Why rocker bottom shoes

In general, the rolling phenomena along the bottom surface of the rocker shoes, as well as an increase in the duration of simultaneous curve rolling and ankle rotation, could contribute to the reduction of plantar force for both rocker designs. The possible mechanism is the conversion of vertical kinetic energy into rotational kinetic energy.

To conclude, since plantar force is related to foot-ground interface and deceleration methods, rocker-design shoes could achieve desired plantar force reduction through certain rolling phenomena, shoe-sole stiffness levels, and locomotion speeds. In order to treat, rehabilitate, or carry out preventative care, clinicians often develop customized foot orthoses, the rocker-soled shoes, with a specially curved outer sole. These allow smooth progression through the stand phase of gait, reduce overbending of foot joints, and reduce local impacts and stresses on the foot [ 1 ].

The biomechanical effects of rocker-soled shoes are those of reinstating the lost motion of the lower extremities and reducing plantar pressure on specific parts of the foot [ 1 ]. Furthermore, for jogging, rocker-soled shoes changed dorsiflexion angles during heel-strike and mid-stance, reduced ankle plantar moments and first medial force peak [ 2 ].

Changes in plantar force distribution and ankle joint movement were found at rocker-soled shoes to be the reason for increases in variability at the microscopic level [ 3 ]. Therefore, rocker-soled shoes have thus become the most common type of specialized footwear [ 1 , 4 — 8 ].

Moreover, to improve the gait of regular users, and reduce the chance of injury, numerous mass-producers of shoes also have designed soles with a slight curvature [ 3 , 9 ]. The general structure of the rocker shoes is an outer surface curved in the front, and a flat middle section. The curve in rear section is especially intended to decrease pressure on heel strike, and reduce the need for ankle motion.

This kind of heel rocker often focuses on the user who with special needs to alter their ankle kinetics [ 1 , 7 ]. During normal roll-off, in a normal step, the progression of the line of gravity is slowest at the metatarsal heads, resulting in relatively long acting ground reaction forces during this rotation [ 10 ].

Therefore, the apex of the rocker shoes should be placed proximal to the area in which pressure relief is desired [ 1 ]. Furthermore, to achieve an ideal equilibrium, Chapman et al. Some studies evaluated the effect of the prolonged wearing of rocker-soled shoes [ 3 , 11 ]. They compared the variability of biomechanical variables using rocker-soled shoes and conventional shoes.

The results showed that prolonged wearing of rocker-soled shoes could increase postural control performance, decrease centre of pressure displacement, and decrease postural control system error.

It is possible to carry out proprioception interference training using rocker-soled shoes, without taking specific device under certain circumstances. Other studies confirmed the hypothesis that the capacity of the plantar sole of the foot to convey somatosensory feedback about foot could be restored by inserting textured or noise-based insoles or changing footwear conditions [ 12 — 14 ]. From a biomechanical point of view, the goals in designing rocker-soled shoes include: 1 the curved surface at the front of the sole primarily functions to reduce stress and shear force in the push-off phase, reduce excessive bending of the metatarsal-phalangeal joint, and increasing forward thrust [ 1 , 4 , 8 , 15 ]; 2 the curved surface at the rear of the sole primarily functions to reduce impact force during heel strike, and protects the heel bones and ligaments [ 1 , 2 ]; 3 the flat middle part primarily supplies stability and support in midstance, as well as level plantar force [ 1 , 2 , 4 , 6 , 7 ].

Furthermore, previous studies have indicated that in order to provide maximum surface area of contact with the sole of the foot, absorb shock, and provide optimal support, compound materials are recommended in shoe-sole design [ 1 , 5 , 16 , 17 ].

For example, soft, moldable polyethylene has been recommended for contact with the sole of the foot. Firm molded cork or dense ethylene vinyl acetate EVA also has been recommended for the middle layer, to absorb reaction forces and provide excellent support. The lowest layer often utilizes fine, dense sponge rubber with anti-compression qualities, in order to absorb excessive shocks and provide good traction. However, with so many studies having examined the differences between rocker shoes and traditional shoes, one major factor, the stiffness, which is changed by some specific portions seldom been discussed [ 6 , 7 ].

