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Topo Athletic Ultrafly 4: Filling a Void
By Chief Editor Matthew Klein

The concept of stability and guidance has evolved over the last several years in the running industry. New concepts have been debuted, including sidewalls, geometry and other methods. While these are evolutions from traditional methods, strategies like posting still work for certain people. The Topo Ultrafly 4 is unique in that it is designed by a naturally minded company but uses a traditional stability method. This creates a rare shoe that will fit a certain customer's needs due to featuring an anatomic toe box, lower drop, and a medial post.

Price: $135 at Running Warehouse
Weight: 9.6 oz, 272 g (men's size 9), 7.7 oz, 218 g  (women's size 8)
Stack Height: 28 mm / 23 mm
Drop: 5 mm 
Classification: Mild/Moderate Stability Daily Trainer


The Topo Ultrafly 4 is a low drop, posted stability road shoe for those who want a slightly more anatomic and natural ride for daily training. Full-length firm Zipfoam cushioning provides a grounded ride, while a medial post, wider last and large TPU external counter provide a moderate level of medial support. An anatomic toebox combined with a more normal width in the rearfoot/midfoot provides a secure fit with plenty of room for the toes. The Topo Ultrafly 4 returns as a daily training shoe for easy miles for those who need a traditional medial post, a lower drop, and an anatomic fit featuring new sustainable materials in the upper.


The Topo Ultrafly 4 fits me true to size in my normal men's US size 10. The upper is a new engineered mesh with Topo's typical anatomic toe box. The heel and midfoot fit normal to slightly wider. The laces and upper integrate well, so tightening them down gave me a more secure fit. I had no heel slippage, so did not have to lace lock the shoe. The slightly thicker tongue is not gusseted but is well secured with two loops that the laces go through toward the top. The mesh in the forefoot and midfoot is fairly breathable with mild stretchability. The rearfoot features a thicker and more comfortable material with mild to moderate heel collar cushioning. The internal heel counter is fairly flexible and has given me no trouble. Those with heel/calcaneal sensitivities should do well in this shoe, but should still at least try it first before running. This is not a shoe I would wear sockless as there are a few seams, but the internal mesh is plenty comfortable for thin or thick socks. Overall, those wanting a wide toebox with a normal fit throughout the rest shoe will enjoy the Topo Ultrafly 4.


The Topo Ultrafly 4 is a firmer, lower drop daily trainer. The full-length Zipfoam (EVA?) underfoot is slightly softer than the previous version but continues to have a solid underfoot feel with a more moderate stack height (28mm/23mm). The responsiveness for the Zipfoam is moderate to low, making it best for easy runs and mild uptempo efforts. The shoe weighs in at 9.6 oz for men's size 10. This is the perfect trainer weight for me as the Ultrafly 4 feels neither too light or too heavy for daily miles. This is not a shoe I would use for fast days, but it does excel at easier and moderate-length runs. Heel landings were slightly clunky thanks to the small bevel but improved as the foam broke in. The transition through the midfoot is particularly solid thanks to both the post and filled-in midfoot. The forefoot features both some flexibility and a moderate forefoot rocker. This makes for fairly smooth and seamless toe-offs.

Like many Topo shoes, the drop is on the lower side. The Topo Ultrafly 4 features a 5mm drop and it feels in the 5-6mm range. I sometimes have issues with my Achilles tendon in lower drop shoes, but had no problem with the Topo Ultrafly even with moderate-length runs. The outsole durability has been fairly good thus far. I have over 40 miles on my pair with only a little wear in my normal posterior lateral spot. This leads me to believe that the Topo Ultrafly 4 will last for an above-average number of miles as a firmer daily training shoe for most people.


The Topo Ultrafly 4 is a mild to moderate stability shoe for those with medial stability needs. There is a large medial post that runs the full length of the midfoot and heel. This is quite noticeable with significant pressure into the medial arch. It is especially obvious the first few runs and while I have gotten used to it, I continue to feel that medial pressure (this may also be due to the fact that I haven't been in a medially posted shoe for a while). With the medial post, the medial midfoot is filled in and the general last of the shoe is wider. The filled-in midfoot creates additional guidance that is often rare in running shoes. The heel features a fully encompassing external heel counter. This is not obtrusive but provides noticeable medial and lateral guidance during heel strike. With the combination of the wider last, large medial post and large external heel counter, the Topo Ultrafly 4 provides a moderate level of medial stability for those that need it. 


The Ultrafly 4's Unique Niche

As a clinician, finding appropriate footwear for special populations can be difficult. The Topo Ultrafly 4 is a unique shoe as mentioned due to many reasons, but primarily that it is a lower drop stability shoe with a wide toe box. Particularly while treating those with bunions or forefoot issues, finding shoes with wide toe boxes that also address other issues is challenging. It is not uncommon for those with those pathologies to also have additional impairments or problems. Excessive pronation is often common, due to compensatory motion to get around the stiff first toe often seen with bunions. This is a risk factor for Achilles problems, which are common in both the older as well as the masters running population (Becker et al., 2017; Knobloch et al., 2008; Perry & Burnfield, 2010) While the Altra Paradigm and Provision exist, they are often not appropriate for those sensitive to zero or negative drop shoes (which these shoes become with larger individuals using a heel striker running or walking gait). Achilles tendon problems are often sensitive to zero drop shoes, so some heel drop is necessary. Alternatively, shoes with higher heel drop may increase pressure through the forefoot, which can load the first toe joint (where the bunion is) more than necessary.

