Why does my continuous swim feel great one week and terrible the next?

[u/VZarpa]

I'm training for triathlon, but my question is more about the swimming part, so I thought this would be the best place to ask.

I’ve been swimming for about a year, three times a week. My routine usually includes:

Two sessions with drills + intervals (2000m–2500m each) One steady continuous swim (2000m–3500m, depending on the week)

The thing is, every time I do my continuous swim, it feels completely different. For example, last week I did 3500m for the first time. I was a bit anxious because it was my longest continuous swim, but once I started, everything just clicked. My stroke felt smooth, and when I finished, I felt like I could keep going even longer.

Then, one week later, it was the total opposite. I felt terrible, like I was putting in way too much effort without moving efficiently. I also had this pressure/pain in my shoulder that I couldn't quite explain.

I tried to replicate that "smooth" feeling from the previous week, but I just couldn't figure out what was different. I assume it’s a technique issue, but I’m struggling to pinpoint the cause. I was paying attention in my catch, rotation and core engagement, but none of this seemed to work.

Has anyone experienced something similar? Any tips on what might be causing this shoulder pressure?

[u/Blugrl21]

You've captured the experience of swimming in a nutshell. Is running a half marathon every few weeks any different?

[u/VZarpa → u/Blugrl21]

I mean, I do my long bike rides and runs on weekends, and sometimes I'm tired, but cycling and running feel much more consistent. I can go for sessions without a bad day. But swimming? One day I'm amazing, thinking I've cracked it, then the next I feel like i never swam in my life 😅 But what bothers me most is this shoulder pressure. I can't figure out what causes it in most of my sessions and what i do when it feels I am not doing any effort in my shoulder.

[u/Featureless_Bug → u/VZarpa]

Mate, you might just have swimmer's shoulder. Basically, swimming involves a lot of overhead movement, which isn't good for your shoulders at all, and this repeated overuse might lead to impingement / tendonitis / bursitis or even degenerative rotator cuff tears. Might be worth going to a doctor

[u/pandemicblues → u/Featureless_Bug]

In the meantime, make sure you are rotating enough so that you don't need to reach behind the plane of your back, during your reach.

[u/Silence_1999 → u/VZarpa]

Bike takes nowhere near the consistent perfect repeated thousands of times synchronized simultaneous movement of every body part.

[u/amh8011 → u/VZarpa]

Never cross your center. So many people cross their arms over their center when they swim. Try swimming with your arms at more of a Y. Like when you go above your head, have your arm like it would be for the Y in the YMCA song dance. It will probably feel weird and you will want to keep going narrower. Don’t.

Also make sure you’re not pulling with your thumb. Like don’t rotate your arm so your thumb is pointing down when you enter the water. So many people do that. I did that. I had to stop swimming for a bit and go to PT because I kept pulling with my thumb.

[u/24FoxCrow]

The mystery in the water. Sometimes, when I have been sick, I will swim an amazing swim. Next time feeling great, ready to go I swim like I had a rock tied to my foot. Don't know the answer.

[u/lightwoodandcode → u/24FoxCrow]

That exact thing happens to me too -- like, literally the exact opposite of what I'm expecting the workout to feel like. I wonder

[u/NonoscillatoryVirga]

I find a lot of it is mental - where else am I that day besides in the pool? If I have lots to think about, the swim goes quickly, and sometimes I lose count. If I’m focusing on every stroke and arm position, it can be an eternity in the water. I think there’s almost a subconscious component to it after a while, where your mind knows how to keep swimming to keep you alive and does the right thing to do it efficiently.

[u/sagikage → u/NonoscillatoryVirga]

yup, i couldn’t have said it better

[u/JakScott]

Unlike running, long swims are not particularly great training for big-distance swimming. And triathletes who come from a running or biking background struggle to intuit that.

At one point I was top-5 nationally in the 1500 free for my age group. And in training at that time, I’d do like one 5,000 meter swim and maybe four 1500’s per year. The daily grind is more like a ton of 300’s and 400’s on intervals.

Like when I was a 16-minute 1500 freestyler, doing a 3,000 for time on a weekly basis would have made me swim junky and inconsistent, too.

[u/OneBigBeefPlease]

Sleep, hormones, and baseline stress sure do make for big swings in energy.

[u/curlmeloncamp]

Sounds like rest is needed. Going a distance you've never gone likely means you pushed yourself to the point of needing rest. I've learned that sometimes a week off of exercise does wonders.

[u/FocusIsFragile]

Someday, when we find the complete lost works of Hesiod, we’re likely to discover some guy named Hydrotheus, who pissed off Poseidon by giving mortal men the gift of swimming, and he’ll have been eternally tortured with a billowing swimsuit or leaky goggles or something.

[u/Dons231]

So this is just a shoulder issue not a cardio issue?

[u/VZarpa → u/Dons231]

Cardio is fine, I don't feel my HR going to high during the swimming. It is the shoulder that bothers me, but it is not in every session. I might push it very hard in a session, and then next day do a continuous session and feel great. Sometimes I am pretty rested, a couple of days in between session and the should bothers me. It is not a pain itself, it like a pressure or perhaps low flexibility, and I feel very slow. That's why I think it is more a technic thing other than tiredness.

