:INFO The Workout Card Is Not Hard Once You Know the Code Your coach hands you a card that reads "6x100 FR on 1:30 descending." You stare at it. Every guide to swim workouts either explains the notation or explains training zones. None does both. This page does both, and adds the one thing every guide skips: what to actually do at the wall when you are too slow to make your interval. :IMAGE :STATS [icon:CLOCK] Time to read this | 8 minutes [icon:TARGET] CSS test time | 10 to 12 minutes in the pool [icon:BOLT] Zones unlocked | 5 (from one single test) [icon:CHART] Interval format | repetitions x distance, then clock window or rest :INFO Part 1: Cracking the Notation Every swim set follows the same grammar: how many times, how far, in what style, with what clock constraint. Once you can parse that grammar, any workout card becomes readable. A set written as "8x100 @ 1:30 FR" means: • 8 repetitions, each 100 metres (or yards, depending on the pool). • FR means freestyle (front crawl). • @ 1:30 is the send-off interval: a 90-second window from push-off to push-off. If you swim the 100 in 1:20, you get 10 seconds of rest. If you swim it in 1:25, you get only 5 seconds of rest. The interval is not the rest. It is the total window. Fast swimmers earn more rest. Slow swimmers earn less. If you cannot make the interval, see the note at the bottom of this page. :TABLE [title:Stroke abbreviations] Abbreviation | Stroke FR or FS or FC | Freestyle (front crawl) BK | Backstroke BR | Breaststroke FL | Butterfly IM | Individual medley: butterfly then backstroke then breaststroke then freestyle Pull | Arms only, pull buoy between legs, no kick Kick | Legs only, holding a kickboard :TABLE [title:Effort and pacing terms] Term | What it means Build | Start easy, finish fast within the same rep DESC | Descending: each rep faster than the last Neg split | Second half of the rep faster than the first half Drill | Isolated technique work, e.g. one-arm freestyle RI :15 | Rest interval: exactly 15 seconds of rest after each rep :INFO Send-Off vs Rest Interval Two different ways to control a set, and mixing them up causes confusion at the wall. • Send-off ("on 1:30" or "@1:30"): the clock starts when you push off. You push off again 90 seconds later no matter how fast you swam. Rest is what is left over. • Rest interval ("RI :20" or "rest :20"): you rest a fixed 20 seconds after every rep regardless of your swim time. Total set time varies. Faster swimmers benefit more from a send-off interval. Rest intervals give every swimmer the same recovery window. :LINK https://www.aquaplan.fit/blog/how-to-read-a-swim-workout AquaPlan: How to Read a Swim Workout (notation guide) :INFO Reading the Pace Clock The pace clock on the pool deck has one sweeping hand and no hour hand. The top is marked :60 (or :00), the right is :15, the bottom is :30, the left is :45. • "Leave on the top" means push off when the hand is at :60. • "Leave on the bottom" means push off at :30. • "Leave five seconds apart" means the first swimmer leaves at :60, the next at :05, the next at :10, and so on down the lane. To read your lap time: note where the hand is as you push off (last thing before you go), note where it is as you touch the wall (first thing on arrival), subtract. Swims over 60 seconds: add 60 for each full revolution the hand has made. The key technique is the glide-in glance: look at the clock while you are still gliding toward the wall, before you stop. This gives you the time cleanly without having to ask. :NOTE If you cannot make an interval, do not panic at the wall. Push off with the next group, tell your coach afterward, and ask for 5 to 10 seconds added to the interval. Missing by a few seconds means the set is working. :INFO Part 2: Your Five Training Zones from One Test Most beginners skip zone training because calculating zones seems complicated. It is not. One test, two distances, one subtraction: you have your Critical Swim Speed (CSS), and CSS gives you all five zones. CSS is the fastest pace you can hold aerobically, expressed as seconds per 100 metres. Zone 4 sits right at CSS. Zone 1 is 10 to 15 seconds per 100m slower. Zone 5 is 2 to 8 seconds per 100m faster. :INFO The CSS Test (Wakayoshi Protocol) Run this test before any other training in the session. • Warm up 400 to 600 metres easy (Zone 1 pace). • Swim 400 metres all-out. Record your time as T400. • Rest 10 to 15 minutes with easy swimming. • Swim 200 metres all-out. Record your time as T200. The formula: CSS pace (sec/100m) = (T400 - T200) / 2 Example: 400m in 6:40 (400 seconds), 200m in 3:00 (180 seconds). CSS = (400 - 180) / 2 = 110 seconds per 100m = 1:50 per 100m. Retest every 4 to 6 weeks. As your fitness improves, your CSS pace number drops (you swim faster). :LINK https://www.trainingzones.io/en/guides/critical-swim-speed TrainingZones.io: Critical Swim Speed complete guide and calculator :TABLE [title:Five training zones from CSS (pace offset per 100m)] Zone | Name | Pace vs CSS | RPE (1-10) | What it trains 1 | Recovery | CSS + 10 to 15 sec | 2 to 3 | Active recovery, stroke refinement, warm-up and cool-down 2 | Endurance | CSS + 5 to 10 sec | 3 to 4 | Aerobic base, fat oxidation, mitochondrial density 3 | Tempo | CSS + 2 to 5 sec | 5 to 6 | Aerobic power, lactate threshold 4 | Threshold | Within 2 sec of CSS | 7 to 8 | Lactate clearance, fastest sustainable pace 5 | VO2max | CSS minus 2 to 8 sec | 8 to 9 | Maximum oxygen uptake, top-end speed :INFO How Much Time in Each Zone? The 80/20 rule is the most evidence-backed framework for endurance sports and applies directly to swimming. • 60 to 70% of weekly volume in Zones 1 and 2 (easy, conversational pace). • 15 to 25% in Zone 3 (tempo, comfortably hard). • 10 to 15% in Zone 4 (threshold, uncomfortably hard). • 5 to 10% in Zone 5 (VO2max, sprint intervals, very short with long rest). If you train 3 times per week, that means roughly 2 easy sessions and 1 session with a Zone 4 or Zone 5 main set. Most beginners do the opposite by accident: too much Zone 3, too little Zone 1 and 2. :INFO Putting It Together: Reading a Real Set Consider a main set that reads: "5x200 on 3:30, build each 50." Parse it step by step: • 5 repetitions, 200 metres each. • Send-off interval: 3 minutes 30 seconds from push-off to push-off. • Build each 50: within each 200, each 50-metre length is faster than the last. Start at Zone 2 pace, finish at Zone 4. If your CSS is 1:50/100m (110 seconds), a 200 at Zone 2 takes roughly 4:20, which is slower than the 3:30 interval. The coach likely intends this for faster swimmers. Ask: "Is this on 3:30 for the whole lane, or should I adjust?" Adjusting an interval is normal and expected. :NOTE CSS gives you a pace, not a heart rate. Cold water, fatigue, and caffeine all shift the relationship between pace and effort. In a cold pool (below 28 C), your heart rate will read lower than expected at any given pace. Use RPE (the 1 to 10 scale in the zone table) as your cross-check. :LINK https://www.swimoutlet.com/blogs/guides/understanding-the-pace-clock-in-swimming SwimOutlet: Understanding the Pace Clock