These behaviors show that self-sacrifice is directed towards close relatives and that there is an indirect fitness gain.

You cannot make further fitness gains or you actually move backward in your level of fitness.

An evolutionary model explained this finding in terms of increased fertility of the females in maternal lines, hence adding to net fitness gain.

By comparing heart rate over time fitness gains can be observed when the heart rate decreases for running or cycling at a given speed.

Or to make fitness gains.

Yet the mechanism behind the greater fitness gains in 2.5 μg/ml than in 250 μg/ml glucose need not be the glucose concentration itself.

Should this sum be greater than zero a fitness gain will result from the sacrifice.

By raising the treadmill grade, you can make greater fitness gains with no marked fatigue or risk of injury from running downhill.

On the other hand, if you exercise less than twice per week, you are unlikely to make any noticeable fitness gains.

This represents the fitness gain of a female who chooses bigyny over monogyny due to, here, resource holding differences.