How Triathletes Should Train In The Winter Offseason
- Louise Whitting
- Oct 30
- 7 min read
Why Your Competitors Will Be Burned Out By June (And You Won't)
If you're anything like I was when I first started racing triathlons, the offseason feels wrong. That voice in your head is screaming: "If you stop now, you'll lose all the fitness you've built."
I get it. I've been that athlete who kept hammering through November and December, terrified of losing fitness. But here's what I learned: the offseason isn't when you lose your fitness - it's when you build the mental and physical foundation for your fastest season yet.
In fact let's stop calling it the "offseason." That word implies you're doing nothing, when the reality is the complete opposite. This is your building season - the time when the best athletes are made.
What Actually Is The Offseason?
Let's get this straight: the offseason doesn't mean lying on the sofa eating crisps for three months (although a bit of that is absolutely fine). The offseason is a deliberate, structured period that typically runs from late autumn through winter, when you're furthest away from your key races.
Think of it as the foundation of a pyramid. The broader and stronger your base, the higher the peak you can build. This is called periodisation, and it's the backbone of every successful training programme.
For most age-group triathletes in the UK, the offseason typically starts in October or November after your last race and runs through to January or February. That's roughly 12-16 weeks where your training looks completely different from race season.
The Biggest Offseason Mistakes Triathletes Make
Before we talk about what to do, let's address what most triathletes get wrong:
Mistake #1: Diving straight back into structured training after your last race. Your body and mind are exhausted. You need actual rest, not just "easy" training that's still highly structured.
Mistake #2: Maintaining race-season intensity all year. Your body needs a break from high-intensity work, or you'll be burned out before your first key race if you keep doing top threshold and V02 max intervals every week in winter.
Mistake #3: Completely stopping all training. The opposite extreme is just as damaging. You'll lose adaptations and make the return to structured training brutal.
Mistake #4: Neglecting strength training. The offseason is when you should be lifting heavy. During race season, you can't recover from heavy strength sessions in time to nail your key swim-bike-run training.
Mistake #5: Keeping the same training volume as race season. Your offseason should look different. Lower intensity, potentially higher volume in some phases, but different focus.
Mistake #6: Not analysing your performance limiters. Not every gap is a fitness problem. Sometimes it's aerodynamics, running economy, your nutrition or swim technique. Identify the specific gap before prescribing the solution. Not everything is solved by "more training." Take a critical look at your performance in all three disciplines to understand the room for improvement - or hire a coach to help you.
Example: If you're pushing 270 watts but only going 35 km/h on a flat course, your limitation isn't fitness, it's efficiency. You need to work on bike position or aerodynamics. More intervals won't fix that.
The Three Phases Of A True Offseason
Phase 1: True Recovery (2-4 Weeks)
This is non-negotiable, especially if you've raced an Ironman, 70.3, or had a hard season. Your body needs genuine rest. Personally I love to book a big trip abroad around November-December time and take a full 2-3 week holiday!
What this looks like:
Minimal to no structured training
Move for fun when you fancy it (walks, easy rides and runs, casual swims)
No heart rate targets, no power meters, no pace goals
Sleep as much as you can
Eat intuitively without tracking macros
Spend time doing non-triathlon things
I know this feels uncomfortable. You'll probably gain a bit of weight. Your FTP will drop slightly. This is completely normal and will reverse quickly. What you're gaining is far more valuable: full physical and mental recovery. Your central nervous system, hormones, and immune system all need this break. Push through without it, and you'll pay the price with illness, injury, or burnout later.
Phase 2: Transition/Preparation (4 Weeks)
After your recovery period, you move into what we call transition training. This is where you start building momentum that maintains fitness without mental load.
What this looks like:
Light swimming, cycling, running - no structure
Try new things for enjoyment (trail running, mountain biking, rowing)
4-6 hours per week
No prescribed intervals
This phase serves two purposes: it keeps you ticking over physically whilst giving your brain a proper break from the mental load of structured training. If you don't fancy a swim one day, don't do it. Flexibility is the goal here.
(Note: just don't take the entire winter off swimming like I did one year... if you don't come from a swimming background, it will take months to get back to where you were!)
