Most guides on choosing a personal trainer are written by people who’ve never trained a single client.
They’ll tell you to “check qualifications” and “read reviews” and “ensure they have insurance.” All true. All basically useless for actually identifying whether someone can help you achieve your goals.
After a decade training clients across London—and watching friends waste money on terrible trainers whilst brilliant ones go underbooked—I’ve learned that choosing a PT has almost nothing to do with the criteria most people focus on.
Here’s what actually matters.
The Single Most Important Question (That Nobody Asks)
Before you worry about qualifications, testimonials, or session prices, ask this:
“What specific problem will this trainer solve for me?”
Not “will they get me fit” or “help me lose weight.” Those are outcomes, not problems.
The problem might be:
- I don’t know how to programme workouts that actually build strength
- I need someone to stop me skipping sessions when motivation drops
- I have a dodgy shoulder and every programme I try aggravates it
- I’m intimidated by free weights and need someone to teach proper technique
- I’ve plateaued for six months and can’t work out why
The trainer who’s brilliant at solving your specific problem might be completely wrong for someone else’s.
I specialise in hybrid training—helping people combine gym and home workouts effectively. That’s my sweet spot. But if you need someone who’ll scream at you during HIIT circuits at 6am, I’m the wrong person. Doesn’t mean I’m a bad trainer. Means I’m the wrong trainer for that specific need.
Work out your problem first. Then find the trainer who solves it.
Qualifications: What Actually Matters
Right, let’s talk credentials. Because yes, they matter—just not in the way most people think.
The Minimum Bar
In the UK, your trainer should have at minimum a Level 3 Personal Training qualification from a recognised body (CIMSPA-endorsed). They should also have current public liability insurance.
That’s the baseline. If they don’t have this, walk away. Full stop.
Beyond the Basics
But here’s where it gets interesting: the difference between a decent Level 3 PT and an exceptional one with a BSc in Sports Science isn’t the certificate on the wall. It’s how they apply that knowledge.
I’ve got a BSc and over a decade of experience. Does that make me better than a Level 3 PT who’s been training clients for three years? Depends on the client and the problem.
What matters more than the qualification is specialisation. Does this trainer have specific expertise in your area? Training for strength is different to fat loss, which is different to rehabilitation, which is different to athletic performance.
Look for evidence they actually understand your goal, not just that they’re “certified.”
Red Flags in Qualifications
- Weekend certification courses with no practical assessment
- Made-up credentials (“Master Trainer” means nothing)
- Focusing more on their fitness journey than client results
- Instagram-heavy, qualification-light
Experience: The 3-Year Rule
Here’s an uncomfortable truth: most personal trainers quit within the first two years.
Why? Because it’s genuinely difficult. You need to understand programming, biomechanics, behaviour change, business, and how to work with wildly different personalities—all whilst staying motivated when clients cancel or don’t follow the plan.
If someone’s been training clients for three-plus years, they’ve survived the initial “this is harder than I thought” phase. They’ve worked with enough people to have seen what actually works versus what sounds good in theory.
After ten years, I can usually predict within the first conversation whether someone will succeed with a specific approach. Not because I’m magic—because I’ve had hundreds of those conversations and seen the patterns.
How to Assess Experience
Ask:
- “How long have you been training clients?”
- “What types of clients do you typically work with?”
- “Can you give me an example of someone similar to me you’ve helped?”
Pay attention to specificity. Vague answers (“I work with everyone”) usually mean limited experience. Good trainers can describe their ideal client clearly because they’ve found their niche through trial and error.
The Trial Session: What You Should Actually Be Evaluating
Most people use trial sessions to see if they “like” the trainer. Wrong focus.
You’re evaluating whether this person can solve your problem. Here’s what to watch for:
They Ask More Than They Tell
A good trainer spends the first 20 minutes asking questions. About your history, your goals, your lifestyle, your limitations, what you’ve tried before, what worked, what didn’t.
If they jump straight into smashing you with burpees, red flag. They’re not interested in your specific situation—they’re delivering their standard routine regardless of whether it suits you.