Conservative treatment for a bunion involves restoring mobility of the first toe joint into abduction (as it is stuck going medially into abduction) and extension (the lack of the motion is what drives the big toe into adduction or laterally, especially if one pronates off the inner side of the big toe joint). Individuals with this pathology often benefit from toe spacers to gradually help with realignment, but care must be taken to find what specific impairments are actually driving the problem. A wide toe box is instrumental for this pathology to allow the big toe room to return to a more neutral position. Narrow toe boxes are absolutely off the table given that they will continue to exacerbate the problem, especially if the individual is wearing their shoes for >8-10 hours per day.

Thus, with unique cases like the above, a shoe like the Topo Ultrafly 4 can be a helpful intervention to support both runners and walkers. Each person and case is unique and will need certain things, but the combination of a wide toe box, some medial support, a forefoot rocker that still has some mild/moderate flexibility with a mild to moderate level of drop can be helpful to support them on their journey. While this shoe may be helpful for some, it may not be the best choice for others. Like anything being prescribed or worn, the individual or clinician needs to evaluate the exact impairments or characteristics first before making a decision on whether this shoe type is appropriate for them.


Becker, J., James, S., Wayner, R., Osternig, L., & Chou, L. S. (2017). Biomechanical factors associated with Achilles tendinopathy and medial tibial stress syndrome in runners. 
The American Journal of Sports Medicine45(11), 2614-2621.

Knobloch, K., Yoon, U., & Vogt, P. M. (2008). Acute and overuse injuries correlated to hours of training in master running athletes. 
Foot & Ankle International29(7), 671-676.

Perry, J., & Burnfield, J. M. (2010). Gait analysis. Normal and pathological function 2nd ed. 
California: Slack.


The Topofly 4 improved one of my recommendations slightly from version 3. The underfoot feel is slightly softer, but it is still on the firmer side. This does improve inherent stability, but users should be aware of this firmness. The fit has been improved (with the upper update) and my toes are no longer hitting the end. At this point, my largest recommendation is still the heel bevel. Posterior lateral heel bevels are not only known to reduce pronation but also may improve heel transitions. While the softer foam does help compress and make things a little better, the heel is still clunkier than it could be. I understand that Topo has the belief that all runners should land toward the front of the foot, but that goes against the current literature. There is no difference in injury rates between heel and forefoot type lands, there are only differences in jury types (Anderson et al., 2016). Additionally, 70-90% of runners heel strike (Kasmer et al., 2013). With that in mind, it is best to have a shoe that can handle a variety of foot strikes to meet the varying needs of the consumers purchasing the product.


Anderson, L., Barton, C., & Bonanno, D. (2017). The effect of foot strike pattern during running on biomechanics, injury and performance: A systematic review and meta-analysis. 
Journal of Science and Medicine in Sport20, e54.

Kasmer, M. E., Liu, X. C., Roberts, K. G., & Valadao, J. M. (2013). Foot-strike pattern and performance in a marathon. 
International Journal of Sports Physiology and Performance8(3), 286-292.


The Topo Ultrafly 4 is for those looking for a moderate stack height, low to moderate heel drop, firmer, wide toe boxed daily trainer with a variety of stability methods including a traditional medial post. The toe box is anatomically shaped and wide, yet the remainder of the shoe fits a more normal width. This provides room and security with the sloppy fit often found in shoes with extremely wide toeboxes. The ride is on the firmer side but is still protective, so those wanting a grounded ride will enjoy this. The medial post provides noticeable pressure into the arch and combined with the external heel counter locks the heel and midfoot in extremely well. Overall, the Topo Ultrafly 4 improves on the last version with a slightly softer midsole and a redesigned upper. It is a unique shoe given the elements it combines and works well as a daily trainer and all-day walking shoe for those that need some support.


Fit: (Excellent toe box room with secure fit in heel and midfoot)
B/B- (Solid for daily miles, but limited versatility. Can handle some uptempo stuff and on the firmer side which limits it to short to moderate mileage for most)
Stability: A [Moderate] (Although listed as a mild stability shoe, the large medial post, wider last and external heel counter give a higher level of support in a lower drop, moderate stack height shoe)
DPT/Footwear Science: B+ (Excellent integration of often separate designs. However, a larger heel bevel is necessary to improve the rearfoot transition and may further help with pronation modulation)
Personal: B+ (On the firmer end for me to reach for as a training shoe outside of moderate mileage, but is my current favorite walking shoe)
Overall: B+


Price: $135 at Running Warehouse

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Editor's Note: As always, the views presented on this website belong to myself or the selected few who contribute to these posts. This website should not and does not serve as a replacement for seeking medical care. If you are currently injured or concerned about an injury, please see your local running physical therapist. If you are in the Los Angeles area, I am currently taking clients for running evaluations.

***Disclaimer: These shoes were provided free of charge in exchange for a review.  We thank the people at Topo Athletic for sending us a pair.  This in no way affected the honesty of this review. We systematically put each type of shoe through certain runs prior to review. For trainers and performance trainers, we take them on daily runs, workouts, recovery runs and a long run prior to review (often accumulating anywhere from 20-50 miles in the process). For racing flats we ensure that we have completed intervals, a tempo or steady state run as well as a warm-up and cool down in each pair prior to review. This systematic process is to ensure that we have experience with each shoe in a large variety of conditions to provide expansive and thorough reviews for the public and for companies. Our views are based on our extensive history in the footwear industry and years testing and developing footwear. If you are a footwear rep looking for footwear reviews or consultations on development, we are currently looking to partner with companies to assist, discuss and promote footwear models. Partnership will not affect the honesty of our reviews.

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