There can be a huge difference between your chronological age and the biological age of your body,” says lecturer in sport and exercise medicine Dr Gary O’Donovan. “Biological ages of regular exercisers can be at least 10 years younger than their chronological ones.” Precise, age-tailored training can turn back your body clock and have you performing beyond your years. Here’s how.

THE TEST

Whatever your age and whatever your fitness fix, one benchmark will measure how you fare. “Your aerobic fitness naturally declines as you age, so this test takes into account the natural two to three percent decline each decade,” says conditioning coach Bob Smith. Step up to the step test. To measure your recovery rate, and get your age-adjusted fitness rating, stand 30cm away from a 25cm-high step. Step up and down (right foot up, left up, right down, left down) as fast as you can for three minutes, changing your leading leg halfway. Sit down, wait 30 seconds then take your pulse for a full minute.

HOW YOU RATE

Table

20s
TIME FOR TEAM SPORTS
Your strengths You’re virtually bullet-proof. At 24 your bones are at their toughest, your cardio capacity peaks and your fast-twitch muscle fibres are functioning at their max. Enjoy it. Your weaknesses Knees begin to creak in your late twenties. “Shock-absorbing cartilage starts fraying,” says exercise physiologist Dr Mark Hamer. “Adding insult to injury, your stock of chondrocytes – cartilage repair cells – also decreases.” But your biggest danger is yourself. Chances are you’ll do some self-inflicted damage by overworking your body. “Young athletes usually don’t get enough sleep, hydration or adequate nutrition,” says exercise physiologist Professor Carlton Cooke.

Your most important tool is self-control. “The demands of competitive sports are too intense to play day after day without injury,” says Smith. He recommends taking at least one rest day between matches and incorporating non-impact activities such as swimming into your routine. “Men in their twenties often don’t make the connection between food and performance,” says sports nutritionist Anita Bean. Follow her plan for perfect fuelling: Before any one-hour session eat 40g of carbs (200ml of hypotonic sports drink, plus half a banana). If you’re going longer, refuel every hour with 300ml of hypotonic energy drink. Within 60 minutes of finishing, jumpstart recovery with a carb-and-protein snack (chocolate milk and a bagel, or a smoothie).

30s
TIME FOR TRIATHLONS
Your strengths Endurance. The average age of pro triathletes is 38, and there’s a good reason: “You lose fast-twitch muscle fibres – used for sprinting – before slow-twitch fibres, so you’re more suited to distance than speed as you age,” says Hamer. “Plus, your body learns to build and efficiently recruit the key muscles specific to your chosen exercise, so the amount and intensity of your training can defy the clock.” Your weaknesses Besides that half metre of pace deserting you, there’s an uninvited roll over your shorts. And you can’t blame it all on your naturally slowing metabolism. “You need, on average, about 500 less daily kilojoules at 35 than you did at 25, says Hamer. But what really slams on the brakes is less training (thank your career and family) and less lean body mass (you lose roughly four percent muscle mass per decade post 30).

However full your hands are with the Blackberry and nappy-changing, pick up those weights. “Age-related muscle loss can be significantly slowed through strength training,” says Hamer. It also prevents sprains by building connective tissues around joints, and increases your running economy by lowering the amount of oxygen you need. “Three times a week do two sets of 12 lunges, squats, calf raises, hamstring curls, core work such as planks, plus crunches and press-ups,” says Smith. Dodge the rolls by re-evaluating your kilojoule needs. Registered dietician Megan Pentz-Kluyts says, “Find your ideal daily intake by firstly calculating your basal metabolic rate (BMR), using the following simple calculation and then by your demands of physical activity to determine your daily kilojoule intake.”

BMR = (13.75 x weight in kg) + (5 x height in cm) – (6.76 x age) + 66 Then multiply your BMR by:
1.2 – Sedentary (little or no physical activity)
1.375 – Lightly active (light exercise or activity one to three days per week)
1.55 – Moderately active (moderate exercise or activity three to five days per week)
1.725 – Very active (hard exercise or activity six or seven days per week)
1.9 – Extremely active (hard daily exercise or activity and physical work) “Monitor your intake based on this, and never skip meals – it slows your metabolism,” advices Pentz-Kluyts.

40s
TIME FOR MARATHONS
Your strengths You have more control than you think over the ravages of time. “You can offset the natural drop in your VO2 max with strength training and speed work,” says O’Donovan. And you have a secret weapon: “People tend to underestimate the cognitive part of endurance, and mental toughness isn’t genetic – it’s experience.” Your weaknesses One fitness factor is beyond your control: your heart’s pumping ability naturally slows. Plus, post-40, your kidneys become less able to conserve water as you dehydrate, and the nerves in your mouth and throat that signal you’re thirsty don’t function as well. Your bones are also deteriorating. Researchers at Cornell University found bone density in older athletes decreased around one percent a year.

If your takkies have been gathering dust, start slow. “Start running too fast or too much and you’re inviting injuries,” says Hamer, who recommends two years of regular running before tackling a marathon. “As you progress, introduce high intensity intervals. And keep weight training.” The Cornell research found strength trainers had twice the chance of maintaining the bone density levels of their twenties.

“Increase your daily calcium intake by 500mg with 500ml of skimmed milk,” says Bean. And try glucosamine and chondroitin supplements. A study at Brown University in the US found 1 500mg of glucosamine and 1 200mg of chondroitin daily reduce joint pain by 30 percent.

50s
TIME FOR CYCLING
Your strengths Your top-end intensity declines regardless of training, but distance is your trump card. University of Ontario research on veteran cyclists found that while age predicted times for 10km races, putting in the hours training was more important over 30km. “Good news if you’re motivated to do the work,” says Cooke. And though muscular strength peaks around 30, it doesn’t desert you too quickly at this age. Lille University scientists found fortysomething cyclists and seventysomethings had similar leg power. There’s a psychological pay-off, too: University of South Australia research found men who regularly exercise after turning 50 are less depressed, angry and fatigued.

Your weaknesses Your bones keep getting weaker and your risk of knee cartilage damage is twice that of a 40-year-old, hence impact-free cycling is the smart choice. Your lung capacity is waning – by your fifties it’ll have fallen by up to a quarter. Meanwhile your “peak rate flow” – what powers you up that 40 percent incline – drops fastest from your late forties. “Your lungs simply become less elastic, which directly impacts on high-intensity performance,” says Cooke. The fififitness fififix Interval training. “Elasticity of your lungs is governed by variation in exercise intensity,” says Cooke. University of Michigan research found adding 10 60-second bursts of high-intensity aerobic work – at 90 percent of your maximum heart rate – three times a week halved decline in lung elasticity in over-forties. Plyometrics will help maintain your fast-twitch joint stabilisers, according to the Journal of Strength and Conditioning Research, and also improve joint mobility. “If you have joint problems, plyometrics might be too jarring, so try skipping,” advises O’Donovan. Jump rope three times a week, building duration and eventually progressing to jumping one-footed.

Get friendly with the greengrocer. Nottingham University nutritionists found the antioxidant quertecin, present in apples, boosts lung capacity. And lift drooping levels of testosterone – which helps to maintain your bone density – with vegetables such as broccoli, cauliflower and cabbage, and low-fat cuts of red meat. Ready when you are, Miss Zeta-Jones…