They Explain Their Thinking
When they programme an exercise or suggest a modification, do they explain why?
“We’re doing Romanian deadlifts instead of conventional because you mentioned lower back tightness—this variation loads the posterior chain differently whilst keeping your spine in a safer position.”
Versus:
“Right, three sets of these. Go!”
The first shows understanding. The second is just going through motions.
They’re Honest About What They Can and Can’t Help With
If you mention a specific injury or condition and they confidently say “yeah, no problem” without asking follow-up questions or suggesting you get clearance from a physio first—run.
Good trainers know their limits. I’ve referred potential clients to physiotherapists, sports massage therapists, and specialist coaches when their needs fell outside my expertise. That’s not turning away business—that’s being professional.
The Programming Makes Sense
After the session, you should be able to explain why you did what you did. If it felt random or you have no idea what the plan was, that’s a problem.
You don’t need to understand advanced periodisation, but you should grasp the basic logic: “We focused on compound movements today because I’m a beginner and need to build base strength before adding complexity.”
Location and Logistics: More Important Than You Think
Brilliant trainer who’s 90 minutes away? You’ll cancel sessions. Mediocre trainer five minutes from your office? You’ll actually turn up.
Consistency trumps perfection.
Consider:
- Can you realistically get there multiple times weekly?
- Do their available hours actually work with your schedule?
- Is the training environment (their gym, your gym, outdoors, your home) somewhere you’ll be comfortable?
I’ve had clients who initially wanted to train at a particular gym because it was “prestigious,” only to realise they hated the environment and stopped going. Environment matters more than most people admit.
The Home Training Option
Since building the 12REPS app around hybrid gym/home training, I’ve become increasingly convinced that flexibility in location is undervalued.
Best setup I’ve seen: train with a PT at a gym once or twice weekly for technical work and heavy compounds, then follow structured home workouts the other days. You get expert oversight on the complex stuff whilst maintaining consistency on your own terms.
Not every trainer offers this, but it’s worth asking about.
Price: What You Should Actually Expect to Pay
London personal training typically runs £40-£100+ per session, depending on location, experience, and specialisation.
Here’s the reality: you’re not just paying for the hour. You’re paying for:
- Years of education and experience
- Programme design between sessions
- Expertise in adapting to your specific needs
- Accountability and motivation
- Insurance and professional standards
When Cheap Is Too Cheap
£20-30 per session in London? Something’s off.
Either they’re brand new (which isn’t necessarily bad, but you should know that), they’re working in a budget gym with enormous client volume (which limits personalisation), or they’re cutting corners somewhere.
When Expensive Isn’t Better
£150+ per session? You’re often paying for location (Mayfair vs Croydon), branding, or celebrity clientele—not necessarily better results.
I’ve seen £150/session trainers deliver the same generic programme to everyone, whilst £50/session trainers provide thoughtfully customised coaching. Price isn’t quality.
The Real Question
Can you sustain this cost long enough to achieve your goals?
If you need three sessions weekly for six months to build a proper foundation, that’s 72 sessions. At £70/session, that’s over £5,000. Can you afford that? If not, consider alternatives: monthly consultations, small group training, or a structured programme you follow independently with periodic check-ins.
Personality Match: Why "Nice" Isn't Enough
People focus too much on whether they like the trainer personally. Wrong metric.
You need someone whose coaching style matches your response style.
Some people thrive with direct, no-nonsense feedback. Others shut down completely if they feel criticised. Some need constant encouragement. Others find excessive praise patronising.
There’s no right or wrong—but there is right or wrong for you.
Questions to Ask Yourself
- Do I respond better to “push harder” or “let’s modify this”?
- Do I want detailed explanations or simple instructions?
- Do I need someone warm and chatty or professional and focused?
- Will I actually tell this person when something isn’t working?
That last one’s crucial. If you’re too intimidated to say “that exercise hurts my knee” or “I don’t understand why we’re doing this,” you’ll either get injured or waste time doing a programme that doesn’t suit you.
