In today's health matters, a new study says college football players show significant gains in size, strength and power over time, but smaller improvements in speed and agility.
Researchers assessed the physical capabilities of college players throughout their four- or five-year careers.
From freshman to senior year, the players' body mass increased an average of 21 pounds, their bench press strength increased by 31 percent, their squat strength increased by 36 percent and their aerobic conditioning improved.
However, their 40-yard sprint time improved by an average of only 0.2 seconds and their vertical jump height increased by about two inches.
While resistance training programs do appear effective in improving players' strength and body mass, genetic factors may limit the ability to significantly improve speed and jumping ability.