the foot lifted directly up beneath the body to initiate stride recovery. The knees should be bent at all times and the feet should always fall behind the knee at ground contact with heels elevated. It should be noted that before any amount of prolonged time is spent working on Pose techniques, several prior months should be devoted to strengthening those muscles, tendons, and ligaments required to run efficiently and injury free. Several exercise books, videos, and posts are available to guide a runner through to injury-free success with Pose Method running.

Critical points of application: hop on one ball of the foot using hamstrings of opposite leg in quick pull to generate hopping force; short hops and switches on alternating legs between Pose position (head, hips and ankles aligned with slight forward lean and heels elevated 1 inch); progress hopping to slight forward progression; running in place using the hamstrings to pull the foot up rather than quadriceps.

Chi Running (Danny Dreyer, 2004)

The focus of Chi Running is on a postural alignment that promotes the flow of energy, utilizing gravity rather than relying on muscle strength for propulsion.

Its core posture brings the entire body into an open alignment from the head, through the shoulders and pelvis to the ankles. An erect but forward-leaning posture is maintained and supported by alternating legs. The body’s core musculature is used to maintain alignment between the upper and lower body, using the effect of gravity in falling forward to promote varying degrees of propulsion. Stride recovery should be initiated by lifting the heel toward the buttocks and not by the knee and the lower leg should be kept relaxed at all times. The arms should set the cadence with a goal of 90 strides/minute (counting right or left foot only) guided by intensity of driving the elbows back, keeping the wrists neutral and hands relaxed above waistline at all times. The degree of forward lean controls the speed to which the runner moves. Increased speeds are provided by increased stride length, but cadence remains the same.

Critical points of application: alignment of body into Chi posture (1. hand over navel pulling down, other hand under collarbone lifting up, in concert elongating or opening chest 2. feet parallel 3. pull down with hand below navel while applying pressure with back of other hand over sacrum, using abdominals to lift and straighten pelvis); maintain opened Chi posture while adding forward lean into wall through bending at ankles with heels fixed; leaning with support, practice lifting at heel and driving forward with the knee for circular leg motion that mimics a wheel; progress to run with focus on 90 stride (both feet for total 180 foot strikes) cadence with quick heel lifts and rhythmic arms; goal of running through sand pit with even undisturbed prints.

Evolution Running (Ken Mierke, 2005)

Evolution running focuses on increasing running economy, or the ability to move faster using less energy, as well as injury resistance through biomechanics.

African runners have increasingly been a dominating presence in mid and long distance running. They often do not possess any advantages in oxygen or lactic acid processing capacity, limb-length or height-weight ratio, or muscle fiber type versus non-African runners. What has been found is greater efficiency and injury resilience thought to be rooted in barefoot development. Those individuals learning to run barefoot and thus more efficiently are believed to continue doing so even after shoes are donned.

Emulating barefoot patterns entails running with less vertical displacement, shortening stride length and increasing stride rate to 180 foot strikes per minute (counting both feet). With little vertical displacement, propulsion along the horizontal plain is aided by the concerted effort of the hip flexor muscles driving the knee forward and the hip extensors/gluteals propelling the body forward. The prime sources of propulsion however are rooted in gravity and plyometric energy. This energy is harnessed by landing on the mid foot directly beneath the hips and center of mass and in concert with the propulsion phase. Loading connective tissues and muscles effectively loads a spring with energy stored for immediate recoil. Harnessing plyometric energy reduces the demand on nutritional energy stores and oxygen that drive muscles, does not require replenishing and is thus not as susceptible to associated fatigue.

Critical points of application: standing in place with feet together and knees slightly bent, practice hopping 1 inch into the air and landing on the forefoot with heel elevated, feeling the use of elastic recoil rather than muscle activation; standing next to and holding onto rail or partner for balance, extend leg backward with knee straight, holding for 5 seconds to feel tension in gluteals; also standing supported, swing one leg through with knee slightly bent alternately driving knee forward and extending hip backward to feel activation of hip flexors and gluteals; add heel flick to yield circular motion with legs.

Synthesizing the Theories: Elements of Ideal Biomechanics

Foot Plant: Heel Striker

Heel Strike benefits include the natural tendency and actuality for most runners as well as the ability to achieve greater stride length. The calcaneous as a point of contact is rounded to accentuate a roll through the foot and toe with most running shoes structured to toward this stride pattern and can aid in correcting toward a neutral stance phase (keep you upright in rolling through to toe-off). The drawbacks to a heel-strike pattern are more numerous and include the likelihood of striding out too far in order to make heel contact, the potential to place undue stress on bones with forces transferred up the anatomical chain, an increased amount of counterforce and resistance encountered with heel striking, and the result of utilizing muscles inefficiently in a pull rather than push fashion for propulsion.

