Strong, healthy legs are essential for running, and leg training for marathon runners should include not only strengthening, but stretching exercises. Running has many benefits, but increasing your flexibility is not one of them, and many running injuries stem from tight legs.

Even if stretching isn't your thing, it's worth making time for these "big three":

Calf stretch: Place your forearms or hands against a wall. Bend one leg and place that foot on the floor and step the other leg straight back, with your back foot pointing straight ahead. Bring your hips towards the wall, while keeping your back foot flat on the floor. You should feel a stretch in your hamstrings. Hold an easy stretch for a count of 30.

Hip stretch: Sit on the floor with the left knee bent and left foot flat on the floor. Bend the right leg and place the right foot on top of the left knee; your right knee should point out to the right side. Support yourself with your hands so you don't fall backwards. You should feel a stretch in the outer part of your hip. Hold for a count of 10, then switch legs and repeat on the other side.

IT (iliotibial band) Band stretch: Stand up straight and cross one foot over the other. Bend forward from the hips and reach your hands towards the floor. Keep your feet flat on the floor and don't move them, but engage your leg muscles as if you were trying to move your feet closer to each other. This action should engage the IT band along the outside of the back leg. Hold for a count of 10, then relax, and engage the muscles again. Stand up, cross the opposite leg over, and repeat on the other side.

Because the triathlon is a unique combination of events, functional training for triathlons should involve exercises from all major muscle groups. Functional training involves doing exercises that mimic the moves of your sport with additional resistance. The goal of functional training is to build muscle strength and endurance so your muscles learn how to drive you farther and faster during a competition. Pay attention to this type of training and you'll see your performance improve.

Functional training for triathlons should include exercises for a full range of motion. Pool running is one type of functional training that works well for triathlons, and it is also a great way to get a workout in if you are injured or faced with bad weather.

In general, pool running is one of the best cross-training activities that you can do. You can wear a specially designed belt that allows you to move your arms and legs just as if you were running on land. You want to stay vertical and put your legs through the same motion as running, rather than going horizontal and kicking as you would in a swimming workout. If you run in the pool for the same amount of time you'd spend running on land, you'll get an equivalent workout. Or, if you don't have a belt, you can use a kickboard.

To use a kickboard, place the kickboard under your chest and wrap your arms under it. Your feet will hang down into the water. Use a normal running motion to propel yourself forward. The kickboard version of pool running is less aerobic than using a belt because you're not engaging your upper body, but you will still work your leg muscles.

Doing the right exercises for swimming is essential to improving your overall triathlon times.

Strong shoulders and back are the keys to stronger strokes, but it's not all about strength; flexibility is important to make your strokes as fast and efficient as possible.

For a one-two punch to build power shoulders, include strengthening exercises for swimming such as lat pulldowns, and stretching exercises such as the lat and shoulder stretch.

Lat pulldowns: Lat pulldowns are a staple of most back workouts, and they are helpful exercises for swimming.

But remember that your goal is strength, not bulk, so use a weight that allows you to maintain proper form, and to get good form, focus on three things: Shrug, pull, squeeze. Start by shrugging your shoulders slightly, and then, as you pull the weight down, pull your shoulders down your back and squeeze them together. Release to the starting position. Repeat 10-15 times for as many sets as your current swimming workout dictates.

Lat/shoulder stretch: Kneel on a carpet or mat and sit back on your heels. Extend your arms in front of you and pull back, keeping your arms straight while pressing down lightly with your palms. You should feel the stretch in your lats, shoulders, and arms. Increase or decrease the intensity of the stretch by shifting your hips, but don't strain. Hold for 15 seconds and release. Repeat several times before and after your swimming workout. If you want to isolate each side, do the stretch with one arm extended and the other arm bent in a relaxed position on the floor with the forearm in line with your forehead.

To train effectively for endurance events, you have to build your endurance, and the way to do that is with long workouts. When training for marathons and triathlons in particular, long runs will give you the endurance to go the distance on race day.

Want a recipe for marathon success? Be sure to include a long run once a week for 10-12 weeks. The length of that long run varies, but most marathon training plans advise 2-3 training runs of at least 20 miles during the few months before the marathon, depending on whether your goal is to finish or to finish faster.