Furthermore, to ensure the rolling-over effect, rocker shoes are usually designed by adding a stiffened rocker profile; few studies have quantitatively analyzed the biomechanical responses of different stiffness levels of rocker shoes. In this study, we hypothesized that differing stiffness of rocker shoes will affect the stress concentration effect during locomotion. Moreover, the influences of different curvatures and locomotion speeds were also taken into consideration. Two rocker shoes were designed using softer and denser materials, respectively, and examined by comparing them with barefoot and flat-soled shoes.

The specific aims were to test how and by what kinds of mechanisms rocker shoes with difference stiffness would influence the biomechanical parameters of gait pattern.

Before testing, all volunteers were notified of potential risks and signed an informed consent document approved by the Institutional Review Board of Industrial Technology Research Institute Case No. In order to investigate how shoe sole design and materials influence gait pattern and plantar force, this study examined four foot-ground interface conditions: barefoot Bare , flat shoes Flat , rocker shoe-soles with a softer material in the midsole Rocker-1 , and rocker shoe-soles with a denser material in the midsole Rocker Furthermore, to provide appropriate size for all the subjects, three different shoe sizes were prepared a total of 9 pairs of shoes.

Rubber is the only material used. Sole thickness at both heel and middle section is a uniform 25mm; front is 15 mm. Rocker-1 : All rocker shoes were designed and built from scratch; soles have a curved design the middle shoes in Fig 1A.

Outer surface of soles is curved upward at front and rear. Middle section is flat. Thickness of soles at both heel and front of shoes is 15 mm; middle section is 30 mm. The rocker radius is extended toward the front and back direction from the apex with a continuous curve [ 22 ].

Shoe soles have three layers using three different typically non-linear materials. EVA I is used under the arch and at the upper sides of the sole. EVA II is used under the metatarsal head of the forefoot, the calcaneus at rear of foot, and middle layer of the shoe-sole [ 17 ]. The outsole is used for contact with the ground Fig 1C [ 25 , 26 ]. Rocker-2 : Design of the curved outer surface and overall structure of the sole is the same as the Rocker-1 the rightmost shoes in Fig 1A.

According to the position of the markers in space, movement tracks were traced by using the three-dimensional orientation of each segment of the human body.

Pedar insoles systems Noval electronics Inc. Furthermore, to provide appropriate size for all the subjects, three different insole sizes were prepared. Before each subject joined this study, we checked the raw movement tracks which were captured from the Vicon system and confirmed that all subjects were walking and jogging with rear-foot strike. Moreover, the test speed is lower than running and may not facilitate the fore-foot strike pattern [ 27 , 28 ].

Each subject was asked to perform eight different tasks; the order of the four shoes Bare, Flat, Rocker-1, and Rocker-2 and the two activities walking and jogging was randomly assigned.

All subjects provided with appropriately sized shoes, socks, and Pedar insole systems; shoes were put on and tied by the same experimenter. In order to avoid slippage, the Pedar insoles were restricted by the socks in both Barefoot and shod conditions. After giving 10 minutes to get accustomed to each kind of shoes, additional familiarization was permitted until the subjects felt comfortable with the shoes.

We defined jogging as a form of locomotion at a gentle pace between 2. Prior to carrying out each task, subjects were allowed as many practice trials as necessary and moved their starting position along the walkway so that they could land dependably on the two force plates, one for each foot, without altering their stride pattern. A trial was accepted if the subject completely hit the two force plates with the preferred leg without targeting.

In order to calculate the speed, values of distance difference and time difference needed to be obtained. We checked raw movement tracks which were captured from the Vicon system to obtain the difference in distance. The time difference is obtained by measuring the time between the strike of the right and left foot on the force plate.

To avoid the carry-over effect, all tests were divided by a rest period of at least 15 minutes in which shoes were not worn. Moreover, tests were divided into two sessions within one week or at least two sessions within one day in order to avoid long experiment times affecting performance. Before each test, subjects were assigned to put on the shoes and insole system one additional time, and we recalibrated the insole system between intervals.

