Do I know any leg strengthening drills? It seems like my whole life is leg strengthening drills! In Shaolin kung fu there's an abundance of gruelling leg strengthening methods, of which the staple is the horse stance:
Horse stance - Start by standing with your feet together. Turn your ankles to spread your toes as far apart as you can, with the heels together. Now, pivoting on the toes, bring your heels out as far beyond that as they'll go. Now bring your toes in line with your heels so the feet point forward. (The above is an overworked way of saying stand with your feet about two-and-a-half shoulder widths apart.) Now move your knees outwards towards your toes and drop your upper body. It's very important to keep the back straight (that's the hard part), knees out and feet pointing forward. It's an easy stance to execute; the difficulty is in holding it for extended periods of time. Hold this stance until it really hurts, then hold it some more. Don't worry if your legs start to shake; that actually makes it work better. It's more effective the lower you go and the further you spread your feet. Some pictures of a good horse stance
here. Your arms are free, so you can use the time to practise your punching or whatever. Staring at a single point and controlling your breathing will help focus your mind, so you'll be better able to hold the stance through the pain. This technique strengthens pretty much the whole leg. (
This is how the kung fu masters of old used to force students to hold the pose!)
Duckwalk - Stand like you do for the standard hip flexor lunge stretch: one leg forward and bent at a right angle, the other leg far behind with the knee just off the ground. (See
here.) Now,
without your upper body coming up, walk into the same stance with the other foot leading. Walk around like this for maybe 20m to start with. You head and chest should never move vertically.
Squats - Stand with your legs spread and bend your knees so you sink down. Now: up, down, up, down, up, down....
One-legged squats (aka
pistols) - These are a great workout, but difficult for beginners. Stand on one leg. Bend the knee so you go down, then come back up. Stick out the other leg for balance, but never let it touch the ground. Don't expect to be able to get your ass to the ground at first, but that's what you're aiming for.