What they do: The joint that connects your upper leg to your lower leg, the knee is surrounded by ligaments and tendons. “You can’t strengthen ligaments and tendons,” says Michael Lagomarsine, head of strength and conditioning at the Boston University Athletic Enhancement Center. “Instead, the key is to build up the muscles that surround your knee.” When the muscles around your knees are strong, you can complete all the movement that the knees absorb impact from — accelerating, decelerating, changing directions and landing from a jump — without worrying that your knees are going to get injured.
Used commonly when you: Sprint downfield in a lacrosse game, land after a header in soccer, change directions quickly in basketball, serve a tennis ball, drive a golf ball, ski moguls, launch yourself off the halfpipe in snowboarding, or otherwise use your lower body.
Three ways to build solid, stable knees:
Goblet Squats, front and side views.
How to: Stand with your feet just a bit wider than your shoulders and your toes turned out slightly. Hold a 25-pound dumbbell in both hands, like it’s a goblet, next to your chest. Your chest should be pushed out, and your back should have a slight arch. Engage your core and pretend like you’re sitting down in a chair, pushing your knees out to the side. “When you’re lowered, your elbows should graze against your knees,” Lagomarsine says. Keeping your chest up, stand back up. Do 2-3 sets of 10-12 reps.
Overhead lunges, positions 1 and 2.
How to: Start with feet together and your arms extended straight overhead; if you want, you can hold a pole or bar overhead. Take a large step forward with your right foot, landing on your heel. Slowly lower your body until your left knee is just above the ground. Drive through the right heel to return to standing. “Be sure to keep your core engaged to stabilize your lower back,” says Lagomarsine, who adds that this exercise builds both stability and motor control. Return to standing. Do 10-12 reps on the right leg, then 10-12 on the left to complete one set; do 2-3 sets total.
Single-Leg Step Down
Single-Leg Step Downs, positions 1 and 2.
How to: Stand on a step four to eight inches off the ground on your left leg; your right leg bent 90 degrees, so that your thigh is parallel to the ground. Extend your arms straight in front of you at shoulder-height. Then bend at the left knee and hip, like you were doing a single-leg squat, to lower your right leg toward the ground. Touch the ground with your right heel, but don’t put any weight on it. “Do your best to keep your pelvis level and your ankle, knee and hip in alignment in your top leg,” Lagomarsine says. Do 10-12 reps of 2-3 sets.
Let's hear it for the knees: “Strong legs and knees are important in hockey because I get speed and power from them. I am a forward, so I have to stop and start quickly and my knees help me do that. Strong knees allow me to keep my balance when I fire off a shot. They also help me not get knocked off the puck.” -- Bridget Fehily, freshman left wing on the ice hockey team at Boston Latin Academy (Dorchester, Mass.)