Once you cannot complete one more pushup or one more pull down, you have reached muscular fatigue. Your muscles reach fatigue once they can no longer contract; this means your muscles are not getting any more energy from the foods you have eaten, the glycogen stored in your body or from your body fat. If you rest for a few minutes, your muscle cells will replenish their energy so you can contract your muscles to do more pushups or run longer. Use standard exercise tests to measure your muscular fatigue.
Record the test, date, time and results. Use this data to perform another test every four to six weeks; results may be used to analyze the effectiveness of your training program and measure performance improvements.
Perform a pushup test, measuring your upper body muscular endurance fatigue, according to the American Council on Exercise. Put a small, immovable object directly under the center of your chest; the object should be about the height of your clenched fist resting on the pinky side of your palm. Place your hands slightly wider than your shoulders and balance your weight on your toes. Suck your navel toward your spine to maintain a straight line between your head and your feet. Lower your body until your chest touches the object then push back up; do as many repetitions as possible using correct form and resting only in the up position. Record the total number of pushups you can do until muscle fatigue, where you can no longer complete a proper push-up.
Perform an isometric chinup, more commonly referred to as a flex-arm hang by the United States Marine Corps; this test measures how long you can maintain muscle contraction instead of completing a regular pullup. Use a stool to position your body underneath a pullup bar with your hands slightly narrower than your shoulders and your palms facing you; place a secondhand clock in front of you or have a friend start the timer once your chin is above the bar and you are using the strength of your muscles to maintain that position. Stop the timer once your arms are completely straight, recording your time; this is a measure of your anaerobic muscular strength fatigue or your capacity to contract your muscles without the presence of oxygen.
Do these exercises on different days if you wish to complete both tests; rest at least one week between tests.
Get plenty of sleep the night before your test; do not cut your calories or go on a diet the week before you measure muscular fatigue. Eat a good meal of slow-digesting carbs and protein about 2 hours before your tests.
These tests will induce muscle soreness; stretch after each exercise to reduce the magnitude of soreness you will experience.