Strength training is one of the most powerful tools for staying healthy and active beyond 50.
Yet, according to physiotherapist and over-50s specialist Will Harlow, many people are unknowingly sabotaging their results — and it has nothing to do with bad form or exercise selection.
The problem? A lack of intensity.
In a recent video, Harlow explained why this simple mistake could be the reason progress plateaus. Fortunately, it’s also easy to fix — if you know what to look for.
Here’s how increasing your workout intensity can reinvigorate your strength and muscle gains, and exactly how to do it safely and effectively.
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Why Intensity Matters More Than the Weight You’re Lifting
After age 50, muscle mass naturally declines if not maintained. But according to Harlow, showing up and doing the exercises isn’t enough — the body needs a reason to adapt and get stronger.
“If after 50 you’re not training with enough intensity, your body simply will not adapt,” says Harlow. “That means no gains in strength, no gains in muscle, and maybe even a loss of strength over time.”
The misconception is that intensity equals heavy weights or pushing through pain. In reality, intensity is more about the effort you bring to each set, not the number printed on the dumbbell.
Reps in Reserve (RIR): The Key to Training Smarter
One of the easiest and safest ways to gauge whether you’re working hard enough is a method called Reps in Reserve (RIR). It helps quantify your perceived effort and gives a clear performance marker to aim for.
Here’s how it works:
- After each set, ask yourself: “How many more reps could I have performed with good form?”
- Ideal range: You should finish a set with only 2–3 reps left in the tank.
- If you could have done 5 or more, the intensity was too low and the set was too easy to stimulate change.
Take goblet squats for example. If you complete 10 reps and could have done another 5 or more, it’s unlikely your body received enough stimulus. But if you’re near the edge of fatigue, yet could have eked out one or two more with effort, you’ve hit the sweet spot.
3 Ways to Make Sure You’re Training Hard Enough
Intensity can be hard to self-monitor, especially for beginners. That’s why Harlow provides practical tips to double-check whether your workout is at the right level of challenge.
1. Use the Effort Scale
After each set, rate your effort on a scale of 1 to 10. Harlow suggests hovering in the 7 to 8 out of 10 range. You should feel challenged but not completely drained. This zone builds strength while minimizing injury risk.
2. Check Your Form on the Last Rep
Maintaining good form is crucial — but so is observing how it changes under fatigue:
- If your last rep looks identical to your first, the load is likely too light.
- If your form breaks down mid-set, it’s potentially too heavy or fatiguing too early.
Ideally, your final rep should be slower and require serious focus, but you should be able to complete it without cheating or using momentum.
3. Watch for Signs of Fatigue
Slight muscle shaking, labored breathing, or needing full concentration to complete your set are green lights. These are signs you’re pushing your muscles hard enough to stimulate growth and adaptation.
What Intensity Doesn’t Mean
While Harlow emphasizes pushing yourself, he also warns against common mistakes associated with high intensity:
- It’s not about maxing out your lifts every session.
- Don’t train through pain — discomfort and pain are different signals.
- Avoid redlining every workout. Sustainable progress comes from consistency, not exhaustion.
“What’s challenging for you today might not be tomorrow,” says Harlow. “That’s how you know you’re improving.”
Small Changes, Big Results
For many adults over 50, intensity is the missing piece in the training puzzle. You don’t need to overhaul your routine or use complicated techniques. With a few mindset shifts and consistency, you can reignite progress, build strength, and protect your independence for years to come.
Start With These Actionable Tips:
- Aim for an RIR of 2–3 in key exercises like squats, push-ups, or rows.
- Rate your effort on a 1–10 scale each set — stay around a 7 or 8.
- Progressively increase challenge over time: either by adding weight, reps, or cutting rest time.
- Listen to your body to avoid injury — sharp pain is always a red flag.
Smart Training Leads to Life-Long Strength
Harlow’s advice isn’t about gimmicks or pushing to failure. It’s about finding that middle ground of purposeful effort — a concept often overlooked but vital once you hit the 50-year mark and beyond.
With consistent, effort-focused training, you can keep gaining strength, preserve muscle, and stay functionally independent well into your later decades.
Want to go deeper? Harlow has created a free 25-minute video where he explains the full strategy behind training smart over 50:
