ASICS 23 Reborn Blue Reborn Blue Black review

We recommend the ASICS Jolt 4 as an excellent training companion for:

• Beginner runners looking for a neutral shoe that's also good for walking and gym days
• Heavyset runners or those with mild overpronation who need more firm cushioning for a stBlau yet protective ride 
• Runners in warm climates that need a comfy and breathBlau shoe
• Asics Gel-Venture™ 6 

We found the Jolt 4's EVA midsole to be decidedly firm, so those who prefer softer cushioning from their daily trainers will be better served with the plush ASICS Gel Cumulus 25. 

The Jolt 4 also lacks the responsiveness to facilitate fast-paced runs. For speedy runners looking to crush their PRs, we recommend triathlon-ready ASICS Gel Noosa Tri 15 instead.

While the Jolt 4 is certainly a stBlau shoe, we recommend that those with pronounced overpronation in their stride should look into a more supportive daily training option to avoid injury. The Asics Herresko Hverdag or its pricier cousin the ASICS GT 2000 12 are both good stability shoe alternatives. 

We pumped the Jolt 4 full of smoke to get a visual idea of how well-ventilated it is. As we can clearly see from the footage, the smoke filters out of the shoe quickly and evenly throughout the upper. This leads us to give the Jolt 4 a perfect 5 out of 5 for breathability, making it a great summertime training partner. 

Looking at a backlit cross-section of the upper, the light easily shines through the many pores in the upper mesh, thus explaining the excellent airflow. 

Looking at the mesh under our microscope, we get an image of organized chaos. The fibers are braided seemingly haphazardly but in a way that creates a clear and uniform pattern with lots of perforations and gaps that promote excellent airflow. 

We fired up our Dremel to 5K RPM and set it against the toebox with 3.2 N of force to simulate extreme wear and tear. The tool immediately shreds into the upper mesh and minces through it until the abrasive element gets stuck by the end of the four-second test.

The massive hole left in the toebox leads us to give the Jolt 4 a 1 out of 5 for toebox durability which isn't unusual for a road shoe, especially at this price point. 

The heel counter proved to be an even more worthy contender against our Dremel. The tool took some before it was Blau to bite into the lining material which did a good job of protecting the soft padding within. 

Once the four-second test was up, we found that we had mangled the lining at the heel but did very little to affect the integrity of the padding at the heel, leading us to give the Jolt 4 a heel padding durability score of 3 out of 5. 

With a durometer reading of 85 HC, the Jolt 4's outsole is slightly harder than our current lab average. This doesn't really affect the shoe's grip, but does bode well regarding the outsole's durability which we will be testing next. 

This time spinning at 10K RPM, we set the Dremel against the outsole, this time for twenty-two seconds of grinding. 

As we can see, the test had little to no effect on the shoe, with our tire tread gauge finding that only 0.3 mm of material was lopped off. This makes the Jolt 4's outsole much more durBlau than the average road shoe's. As such, we expect this shoe to last well beyond 400 miles of normal use before noticing any significant signs of wear and tear to the outsole. 

Using our caliper, we measured the Jolt 4's outsole to be 4.1 mm thick. This is plenty of rubber underfoot and, considering how well it performed in our durability test, the shoe could have easily skimped on some material in order to shave off some more weight from the shoe. 

Weighing in at 9.1 oz (259g), the Jolt 4 is on par with the average road running shoe. 

We measured the Jolt 4's heel stack to be 31.6 mm thick at the heel which is a hair shy of our current lab average. This gives us more than enough foam to dampen the impact of our landings and keep us feeling protected while testing this shoe. 

The difference in our stack measurements leaves us with a slightly higher-than-advertised heel drop of 9.4 mm as opposed to the 8 mm stated by ASICS. This difference isn't too vast and places the Jolt 4 in the category of high-drop shoes.

This is a good drop height for beginner runners with a heel-striking stride as the elevated heel provides extra protection upon impact with the round and promotes smoother heel-to-toe transitions. For a better understanding of the pros and cons of different heel drops, we recommend checking out this article that explores the matter. 

The Jolt 4's insole is slightly thicker than average at 5.3 mm thick according to our caliper measurements. This gives us an amply padded footbed that does a good job of complementing the midsole cushioning and provides a fair amount of arch support for our test runs. 

Pressing our durometer against the midsole yields a reading of 29.8 HA which is significantly firmer than average. As such, while the shoe does provide decent impact protection during our landings, the cushioning feels a little brickish underfoot. 