The sequence of the eight tasks was randomly assigned to each subject. All subjects had to perform three acceptable trials for each task. Reflective markers were affixed to 16 bony landmarks on the body: bilateral anterior and posterior superior iliac spine, thighs, knees, tibias, ankles, heels, and toes; a 25x25 mm opening was also fashioned in the vamp, to allow placement of reflective markers to be placed on the bony landmark of the toe at the second metatarsal head.

Another marker was placed on the heel counter, which represents the bony landmark of the heel; the thickness of the heel counter was deducted from calculations. Prior to the experiment the infrared camera was used, at a Hz sampling rate, to define movement tracks and establish the seven segmental models 1 pelvic, 2 thighs, 2 shanks, 2 feet. Subjects were given sufficient time to familiarize themselves with the barefoot or shoe-shod condition, as well as with the equipment and testing environment [ 9 , 29 , 30 ].

To measure and subtract the difference between the Pedar insole system and force plate values, adjustments were made based on static calibration measuring several fixed weights in a motionless state as well as dynamic calibration measuring barefoot locomotion [ 31 — 33 ]. The adjustment equations were derived and the data of the Pedar insole system were calibrated test by test. According our calibration result, the linear relationships between the force and the value detected from insole pressure system are excellent; the R 2 of left and right insole are 0.

The experiment collected in total gait cycles, and for each relevant event analyzed the parameters of plantar force, duration of event, and angle.

A - D and E - H show results for walking and jogging, respectively. A and E show Bare. B and F show the four types of foot-ground interface. They are suitable for wear with orthotics and are more forgiving than a traditional rocker shoe. Hoka Clifton. The Hoka Cliftons have a medium level of cushioning, with a greater capacity for speed. They work well as a tempo session trainer, in addition to being suitable for general walking and wear.

They are available in regular and wide fit. Asics Glideride. The Asics Glideride is one of the more stable rocker bottom shoes, being slightly firmer than the Hoka styles. The stack height sole foam thickness is quite high, which make this shoe suitable for orthotic use. They are definitely a running shoe, and not too bad for day-to-day and walking use.

These are also available in wide fit. Nike Zoomfly The Nike Zoomfly is classed as a rocker bottom shoe due to the carbon fibre plate, which creates an entirely stiff sole. The Zoomflys are good for racing , or speed training and are not really suitable for walking. They are quite unstable through the ankle due to foam softness and are not suitable for orthotic wear.

If you are experiencing any foot pain or would like a biomechanical assessment, book in to see one of our friendly podiatrists! Even though walking is generally a safe, low-impact activity , injuries still occur as you start to bump up your miles and speed. For many walkers, overuse injuries to the foot and ankle are most common, as the pressure placed in these areas during toe-off can create problems.

And, like with most injuries involving the lower extremities, footwear can play a big role in preventing and resolving some of these issues. Rocker-bottom shoes have increased in popularity in the last several years, promising to help prevent some of these common injuries by making the walking motion more efficient, and allowing you to walk longer with less effort.

To address these problems, most major walking and running shoe manufacturers have created models with a rocker-bottom sole to relieve some of these issues. But do they actually work? Several recent studies have looked into these designs to see if they are more beneficial in reducing injury risk and increasing efficiency compared to more traditionally designed running and walking shoes.

And, like most controversial topics, results on the subject are somewhat mixed. This study favored the rocker-sole design for those looking to reduce plantar flexion during the gait cycle, which can help relieve stress on the Achilles tendon during toe-off.

As "Rocker" Style shoes gain popularity, this is what you need to know. Author Dr. Miguel Cunha Dr. Miguel Cunha, Board Certified Surgical Podiatrist, founder of Gotham Footcare, and leading podiatrist in Manhattan is a highly trained and skilled foot and ankle surgeon with experience treating a wide array of foot and ankle conditions from minor problems to complex reconstructive foot and ankle surgery.

Cunha takes pride in having a genuine interest in each and every one of his patients while providing them the utmost compassion and exceptional care. Your First Step to Getting Better At Gotham Footcare in NYC, we strive at recognizing your individual needs and desired outcomes while formulating an effective and personalized treatment plan with the highest quality care available.

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