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| Barefoot running vs running shoes |
Barefoot running has increased in popularity over recent
years, risks and benefits have been widely speculated in current literature.
However, there is insufficient evidence on potential advantages and
disadvantages of barefoot running. The purpose of this article was to
systematically review the recent literature about barefoot running to evaluate
the biomechanical measurements and the influence of foot strike modalities
compared to shod running.
Barefoot running is characterized by the absence of external
protection and minimal cushioning against the ground, being its main difference
with the cushioned race the part of the foot that first contacts the ground. Barefoot
runners usually land with the front foot or forefoot before lowering the heel,
but sometimes land with a flat foot or midfoot or, less frequently, with the
heel or rearfoot. On the other hand, mostly shod runners, land with the
rearfoot facilitated by the raised heel and the padding of modern footwear (1).
Differences in race conditions and foot strike can be
related to possible spatio-temporal, kinematic and muscle activity changes
between one group and another of runners.
Biomechanics Analysis
The knee must absorb less energy in barefoot running and, on
the contrary, the ankle absorbs more energy in barefoot running midfoot and
forefoot. The angles of the ankle when landing forefoot are plantar flexion
compared to dorsiflexion in the rearfoot strike. The gastrocnemius suffer
greater muscular activity in the forefoot and midfoot group, and the tibialis
anterior is more active in the rearfoot group. In addition, the centre of mass
is more advanced and the cadence increases in barefoot running.
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| Foot strike |
Spatio-temporal Variables
In all the reviewed studies there is homogeneity regarding
the effect on the speed variable, it was observed that both the footwear
and the type of strike do not influence the running speed. However, the stride
length was significantly shorter in barefoot running but it is compensated by
an increase in the cadence, which results in a decrease in the support
and oscillation phase. According to previous studies, it can be
considered that the increase in cadence can be an effective strategy to reduce
the loads to which the knee is subjected, and it could be useful in the
modulation of biomechanical factors that can contribute to patellofemoral pain
(2).
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| Speed - Cadence - Stride phases |
The impact and load rate suffered by the body during
the race must be distributed by the absorption mechanisms inherently possessed
by the body against this potential damage, through active absorption (with
joint alignment and muscular forces) or passive absorption (through of the heel
pad, synovial fluid, bone and articular cartilage) (3). Studies show that
during the road race the knee absorbed more energy than the ankle in all foot strike
conditions. However, in barefoot running with support in midfoot and forefoot
this absorption is reversed and the ankle becomes the joint that absorbs the
most load, better for the knee that absorbs less energy. Since in barefoot
running the force of impact and the load rate are lower compared to shod
running and with forefoot strike is less than rearfoot, the knee is the most
benefited in this condition and this type of foot strike.
The cushioning found in modern footwear is designed to
attenuate and reduce the forces of impact, the shoe sole being an element
that contributes to reduce pressure by using materials and concrete geometry
depending on the pattern of the corridor (34). However, it has been observed
that 85% of shod runners use a rearfoot strike, which may derive from the
design of the footwear and, ultimately increase the mechanical load in the
lower extremity as the rearfoot strike group which has the greatest impact (1, 4,
5).
In contrast, the tibial impact was greater in the barefoot
forefoot strike, with high impact rates associated with the appearance of race associated
injuries such as tibial stress fracture and tibial periostitis (6, 7), which is
why It is necessary to delve into this topic, since only one study showed this
information. Similarly, there are discrepancies in the literature because
according to Williams et al. (8) the type of forefoot strike reduces the tibial
impact in barefoot running, and according to Olin et al. (9) the tibial impact
time was significantly shorter in this race modality. In addition, it has been
observed that certain types of heel wedges can increase tibial stress (4).
The impulse and the plantar pressure peak are greater in the
first and second metatarsals in the barefoot forefoot strike, may be associated
with stress fractures when the transition from shod running is made quickly (10).
Likewise, the current footwear has reinforcement in the midsole of this region
to reduce the impact (4).
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| Foot strike impact |
Cinematic Variables
The biomechanics of the lower limb can be influenced by the
type of foot strike and by running conditions. There were significant
differences in range of motion of the ankle and knee in both running
conditions, but there was no homogeneity in the hip literature. The angles of
the ankle at forefoot strike landing are plantar flexion compared to
dorsiflexion in the rearfoot strike. In the forefoot strike, the foot lands
first with a plantar flexion posture followed by a dorsiflexion movement that
is controlled by the eccentric contraction of the leg muscles, serving as a
buffer for the runners and this range of motion being greater in the condition
barefoot. The angles of the knee when landing forefoot strike are greater in
flexion in both barefoot and shod running, in addition the angle of knee more
flexed in the initial contact provides a greater cushioning effect. All this is
because if the ankle is in a greater plantar flexion in the initial contact,
the knee will be more flexed to establish the hitting position closer to the centre
of mass projection (8).
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| Range of motion barefoot landing phase |
Muscle Activity
For the normally runners with shoes, the biggest challenge
in the change to the forefoot strike may be the increasing activity of the gastrocnemius
during the support phase. Based on electromyographic signals (9, 11, 12), the
gastrocnemius show a significantly higher forefoot strike than rearfoot strike activity
in preactivation and support phases. Considering the observed results, it is
necessary to advise the runners to carry out an adequate training of the
gastrocnemius to provide adequate cushioning. However, excessive training could
cause a high load of this musculature increasing the risk of suffering injuries
to the Achilles tendon (13).