Red Flags That Should Make You Walk Away
After ten years, here are the warnings I wish I could tell every potential client about:
They Promise Specific Results in Specific Timeframes
“I’ll get you a six-pack in six weeks!” / “Guaranteed 10kg weight loss in a month!”
Nope. Too many variables they can’t control: your genetics, your lifestyle outside the gym, your adherence, your sleep, your stress levels.
Good trainers talk about likely outcomes with consistent effort. They don’t make guarantees.
They Push Supplements or Meal Replacement Shakes
Unless they’re a registered nutritionist or dietitian, they shouldn’t be selling you products or prescribing detailed meal plans.
Basic nutrition guidance? Fine. “Eat more protein, here are some ideas” is reasonable. “Buy this £80 shake that I coincidentally get commission on”? No.
They Never Modify or Progress Your Programme
If you’re doing the same routine in month six that you did in month one, something’s wrong. Training should evolve as you adapt.
Progressive overload isn’t optional—it’s the entire mechanism by which you improve.
They’re Always on Their Phone
If they’re scrolling Instagram whilst you’re mid-set, they’re not watching your form. They’re not adjusting your programme based on how you’re performing. They’re collecting your money whilst delivering minimal attention.
This is surprisingly common at budget gym chains with high client volume.
Everything Is “Just Push Through the Pain”
Pain is information. Sometimes it’s just discomfort (which you do push through). Sometimes it’s your body telling you something’s wrong (which you don’t).
A good trainer knows the difference and doesn’t dismiss genuine pain as weakness.
The Question Most People Forget to Ask
“What does success look like, and how will we measure it?”
Vague goals get vague results. “Get fitter” means nothing. “Deadlift 100kg for reps whilst maintaining neutral spine” is measurable.
A good trainer will help you define clear metrics—whether that’s performance benchmarks, body composition changes, improved movement quality, or simply “train consistently three times weekly for three months.”
Then you track progress systematically. Not every session, but regularly enough to know if the approach is actually working.
If your trainer can’t articulate how they’ll measure progress toward your specific goal, they’re guessing.
My Actual Recommendation
If you’re serious about hiring a personal trainer in London, here’s the process I’d follow:
Step 1: Define your specific problem (not just your goal)
Step 2: Research trainers who specialise in solving that problem
Step 3: Check they have minimum qualifications (Level 3, insurance) and ideally 3+ years experience
Step 4: Book trial sessions with 2-3 trainers
Step 5: Evaluate trial sessions based on:
- Do they ask questions before prescribing solutions?
- Do they explain their programming logic?
- Is their coaching style compatible with how you respond?
- Can you realistically maintain this schedule and cost?
Step 6: Choose based on who you believe will actually solve your problem—not who’s cheapest, closest, or most popular on Instagram
Step 7: Commit to at least three months before evaluating results. One month isn’t enough to know if an approach works.
The Alternative Worth Considering
Look, I’m a personal trainer. I make money when people hire me for sessions.
But I’ll be honest: not everyone needs ongoing in-person training.
Some people need intensive coaching for 3-6 months to build foundations, then they’re better off following a structured programme independently. The 12REPS app exists specifically for this scenario—you get professional programming based on my methodology, comprehensive exercise demonstrations, and structured progression without needing me standing over you every session.Others genuinely benefit from long-term coaching. They need the accountability, the real-time feedback, the relationship.
The key is being honest about which category you’re in. Don’t hire a trainer because the industry tells you to. Hire one because you’ve got a specific problem that professional coaching is the best solution for.
And if you do hire one, make sure they’re actively working toward making you less dependent on them, not more. That’s the mark of a professional who actually cares about client outcomes over recurring revenue.
About Will Duru: BSc-qualified personal trainer with over 10 years experience training clients across London. Creator of the 12REPS app and specialist in evidence-based training methods. Available for in-person training and consultations.
Related Articles:
- Do I Need a Personal Trainer? A PT’s Honest Answer
- The Real Cost of Personal Training in London
- Online Training vs In-Person: Which Is Right for You?
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