Puma Run XX Nitro Review: What Do Women Want (in a Running Shoe)?
By Contributors Andrea Myers and Megan Flynn
A majority of unisex running shoes out there are designed from data primarily from males, despite the many differences between males and females regarding gait mechanics, foot strike, foot shape, and more. Introducing Puma’s Run XX Nitro, part of Puma’s “Run for Her” initiative, which is designed specifically for women. In fact, the name “XX” is referring to the xx female chromosomes. Some specific differences seen in the Run XX Nitro include a narrow heel with improved guidance of the foot as well as a narrower fit at the arch. It also accounts for the fact that women have a wider base of support compared to men with a greater hip angle – also known as the Q-angle. I was pretty excited to have the opportunity to test these shoes and see if I noticed a difference running in sneakers designed specifically with women in mind. Offering more stability than my preferred neutral trainers, I was pleasantly surprised at the comfort and ride of the shoe.
Price: $130 at Puma
Weight: 8.25 oz
Stack Height: 31mm/23mm
Drop: 8mm
Classification: Women's specific daily trainer
RUNNING SHOE SUMMARY
Andrea: The Puma Run XX Nitro is a women's specific daily trainer that is based on PUMA's internal research on sex-related foot shape and running biomechanics. The result of this research is a shoe that is supposed to fit a woman's foot better at the heel, instep, and arch as well as RUNGUIDE, a midsole rim that is supposed to keep the foot centered with each stride. As I have written in a previous review, the need for sex-specific shoe designs is questionable at best. I was interested to see what assumptions PUMA made about female runners in the design of this shoe.
Megan: Designed specifically for women, the Run XX Nitro is composed of a generally narrow last, noticeable mostly in the heel and midfoot/arch with more freedom for movement in the forefoot. The shoe features foot strike guidance, called RunGuide, which is a firm density rim that wraps around the heel of the foot and promotes proper alignment of the foot throughout each stride, specifically increasing stability in the rearfoot. The midsole is made of Puma’s Nitro foam, infused with nitrogen to allow for a more lightweight, cushioned, and responsive ride and making this shoe equipped to handle many, many miles. The outsole is made of PumaGrip which provides traction on various surface types.
FIT
Andrea: I received my usual women's 9.5 from Puma. The shoe fits true to size in length, but I found the toe box to be a little narrow, which created pressure on the lateral aspect of my 5th MTP and toe. It took me a few runs to dial in the lacing to reduce pressure on my 5th toe, but I was never able to make it completely go away. There is a rigid lower external heel counter and a somewhat padded internal heel collar. I found the heel to fit well without creating any irritation or hot spots. There is also an external plastic heel clip that runs from the posterior heel to the medial and lateral aspects of the midsole. I was completely unaware of the heel clip while running, but it may contribute to better upper stability. The mesh upper is thick, padded, and does not breathe well. I would not choose to wear this shoe in the summer due to its lack of breathability (I tested it on several 70-80F runs). I did not have any issues locking my foot down in the shoe and did find the low boot construction to be overall comfortable, except for the slightly narrow toe box. The gusseted tongue is moderately padded and stayed in place well. The insert is on the thicker side and has mild arch support and a metatarsal button, the latter being a feature not often seen in stock inserts. The posterior half of the insert is raised medially and laterally, which cradles the heel and midfoot without being intrusive. Overall, I found the shoe to fit fairly well except for the toe box (and I normally prefer a wider toe box than average).
Megan: The Run XX Nitro fits true to size in terms of length and width of the shoe. The last of the shoe is narrower at the rearfoot and midfoot and then widens at the forefoot. The midsole is composed of Puma’s Nitro foam, infused with nitrogen to make it more lightweight, responsive, and cushioned. The foam feels relatively firm, but provides enough cushioning and shock absorption for the slower/easier recovery runs. The mesh upper is comfortable with a more snug fit around the midfoot and extra room in the forefoot. The downside of the upper is that it is thicker with the decreased breathability apparent on hotter summer days. The tongue is gusseted at the forefoot and padded throughout except for a thinner fabric where it makes contact with the ankle. The shoe comes with a removable insole that provides mild arch support and cradles the heel. The midfoot feels secure with the lacing system and more snug upper hugging the foot. The firm heel counter is coupled with the RunGuide piece that was added to promote proper alignment throughout the stride. This piece made me skeptical in that it would provide too much stability at the rearfoot, but I actually didn’t notice it too much. Looking at it closer, the RunGuide piece is easily movable at the heel and on the medial and lateral sides with one point of attachment to the outside of the heel cup about an inch medial and lateral from the heel. If it were attached throughout, I could see it adding more stability, but the fact that it moves makes me wonder if it is actually doing anything in terms of stability. As someone that doesn’t love stability in a shoe, I’m not complaining. Besides the upper being a bit thicker for hotter weather, no complaints about the fit or comfort of the shoe.
