What an AI fitness coach actually does: how Trael builds your plan

Step one: the questionnaire

You pick a direction first, from five: Lean & Light, Athletic & Toned, Strong & Built, Home Fit, and Fresh Start. These are a starting point rather than a commitment. Then you answer a questionnaire that takes a few minutes, and after it you confirm the goal itself from four options: Lose Weight, Lose Fat & Build Muscle, Beginner Restart, and Trim & Energise. The direction you picked pre-selects the matching goal, and you can change it.

The questionnaire asks for your age and sex, your height, weight and waist, what training setup you have (a gym, some equipment at home, or nothing at all), how much time you can give it, your dietary preferences, and a set of health and safety questions. That last group is not padding: it is what stops the software prescribing something inappropriate.

Trael is designed for adults aged 18 to 55. It is not suitable during pregnancy or the early postpartum period, or for people with a history of disordered eating or who are underweight, and the questionnaire screens for this before any plan is produced. In those cases the right support is a GP or a qualified professional, and Trael says so rather than building a plan anyway.

Step two: the plan

You get a workout plan and nutrition targets, both personalised to the answers you gave.

• The workout plan sets your training days and, for each session, the exercises, sets and repetitions. It is built around the equipment you actually have, so a home plan with no kit looks different from a full gym plan.
• The nutrition side sets a daily calorie target and a daily protein target. Both are personalised, and both move as your plan does.
• Exercises come with video clips so you can see the movement before you attempt it, and you can swap an exercise for another in the same family if a machine is busy or a movement does not suit you.

Safety limits are applied to the plan itself rather than left to a disclaimer. Calorie targets cannot fall below a hard floor (1,200 kcal for anyone, 1,500 kcal for men), week-to-week changes in training volume and calories are deliberately capped so nothing can ratchet up or down quickly, and the plan keeps rest between sessions rather than stacking them.

Step three: the coach, by text or voice

You can type to the coach or talk to it. Both go to the same coach, which can see your plan and your recent activity, so questions like why an exercise is in your plan, or what to do about a session you cannot finish, get an answer that relates to your actual programme rather than a generic one.

Voice is hands-free and useful mid-session, when typing is impractical. It is available for up to 4 hours a day. Voice audio is transient: it is processed to produce a reply and is never stored. During a workout the app also gives spoken cues for the exercise you are on and for rest periods, so you can keep your phone in your pocket.

There are things the coach will not do, by design. It will not assess symptoms, diagnose anything, or tell you to train through pain. If you describe pain, concerning symptoms, or distress, it stops and points you to the right service rather than continuing the workout conversation.

Step four: the weekly check-in

Once a week you record your weight and waist and say how the week went. That check-in is what moves the plan: the next week is regenerated from your real results rather than following a fixed schedule written in advance.

Adjustments are small by design. The same caps that apply to the first plan apply to every regeneration, so a bad week cannot trigger a dramatic cut and a good week cannot trigger a dramatic jump. Alongside this you get progress tracking for weight, waist and training streaks, and an optional daily workout reminder in the app and by email that you can turn off in Settings.

What a week actually looks like

Stripped of the feature list, using it is fairly plain. On a training day you open the app, see the session for today, and work through it with the exercise clips and spoken cues if you want them. On a rest day there is nothing to do. Once a week you spend a minute on the check-in.

The coach is there in between for the questions that come up: swapping an exercise, what to do about a session you had to cut short, whether a meal fits your targets. You can ignore it entirely and still follow the plan, or use it constantly. Neither is the wrong way round.

What Trael does not do

The honest list, stated the same way on the pricing page:

• No carbohydrate, fat or water tracking. The nutrition side covers calories and protein.
• No step-count targets. You can log steps, but Trael does not set a target for them.
• No form checking. Trael cannot see you train, so it cannot tell you your knee is caving in. That remains a genuine advantage of an in-person personal trainer.
• No medical care. Trael provides general fitness guidance and cannot assess symptoms, diagnose, or treat anything.
• No crisis service. In an emergency call 999; for urgent medical advice call NHS 111. The support and safety page lists these and other services.

That list describes today. We would rather tell you what is missing than describe a roadmap, so nothing above should be read as a promise about what comes next.

Where your data goes

A fitness coach necessarily holds health information, so it is worth being specific. Trael complies with the UK GDPR and is registered with the Information Commissioner's Office, registration reference 00014709305.

• Database and authentication: Supabase, in the EU.
• Plan and coach-reply generation: Mistral AI, in the EU.
• Speech to text and text to speech: Trael's own servers in Germany. Audio is not stored.
• Payments: Stripe. Card details never reach Trael's servers.
• You can export or delete all of your data yourself, at any time, from the Account screen or Settings.

What it costs and how to stop

£24.99 a month. New accounts start with a 3-day free trial with nothing held back, and no card is needed to begin it. Cancelling is self-service through the Stripe billing portal on the Account screen, and cancelling never forfeits days you have already paid for: access continues to the end of the period you paid for and nothing further is charged.

Sources

• NHS - physical activity guidelines for adults aged 19 to 64
• Information Commissioner's Office