Strong legs stem from working the muscles until the fibers break down and repair themselves to become bigger. On land, that might be done through weight-training or leg-focused cardio, such as biking or running. If those exercises hurt your joints, though, or if you're just a fish at heart, you can also strengthen your leg muscles in the pool.
Before you hop in the water, prep yourself by donning water shoes to help with traction on the pool floor and have a pool noodle or floatation belt nearby to keep you upright in the deeper water. Remember, too, that you won't notice any sweating during your workout, but your body still gets dehydrated and needs plenty of water after a hard muscle-building session.
Shallow Water Leg Exercises
Start in the shallow end of the pool to get your sea legs before moving into the deep end.
Stand next to the pool wall and hold onto it lightly. Lift your leg out to the front, like you're kicking but with your knee straight. Return it to the first position, and then kick it to the side. Return again to the starting position and kick it backward. Do three sets of 10, and then switch to the other leg.
Standing Knee Lift
Face away from the pool wall with both of your feet on the floor. Bring one knee up, like you were marching in place, and then kick your leg out and straighten the knee. Bend and straighten that knee 10 time, return to the starting position and then switch to the other leg. Standing against the pool wall is good for a beginner's balance, but move away from the wall for added challenge.
Deep Water Exercises
If you feel comfortable in the water, doing these exercise sans floatation device will make them extra challenging. However, those who are timid shouldn't hesitate to grab a pool noodle or floatation belt.
Bring your knees up so your thighs are perpendicular to your body and then imagine that you're riding a bike by making large circular motions with your leg. If you need a little extra help, hold onto the pool wall with one hand.
Start with your legs pressed together, hanging straight down. At the same time, kick one leg forward and one leg backward, like a pair of scissors opening. Return to the starting position and alternate the direction of your legs. Once you're comfortable with the movement, kick your legs out repeatedly in a smooth motion rather than stopping in the middle.