The success of triathlon, duathlon, and adventure racing has been largely due to athletes 'crossing over' from different sports. Traditionally, cyclists have been very shy of practising anything other than riding a bike, but triathletes (and their ilk) have found that rather than inhibit performance in their primary sport, training in others has enhanced it.
Mountain bikers, cyclo-cross riders and anyone who rides uphill will certainly benefit from more arm strength
There is some debate that suggests less well-trained athletes have more to gain from cross training than elite riders and that elite riders should only concentrate their training on cycling. However, for reasons of variety, overall body balance and more efficient training, there is a great deal in favour of cross training.
Good activities to complement cycling include weight training, running (especially if you are a mountain biker), swimming, roller blading or speed skating, rowing, weight training, circuit training and aerobics. If you have the opportunity, cross county skiing is excellent too. Even alternative cycling disciplines can be beneficial.
Reduce injury
When we exercise we place stress on our muscles, which damages the fibres. During rest, the muscles are regenerated and become stronger. If cycling is your only exercise, the same muscles are always stressed and in the same fashion. This increases the likelihood of the muscle being 'pushed' too hard and picking up an injury. Flexibility training such as pilates, yoga or a good stretching routine also reduces the chances of injury, as you develop a wider range of motion and such exercises can improve the blood flow to the muscles.
Swimming is good cross training
Balanced fitness
By combining a variety of activities, different muscles are used and a more balanced overall fitness can be achieved. Cyclists are notorious for having very strong leg muscles (though often short, or tight hamstrings) but relatively weak upper body strength.Instead of doing a long cycle ride, sometimes do a shorter intense ride and spend more time weight training. Mountain bikers, cyclo-cross riders and anyone who has to ride up hill, will certainly benefit from more strength in their arms.
In the gym
Other activities such as aerobics or circuit training can be very useful to develop improved cardiovascular fitness in quite short sessions. Weight training too will show greater benefits as you can easily isolate particular muscle groups, control the exercises and adjust the load more easily than you can if you just ride a bike.
Such exercises can also help to balance muscle usage to prevent problems. Since cycling is a very repetitive action, the big quadriceps muscles can become overdeveloped and may actually cause problems with the knee (or hamstrings, sic). Alternative exercises off the bike can help to keep the opposing muscles in good condition and prevent many injury problems.
Add variety
With more variety in your programme there is less of a routine to training, which is great to alleviate boredom and keep you motivated. Each time you come back to an activity it will feel 'fresh' and you'll be keen to work hard at it, rather than feeling you're stuck in a regular groove of repetitive activity.
Arm strength will benefit your cycling
If you're a road rider, even just going mountain biking can be beneficial for variety, improved leg strength (because off road riding involves higher rolling resistance) and more upper body strength. Similarly, mountain bikers can benefit from road riding to improve their cadence and speed, and allow their bodies a bit of respite from the regular battering received from off road riding. Longer rides are also possible, which will help improve stamina.
When to do what
Out of season you can spend a bit more time on alternative activities such as weight training, aerobics and circuit training, but during the season it's best to concentrate your time on exercise which is more directly related to cycling. Track riders may spend some time weight training during the season, as might mountain bikers and cyclo-cross riders who would also benefit from some running training too. Swimming is a very good recovery exercise for cycling as it rests the usual cycling muscles, works the upper body and provides good cardiovascular benefits without having to be strenuous.
Cross training and injury
While some injuries require a total break from any exercise, others require total rest from cycling only - particularly high intensity, strenuous or endurance riding. Research has proved the benefit of staying active even when injured. The injury heals more quickly (through improved blood flow) and you do not lose too much fitness - so you can regain your level of fitness more rapidly once the injury has healed.
Research has proved the benefit of staying active even when injured
For example, with a broken wrist or collarbone, you may be able to use a turbo trainer on which to exercise, or do some lower limb exercises in a gym. A broken leg will prove more of a hindrance but again, a multigym machine may prove to be ideal for maintaining (or developing) some upper body strength. Aqua aerobics or water running have been used in this way by some top riders to speed up their recovery from such injuries. Any alternative activity which does not aggravate the injury will provide positive physical and mental benefits to accelerate the healing process.
Cross training plan
Be careful when introducing new activities into your training plan. Cyclists are particularly at risk because they usually have very good cardiovascular fitness, but do not have the muscular fitness to cope with these alternative activities to the same degree as their cycling.
Cross training is probably of greatest benefit to cyclists during the winter months when it may be too dark, cold or icy to ride safely outdoors. During the season it's best to spend more time actually riding, to hone your skills and keep muscle usage specific to cycling, unless your chosen discipline involves other exercises (such as running in some mountain bike events). However, you may find it useful to have an exercise such as swimming, as an 'active recovery' session to help manage your hard training and racing programme.