Sports knowledge: influence of body fat on sports performance
We know a fact that body fat have huge influence on sports performance. The authors recruited a number of 170 pound athletes and have them load 3.4 pounds (or 2% body fat) and complete some power tests. The athletes gaining 3.4 pounds might end up with vertical jump height loss of 2 inches and a 40 yard sprint time increase of 0.26 seconds. It is obvious that body fat decrease sports performance.
The author pointed out that losing body fat without losing muscle can enhance performance. If you are a professional runner with 20% body fat, the fat is going to have a enormous impact on your muscle and joints. It is deeply believed that it benefits sports performance.
Here is another question: What about gaining weight by increasing muscle mass? Does that decrease performance?
No, it does not overall. In general, increasing muscle improves athletic performance. The power derived from 2 pounds of muscle can bring advantages and offset the detriment of increasing the 2 pounds of body weight. In some cases, losing body weight can benefit cyclists for going faster, but is might have been proven with other sport fields.
References: How much does body fat decrease athletic performance, by Mark Perry, CSCS, CPT