Brooks Glycerin 21 Review (includes Glycerin GTS 21)
The Brooks Glycerin 21 is Brooks’ most cushioned everyday training shoe and we got a pair early to review, in time for launch day! The Glycerin 21 is available in both a neutral version (Brooks Glycerin 21) and a version that offers a mild amount of anti-pronation support (Brooks Glycerin GTS 21).
The Brooks Glycerin is designed for easy run miles and longer runs. Essentially, all of your running except your quicker days or off road running days. The initial feel of the shoes is very soft and comfortable. Brooks are experts at making shoes that have a high level of step-in comfort and the Glycerin 21 and Glycerin GS 21 are no exceptions. The heel cup is a full height plastic cup designed to hold the heel and offer a high level of stability. The internal part of the heel cup is lined with a luxuriously feeling padding and so is the cuff. The tongue is well padded, which adds to the cushioned, comfortable feel of the shoes. The upper is made from a very soft engineered mesh and the fit is roomy, which is a pleasant surprise. Essentially Brooks have done everything to make the Glycerin 21 a shoe that remains comfortable, even after you have spent a lot of time in the shoes.
The laces effectively pull the upper in around the foot to give a secure fit, locking you into the heel cup. If you have a narrow heel and often have problems with your heel lifting in shoes then there is an extra lace hole you can use to pull the cuff of the Glycerin in further or to butterfly lace the shoes to create a lace lock. Judging on the snug, secure fit that I felt I would think that most runners won’t need to tighten up the heel fit.
The midsole is made from DNA Loft v3, which is Brook’s softest Nitrogen infused midsole. Midsoles that are Nitrogen infused are essentially sealed so the air can’t escape and water and grit can’t get into the midsole. This makes the midsole more durable as it is less prone to compression, and the ingress of water and dirt doesn’t breakdown the material. This type of midsole also has a more ‘bouncy’ feel to it. The big change from the Glycerin 20 to the Glycerin 21 is that the midsole height has been increased by 2mm to 28mm at the heel and 18mm at the forefoot. The cushioning does not feel super-soft and soggy. It could even be described as quite firm when you initially stand up in the shoes. However, don’t be fooled. These are exceptionally well cushioned running shoes. When your foot hits the floor, 3-5 times your body weight goes through the midsole of the shoes. If a shoe is too soft then it can bottom out when it is put under this level of pressure and supply less shock absorption than you might expect. A firmer feel to the cushioning also gives your body the feedback that it needs to know you have hit the ground. This gives your feet the chance to function in the shoes and absorb shock and stabilise you.
When running you are aware of the soft cushioning. It doesn’t feel like it compresses a lot, so you don’t feel like you are sinking into the shoes. The rebound or bounce is quite noticeable. The extra 2mm of midsole does reduce the feel for the floor slightly in comparison to the Glycerin 20 but not totally. There also isn’t a rocker in the midsole of these, so you do feel like you are running in the shoes rather than riding the shoes, which is often the feeling that I get. The heel to forefoot drop is 10mm, which is quite high and favours the heel striker more than the midfoot striker. However, I had no issues comfortably landing on my midfoot. This is because there is enough flexibility in the midsole to allow you to land at any point. The lack of a rocker was also quite nice. I often find that shoes with a rocker can encourage me to run quickly when I just want to run nice and slowly on my easy run days. The forced quicker cadence that the rocker encourages often leads to me having sore hamstrings, especially if I have done a very long or quick run the previous day. In the Brooks Glycerin 21 I felt in complete control. Able to pick the pace up a bit if I wanted or jog a long nice and slowly if I didn’t.
The fit of the Glycerin 21 in my experience is inline with other Brooks shoes. If you wear Brooks running shoes and are happy with the fit then I would suggest trying the same size. Brooks are one of the more generous fits. I wear a UK 11 in Brooks, Saucony, Altra and Topo Athletic. To get the same fit in Hoka, New Balance, Karhu, La Sportiva, Inov-8, On, VJ, Walsh I would wear a UK 11.5. The Brooks Glycerin 21 is available in wide fit. As with all running shoes we would suggest having a thumb width of space between the end of your longest toe and the end of the shoes. This is when you are stood up in the shoes with them laced. Width wise you should have no excess bulging at the sides of the shoes and your toes should be free to wiggle.
