Master Track & Field News - Daily Newsletter from Ross Dunton, USA


TRAINING ADVICE/RUNNERS, THROWERS AND JUMPERS

INFORMATION FOR THE WORLD MASTERS, MASTERS AND SENIOR GAMES ATHLETE

 

INTERNET EDITION--------------------------------------------------------------------------#170--July 6, 2004

coachr880@bellsouth.net  -------------------------------------------  http://www.coachr.org/

DUNTON SPORTS MANAGEMENT, 2251 Robertson View Point, Sevierville, TN, USA, 37876

 

Barefoot Running:

A Natural Step For The Endurance Athlete?

 

By Dennis G. Driscoll

Head XC Coach, Natick (MA) High School

 

This comprehensive look at research on barefoot vs. shod running gives much food for thought. It was presented to USATF Coaching Education in August 2003, in accordance with Level III certification requirements.

"The human foot is a work of art and a masterpiece of engineering." Leonardo Da Vinci

 

INTRODUCTI0N

    Abebe Bikila raced barefoot to a gold medal in the 1960 Olympic marathon. Herb Elliott, the 1500m victor at the same Games, ran 17 sub-four-minute miles and was never defeated at either 1500m or one mile. Photographs of Elliott during barefoot training runs twice graced the cover of Sports Illustrated. Two time world cross country champion and former 5K world record holder Zola Budd competed and trained barefoot. The first lady of American distance runners, Doris Brown Heritage, as a youngster enjoyed barefoot ten-mile runs on the beaches and forest trails near her home. And the stories of barefoot Kenyans running throughout their homeland are legendary.
    Running barefoot does not appear to have been detrimental to the development of these elite endurance runners. In fact, it may have been beneficial to their train- ing. Why, then, don't we see more barefoot endurance runners?
    In some cases the answer has been legislated. The National Federation of State High School Associations, for example, mandates in its rule book that track & field and cross country athletes wear shoes. Another reason is certainly that runners believe they are better off donning footwear. After all, athletic footwear has been touted as reducing the number of running-related injuries as well as improving performance.
    It would seem, however, that footwear may interfere with some naturally selected adaptations to the human form. There are some anthropologists who believe man evolved as a diurnal endurance predator. Stories exist of Bushmen relentlessly pursuing and wearing down the much faster zebra and of Navajo Indians doing much the same with pronghorns.
    The evolution of an anatomy featuring long, tapered limbs with more mass concentrated near the hips, energy conserving spring-like tendons, and the cooling effects of sweat glands working with a nearly hairless body gave us a being that was an adept endurance runner.1,2

    It follows that the human foot would also have evolved as a mechanism for efficient endurance propulsion.
    The purpose of this paper is to investigate some of the scientific studies that have been done in the area of running both barefoot and with footwear. Is there an advantage to training, or racing, barefoot? Or, is the modern running shoe a technological marvel that helps reduce injury and makes us more efficient runners?

 

BIOMECHANICAL ANALYSIS OF THE STANCE PHASE

    An analysis of the biomechanics of the stance phase during barefoot running reveals several differences when compared to shod running. Unlike the dorsiflexed ankle of the shod runner, at heel contact the barefoot runner's ankle is plantar flexed leading to a more horizontal position for the foot. One study described a sole angle difference of 14° for a runner at a velocity of 4.5 m/s with increasing angular differences as velocity increased.
    A more horizontal foot would have fewer shear forces acting on the heel. Also, maximum pressure on the heel is reduced with a more horizontal foot at touchdown. The lower leg is more vertical for the barefoot runner at this point thanks to a greater knee flexion. Both the increased plantar flexion of the ankle and increased knee flexion occur prior to touchdown, suggesting an "actively induced adaptation strategy to barefoot running."3
    The initial foot strike is at the posterior end of the heel. Unlike shod running where heel strike typically occurs at the lateral posterior portion of the heel, the barefoot heel strike is centered between the lateral and medial parts of the heel. As the barefoot runner moves forward, the heel smoothly rolls over the center of the calcaneus. The bottom of the calcaneus features a concave tuberosity and bursa which allow for a smooth forward roll of the heel as weight is shifted forward.4 The shod runner, whose foot strike occurs away from the center of the heel, is unable to take advantage of the naturally intended function of this anatomical design.
    The entire plantar surface of the barefoot heel is in contact with the ground whereas the shod foot makes contact only with the posterior lateral edge of the heel.
    The greater plantar area covered for the barefoot runner leads to an increased deformation of the fatty heel pad and superior shock absorption. A barefoot runner ambling at 4.5 m/s can expect a maximum heel pad deformation of 60.5% (+/- 5.5%) compared with only 35% (+/- 2.5%) for a shod runner.5
    During this initial contact phase, sensory feedback from the glabrous epithelium of the bare foot brings about greater flexibility of the foot. This suppleness helps the foot adapt to irregular ground surfaces and allows it to act as a shock absorber.
    Much of the shock absorption during this phase occurs through natural pronation and the associated downward deflection of the medial longitudinal arch. Much of this is tempered, or even lost, in the shod foot.
    Sensory feedback is greatly diminished by the insulating sole of the shoe. The result is a more rigid foot which disables the deflection of the medial longitudinal arch, reducing the foot's ability to moderate impact shock. Arch supports built into most shoes further reduce the ability of the arch to deflect. 6
    Additional evidence exists relating sensory feedback the foot receives during impact to intra-limb coordination patterns of the lower extremity. Kinematic changes of the lower extremity diminish the quantity of impact forces. The kinematic changes related to intra-limb coordination appear to depend on this sensory information. Running shoes, typically designed to decrease the forces on the body at impact, tend to reduce this important sensory feedback.7,8................

