When time is short, many swimmers instinctively want to jump in and swim nonstop. Regardless of how much time you have, you should always ask: “What will benefit me the most?” If you feel aerobic conditioning is paramount, a continuous 30-min swim might not bring the greatest benefit since your pace is likely to be slow and heart rate fairly low, unless your “skill circuits” are sufficiently robust to maintain a constant Stroke Length and Stroke Rate throughout.

A potential benefit of a continuous 30-minute swim could be to test the durability of your muscle memory and focus.  For an exercise in Mindful Swimming, you could cycle through three “stroke thoughts” for 30 minutes of uninterrupted swimming E.G. Marionette Arm Recovery for 50 yards and Mail Slot Entry for 50 yards and Patient Catch for 50 yards, continuing that way for 30 minutes. Learn more about these “stroke thoughts by downloading a free “Easy Freestyle”  e-book.

Or in an exercise that will increase your ability to calibrate and adjust your Stroke Length,  alternate two or three strokes counts. E.G. Swim at 15 SPL (Strokes Per Length) for odd 25s and 16 SPL on the even 25s. When you add 1 SPL, you should notice an increase in speed.

Alternatively, you could work on consistent pacing by swimming with a goal of maintaining a consistent SPL with a particular Tempo Trainer setting. E.G. Set TT at 1.30 sec/stroke and maintain 15 SPL. Continue swimming so long as you keep completing laps at 15 SPL. If your count goes above 15, give yourself one more length to try to bring it back down. (Remember, adding a stroke at a 1.30 tempo means your pace on that length was 1.3 seconds slower. If you keep swimming with the higher SPL, you’re not improving aerobic fitness — you’re training yourself to lose pace.) If you can’t return to 15 SPL, take a break, say 5 to 10 beeps. Then resume swimming. Keep track of the number of times you need to rest in 30 minutes. If it was 10 times, your goal for your next continuous 30-minute swim could be to maintain a 15 SPL – 1.30 SR with nine or fewer breaks.

Most swimmers will benefit more from a series of shorter swims. At times, having only 30 minutes to swim, I’ve done 30-minutes of 25-yard and/or 50-yard repeats because I gave myself a task so exacting that I couldn’t complete it successfully if I swam farther. E.G. I can maintain 12 SPL at a tempo faster than 1.20 sec per stroke only for 25 yards. If I attempt a 50, it’s almost inevitable that I’ll take 13 SPL on the second lap. If I decide to swim 50s, then I’ll set the bar for the task at not exceeding 25 total strokes at a tempo of 1.20. Or I could allow a faster tempo and find the lowest number of strokes I can hit for 50 yards with unblinking focus.

The main takeaway here is that you should evaluate the benefit of any practice – even those that are quite brief – on the mental and neuromuscular adaptation they produce, not just the metabolic. In fact the argument for emphasizing mental and motor training over conditioning in a short practice is far stronger since it’s nearly impossible to get a metabolic effect in a time period that short, while your nervous system can make considerable adaptation.

Understand that I’m not arguing against doing a continuous 30-minute swim. I’ve made that choice at times. But I made sure the content of my 30-minute swim – e.g. to maintain a challenging combination of SPL and TT setting – would result in strengthening my neuromuscular “efficiency imprint” and require complete attention for every stroke I took (probably around 1500 in 30 minutes) during that swim. Fifteen-hundred beneficial imprints is definitely a positive return on a 30-minute practice.