The key principles of training in sport are: overload, specificity, recovery and adaptation.
Overload: muscles strengthen when they operate beyond their normal range of movement. This is achieved by increasing the resistance, number of intervals or the intensity of the exercise.
Specificity: training must be focussed to the specific sport being trained for.
Recovery and Adaptation: in order for the body to recover from training it needs rest.
This will enable adaptation (i.e. allowing the body to react to the training) to occur. It should be noted that adaptation will occur during a recovery period after completion of the training.
When training for a running event e.g. a 10k or a marathon the basic training will be based on running and include the typical elements of long runs, hills, intervals etc., and should include some specific strength exercise as may be required by the individual.
When training for a specific running event which may continue over several months, adding cross training should be considered. Cross training can be defined as including exercise from other sporting disciplines to which the athlete is training. It will help build muscle strength and flexibility that running doesn’t utilise by correcting for imbalances. Including variety into a training programme will help reduce potential boredom or possible burnout. It must be noted that cross training is not intended as a substitute for running. If in the training plan you are following it calls for a 20 mile run, then a 20 mile or even 40mile bike ride is not an equivalent session. Training must always be specific.
There are some sports that are incompatible to running and hence should not be practised as cross training. These typically are the high impact activities that require sudden movements with stop and go, bounding etc. Examples of these include tennis, squash, badminton football, rugby, netball, volleyball etc. Cross training sports for a runner to consider include cycling, swimming, aqua-jogging, walking, machine rowing, fitness classes etc. to supplement the running programme.
Cycling: will strengthen the leg muscles in particular the quadriceps, calves and hamstrings. There is evidence available that cycling will strengthen the connective tissues to the knee, hips and ankles. This should help in the reduction of injury in these areas caused by running.
Swimming: is a good form of a cross-training activity as it builds muscular strength and endurance while improving flexibility with zero impact. An area often ignored by runners is upper body exercise; this will be developed by swimming. Water can also provide a therapeutic effect for all muscle groups.
Aqua-jogging: in deep water, wearing a flotation belt is probably the best form of cross training for all runners. Some consider aqua-jogging only as rehab exercise following an injury. However, aqua-jogging can be an alternative to a recovery run or a mid-week easy run. It emulates running technique with absolutely zero impact i.e. no shock from the foot strike.
Further details on aqua-jogging
Walking: can provide therapeutic benefits following a long run or intense speed work. Walking should not be used to replace an easy running day but can be used to warm up or loosen up the legs the day prior to a race. Speed walking and Nordic walking are available options to maintain cardio-vascular fitness.
Machine rowing: if you have access to a gym then using a rowing machine will provide a cardio-vascular workout whilst strengthening quadriceps, hips, buttocks, and upper body.
Fitness Classes: many fitness classes are available that can benefit runners. Yoga and Pilates will help to improve flexibility and core strength. Try to avoid classes that focus on sudden movements and high impact.
Cross training should be built into a training programme as a specific module and not to replace a rest day. Rest is an essential element in all training programmes; this enables the recovery and adaptation principle of training.