 

...........Finally, how does running economy compare between the barefoot and shod state? Oxygen consumption has been shown to be 4.7% higher while wearing shoes (approximately 700g per pair) and running at 12km/h.20 Reasons for this include the mass of the added footwear requiring additional energy to move the shoes through each stride, energy being absorbed by the shoe's cushioning, and the energy expense of flexing the sole of the shoe.
    When these energy drags are combined with the previously detailed loss of a stretch reflex from the lower leg it becomes understandable that barefoot running is more economical.

 

CONCLUSION

    Dr. Benno Nigg, founder of the Human Performance Laboratory at the University of Calgary, believes barefoot running reveals the body's preferred movement pattern. The body's locomotor system adheres to the same pattern even when shoes, inserts, orthotics, or other interventions are introduced. The neuromuscular system automatically prevents straying from this preferred pattern. Footwear that does not support the natural pattern will have a deleterious effect on a runner's performance.25,26
    Unfortunately most of us are wearing shoes that are not in sync with our body's preferred movement patterns. The result is that we do not experience normal gait and propulsion. Podiatric surgeon Ray McClanahan offers, "Shoes and their construction have been hypothesized to be the single most important identifiable feature that separates our long distance runners from those who grew up in countries where their feet and legs developed normally."11
    In the absence of the "perfect" shoe, barefoot running deserves serious consideration. The likelihood that all shoe-wearing runners will immediately abandon their footwear and take up full-time barefoot running is remote. Yet increasing the amount of time we run or walk barefoot should be beneficial. In their paper on running-related injury prevention, Robbins and Hanna concluded, "The solution to the problem of running-related injuries could be as simple as promoting barefoot activity."6
 

FROM: TRACK COACH 168----Contact me if you would like a copy of the complete paper. RKD

 


 

Effects of a Carbohydrate-Protein Beverage on Cycling Endurance and Muscle Damage

Medicine & Science in Sports & Exercise. 36(7):1233-1238, July 2004.
SAUNDERS, MICHAEL J.; KANE, MARK D.; TODD, M. KENT

 

ABSTRACT

 

Introduction: The purpose of this study was to determine whether endurance cycling performance and postexercise muscle damage were altered when consuming a carbohydrate and protein beverage (CHO+P; 7.3% and 1.8% concentrations) versus a carbohydrate-only (CHO; 7.3%) beverage.

Methods: Fifteen male cyclists (mean VO2peak = 52.6 +/- 10.3 mL/kg-/min-1) rode a cycle ergometer at 75% VO2peak to volitional exhaustion, followed 12-15 h later by a second ride to exhaustion at 85% VO2peak. Subjects consumed 1.8 mL/kg-1 BW of randomly assigned CHO or CHO+P beverage every 15 min of exercise, and 10 mL/kg-1 BW immediately after exercise. Beverages were matched for carbohydrate content, resulting in 20% lower total caloric content per administration of CHO beverage. Subjects were blinded to treatment beverage and repeated the same protocol seven to 14 d later with the other beverage.

Results: In the first ride (75% VO2peak), subjects rode 29% longer (P < 0.05) when consuming the CHO+P beverage (106.3 +/- 45.2 min) than the CHO beverage (82.3 +/- 32.6 min). In the second ride (85% [latin capital V with dot above]O2peak), subjects performed 40% longer when consuming the CHO+P beverage (43.6 +/- 12.5 min) than when consuming the CHO beverage (31.2 +/- 8.7 min). Peak postexercise plasma CPK levels, indicative of muscle damage, were 83% lower after the CHO+P trial (216.3 +/- 122.0 U/L-1) than the CHO trial (1318.1 +/- 1935.6 U/L-1). There were no significant differences in exercising levels of VO2, ventilation, heart rate, RPE, blood glucose, or blood lactate between treatments in either trial.

