Is there any value in joining the
bare foot running movement?
Largely in part to the best selling book Born to Run by Chris McDougall as well as an accumulation of scientific studies that conclude modern running shoes may precipitate injury, the bare footed running movement has gained popularity. In most instances, without any formal instruction, a normally heel striking shod runner will be observed to make the following changes in running technique when eliminating shoes:
Land on the ball of foot rather than the heel
Land with a greater degree of knee flexion
Utilize a greater degree of ankle dorsiflexion mobility
Increase cadence or “turnover”
These modifications are collectively known as impact moderating behaviors and data from biomechanical studies demonstrate highly significant reductions in both ground reaction forces as well as in joint torques.
Observational analysis usually reveals that the bare foot runner will move in a more compact manner and be lighter and quicker on his or her feet. The time on support (stance time) will be reduced and there will be less displacement of the body’s general center of mass. A bare foot runner appears to engage the entire body rather than running with only the legs. Additionally, runners become more focused as they are scanning with their eyes in an attempt to avoid landing on hazards. These changes are generally considered excellent starting points to improved running technique. However, observation of hundreds of runners reveals that 10-15% of heel striking shod runners will make no such changes when initially attempting to run bare footed; at least not immediately.
It is important to realize that despite reductions in overall impact, bare foot running induces different stresses on the musculoskeletal system; and some of these may be increased relative to their former levels. For our purposes, the most important consideration may be the forces that are transmitted from muscles to tendon and bone. Because bare foot running changes a variety of important muscular factors including both the rate of force development and sequence with which muscles contract, there is the potential to create an injurious overload. Injuries to tendons are diagnosed as tendonitis while bone trauma is described on a continuum that ranges from stress reactions to fractures.
The muscular weakness and loss of joint mobility that results from the habitual use of modern footwear, including stability or motion control running shoes, may require many months to reverse. This muscular insufficiency becomes clearly evident to runners that are new to bare foot running as significant delayed onset muscle soreness is often experienced following introductory trials. It has been recommended that 30 minutes of bare foot running on a soft surface is a reasonable starting point for most runners. However, in our experience, even this may be excessive for some as there is no general recommendation that can be made to safely guide today’s diverse running population.
All runners (and their feet) are not created equally. As an example, the shape or posture of the foot’s inner longitudinal arch is highly variable and is often categorized as being either planus or cavus. A planus foot is one in which the arch appears flattened and flexible while the arch of a cavus foot is rigid and elevated. The arch shape may or may not be indicative of the orientation of the underlying bones and joints as some individuals that are diagnosed with “flat feet” have a neutral ankle joint and vertically oriented heel bone (calcaneus) while others that have a similar looking arch actually have a collapsed or pronated ankle with an everted heel. To the untrained eye both of these cases may appear similar; however, structurally and functionally they are unique and therefore require a different initial approach to bare foot running.
For the individual with a flat arch and a neutral joint alignment, the rate at which bare foot running should be advanced is the time required for the body’s collagen to adapt. Collagen is the primary structural constituent of tendon and bone. In scientific studies of animals and humans this is in the order of 8-12 weeks. For successful adaptation to occur two requirements must be satisfied. First, the new load must exceed a given stimulus threshold; and secondly, the loading must occur with ample frequency. This is of course assuming that all the essential nutritional and hormonal precursors are present and that excessive catabolic factors are controlled. For endurance athletes, negative energy balance, dietary shortcomings, and excessive stress, leading to high cortisol levels, may limit collagen’s adaptation potential.
Let’s assume that the stimulus threshold for adaptation to take place in the collagen of the Achilles tendon is 1.5 above habitual loading levels and that forces on the tendon are increased in the order of 2 for slow speed running, 3 for moderate speed running, and 3.5 for sprinting relative to the shod condition. In this scenario, a runner should consider a period of 8-12 weeks at a frequency no less than 3 times per week to engage in slow speed running in order to achieve a level of structural adaptation that is consistent with a new baseline of collagen strength. If the individual wishes to engage in faster speed running or sprinting activities a second phase of development utilizing a similar frequency and duration would need to take place in order to allow for the next level of collagen adaptation to occur.