PERFORMANCE
Andrea: This shoe runs like a stable daily trainer. I found the shoe to feel heavy and firm, which surprised me based on the thick NITRO midsole. I found it particularly harsh when my legs were tired from intervals the previous day. I hope PUMA will tune the midsole to be a little softer for future versions. Due to its weight and firmness, it is not a shoe for intervals or even tempo days. Despite the heel bevel and forefoot rocker, I did not feel like the shoe helped me progress from initial contact to push off. The firm midsole also makes it feel very much like an 8mm drop shoe, whereas some 8mm drop shoes with softer midsoles feel like less than their stated drop. My longest run in this shoe was 7 miles and I was ready to be done due to the firmness. I would not personally use it for a long run shoe because of its lack of responsiveness. One feature of the shoe I did like is the PUMAGRIP outsole, which is exceptionally high traction rubber. I was very impressed with the traction of the outsole on wet roads and sand. I have 40 miles on my pair and there is minimal wear on the outsole. I would expect durability in this shoe to be above average.
Megan: The Run XX Nitro definitely falls into the category of easy, recovery daily trainers, primarily because of the midsole foam. Although it is comfortable, the midsole foam doesn’t have much bounce and didn’t feel very responsive. It’s flexible at the forefoot, but limited flexibility in the midfoot, which I think has to do with the attachment of the RunGuide piece which crosses close to the midfoot onto the outsole. The midsole foam does serve its primary purpose of absorbing shock and providing protection on landing – which is perfect for recovery runs, but I wouldn’t grab for these shoes for any faster workouts or races. The heel is beveled which adds to a smooth transition from initial contact through midstance and there’s a mild forefoot rocker which promotes a smooth push-off. The combination of these two result in a smooth transition from initial contact all the way through to push-off. The outsole is made of PumaGrip which provides excellent traction in any condition (rain or shine) or surface (dirt, road, gravel) I tested them on. The triangular shaped lugs at the forefoot further improve traction during push-off. Overall, the Run XX Nitros provide a smooth and comfortable ride, but doesn’t shine in the responsiveness category.
STABILITY
Andrea: The Puma Run XX Nitro has several features that promote stability throughout stance phase. RUNGUIDE, which is the firmer density rim around the heel, is supposed to promote more neutral alignment at initial contact. The heel bevel may promote a smoother transition from initial contact to mid-stance, and the wider forefoot combined with the forefoot rocker may promote a smoother, more stable push off. The rigid external heel counter and the flexible plastic heel clip do feel like they help to center the calcaneus in the shoe, but do not feel like they force motion. The forefoot has moderate medial and lateral sole flare that helps to center the foot during late stance phase. There is a guide line in outsole that may also contribute to smoother transitions. The stiff outsole may also contribute to the overall stability of the shoe. This shoe does not feel like a traditional stability shoe with a medial post, but the combination of the above features do make the Run XX Nitro feel quite stable. As someone who greatly dislikes traditional stability shoes for their excessive motion guidance, I did not dislike the guidance present in the Run XX Nitro.
Megan: The Run XX Nitro offers a decent amount of stability, mostly in the rearfoot. The firm heel counter provides a decent amount of stability in the rearfoot, and the RunGuide is meant to add to this stability (jury is still out for me on the effectiveness of the RunGuide technology, though). There’s a noticeable decrease in stability as you move from rearfoot to forefoot, which I find to be a good thing. The midfoot is narrower with a mild arch support preventing excessive pronation. Since females tend to have wider hips than males, they also have a higher Q-angle (angle from the hips relative to vertical) than males, which ultimately tends to increase pronation at the foot. The design of the Run XX Nitro is meant to assist in decreasing this motion by adding stability/support at the medial arch. The forefoot allows for more movement in a few ways. First, the midsole seems to be more flexible at the forefoot. Second, the upper is less secure and allows for more space. Third, the last of the shoe is widest at the forefoot. All of these put together allow for adequate toe splay, natural mechanics of the foot, and provide a good balance for the high stability of the rearfoot. Overall, this shoe is on the more stable end of the spectrum in terms of trainers that I would use, but it will continue to be in my rotation after testing.
THOUGHTS AS A DPT / FOOTWEAR SCIENCE
The Challenges of Sex Specific Running Shoes
By Contributor Andrea Myers
We are seeing multiple running shoe companies introduce women's specific running shoes. They all say that their research (which is often not published) has found that women need a specific fit in the heel, midfoot, and/or forefoot; that women need a different drop compared to men; or that women have specific biomechanical needs that led them to the design of their shoe. While there is no information about the Run XX Nitro research on Puma's website, multiple shoe review websites state that Puma did a study at the University of Massachusetts Biomechanics Lab to test the Run XX Nitro. The subjects were 224 female runners who logged more than 36,000 miles over eight weeks (which comes out to 160.7 miles per subject over the course of 8 weeks, or 20 miles per week per subject). Puma apparently found that 81% of the subjects preferred the Run XX Nitro over the control shoe, but there is no information regarding what shoe was used as the control. I would be very interested in reading the actual study and would be interested in seeing the data that Puma used to develop the Run XX Nitro in the first place.
