Cycling, even for short periods, gives you an all-round aerobic workout. But cycling regularly and for long distances can strain your knees and, if you're a man, may put fertility at risk.

"The main problems I see with cycling involve the hips and kneecaps," says Gavin Burt, the London-based osteopath and spokesman for the General Osteopathic Council. "If your thigh muscles are out of balance, your kneecaps won't be stable - they'll move slightly sideways with the bending motion of your knee. That can cause grinding and inflammation."

Cycling can also harm male fertility. Recent studies show that 3 per cent of male cyclists who ride regularly become impotent, and virtually all of them felt pain or numbness before the problem occurred. The studies found that the more a person rides, the greater the risk of impotence or loss of libido.

Risk reduction Burt recommends the following exercise to strengthen your quadriceps and surrounding muscles. Lie down on your back with a rolled towel under your knee. Keeping your heels on the ground, press each knee down into the towel as if trying to straighten your legs.

Men who cycle for short or moderate periods shouldn't worry about fertility. Serious cyclists should take regular breaks along you cycling route - say every 30-40 minutes. Some bicycle seats such as Easy Seat (from £30; www.derri-air.com; 001 406 889 5288) are now specifically designed without the usual "nose" that compresses blood and nerve supply.


Running isn't as bad for your knees as most people think, says Siobhán O'Donovan, the chartered physiotherapist and sports rehabilitation specialist. "A study at Stanford University looked at the cartilage in the knees of runners," she says. "They found that in people who took up running while young, and continued to run, the sport had a cartilage-strengthening effect." For this benefit, you need to start running in your 20s, while your body is still growing. A sudden decision to take up running and cover long distances, without preparatory training, can cause knee strains.

The main risk for regular runners is Achilles tendonitis. "If the arch of your foot is slightly collapsed, your Achilles tendon will be slightly twisted. Run on it repeatedly, and the tendon will eventually become strained and inflamed."

Risk reduction Build up any running regime slowly and seek appropriate advice in choosing a good pair of shoes. O'Donovan, the clinical director at Meridian Sports in Bolton, recommends seeing a podiatrist or sports professional to get your feet screened. "This will identify if you have low or collapsed arches," she says. "You can then rectify the problem."


Swimming is a great low-impact sport which strengthens and tones muscles of the whole body - and gives cardiovascular fitness a boost. But take into careful account which stroke you use. While front crawl is great for improving all-round muscle tone and fitness, O'Donovan believes breast stroke is so harmful, it should be banned.

"It's bad for your neck, back and knees," says O'Donovan. "Keeping your head above water compresses your neck, contributing to neck pain and tight shoulders. It also strains your lower back. Knees also suffer. "Your knees joints are made to kick up and down, not to kick out sideways as in breast stroke. This movement can strain ligaments and irritate membranes within the joint."

Risk reduction If you insist on doing breast stroke, you can minimise the strain by keeping your head in the water while swimming and coming up for breaths of air. Burt recommends reducing knee strain by propelling yourself forward using the momentum of your upper-body and kicking gently with your legs. Never extend them completely so that they are straight.


Beware of the classic tennis injury, tennis elbow. Caused by the backhand movement, the muscle and ligament leading from the forearm to the outer elbow becomes torn and inflamed.

Risk reduction As tennis elbow is painful and difficult to treat, your best strategy should be prevention. Using a double-handed backhand, where you use both arms to take the impact of the ball, will help.

Burt recommends this exercise for people with tennis elbow: place a moderately tight elastic band around the fingertips of your injured arm. Pull open your fingers against the resistance of the band and repeat several times every day. The exercise builds "support muscles" which help you use your arm while the strained ligament recovers.


Rowing is one of the best sports for a strong back, but rowing machines in the gym can put your lower back at risk unless you get tuition in technique, says O'Donovan. Rowing outdoors may also put your lower back at risk if it is stiff. If you have scoliosis - a sideways curve along the spine - one side of your back may end up stronger than the other, causing muscular imbalances and strain.

Risk reduction O'Donovan suggests that you first ask yourself whether rowing is the best sport for you. "If your lower back isstiff, rowing could easily strain the joints, causing irritation and muscle strain," she says. "In extreme cases, it could lead to a prolapsed or slipped disc." If you do row, it's best to get professional advice. Burt says: "Your legs, low back, upper back and arms should all be involved in one effortless movement to propel yourself with each stroke."


While yoga and Pilates help prevent injuries by improving flexibility and strengthening abdominal muscles, both can cause the very injuries they're designed to protect against. "Overstretching can tear muscle fibres and irritate tendons or ligaments," says Burt.

Risk reduction Warm up properly before any stretching to prevent muscle tears in stiffness the following day, says O'Donovan. In winter, when the outdoor temperature is cold, give your body a good 20 minutes to warm up.


You don't get a rush without risk. And when it comes to winter sports, snowboarding tops the list for both. It offers speed and adventure along with a risk of knee strain, whiplash and wrist injury. "Your feet are fixed on to the snowboard in a way that stresses the knees," says Burt. "And if you fall, your upper body twists but your low body is fixed - that can snap and strain the cruciate ligaments of the knee." Falling forwards or backwards at speed on to compacted snow can cause wrist sprains and whiplash injuries respectively.

Risk reduction Get instructions and don't take on difficult slopes before you're ready. Protect your wrists from fractures or sprains by wearing wrist guards. Knee-braces worn under your salopettes can reduce any twisting when you fall.

Tips for safe and successful sport

Siobhán O'Donovan suggests picking a sport that will complement and help your physiology - then building up your fitness routine at a gradual rate. "I wouldn't recommend that someone prone to shoulder dislocation takes up rugby, for obvious reasons," she says. "Likewise, I'd be careful about suggesting rowing to somebody with a stiff lower back." Often, she adds, people may be predisposed to particular injuries without their realising.

Most people wouldn't know if they had a low foot arch, or if their pelvis was slightly twisted leaving one leg slightly longer than the other. These conditions are very common and can lead to muscular imbalances, tightness and injury in a wide range of sports.

She recommends a pre-exercise screen: an examination that looks at foot posture, leg length and your muscle balance. Orthotics and specific exercises can then ensure your bio-mechanical alignment is good to begin with.

A thorough warm-up routine is recommended before any sport - consisting of around 20 minutes of gentle aerobic activity and some stretches. It's vital not to overstretch early on, or you risk causing tightness and strain. Remember to finish any brisk activity with a 10-minute warm-down to help your physiology gradually adjust from an active to an inactive state.

Pre-exercise screening (£50 for one hour) is available at Meridian Sports in Bolton ( www.getmebetter.co.uk; 08007 312 738). Consultations with podiatrists and physiotherapists are available at Health and Fitness Solutions, London (020-7702 1112).

For further details on sports injuries and rehabilitation, go to www.sportsinjuryclinic.net.