To maximize this pattern a runner may focus on strengthening the quadriceps muscle to keep the knee in alignment. Both it and calf complex (Gastrocnemius and Soleus muscles) should be strengthened including with plyometrics to aid in strong and even explosive toe-off. Additionally, strong hip flexors will be required to pull and drive the knee back forward in the recovery phase of the stride cycle.

Related potential injuries: tibial stress syndrome, bursitis at knee, spinal compression.

 

Mid Foot Faller

Benefits to landing toward the midfoot include the potential to use the smaller muscles and connective tissues in the foot to disperse shock and store energy for recoil, the ability to reduce counter-forces and friction if planted as the forward foot begins its return, fosters improved alignment of one’s center of mass over the base of support, and fosters increased cadences and reduced ground contact times. Drawbacks include the potential for placing more sustained stress on the calf complex and Achilles tendon as well as arch/fascia if the heel is not factoring into base of support. This may be exaggerated in those departing from using a heel-strike pattern through physiological development. Other potentials are for increased forefoot compression and stress and decreased stride length.

Runners maximizing this pattern may focus on maintaining quick lower extremity coordination, a smooth heel flick aided by the hamstrings, and strong balanced hip extensors and flexors for a cyclic stride pattern. Massage and dynamic stretching may be focused on the calf to insure that the Achilles is up to the challenge of increased downward force placed at the ankle. Time should be spent in drills or leisure barefoot to insure that the smaller/intrinsic muscles and ligaments in the foot are able to accommodate load bearing and responsive to recoil capacities.

Related potential injuries: inflammation of Achilles tendon or plantar fascia

 

Forefoot Pounder

Benefits include the potential for a gravity harnessing forward lean to achieve a forefoot landing, increased cadence/turn-over with decreased ground contact time, and the potential to predominately utilize larger hip and lower extremity musculature. Drawbacks include the potentials for excessive strain on the Achilles Tendon as well as bony structures up the anatomical chain, excessive vertical displacement, a reduced capacity to harness plyometric energy or connective tissue recoil. Probably the least common and potentially efficient of the three, we’ll leave off with further review of this pattern.

The Winner Is…

There isn’t one really. Yes, the secrets out. There are too many factors that dictate the type of foot plant that is appropriate for one individual versus another. Additionally, the most efficient runners studied and viewed may alternate foot plant patterns based on the speed, the event, and level of fatigue. What is known is that the culmination of several aspects of form will dictate where and how the foot is planted.

Although nearly all runners are heel strikers to some extent, a more recent shift in biomechanical evaluation and training has been toward the promotion of landing toward the mid foot. The ideal strike zone is on the outside of the foot between the little toe and heel, allowing the foot to flatten or roll in slightly in accommodating the load and forming a stable base of support. In theory this pattern reduces braking forces associated with heel striking, decreases ground contact time, places the individual’s weight directly over the base of support, and elicits the strongest activation of both large muscle groups and the elastic recoil of connective tissues and tendons.

Those with more flexible feet may land with a flatter foot and require either increased muscle strengthening or increased control in a shoe to secure a stable base of support at foot strike. Those with more rigid feet and less elasticity in their ligaments and tendons may require increased cushioning or support of the plantar fascia to avoid trauma and inflammation. Form should can be broken down into components, but changing one of those components such as foot strike too quickly and without addressing the other components that make it possible begs for injury.

Application Opportunities

Barefoot jogging on firmer surface.
Comparing hopping on mid foot to hopping on heels with toes raised.
Use of scooter on flat and uphill.

Knees

It should be the focus of the knees to lead the motion and pull the foot from the ground, not to push or pull the body through running. Although all muscles of the legs must work together for smooth, effort free and/or explosive propulsion, maximal quadriceps extension translates to increased vertical rise during toe off. Conversely, an extended knee with quadriceps firing at first contact will translate to inefficient braking forces. The quadriceps must stabilize the knee enough for energy to be transferred through to the springs of the feet and provide the lever with which to lift and cycle the foot forward.

Posture

Shifting away from the historical upright views, contemporary theories advocate for adding a slight forward lean to an erect posture maintained by strong core musculature. The degree of pelvic tilt is continuous with not only the upper, but also the lower body for full alignment. Visualize being strapped to a board running from your ankles to your head. Leaning forward would require you to flex at the ankles to the point of falling over, all the while in full body alignment. The further you lean, the stronger the pull of gravity and the quicker the response time that would be needed in the legs. Maintaining a slight forward lean harnesses gravity, minimizes vertical displacement, reduces the likelihood of striding out and heel striking, and places the lower body in a better position to push with the gluteals and pull with the hip flexors. At all points however a straight line should be found from the ears through the shoulders and hips to the ankles. Additionally, by focusing the lean at the ankles and not simply the upper body, you stand a better chance of insuring that your hips and shoulders efficiently follow in alignment.