My bike fitting experience makes me question whether gender specific running shoes are really necessary. The cycling world went all in on women’s specific bikes and shoes 15 years ago, and have completely backtracked in the past 5 years due to massive data collection done by bike fitters and retailers. The assumption that the cycling industry made regarding women’s bikes was that women have proportionally longer legs and shorter torsos as compared to men, so they need bike frames designed to match. Women’s cycling shoes were made on narrower lasts and with narrower heels. Retul, which is a bike fitting company now owned by Specialized, compiled biometric data from 7750 bike fit clients and determined that there was no correlation between gender and limb/torso proportions. They also analyzed data from 9831 foot scans and found little to no gender-related difference in the proportion of the length of the foot to the width of the ball of the foot. This data led Specialized to conclude that there is no need for gender specific bike frame geometry or shoe design. They emphasized the need for a wide range of frame and shoe sizes to accommodate men and women of various heights and foot sizes.
Similarly, running shoes that are designed for a stereotypical “woman’s foot” may fit some women best (those who have narrower heels in relation to their forefoot), but many women may fit better in a men’s shoe, and vice versa. A 130 lb. male runner may benefit from less dense cushioning in a shoe as much as a 130 lb. female runner. If a women’s shoe is designed for a runner with a higher arch, it may not be as comfortable for a woman with a low to moderate arch height. I think that runners will be best served when shoes are engineered for particular body characteristics (forefoot width, arch height, runner weight, etc.), as opposed to generalizations about male and female anthropometrics that may not be accurate.
References:
Puma Gets Progressive With Its First Woman-Specific Running Shoe. Gear Patrol website. https://www.gearpatrol.com/fitness/a40284558/puma-run-xx-nitro-launch. July 1, 2022. Accessed July 1, 2022.
Jett, R., Chabra, S., and Carver, T. When to Share Product Platforms: An Anthropometric Review. https://specialized.picturepark.com/Go/drxAWjId/D/59574/1 . Accessed January 4, 2022.
RECOMMENDATIONS
Andrea: The fit of the shoe is decent, but I would prefer a slightly wider toe box to relieve pressure on my 5th toe. My major recommendation would be to improve the responsiveness of the midsole. A shoe with this much stack should feel more cushioned that the Run XX Nitro does. I think this shoe will work for more runners if Puma softens the ride. I would also recommend improving the breathability of the upper. A thinner mesh would improve the shoe's performance in hot weather as well as help reduce the weight of the shoe. I would also encourage Puma to publish its research on this shoe, so we may all have a better understanding of how they came to develop this shoe specifically for women.
Megan: I didn’t find anything drastically negative or uncomfortable about the Run XX Nitros. The main thing that Puma could improve on in the future is the thickness of the upper. If the mesh were thinner it would not only improve the breathability, but it may even make the shoe lighter. I’m also curious to see how the shoe would feel if the RunGuide was removed and if it is actually making a difference in terms of stability and alignment of the shoe.
WHO THIS SHOE IS FOR
Andrea: This shoe is for runners who are looking for a firm, stable daily trainer. Runners with a narrower forefoot will be most comfortable in the Run XX Nitro. The weight and firmness of the shoe prevented it from being a comfortable long run or interval day shoe for me, but there may be some runners who prefer those characteristics. The stiffness of the sole and the well fitting upper may also make this a nice walking or work shoe.
Megan: The Puma Run XX Nitro is a daily trainer designed for easier, recovery runs and is equipped to handle higher mileage. It’s a good option for someone who favors some stability without being overbearing. The firm cushioning and smooth transition from heel to toe result in a comfortable ride and is easier on the body. Although it is designed for women specifically, I’d be curious to see what a male runner would notice wearing these. In all honesty, I’m not sure I noticed the difference regarding the women-specific design; maybe that’s a good thing? I had high expectations since this is the first shoe I’ve run in specifically designed for women but really didn’t notice too much of a difference. Overall, they’re good trainers but I didn’t notice anything crazy good (or bad) about them.
GRADING
Andrea
Fit: B+ (nice fitting heel and midfoot, forefoot too narrow for me, creating irritation at 5th toe)
Performance: B- (too heavy and firm for anything but shorter, easy runs)
Stability: A (a very stable shoe without a traditional medial post)
DPT/Footwear Science: B- (lack of evidence supporting sex-specific footwear, companies need to be more transparent with their data)
Personal: B- (shoe was just okay, did not particularly enjoy my runs in it due to weight, firmness, and narrow toe box)
Overall: B
Megan
Fit: B+ (The fit is true to size in length and width. It’s comfortable throughout the foot with internal padding at the heel and a padded tongue. The thickness of the upper is where this shoe lost points for me in this category.)
Performance: A- (They’re a great option for easy, recovery run days. The midsole Nitro cushioning is great and provides adequate shock absorption on contact. They aren’t the most responsive trainer, but that’s not the priority on most easy/slower runs.)
Stability: B+ (They’re designed to be more stable than shoes I usually train in, but I didn’t notice too much of the stability factor. I’m not so sure about the role of the RunGuide, but the heel counter added to the rearfoot stability and the narrower midfoot also provided additional support preventing excessive pronation.)
Personal: B+ (Maybe my expectations were too high solely because this is the first shoe I ran in designed specifically for females, but I wasn’t blown away by them.)
Overall: B+
SHOP | SUPPORT DOR
Price: $130 at Puma
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