The results of scientific studies reveal that force and frequency are the most important parameters to consider in the development of collagen and skeletal strength. Significant increases in bone density have been demonstrated to occur with as few as 5-10 repetitions of loading per day, usually in the form of maximal jumping and landing exercises, and require at least 3 training sessions per week. The optimal frequency of loading is most likely higher as daily loading regimes have demonstrated significantly greater results than protocols involving 3-5 sessions per week.
For the individual with a planus foot that has a structural collapse (pronation) in standing or demonstrates significant collapse during running, we recommend a comprehensive structural examination by a trained sports medicine professional. Common structural causes of a collapsing arch that are amenable to care include limitations in joint mobility, muscular weakness, and technical errors in running. Often mobility restrictions and weakness as far away as the spine and hip are manifested as excessive ankle pronation. However, some cases of compensatory pronation are related to alignment and/or geometry of the lower extremity bones and joints and may not be amenable to treatment. Common examples include femoral anteversion, tibial torsions, and varus deformities of the knee, lower leg, or forefoot.
Rehabilitation of the individual that presents with a significant collapse of the ankle due to a modifiable factor is contingent upon establishing an operational diagnosis of the cause and then implementing treatment. For example, if limited ankle dorsiflexion mobility is identified, a program of range of motion exercises are prescribed and frequently complimented with manual therapy procedures. A typical routine would involve having a client perform 6-10 repetitions of a self-treatment exercise every 2-3 waking hours for as long as it requires to re-establish normal mobility. Manual therapy procedures including mobilization, manipulation, or soft tissue release techniques may be utilized on an as needed basis to ensure a consistent and timely rate of progression.
The rate of improvement in treating a dysfunctional foot/ankle is contingent upon the nature of the limitation. While certain situations can be resolved or improved dramatically with a single application of manipulation other cases may require vigilant treatment for weeks or even months. This is especially true for adaptive stiffness that followed a previous injury and/or immobilization. Frequently, middle aged runners have experienced severe ankle sprains or fractures earlier in their lives that resulted in subtle range of motion or strength deficits that were never fully rehabilitated. These residual limitations may have been masked during shod running but frequently produce running gait abnormalities or injury when subjected to the larger mobility and force demands of bare foot running. Following the resolution of any relevant deficits in range of motion, strength, or technical running errors, the progression of collagen conditioning can begin as outlined for the runner with normal alignment.
We would encourage those of you interested in becoming bare foot or minimalist shoe runners to consider the following points:
When not running, spend as much time as possible in bare or stocking feet. This is especially true for activities that involve standing, walking, or lifting.
Consider eliminating or minimizing the use of rigid dress or casual shoes that have a significantly elevated heel. Daily use of minimalist shoes provides long term loading to the muscles that favors plastic (permanent) versus elastic (temporary) changes in flexibility.
Regularly practice basic balance and strengthening exercises throughout the day. Excellent examples include the single leg standing pose with eyes closed (aim for > 10 seconds), “gripping” the ground with your toes, or performing some small amplitude elasticity exercises (simulated rope skipping or jumping jacks for 30-60 seconds).
Be considerate of the time required for the adaptations to occur in collagen (8-12 weeks) and avoid doing too much too soon. The resolution of delayed muscle soreness following introductory training sessions is not necessarily a good indicator of your capacity to advance.
The frequency and intensity of loading is more important than the number of repetitions performed. At least three loading sessions per week appears necessary and more is likely better. Even if optimal running frequency cannot be maintained, consider doing short session of elasticity or jumping exercises in order to satisfy the necessary loading frequency requirement.
Discontinue daily rigid footwear and transition to flexible dress shoes with minimal/nil heel elevation.
Initiate a basic exercise program to facilitate dormant muscles and improve mobility. Emphasis should be placed on exercises that resolve any limitations in mobility and improve muscular strength as well as start to develop a tolerance for faster speeds of muscle contraction. Examples of commonly prescribed exercises include:
Ankle inversion or arch elevation routines,
Isometric toe “gripping” of the floor,
Single leg standing balance +/- perturbations,
Nicholas Romanov’s “switch drill”,
Small amplitude (< 3 inches) vertical rope skipping movements with a bilateral landing pattern.
