While the UA Rush was a bit too warm for Arizona, it is a decent athletic shirt with a significant amount of stretch. For those that feel constricted in most shirts, this might be a good option.
To start with the positive, Under Armour's proprietary "Rush" fabric is quite comfortable. The material is extremely stretchy, and it moves with you no matter what exercise you're doing. Rock climbing and other overhead arm movement activities were unencumbered, and the waistline of the shirt didn't rise up too high. The athletic fit wasn't wildly tight like some shirts we have tested, putting it a little closer to the relaxed fit end of the spectrum.
We tested size large shirts exclusively. This was the most generously sized cut. For gym workouts the length kept the shirt from rising over our love handles and the fabric stretch allowed for full range of movement.
Unfortunately, the nice fabric was joined together with prominent, chunky seams. While this wasn't an issue when wearing the shirt as a standalone layer, if we put on our running pack, backpack, or even a warmer layer on top, the seams were uncomfortable.
Part of what gives the UA Rush its supple and comfortable feel is the tightly woven polyester/elastane fabric. This fabric is incredibly stretchy, which allows for a wide range of stretch; the result is a fabric that isn't incredibly breathable. On the trails of Mt. Lemmon, in southern Arizona, we wanted a bit more airflow through the shirt. Cooler mornings before the sun had risen were more appropriate for the UA Rush, as it did feel as if it was hanging onto our warmth a bit more than it was shedding the heat.
This critical metric is an indicator of how well a shirt might help or hinder the evaporative cooling effect. During the standardized portion of his test, the UA Rush impressed us. During the initial weigh-in after a wash and spin cycle, the UA Rush held onto 27% of its weight in moisture but was able to lose 98% of that moisture weight within the first ten minutes of drying. After twenty minutes, it was entirely dry. This indicated to us that despite how this shirt felt out on the trails, it does breathe and dry quickly.
Our real-world testing, which has many variables to account for, wasn't quite as promising. When the sun came out, and the sweat started pouring, we felt saturated in the UA Rush. We know that humidity and wind have a significant influence over these results, but our experience was unquestionably less miserable in other shirts in the same circumstances.
While the breathability, drying speed, and comfortable fabric make this shirt appropriate for running, gym work, or pretty much any general exercise you can think of, the chunky seams cut into the versatility of this shirt. The difference between flat and unnoticeable seams vs. large protruding seams is quite pronounced, especially when trying to add layers or packs on top. Essentially this shirt is only versatile up until the point where you need to pull anything over the top of it.
We found the UA Rush was great for gym workouts and heading out for a recovery run. In a pinch you could sub this shirt in for a mountain bike ride or use it for any other application that requires a synthetic shirt.
The price is a lot for a shirt that isn't of excellent quality. While we do appreciate it, particularly the soft fabric, stretchy unencumbered movement, and generous length (keeping our midriff covered), it lacks the necessary breathability and versatility needed to make it a great value. While it is on the brink of being a good value, we'd like to see flattened out seams before we deem it as such.
The UA Rush is a functional running shirt that offered satisfactory performance. However, there isn't really anything exceptional about this shirt, and it was a bit too warm and stifling in high temperatures. The versatility also took a large hit because of the chunky seams, which caused comfort issues when we tried to add a running pack. If you live in a mild climate, this shirt might be worth the money.