Will Cross Training Prevent Injuries?
As for injuries, so far there haven't been any studies on runners who cross train. However, the researchers in the New Hampshire study mentioned earlier noted that the weight-training runners had fewer injuries. In other sports, we know soccer players at the University of Maine in Orono who weight trained increased muscle strength and cut their injury rate in half. Then there's this pesky study on swimmers that found higher injury rates among cross training swimmers. Swimming is a low-impact sport, and upper body injuries are more common than lower body injuries. The cross training techniques that increased injuries in the swimmers were running or sprinting, running stadium steps, and pulling weighted sleds. These are all weight-bearing activities involving lower body impact, which is where the injuries occurred. Since swimming is a low impact, low injury-rate sport, it doesn't follow that cross training with high-impact activities would increase injuries when the lower body is already accustomed to high impact.
Cross Training Options
All this does nothing to dispute the validity of the principle that training is specific. Run long once every week or two, and run fast once or twice a week to improve your running. But that's not the whole story. Although there are no studies comparing injuries between runners who do not cross train and runners who do, it makes sense that exchanging some running time for a lower impact sport may reduce running injuries. And if the cross training activities are lower-injury sports compared to running, then overall injury rate should decrease. Cycling and swimming are attractive for runners to use for recovery after hard workouts on the track or roads, and for those who would welcome some variety in their training.
Cycling is a major sport in Europe and is growing in popularity in the US. It's complementary to running because you use chiefly your leg muscles, but in a different way from running. There's less injury risk than for running because cycling is not weight bearing. You can ride on the roads, and in some areas on trails and mountain paths. If you want to try racing, there are single and multi-stage races, and also time trials on roads. There are also sprints and pursuits on the track, sometimes called a velodrome. Find some good hills, and you can use Tom Miller's interval technique to spice up your running race times.
Swimming is less popular than cycling for runners, but has special advantages. It is non weight bearing and is a relatively low injury sport. Leg injuries are rare, although the frog kick used in the breast stroke has more risk than the flutter kick used in the crawl. Another advantage is that swimming works out your shoulders and arms, which typically are weak in runners. Most of the common injuries in swimmers are to the shoulders and back.
Developing a Schedule
If you want to achieve maximal payoff for your cross training it is hard to beat lifting weights or working the resistance machines. Resistance training will increase your oxygen capacity, help reduce your body fat, strengthen your muscles and maybe make them larger, and will increase the density and strength of your bones. And since stronger muscles help to protect your joints, you may decrease your risk of injuries.
You get best results by building up to heavy loads. And one set of eight to 12 repetitions of each exercise, two or three times a week, will give you most of the benefits gained from two or three sets.
A reasonable, balanced program for runners would include half squats and lunges for combined leg muscles; heel raises for calves; toe raises for shins; leg extensions for quads; hamstring curls and bent leg situps for abdominals; deadlift for thighs, buttocks and lower back; bench press for chest; bench pullover for upper back and chest; upright row for upper back, neck and shoulders; military press for shoulders; behind the head triceps curl, hammer bicep curl, and regular and inverted wrist curls for forearm muscles. You don't have to do every exercise at each workout, and alternating exercises helps prevent boredom with resistance work. Good form is important for effective training, so it's a good idea to sign up with a certified trainer or instructor to get you started.
These are the most popular ways that runners cross train. Think of them as supplementing and reinforcing your running, contributing to better overall fitness, and reducing your risk of impact injuries.
Here's a final thought. A few runners, through injuries or illness, may have to face the likelihood that continued running is either not possible or unwise. Those who cross train will have their substitute activities built in, and will find the adjustment much easier.