"Being able to run miles a day is a good measure of cardio endurance, but it's not the best measure of muscle endurance," says fitness expert Robert Dos Remedios, author of Cardio Strength Training. That's because running for distance primarily challenges your heart and lungs, not your legs. (Yes, your legs may feel tired, but your muscles aren't actually exhausted.) When you focus on muscular endurance--your ability to sustain resistance over time--you gain the strength to power through longer, more intense workouts, says Dos Remedios. The following test challenges both aspects, showing you how long your lungs and muscles can last before calling it quits.
The Test Leg Matrix
Do all four moves back-to-back without rest. If you stop or can't do the move with proper form, that's the end of the test. Track your success through reps: On your first try, do 10 reps of each move. Wait two days, then repeat with 15 reps. Then test two days later with 24 reps.
Stand with feet hip-width apart, hands behind your head, and lower until your thighs are parallel to the ground. Push through your heels to return to standing.
Lower into a squat as described in the first move, then jump off the ground as high as you can. Land softly, and immediately lower into another squat and repeat.
Stand with hands behind head, then step forward with your left foot and lower until your right knee almost touches the floor. Return to start; repeat on the other side.
Lower into the lunge as described in the last move. Jump as high as you can and switch legs in the air. Land softly, then lower into your next rep on the opposite side.
Can complete 24 reps of each move with proper form without stopping → Excellent
Can complete 10 to 15 reps of each move with proper form without stopping → Good
Cannot do 10 reps of each move with proper form without stopping → Below Average
Amp Your Endurance
Boost both your aerobic and muscular endurance by adding intervals--high-intensity work followed by low-intensity recovery--into your strength training. You'll torch more calories in less time and train your body to push harder for longer. Try this three-week plan from Dos Remedios: During week one, do each of your strength exercises for 20 seconds, then rest for 40 seconds. In week two, work for 30 seconds and rest for 30 seconds. For week three, follow a 40-second work and 20-second rest interval.