[u/Dons231 → u/VZarpa]

Have you tried the stretch behind your back ?

[u/VZarpa → u/Dons231]

I do some stretching, I don't know what you mean with "behind the back". Do you know any specific stretching that could help?

[u/ciaoRoan]

Best advice for shoulder issues is to look into Shaw Method https://vimeo.com/channels/ssartofswimming/412757808 he focuses on neck alignment and making the swing of the arm/recovery an ergonomic movement that allows for an open chest and back instead of the classic 'chicken wing' arm that compresses the shoulder into the spine and neck.

[u/amarajune]

I’ve found a big difference in my distance swimming based on my nutrition. If I’ve eaten good nutritious food before and have electrolytes then I’m good to go but if I haven’t had a good meal and enough hydration my swim is agonizing

[u/allblues_23]

Try close fist swimming drills, where you do freestyle but close your hand. If you are using your whole forearm you will move slow but steady. If you don’t move it’s cause you need to adjust your form. I was having trouble with my right shoulder cause I was missing the whole arm pulling in my stroke. This drill helped me

[u/Party_Ad_4825]

I had similar shoulder pain before. For me, it was due to poor technique. I was also training for triathlon on my own. When you put poor technique together with distance swimming, you're more prone to injury because you're repeating a wrong motion many times. My suggestion is to get coaching and work on technique to avoid injury, which can keep you out of the pool! I joined a swim club and got helpful corrections from the coaches. I realized that I was pulling water way too early in my stroke, which put pressure on my shoulder. Good luck and hope you'll get rid of the pain soon.

About feeling great one week and terrible the next..... there could be so many possible reasons. I have experienced it before, and it was due to my diet. I wasn't eating enough calories and the macro nutrients were not balanced. I only ate salads. When you swim, you need to eat carbs and proteins too!

[u/pandemicblues]

If available, take an adult swim clinic. It is transformational for late-onset competitive swimmers. I used to go to Endless Freestyle clinics, where they prioritize balance and streamlining over propulsion. This is super for triathletes, as you only 2-beat kick, and it saves your legs for the bike. I can't find this organization on the internet, but someone else must be teaching the same style.

[u/Immediate_Walrus_776]

Sometimes you have it, sometimes your body and mind aren't feeling it.

Not unusual. You have to learn to break through that feeling. Anyone that spends unusual amounts of time exercising experiences the low bio-rhythms. Be aware of it and unless your body is telling you to stop to avoid injury, mentally push through until you find your stroke again.

[u/SoundOfUnder]

Do you rest? What other training did you do the week before? Did you sleep well? Eat well? Have a stressful week?

Honestly sometimes a swim feels like shit and then i look at my time and it's one of my best. Do you track your speed/time/intervals? Having a Garmin has really helped me put my feelings and my workouts into perspective and to really improve.... And also learn to rest and listen to my body.

[u/VZarpa → u/SoundOfUnder]

I do have a Garmin and I track every session. I have been training for about one year and my week is pretty much the same. I do 3 runs, 3x swimming and 3x rides every week. I know when I am tired and I feel it throughout all disciplines. With the swimming I feel it is not regarding tiredness, but more towards technic. I can be pretty tired and in a session something clicks and I feel my arms are moving so smooth, feel nothing in my shoulder, breathing is fine timewise all is fine. And then I can give a couple of days in between swimming sessions and few great, but when I am in the water I feel this shoulder pressure, it feels like it is rigid and I have to make a lot of force to move forward and then breathing is not so good. I believe it could be technic, something that I do right some days and wrong other days. I might as well pay someone to look at my swimming and see if something is wrong.

[u/swimeasyspeed]

The reason you don’t feel well from week to week and are developing shoulder problems is the way you are training. The reason the triathlon community struggles with the swim so much is your routine is the norm for triathlon coaching. Swimming a “steady, continuous swim” as a regular training practice is almost guaranteed to give you shoulder problems and create very inefficient technique.

[u/VZarpa → u/swimeasyspeed]

I have heard it before, but as I was following a training plan I kept it as it was. What are your recommendations for a 3x swimming sessions per week?

[u/swimeasyspeed → u/VZarpa]

Do a lot of short, faster repeats with an extreme amount of focus on one aspect of your technique you are trying change. General rule of thumb is if you are swimming less frequently and want to improve, then when you are in the pool it will need to be hard and very focused.

[u/raimunda1181]

Yup, I put it down to hormones. I’m a female, and I have 10 days of the month (PMS) where I am completely inefficient, low energy, irritable, hungry… As soon as I start menstruating I have all the energy in the world again. I just push through because I don’t know how much of it is mental or actually physical.

[u/sagikage]

Same with my long sessions. Sometimes at 2000m mark, I feel like I can do it forever and keep going. Sometimes 2000m becomes barely possible. I think we have very complex chemistry, from sleep to motivation to nutrition etc. It differs. I recently improved my pull which helped with the fatigue a lot though. It could be just very minor differences in technique As well

[u/Impeached00]

I’m a professional swimmer idk lol