You might not know it, but you use muscular strength and muscular endurance every day. Muscular strength allows you to carry heavy grocery bags, while muscular endurance lets you rake all the leaves in your yard without tiring. Almost all sports require both strength and endurance. Exercises for strength focus on lifting heavy weights for fewer reps, while building endurance involves lifting lighter weights for more reps.
Building muscular strength enables you to lift heavy boxes on moving day, and it also translates to better sports performance. For example, strength plays a crucial role in rowing, wrestling, football and basketball. Strong, powerful legs let you run faster and jump higher, and a strong core and upper body help you swing a baseball bat, shoot a basketball and throw a football.
Endurance is a muscle's ability to perform repetitive motions for long periods of time. Runners need muscular endurance in their legs to keep pounding the pavement, as do cyclists peddling for miles and miles. Swimmers need to kick with their legs and stroke with their arms for both short and long distances.
Recovery is a crucial part of any program whether your goal is strength or endurance. However, because of the demands on the body, you need considerably more rest in between strength workouts than you do in between endurance workouts. Plan on at least 48 to 72 hours between heavy lifting sessions. Endurance sessions, depending on intensity, can be done every other day.