Application Opportunities

Jogging with backward, upward, and forward leans.
Changing speed through altering the degree of forward lean.

Arms

The arms should be held at the sides with linear movement stemming from the shoulders with the production of forceful but rhythmic backward driving with the elbows. The wrists should be straight with fingers cupped but relaxed, with varying degrees of elbow flexion through the cadence with the hands remaining above the waist but below the below the shoulders. The hands may pass slightly in front of the chest but never cross midline. Arm swing should be the metronome for the legs with a target cadence of 180 elbow drives per minute.

Application Opportunities

Running with a tortilla or potato chip in hand.
Use of elastic shoulder/arm bands to promote efficient carriage..
Comparing jogging with straight arms to varying degrees of elbow flexion.
Sensing the relationship between the direction of arm movement both laterally and vertically with the legs.

Head and Neck

Avoid excessive movement and keep in alignment. Most importantly though, keep them relaxed. If you don’t look like you’re enjoying the task at hand, chances are your body isn’t appreciating the way you’re doing it.

Stride Mechanics

Working on mid foot landing and insuring that one’s center of mass is over the base of support at all times will foster an appropriate stride length. Runners should avoid over striding as the result is an inefficient and slower heel-strike pattern. Potentially more beneficial than stride length is the rate of turn-over or cadence. Immediately after foot strike the runner should focus on lifting the heel toward the buttocks, driving the flexed knee forward, not upward. The desirable stride rate is approximately 180 steps or strides per minute. It has been found that as a runner gets older they become more prone to swinging their foot through lower to the ground and with longer ground contact time during the stance or support phase. The result of both is increased inefficiency and slower running, emphasizing the importance of quick high heel lifts and quick turnover.

Application Opportunities

Running in place comparing lifting at heels with lifting at knees.
Striding out with foot strike in front of body and base of support.

Hills

Hills represent greater potential gains for using proper biomechanics than flats. With downhill running it becomes even more crucial to assume a slight forward lean with the center of mass falling in front of the base of support and allowing gravity to provide the horizontal propulsion. What will take time is becoming more comfortable with having your foot land behind your hips and exploring vastly quicker leg turnover. It is not uncommon to hold back in order to restrain downhill speed. In some cases it would be dangerous not to. Your lean is your accelerator, but self-imposed speed limits aren’t always bad things.

With uphill running an athlete should focus on maintaining a cadence of 180 strikes per minute, but with a shorter stride length and increased effort at vertical displacement. With decreased downward forces placed perpendicular to the ground and through the foot, less plyometric energy is gained or available for recoil. To compensate the quadriceps, which are not primarily recruited in running over flat ground, are required to achieve the forceful knee extension needed for vertical propulsion. Additionally, the hip flexors will work harder in conjunction with short quick upward driving movements of the arms for a more forceful vertical lift.

In Closing

Your body has paired an anatomical framework dictated by genetics, with the demands of interests, occupations, and societal influences placed upon it from birth. In many cases it has chosen the path of least resistance in wiring neuromuscular patterns. In some cases you’ve had a hand in forcing it in directions that it didn’t ask to go. What all the scientists, coaches, or fitness trend creators in the world cannot prove is the precise culmination of those influences playing out in your running biomechanics. Without that, complete perfection can never be certain and that should not be the goal.

The most critical factor will be learning to better listen to and understand what your body is telling you. What will be presented are aspects of “ideal”, and less than ideal, aspects of form based on current understandings. For most embodying excellent form, chances are it has come naturally and through many miles and years, not from the learning of form theories. For some though theories have been systematically applied with success, shaved minutes off of times, and led to injury free running. Success though will require time, patience, and the willingness to spend time strengthening your body in new ways based upon the new stresses that will be encountered.

It will take time to retrain the body and, in effect, redevelop postures, strengths, weakness, and interplays between muscles, joints and ligaments. In that time intensity of training should be reduced if not eliminated, and moments taken away from overanalyzing how you should be running. The goal is to enjoy running, become a bit more efficient, a little less prone to injury, and, if possible, a little quicker in the process. While efficient form ultimately should remain the path of least resistance, rushing into new territory too quickly will surely lead to frustration and injury. So enjoy playing with your biomechanics, but ultimately don’t take the fun and ease out of the running style that comes naturally to you.

Ian Golden is owner and operator of The Finger Lakes Running & Triathlon Company.

Photo courtesy of left-hand
2016-12-08T22:24:15-05:00 Categories: Training|Tags: , |0 Comments

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