https://community.usms.org/swimming/f/general/12529/what-should-threshold-css-pace-feel-likeIt seems as though there are a few methods out there to attempt to determine what your anaerobic/aerobic divider zone is for targeting training for distance events. I&#39;m having a bit of trouble determining on my own if I am actually swimming at this &quot;sweeten-USTelligent Community 12https://community.usms.org/thread/199224?ContentTypeID=1Fri, 26 Aug 2016 12:38:39 GMT3187ac58-ba85-4314-b79a-c45cd885e09a:ad5008a3-c4fb-49c0-a427-4de38817fed8m2tall2What&#39;s CSS? The same thing as threshold. At least, I think it&#39;s supposed to give you the same pace as Threshold. I think it&#39;s just what swim smooth calls it to make it seem magical, but I found a lot of other web resources using that term. It&#39;s supposedly &quot;Critical Swim Speed&quot;. But the only speed I think is truly critical is the one you&#39;re going to race at.<div style="clear:both;"></div>https://community.usms.org/thread/199216?ContentTypeID=1Fri, 26 Aug 2016 12:20:20 GMT3187ac58-ba85-4314-b79a-c45cd885e09a:78034fac-0ef1-4932-98a4-a9247266a6b1knelsonWhat&#39;s CSS?<div style="clear:both;"></div>https://community.usms.org/thread/199209?ContentTypeID=1Fri, 26 Aug 2016 12:04:58 GMT3187ac58-ba85-4314-b79a-c45cd885e09a:6dc00f77-5201-4a34-b71a-b83baa6a8d92m2tall2&gt; What should threshold/CSS pace *feel* like? Maybe like you have a piano on your back at the end? That&#39;s the feeling I had been getting by doing the 3x300 on 1:00 rest test. I used that method for several months this winter, retesting every 4 weeks, and was positively dead at the end of a Threshold set and it was impossible to hold T-pace on repeats of 200 yards or more. Couldn&#39;t do it. Quite honestly, when I had done a set of say 17x100 on 15 seconds rest, that pace was extremely difficult. A big fat piano at the end. Right now I&#39;m using the 400/200 test results and what the CSS calculator spit out (much slower than how I swam the 400 &amp; 200). A set of 20x100 on 15seconds rest feels easy at the beginning but do-able at the end. Like I tried but if a coach wanted to throw me on the blocks for some sprints after a short recovery swim I&#39;d be able to put up one or two good numbers. Definitely not a piano feeling. If I do longer intervals, like 200&#39;s or 300&#39;s, I can actually hold this pace unless the set passes 30 to 35ish minutes and then I start to tank. I like the idea of not quite working so hard to get faster. Certainly, my recovery between swims has been much better. I&#39;ve actually bumped up the pace in tiny bits a couple times since the beginning of August and am swimming slightly faster at the same level of effort. I did the same exact workout with an 18x100 set today that I had done 20 days ago on similar rest and it was 1.5 seconds per 100 faster on average. I could have gone faster both times but not without completely wasting myself. I&#39;m willing to see how far I can get with this new, easier feeling before my improvement gets stale. I did an open water 1.2 mile swim at a race this past weekend and I went very close to my new T-pace, which makes me feel like I just might be on the right track.<div style="clear:both;"></div>https://community.usms.org/thread/199160?ContentTypeID=1Thu, 25 Aug 2016 13:07:26 GMT3187ac58-ba85-4314-b79a-c45cd885e09a:2cd80eaf-38b4-4721-9b12-b3d8ddd673c5Former MemberFlystorms , 3000 m free style , trying to keep highest possible even speed. One may go over TH speed for few hundreds at the beginning , but not later then 1000m. After that ,as soon as max effort applied , one goes with true TH speed for that current date.<div style="clear:both;"></div>https://community.usms.org/thread/199131?ContentTypeID=1Thu, 25 Aug 2016 11:31:07 GMT3187ac58-ba85-4314-b79a-c45cd885e09a:5991b91e-77e0-420e-890b-c7844ba231b0Former MemberBest is T-3000 with max effort , 10x200 is also reasonably good , if rest doesnt exceed 10-15 sec. But effort should be max especially at last few 200s. Acidosis doesnt let you go faster then TH. As for feeling - You should be tired upon completion , but have ability for some good sprints and/or recovery swimming, since you is about to consume glycogen at 200s , but not fats and phosphocreatine. TH test should be performed on a day after rest or recovery session,preferably at the same day of the week. To do every 3-4 weeks.<div style="clear:both;"></div>https://community.usms.org/thread/199198?ContentTypeID=1Thu, 25 Aug 2016 09:34:36 GMT3187ac58-ba85-4314-b79a-c45cd885e09a:58cd2559-8ea9-457b-8c98-0d946dc78165smontanaro&gt; What should threshold/CSS pace *feel* like? Maybe like you have a piano on your back at the end?<div style="clear:both;"></div>https://community.usms.org/thread/199156?ContentTypeID=1Thu, 25 Aug 2016 08:18:03 GMT3187ac58-ba85-4314-b79a-c45cd885e09a:878d3ec0-851e-4937-94ba-e43f00bcabe5flystormsLED what does this mean &quot;Best is T-3000 with max effort &quot;?<div style="clear:both;"></div>