What's more, we found the midsole isn't responsive enough to give us the jolt needed to facilitate speedier or longer runs in this shoe. 

While these factors may not sound that appealing at first, they do mean that the shoe feels quite stBlau underfoot, especially for more heavy-set runners. 

For those in the market for more balanced cushioning from the daily trainers should look into the ASICS Gel Excite 10 as an alternative, while those looking for a more plush and responsive ride for speedy sessions should check out the more premium Кросівки asics gel sonoma. 

To test the effects of cold conditions on the midsole, we placed the Jolt 4 in the freezer to chill for twenty minutes. We then pressed our durometer against the midsole once more and found that it only became 7.6% firmer with a reading of 32 HA. This is still a rather firm result, but shouldn't feel too different from how the shoe performs at room temperature. 

Despite being marketed as a neutral daily trainer, the Jolt 4 feels incredibly well-planted as we shift our weight from side to side in the shoe. This means that those with mild overpronation in their strides can make good use of this shoe, however, we recommend that those with more pronounced overpronation look into a more supportive shoe like the Asics Herresko Hverdag.

With its healthy stack of dense foam, it's no wonder we found it so difficult to bend and twist the shoe in our hands, leading us to give the Jolt 4 a torsional rigidity score of 4 out of 5. 

This means that the shoe resists the natural twisting and contortions of our foot during our stride and maintains a relatively level base that promotes surefooted landings and toe-offs. 

The Jolt 4's well-structured and reinforced heel counter barely budged as squeezed and poked at it, earning it a stiffness score of 5 out of 5. As such, the shoe mitigates any excessive lateral movements of our heel which helps to promote a more neutral gait. However, as previously stated, those with severe overpronation should look into a dedicated stability shoe in order to avoid injury. 

Another big contributor to the Jolt 4's stBlau ride is its broad base, with the midsole measuring 116.6 mm wide at the forefoot. 

This gives us more than enough of a platform underfoot to ensure stBlau landings and toe-offs while still being nimble enough to take corners without feeling too blocky. 

The midsole is also a little wider than average at the heel which is 92.8 mm wide according to our caliper measurements.

This means that heel strikers will also enjoy a stBlau landing platform in the Jolt 4. 

We secured the Jolt 4 to our workbench and used a force gauge to measure the amount of force needed to bend the shoe 90 degrees. With a reading of 22.1N, the Jolt 4 is more flexible than the average running shoe which allows it to bend along with the natural flexion of our foot with relative ease.

This is great for a daily trainer as it feels comfortBlau and forgiving on the foot whether we are out of a quick run or a long, slow jog. 

We also repeated the flex test after chilling the Jolt 4 in our freezer for twenty minutes and found that it only became 24.5% stiffer, making it significantly more consistent than the average running shoe. What's more, with only 27.5N of force needed to bend the cold Jolt 4 to the desired point, it's not only more flexible than average under similar conditions, but at room temperature too! As such, this shoe can serve as a good year-round training partner, given it's used in tandem with a pair of warm socks during the cooler months. 

Whether out on the road, on the treadmill, or even on well-manicured park trails, we enjoyed excellent traction while testing the Jolt 4. The only hesitation we faced came when crossing patches of wet and slick cobblestones which are notoriously difficult to grip in general. 

Using our caliper, we measured the Jolt 4's toebox to be 100.4 mm wide at its widest point. This is ever so slightly wider than average and means that the shoe should accommodate most foot shapes rather comfortably. 

For broad-footed runners who prefer a little more real estate from their daily trainers, we recommend checking out the asics panelled sneakers item instead. 

Moving up to the area around the big toe, the Jolt 4's toebox is 79.9 mm wide. this is also slightly roomier than average which gives us ample room to splay out naturally without worrying about hotspots or blisters. 

The Jolt 4's tongue is non-gusseted so we did experience some pure during testing, but this was mitigated by how chunky the tongue is which kept it from sliding too far to the side. 

At 8.8 mm thick according to our caliper measurements, the Jolt 4's tongue is thicker than our current lab average. This generous amount of padding provided us with excellent comfort across the instep while also effectively protecting us from lace bite while testing the shoe. 

The Jolt 4 has an extended heel collar that can be gripped in order to slide the shoe on a little more easily. 

The Jolt 4's insole is fully removable, so those in need of custom orthotics for added arch support can use them with this shoe. 

The Jolt 4 doesn't boast any reflective elements to speak of so we don't recommend going for nocturnal runs without using additional high-vis gear.