Phase 3: Base Building & Addressing Your Specific Gaps (8-12 Weeks)
This is arguably the most important phase of your entire year. Base training builds the aerobic foundation that allows you to handle the high-intensity work during the build phase. This is lower intensity, higher volume training to build aerobic endurance and durability.
What base training involves:
Aerobic endurance work: Heart rates, powers, and paces are generally kept under lactate threshold. This is proper Zone 2 training - conversational pace where you could chat comfortably.
Gradually increasing volume: Don't jump straight into massive training weeks. Build your volume progressively. Start at perhaps 60-70% of your peak race-season volume and build from there.
Strength training: Base phase is an excellent time to implement concurrent strength training, as any muscle soreness from lifting is unlikely to have a detrimental effect on the otherwise low-intensity training. This is when you should be in the gym lifting heavy.
Technical work: The best time to make changes to your form is when you're going slow for long periods of time. Work on your swim technique, cycling position, and running form now, not when you're trying to hit threshold intervals in March.
Cross-training: General aerobic cross-training like cross-country skiing or rowing fits in nicely early in the base phase. Don't be afraid to mix things up.
The discipline-focused block strategy:
Alongside base training, it is advisable to spend time on your weakest discipline with a focused block: 6-8 weeks of doubling down on one area. This strategy can work wonders if you want to see big improvements in one sport.
Example: if swimming is your weaker sport and you were swimming 2-3 times a week before, up this to 4-5 times a week and consider joining a swim club for a motivation and fitness boost. Scale back the runs and cycles to just 2-3 sessions a week for maintenance.
Strength Training: Your Offseason Secret Weapon
This deserves its own section because it's criminally underutilised by triathletes.
Triathlon-specific strength training focused on high weights and low reps improves speed, power, efficiency, and the ability to push through the most challenging parts of the race such as transitions, hills, and the kick at the finish. Not to mention, it adds an extra layer of resilience against injury.
What proper strength training looks like:
2-3 sessions per week
Compound movements (squats, deadlifts, lunges, push-ups, rows)
If you are just starting out, begin with medium weights with 8-12 reps, and work towards heavy weights (3-5 sets of 4-8 reps) as you build confidence and strength
Progressive overload (gradually increasing weight over weeks)
Sport-specific work (single-leg exercises for running, balance, core stability etc.)
I'm a personal trainer as well as a triathlon coach, and I can tell you that most triathletes lift weights completely wrong. You should be lifting heavy enough that the last rep of each set is genuinely difficult. If you can comfortably do 15 reps, the weight is too light.
Mental Recovery: The Component Everyone Ignores
Physical training is only half of the offseason equation. Your brain needs recovery just as much as your muscles. I have written all about this in Why Recovery Days Are Making You Faster (Not Slower)
Racing season is mentally exhausting. Every session has targets. You're constantly analysing data, worrying about whether you're doing enough, comparing yourself to others on Strava. It's draining.
When To Move Beyond Base Training
After 8-16 weeks of base training, it's time to move on to the build phase, where workouts become more race-specific. For most age-groupers training for spring/summer races, this means starting your build phase around late January or February.
You'll know you're ready when:
Your aerobic sessions feel comfortable at higher volumes
You're consistently hitting your easy zones without drifting
Strength gains have plateaued somewhat
You're mentally ready for harder, more specific work
You're within 16-20 weeks of your first key race
The Bottom Line
The offseason isn't wasted time. It's not when you lose fitness. It's when you build the foundation that allows you to train harder, race faster, and stay healthy throughout the entire season.
I know it feels counterintuitive to slow down when others are pushing hard. But here's the truth: the athletes who embrace a proper offseason are the ones who show up to their key races feeling strong, fresh, and ready to perform at their best. Your competitors who grind through winter? Many of them will be injured, burned out, or plateaued by June.
So give yourself permission to rest after race season. Spend time in the gym building proper strength. Keep your aerobic sessions genuinely easy. Take mental breaks from training data, and take guilt-free holidays. Enjoy the process without the pressure of looming races. Your fastest season yet starts with a proper offseason.
If you're a triathlete who wants a systematic, science-based approach to periodisation and building sustainable performance, let's chat about how coaching or personal training can help you nail your offseason and set yourself up for your best season yet.
