The Nike Free as a useful tool for video-gait analysis.

In recent years running has increased in popularity and just like with any physical activity, injuries inevitably will occur. The majority of the injuries observed are attributed to the overuse of the musculoskeletal system. In order to treat these injuries, the use of video-gait analysis on a treadmill has been implemented to observe the mechanism of injury. The best technique to observe the underlying condition would be to observe the patient running barefoot, but the safety issues associated with running barefoot on a treadmill do not make it a favorable technique.

Two years ago, we began using the Nike Free running shoe in conjunction with video-gait analysis. The Nike Free allows the feet to move through their natural range of motion which creates the feeling and effects of running barefoot. The Free design also helps overcome the safety issues attributed with barefoot treadmill running without hindering the analyzing process.

We incorporated the shoe into analysis at two locations--the Orthopedic Rehabilitation Specialist, where Bruce Wilk is a senior physical therapist; and a running specialty shop, the Runner's High, which is owned and managed by Wilk. Both facilities are equipped with video-gait analysis equipment, including a treadmill and video camera with monitor. This equipment is used to evaluate and consider possible corrective measures for both rehab patients and customers. The key is to observe the patient running at pace while using the Nike Free shoes because they do not change the visual observation of the underlying problem.

Researchers have suggested that runners may be harming themselves by wearing more supportive footwear, a perk of modern technology. Increased support was added to compensate for the strains paved surfaces create on the foot when running, and runners searched for a shoe that helped make these forces bearable. Shoe companies knew that in order to sell shoes, they would have to have the reputation of having the latest and greatest technology available in footwear. The constant competition among companies led to some pretty radical ideas, and the creation of many sensible technologies to help millions run safely and comfortably.

The implementation of more cushion and supportive features in shoe design definitely has benefits but it has also contributed to atrophy of the muscles in the foot. The increased support has allowed the muscles to neglect their jobs as the natural supportive structures of the foot. Modern footwear may also be at fault for creating balance issues and abnormal changes to a human's natural gait. Nike attempted to address this issue by creating a shoe that mimics barefoot running; thus, the Nike Free was born. The Free was designed to allow the foot to move freely through its natural range of motion by removing all supportive components. In turn, the body would have to adapt by increasing muscular strength and tone. The Free's exceptional design lent itself to be used as an integral part of video-gait analysis because it does not hinder the foot's natural movements, which even the least supportive shoe can.

A tremendous amount of force is applied to the entire body during running activities. These forces are focused mainly on the foot and ankle then continue through the leg and up the body. Because the foot is the foundation of the body, a misalignment of the subtalar joint can lead to further complication elsewhere. Corrective measures must be taken in order to correct or even prevent a pathological condition from occurring. This is why we incorporated the Nike Free into video-gait analysis. Experience tells us the Free is a very good tool that can help determine which corrective shoe would best address the underlying subtalar issue. The subtalar conditions the Free allows you to observe include overpronation, supination, and any other gait abnormalities attributed to a subtalar condition.

If the Nike Free is such a great tool to mimic the natural biomechanics of the foot, then why not just observe the patient running barefoot on a treadmill during analysis? There are many safety issues attributed to barefoot running due to the dynamic accelerating forces generated by the treadmill upon initial heel strike. In addition, the majority of people would find running barefoot uncomfortable. Although they provide minimal support, the Nike Free still provides a barrier between the floor and the foot. This enables the individual to run naturally without the pain and possible dangers associated with barefoot running.

Based on our observations over the last two years, we contend that the Nike Free, when used with video-gait analysis, allows for proper assessment of running biomechanical abnormalities that contribute to injury. This in turn allows for proper corrective measure to be taken. We are not sure if the Nike Free will ever take the place of corrective shoes, but are optimistic that future research may find new applications for these shoes. In addition to its possible training applications, the Nike Free is an excellent tool for assessing running biomechanics on a treadmill.

Bruce R. Wilk, PT, OCS, and Sokunthea Nau, DPT, are physical therapists and Daniel A. DeLeon is a physical therapy aide at Orthopedic Rehabilitation Specialist in Miami, Florida.

REFERENCES

Can barefoot technology improve your customers running experience? Performance Sports Retailer. June 2007.

Foster JB. Barefoot-like designs challenge footwear conventions. Biomechanics 2007; 16:21-27

Yessis M. Running barefoot vs. running in shoes. AMAA Quarterly 1998;12:5-7.

By Bruce R. Wilk, PT, OCS; Sokunthea Nau, DPT; and Daniel A. DeLeon