Rope skipping movements and/or small amplitude elasticity exercises may be gradually advanced to include single leg landing strategies and/or diverse landing patterns. A variable or “heterogenic” loading pattern is known to be more anabolic to bone than a monotonous one and more closely mimics the functional demands of running over varied terrain.
3 sessions of bare foot running per week with an emphasis on the development of technique and skill. We favor the use of short repeated runs of 30-100 meters in length coupled with drills for improving the execution and perception of proper landing as well as decreasing time on support. The length of each session is contingent upon and individual’s quality of movement and fatigue resistance. Decay in running technique is an indicator that the session has lasted too long.
Increase frequency, not duration or speed of running, from 3 to 6 sessions per week by adding a session per week.
Transition three running days per week from short to progressively longer intervals. Distance run is based on the maintenance of proper technique rather than time or heart rate. A track is an excellent venue as it provides a coach with the opportunity to see how an athlete maintains form over distances from 200, 400, 800 meters and allows for a more objective baseline comparison from which progress can be measured.
Transition to daily (or near daily) continuous running with no (or minimalist) shoes.
Increase in total distance should be governed by the maintenance of excellent running technique.
Significant changes in running speed (or terrain) should be approached in a manner that is consistent with the need for an additional 8-12 weeks of time to allow for a new level of structural adaptation to occur.
Remember that all training adaptations are reversible and if an extended period of time elapses during which no bare foot running is performed, the need to return to a baseline level of loading is mandatory.
Although developing improved strength and flexibility are excellent by-products of bare foot running the greatest value of the endeavor may be the improvement in a runner’s level of perception. Through this experience many runners are impressed by how much impact and stress can be reduced by the elimination of modern running shoes and by subtle changes in technique. Bare foot running is not a panacea for injury prevention or technical excellence but should be considered a valuable adjunct to a comprehensive running program.
For additional information on the subject consider the following articles and resources:
Barefoot Ted’s web site: http://www.barefootted.com/index.php?q=/
Barefoot Wikipedia web site: http://en.wikipedia.org/wiki/Barefoot
Collier R (2011) The rise of barefoot running. CMAJ 183(1):E37-38.
Hamill J, Bates B (1988) A kinetic evaluation of the effects of in vivo loading on running shoes. J Orth Sport Phys Ther 10(2):47-53.
Kerrigan D, Franz J, Keenan G, Dicharry J, Della Croce U, Wilder R (2009) The effects of running shoes on lower extremity joint torques. PM R 1(12):1058-1063.
Kerrigan D, Lelas J, Karvosky M (2001) Women’s shoes and knee osteoarthritis. Lancet 357(9262) 1097-1098.
Lieberman D, Venkadesan M, Werbel W, et al. (2010) Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature 463(28):531-535.
Daniel Lieberman’s web site: www.barefootrunning.fas.harvard.edu
Morio C, Lake M, Guenguen N, Rao G, Baly L (2009) The influence of footwear on foot motion during walking and running. J Biomech 42(13):2081-2088.
Robbins S, Gouw G (1991) Athletic footwear: unsafe due to perceptual illusions. Med Sci Sport Exerc 23(2):217-224.
Robbins S, Gouw G (1990) Athletic footwear and chronic overloading A brief review. Sports Med 9(2):76-85.
Robbins S, Gouw G, Hanna A (1989) Running related injury prevention through innate impact-moderating behavior. Med Sci Sport Exerc 21(2):130-139.
Robbins S, Hanna A (1987) Running-related injury prevention through barefoot adaptations. Med Sci Sport Exerc (19(2):148-155.
Robbins S, Hanna A, Jones L (1988) Sensory attenuation induced by modern athletic footwear. Journal of Testing and Evaluation (16):412-416.
Shakoor N, Block J (2006) Walking barefoot decreases loading on the lower extremity joints in knee osteoarthritis. Arthritis Rheumatism 54(9):292302927.
Warburton M (2002) “Barefoot Running” Sportscience 5(3) sportsci.org/jour/0103/mw.htm.