Strength, Endurance, and Real Life: A Coach's Guide to Training for Triathlon and HYROX
For busy professionals training for events like triathlons or HYROX, the biggest challenge isn't the training itself—it's fitting it around a full-time job, travel, and life's unpredictability. Harry Armstrong, a performance coach who works across strength, endurance, and nutrition, shares his approach to making training work for real people, not just ideal scenarios.
When Standard Plans Fail
Armstrong recalls a client who worked in finance, traveled frequently, and was training for a 70.3 triathlon while also wanting to get stronger and leaner. The standard advice—a 12- to 16-week plan with fixed days—fell apart when the client faced a week of conferences, hotel stays, and networking dinners.
"Most plans treat that week as a failure. Miss the sessions, feel guilty, try to cram them in when you get home, end up cooked," Armstrong says. Instead, he built a travel version of the week: strength reduced to one full-body dumbbell session, bike work moved to a hotel Peloton with power data synced to TrainingPeaks, runs outdoors from the hotel, and nutrition simplified to a few targets like protein first and carbs around sessions.
"The aim wasn't to win that week. It was to keep the thread going so he came home ready to train, not ready to start again," he explains. For people with real jobs, such weeks aren't the exception—they might be one in five. "If the programme doesn't have a plan for them, it isn't a programme for that person."
What Most Advice Leaves Out
Armstrong identifies three key areas that are often overlooked in mainstream training advice: fuelling, stress, and structure.
First, fuelling. "Most people I speak to are trying to drop body fat while training eight to ten hours a week and they're doing it by under-eating around their sessions," he says. His rule: once total training for the day exceeds an hour, fuel during the session, even if it's easy. "That's on top of your daily calories, not instead of them. Carbs are your friend when performance is the goal."
Second, work stress is training load. "Your training app doesn't know you slept four hours and had a 6am flight. A plan written for someone with perfect sleep and free evenings will break a busy person," Armstrong notes. Volume must be set around the life you actually have.
Third, structure. "People think they need more motivation. They don't. They need to know Monday is legs and a swim, Tuesday is bike and run, without making a decision every morning," he says. "Start the week strong and the rest usually follows."
Common Mistakes When Building Strength and Endurance
Armstrong sees several recurring errors. The first is trying to do everything at once: a big calorie deficit, rising endurance volume, and new strength PBs in the same block. "Something has to give and it's usually the person," he warns. Instead, he phases it: drop body fat first, then build back up with more food and more performance. "The aim is to end up eating properly and still lean."
Another mistake is booking the event before building the habits. "Signing up for an Ironman or a HYROX doesn't change your life on its own. The routine has to exist first," Armstrong says. He advocates year-round training across strength, speed, and aerobic base, rather than a panicked 12-week block followed by three months off.
Poor session stacking is also common. "A classic one with HYROX is doing an hour of heavy strength work and then going straight into 40 to 45 minutes of conditioning on top. That's a lot of fatigue and the quality of both suffers," he explains. Hard days should be hard, easy days easy, with big sessions planned so they don't conflict.
Finally, people add volume before proving consistency. "Five or six hours a week you'll actually do beats ten you'll miss half of," Armstrong says.
Practical Takeaways
For those balancing strength and endurance training with a busy life, Armstrong's advice boils down to: plan for disruptions, fuel your sessions, account for life stress, and build habits before signing up for events. His approach, detailed on Harry Armstrong Coaching, emphasizes sustainable progress over perfect plans. As he puts it, "The aim is to end up eating properly and still lean"—and still enjoying the process.