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| Muscle activity |
Injuries
The main question in the mind of runners, coaches and
physiotherapists is whether the barefoot running has any effect on the ratio of
injuries. The positive effects of the barefoot running have been widely
speculated, but there is an ongoing debate about the advantages and potential
dangers of the barefoot running and the adaptation of a barefoot running style.
The interpretation of this type of studies comparing barefoot running with
modern shoes is that the loads are lower in certain areas, but higher in
others. For example, Shih et al. (11) showed that the load on the knee was
lower running barefoot, but the load on the ankle was greater. While Thompson
et al. (14) showed that the heel impact was reduced by running barefoot and
Olin et al. (9) indicated that the tibial load was greater in the group of
barefoot runners. This means that the load is transferred from one place to
another, there being no systematic benefit of one over the other. This can have
specific individual benefits, not extrapolated to everyone. A higher load on
one type of tissue may increase the risk of injury in some individuals, but not
in others.
Patients with knee pain would benefit more from one style
than another due to the loads. If the shod runners manifest an increase in
symptoms on or around the knee, you should consider changing your foot strike
to a mid-forefoot pattern or even attempting the barefoot running. Conversely, barefoot
running tends to increase the impact load around the lower leg and ankle, which
increases the risk of injury in this anatomical region.
In this scenario, the runner should be advised to change to
a rearfoot strike or even try different shoes. Finally, the transition to the
barefoot running from the road must proceed with caution to avoid injury.
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| Knee injuries |
Conclusion
The barefoot running can modify biomechanical parameters of
the race compared to shod running; being the most remarkable: the cadence, the
load rate, the absorption of energy, the ROM of the ankle in the support phase
and the muscular activity of the gastrocnemius.Possibly, the most relevant factor in the biomechanical
modifications that are observed in the barefoot running is the type of foot strike,
which is normally done with forefoot.
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| Forefoot strike |
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| Rearfoot strike |
Bibliography
1. Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D'Andrea
S, Davis IS, et al. Foot strike patterns and collision forces in habitually barefoot
versus shod runners. Nature. 2010 Jan 28;463(7280):531-5.
2. Lenhart RL, Thelen DG, Wille CM, Chumanov ES,
Heiderscheit BC. Increasing running step rate reduces patellofemoral joint
forces. Med Sci Sports Exerc. 2014 Mar;46(3):557-64.
3. Ly QH, Alaoui A, Erlicher S, Baly L. Towards a footwear
design tool: influence of shoe midsole properties and ground stiffness on the
impact force during running. J Biomech. 2010 Jan 19;43(2):310-7.
4. Fernández
Villarejo M, Gijón Nogueron G. Factores del calzado deportivo de carrera que
influyen en la práctica deportiva: revisión sistemática. Arch med deporte.
2014:105-10.
5. Lieberman DE,
Castillo ER, Otarola-Castillo E, Sang MK, Sigei TK, Ojiambo R, et al. Variation
in Foot Strike Patterns among Habitually Barefoot and Shod Runners in Kenya.
PLoS One. 2015;10(7):e0131354.
6. Milgrom C, Finestone A, Segev S, Olin C, Arndt T, Ekenman
I. Are overground or treadmill runners more likely to sustain tibial stress fracture?
Br J Sports Med. 2003 Apr;37(2):160-3.
7. Fredericson M, Bergman AG, Hoffman KL, Dillingham MS.
Tibial stress reaction in runners. Correlation of clinical symptoms and scintigraphy
with a new magnetic resonance
8. Williams DS, 3rd, Green DH, Wurzinger B. Changes in lower
extremity movement and power absorption during forefoot striking and barefoot
running. Int J Sports Phys Ther. 2012 Oct;7(5):525-32.
9. Olin ED, Gutierrez GM. EMG and tibial shock upon the first
attempt at barefoot running. Hum Mov Sci. 2013 Apr;32(2):343-52.
10. Murphy K, Curry EJ, Matzkin EG. Barefoot running: does
it prevent injuries? Sports Med. 2013 Nov;43(11):1131-8.
11. Shih Y, Lin KL, Shiang TY. Is the foot striking pattern
more important than barefoot or shod conditions in running? Gait Posture. 2013 Jul;38(3):490-4.
12. Sinclair J, Atkins S, Richards J, Vincent H. Modelling
of Muscle Force Distributions During Barefoot and Shod Running. J Hum Kinet.
2015 Sep 29;47:9-17.
13. Lieberman DE. What we can learn about running from
barefoot running: an evolutionary medical perspective. Exerc Sport Sci Rev.
2012 Apr;40(2):63-72.
14. Thompson MA, Lee SS, Seegmiller J, McGowan CP. Kinematic
and kinetic comparison of barefoot and shod running in mid/forefoot and rearfoot
strike runners. Gait Posture. 2015 May;41(4):957-9.
Barefoot vs running shoes Running shoes Barefoot running Running
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