The key is to build up gradually and allow your body to adapt. Assuming that you are running at least 20 miles a week for 5-8 miles at a time, start by running 8-10 miles one weekend. Then follow this guide:

Week 2: Run 10-12 miles

Week 3: Try for 12-15 miles.

Week 4: Drop back to 10 miles.

Week 5: Try for 15-17 miles

Week 6: Go for 20 miles, but keep the pace easy.

The week after a 20-mile run, make your "long run" 10-13 miles, or less if you are new to long distances and you still feel tired. Repeat this pattern at least one more time before the marathon, working up to a second 20-mile run and then backing down. Some trainers advocate working up to 26 miles in training prior to the marathon, while others contend that your long training runs need not exceed 20 miles. If you want to work up to 26 you can, but don't do a run that long closer than 3 weeks to your "official" marathon.

If you can't run or bike outdoors because of an injury or bad weather, riding a stationary bike is another option for training for cycling. Also, stationary biking is a good alternative to running if you have a foot injury because you aren't putting much pressure on your feet, and it is a safe alternative exercise for some knee and hip injuries as well.

Even if you aren't injured, biking is a great supplemental activity to running because you can pedal at a brisk pace and build leg strength without the pressure on your joints of additional running or road cycling. But stationary biking does require a little more effort to replicate the benefits of running. In general, cycling on a stationary bike provides 60-80% of the strengthening and cardiovascular effects of running, so if you are compensating for a 45-minute run, add about 20% more time (about 9 minutes) to your bike time.

Before you start any type of stationary biking, be sure to adjust the seat. Because you're not the only one using the stationary bikes at your gym, remember the correct setting for you and check it before you get started. The right seat height is high enough so your knees aren't coming up to your elbows, but not so high that you are straining to reach the pedals. Your knees should not bend more than a 90-degree angle while you are pedaling, and you should have a slight bend in your knee when your leg is extended. If the seat is set incorrectly, you could set yourself up for an injury because you are stressing your legs in an unnatural position.

To get the most out of your cycling workouts, make sure that you are observing good form. During long rides to build endurance, keep these points in mind:

• Don't use too much tension. If you are going for a long ride, remember that too much tension will put more stress on your knees and tire you out earlier, so you may have a tougher time on a long ride. Instead, use less tension for the long rides and crank it up for interval and tempo workouts.
  
• Remember to relax your upper body. Although you will grab the handlebars for more support when doing hill workouts or intervals, try to relax your upper body during long endurance rides. Being in a crouched position for extended periods of time can put stress on your lower back, so try to keep your arms loose and your grip steady but not tight.

Shoulder injuries are more common among cyclists than you might expect, so part of a cycling workout should include some pre- and post-ride shoulder stretches.

Try these easy options:

• Door frame stretch: Stand slightly in front of a reach back with both hands to grasp the door frame. Let your arms straighten as you lean forward, keeping your chest up and chin slightly tucked.
  
• No door handy? Stand with your hands clasped behind your back. Continue to stand as straight as possible, but gradually try to raise your clasped hands upwards until you feel a stretch in the shoulders, chest, or arms.

Hold these stretches for 5-15 seconds at a time and repeat as needed.

And if you work at a computer when you're not out cycling, these shoulder stretches will help relieve "desk hunch" too.

Tempo workouts are a great way to improve your conditioning for marathons, triathlons, and cycling events without having to find a track.

Here's how to add a tempo run to your marathon training plan:

During any medium distance run during the week, simply pick a point on your route or a time on your watch, and pick up the pace for 5 minutes. Don't sprint; keep the pace at about 80% of your maximum effort. Then slow down and run at a relaxed pace for 10 minutes, then do another 5-minute pickup. Not wearing a watch? Pick up the pace until you reach the end of the street. Vary your tempo runs by picking up the pace for 3 minutes, or 10 minutes, or even 20 minutes, during the middle of a weekday run. But when the schedule calls for an easy run, keep those runs easy. Tempo runs are the equivalent of a track workout or hill workout.

Similarly, you can design a tempo workout on a bike, either on the road or on a stationary bike. Try pedaling at about 80% of your maximum effort for 2 minutes, than easy for 2 minutes, and repeat several times, but steady pedaling will build length strength, too. Spinning is a different type of cross-training on a bike that involves high-speed pedaling and it is a more intense workout than steady biking. If you take part in a spinning class, your legs will be as tired as they would be if you did speed work on a track.