October 2012

Wearing athletic shoes affects some performance measures

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Standing long jump distance improves

By Cary Groner

Research has recently begun to clarify footwear’s effects on gait and functional performance in children, but the broader implications of the findings remain a matter of debate.

At the 2012 International Foot & Ankle Biomechanics (i-FAB) Congress in Sydney, Australia, researchers from the University of Sydney presented a poster delineating the difference between children’s performance barefoot and in athletic shoes. The researchers had nine boys and 10 girls (mean age, 10 years) perform four activities barefoot, then in athletic shoes, in a randomized order. The activities were a single-leg balance test (eyes open, then closed); a standing long jump; and a timed running agility test in which the subjects ran 10 m four times (they picked up an object at the end of one 10-m leg, carried it on the next leg, dropped it, and picked up another to carry—hence the “agility” aspect of the test).

The researchers reported that shoes did not alter single-leg balance whether subjects’ eyes were open or shut, nor did they have any significant effect on running agility. Shoes did, however, improve standing long jump performance; the authors speculated that this may have been due to a perception of better protection, improved friction between the outsole and the carpeted surface, better transfer of force from the calves, or some combination of these.

Lead author Caleb Wegener, an Australian podiatrist and PhD candidate at the university, told LER that additional data, unavailable at the time of the conference, showed that shoes negatively affected standing jump height—an effect possibly caused by the shoes’ weight.

An earlier review by Wegener and his colleagues found that about 75% of pediatric gait variables differed between walking barefoot and wearing shoes.  Shod children walked faster, taking longer steps with greater ankle and knee motion and increased tibialis anterior activity; on the other hand, shoes reduced foot motion and increased the support phase of gait. During running, shoes had three primary effects: a reduction in swing-phase leg speed, shock attenuation, and encouragement of a rearfoot strike pattern.

Other studies have reported similar results. For example, a 2009 paper by Lythgo et al in Gait & Posture reported that children’s gait speed, step length, stride length, support base, and step and stride time all increased with athletic footwear, whereas foot angle and cadence decreased. Another of Wegener’s studies found that children’s school shoes increased sagittal ankle motion during loading and propulsion, but decreased frontal plane motion during midstance and propulsion.

The practical implications of such research remain to be determined, Wegener acknowledged.

“Shoes reduce motion, which could reduce the stimulus to the muscles, which could impede muscular development,” Wegener said. “But we need to confirm that hypothesis.”

In fact, when younger, Wegener often competed in track and field events barefoot, on a grass track. He acknowledges that barefoot athletic competition has its limits, however.

“I’d never play soccer or basketball barefoot,” Wegener said. “Shoes do change the way the foot functions—but they also provide protection.”

Russell Volpe, DPM, professor of orthopedics and pediatrics at the New York College of Podiatric Medicine in New York City who has written about athletic foot­wear for children, examined the studies by Wegener and others and concluded that the reported gait and performance changes are probably neutral to positive.

“These are fairly minute gait changes,” he said. “Some are biomechanically logical changes in sagittal plane ankle motion, and there are other principles of the effect of shoes on gait that can be extrapolated to how they’ll affect children.”

Volpe does think that, where children are concerned, minimal is better.

“I generally like a lighter-weight shoe with soles that aren’t too thick,” he said. “It should have a firm counter to prevent excessive rearfoot motion, and it should bend easily in the ball.”

Volpe rejects the idea suggested by some that wearing shoes weakens the feet, however.

“There’s no evidence that the development of the muscles of the longitudinal arch is hampered by shoes,” he said. “But in a child, you don’t want anything so heavy or bulky that it’s going to cause bigger alterations in gait.”

Cary Groner is a freelance writer in the San Francisco Bay Area.

Sources:

1. Wegener C, Greene A, Millar R, et al. Children’s functional performance barefoot and in sports shoes. J Foot Ankle Res 2012;5(Supp1):31.

2. Wegener C, Hunt AE, Vanwanseele B, et al. Effect of children’s shoes on gait: a systematic review and meta-analysis. J Foot Ankle Res 2011;4:3.

3. Lythgo N, Wilson C, Galea M. Basic gait and symmetry measures for primary school-aged children and young adults whilst walking barefoot and with shoes. Gait Posture 2009;30(4):502-506.

4. Wegener C, O’Meara D, Hunt AE, et al. Three-dimensional ankle kinematics in children’s school shoes during running. J Foot Ankle Res 2012; 5(Supp1):20.

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