Conclusion: A carbohydrate beverage with additional protein calories produced significant improvements in time to fatigue and reductions in muscle damage in endurance athletes. Further research is necessary to determine whether these effects were the result of higher total caloric content of the CHO+P beverage or due to specific protein-mediated mechanisms.

 


 

The "Active Release Technique"

 

This is part of an e-mail message that I received yesterday: Hi Ross,
I am currently being treated for achilles tendonitis by a chiropractor who uses the Active Release Technique or ART. It is a massage technique that releases adhesions or scar tissue related to the injury.  I have had this problem since November of 2003 and thought for 8 months that it was plantar fasciitis. I am interested in the stretches that you used to recover. I currently cannot walk for exercise and my job requires me to stand a lot during the day.

 

I had never heard of the "Active Release Technique", so I did a search and came up with the following information:

 

What is Active Release Technique (ART)?

ART is a patented, state-of-the-art soft tissue system that treats problems with muscles, tendons, ligaments, fascia and nerves. Headaches, back pain, carpal tunnel syndrome, shin splints, shoulder pain, sciatica, plantar fasciitis, knee problems, and tennis elbow are just a few of the many conditions that can be resolved quickly and permanently with ART. These conditions all have one important thing in common: they often result from injury to over-used muscles.

How do overuse injuries occur?

Over-used muscles (and other soft tissues) change in three important ways:

acute injuries (pulls, tears, collisions, etc),
accumulation of small tears (micro-trauma)
not getting enough oxygen (hypoxia).


Each of these factors can cause your body to produce tough, dense scar tissue in the affected area. This scar tissue binds up and ties down tissues that need to move freely. As scar tissue builds up, muscles become shorter and weaker, tension on tendons causes tendonitis, and nerves can become trapped. This can cause reduced range of motion, loss of strength, and pain. If a nerve is trapped you may also feel tingling, numbness, and weakness.

What is an ART treatment like?

Every ART session is actually a combination of examination and treatment. The ART provider uses his or her hands to evaluate the texture, tightness and movement of muscles, fascia, tendons, ligaments and nerves. Abnormal tissues are treated by combining precisely directed tension with very specific patient movements.

These treatment protocols - over 500 specific moves - are unique to ART. They allow providers to identify and correct the specific problems that are affecting each individual patient. ART is not a cookie-cutter approach.

What is the history of Active Release Techniques?

ART has been developed, refined, and patented by P. Michael Leahy, DC, CCSP. Dr. Leahy noticed that his patients’ symptoms seemed to be related to changes in their soft tissue that could be felt by hand. By observing how muscles, fascia, tendons, ligaments and nerves responded to different types of work, Dr. Leahy was able to consistently resolve over 90% of his patients’ problems. He now teaches and certifies health care providers all over the world to use ART.

From the ART web: http://www.activerelease.com/
 

Apparently, in this case, "ART" didn't help with the Achilles tendon problem. Perhaps it works better on other tendon and muscle problems.

 


 

Discus learn – by - doing

Basic technique for discus throwing

By: Mark Harsha

Portage High School Girls’ Head Coach

 

 Goal One: Discus grip and release

1.      Holding the discus

Ø      Place discus in your throwing hand

Ø      Spread fingers out with index finger inline with wrist

Ø      Place fingers first knuckles over the disc

 

2.      Release the discus

Ø      When releasing the discus have your palm down

Ø      Squeeze the discus out (bar of soap)

Ø      The disc will come off the index finger

Ø      The disc will spin in a clockwise direction for a right handed thrower

 

3.      Drills used to teach the grip and release – excellent time for a competition

 

Ø      Arm swings – Use this drill to teach about centrifugal force

a)      The thrower stands with feet shoulder width apart

b)      Place the disc into throwing hand

c)      Swing the disc level with the shoulders back and forth catching it in your left hand

d)      The athlete should feel the discus pushing out on the hand

 

For the complete paper: http://www.everythingtrackandfield.com/catalog/matriarch/OnePiecePage.asp_Q_PageID_E_209_A_PageName_E_ArticleBasicDiscusTechnique

 


 

To aid in your search for specific training information, there is a "search engine" on my web.

To access it, click here.

 

Ross Dunton    coachr880@bellsouth.net

 

 

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