As mentioned, the Brooks Glycerin 21 is available in two versions. A neutral shoe and a shoe designed to reduce overpronation. When your foot hits the floor, your arch compresses to absorb the shock and stabilise the foot. Your arch should then reshape and you should push off from the end of your big toe. In some cases the foot doesn’t reshape quick enough and this can lead to the runner pushing off from the inside of the foot. As running is very repetitive this action can lead to blisters on the inside of the foot and aches in the shin, knee, hip and lower back. This is because as the foot rolls inwards the knee follows, which means that the ankle, knee and hip joint are slightly out of alignment. A smaller area of the legs takes the force.
If you think that you need a little bit of support, then the GTS 21 with its GuideRail roll bar will do the job. This is a firmed up piece of midsole that sits on top of the midsole and runs around the shoes. This doesn’t actively stop your feet from rolling inwards but instead only guides the foot if the foot rolls against the firmer piece of midsole. This means that the Brooks Glycerin GTS 21 can be worn by neutral runners as well as those requiring from anti-pronation support. The ride of the GTS version does feel a little bit more supportive but has no shaping inside the arch of anything in the shoe that reduces foot function or controls the gait. It still feels nice and cushioned and easy to run in.
The Brooks Glycerin 21 is a light shoe for one that has so much cushioning. The men’s UK8 weighs 277g in the neutral version and 297 grams in the GTS version. The additional weight comes from the addition of a guide rail in the GTS version. In a women’s UK5 the neutral version is 252g and the GTS version is 266g.
Most max cushioned shoes are neutral. They do have some additional support in that the base of the shoe is broader but the midsoles are often very soft which can also reduce pronation support. The Brooks Glycerin GTS 21 offers a rare combination of max cushioning for those runners that need some pronation support in their running shoes.
In summary if your looking for a cushioned ride in a shoe that is easy to run in and very comfortable to wear then the Brooks Glycerin 21 or Brooks Glycerin GTS 21 is well worth a go!
Neutral Alternatives to Brooks Glycerin 21
Topo Atmos: Topo also don’t make their cushioning too soft so that it encourages foot function. The toe box is broader and more rounded to give room for your feet to spread on impact. The ride is a little smoother due to the rocker but, this does have the drawback that it takes over a bit but, Topo rockers aren’t as aggressive as some others. https://www.northernrunner.com/blog/topo-athletic-atmos-review/
Karhu Mestari: Another firm feel to the cushioning. A lot more propulsion provided by a rocker and Karhu’s Fulcrum. To me this feels more natural than a rocker a lone and gives a smother ride. https://www.northernrunner.com/blog/karhu-mestari-run-1-0-review/
Altra Via Olympus 2: A broad rounded toe box and zero drop provide a more natural ride. Although there is a slight rocker the Via Olympus 2 is a nice shoe to jog in on those easy days and doesn’t try to pull you a long faster than you wish to go. https://www.northernrunner.com/blog/altra-via-olympus-2-review/
Brooks Max: 6mm heel to forefoot and a rocker means that the Brooks Max gives you a bit more assistance than the Brooks Glycerin 21. It doesn’t feel a luxurious or as cushioned. https://www.northernrunner.com/blog/brooks-ghost-max-review/
New Balance 1080v13: A much softer and bouncier shoe with a very unique ride. On flat roads you really do feel like you aren’t making contact with the road. https://www.northernrunner.com/blog/new-balance-1080v13-review/
Hoka Bondi 8: A 5mm heel to forefoot drop to reduce heel strike. A softer feel to the cushioning and a rocker gives a smooth ride. https://www.northernrunner.com/blog/hoka-bondi-8-review/
Support Alternatives to Brooks Glycerin GTS 21
Altra Paradigm 7: A broad rounded toe box with a zero drop gives the Paradigm a more natural ride. Like the Glycerin 21 the Paradigm also uses a roll bar so they can be worn by a neutral runner as well as one requiring some anti-pronation support. https://www.northernrunner.com/blog/altra-paradigm-7-review/
Hoka Gaviota 5: A softer ride to the cushioning and a more supportive feel. The rocker provides a smooth ride and reduces heel strike. Essentially these are the anti-pronation support version of the Hoka Bondi 8. https://www.northernrunner.com/hoka-m92/gaviota-5-t185
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